Rotating Shift Work and Metabolic Syndrome Components among Workers at an Electricity Distribution company in Ismailia City
Thesis submitted as partial fulfillment of the Doctoral Degree in
Industrial Medicine and Occupational Health
By
Hebatalla Mohamed Aly
M.B.B.Ch., Suez Canal University, 2008
Master of Science in Industrial Medicine and Occupational Health, 2013
Assistant lecturer of Industrial Medicine and Occupational Health
Department of Public Health, Community, Environmental and Occupational Medicine
Faculty of Medicine – Suez Canal University

INTRODUCTION
Modern society is moving toward a pattern of working 24 hours a day in many diverse settings ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/s13098-015-0041-4”, “ISSN” : “1758-5996”, “author” : { “dropping-particle” : “”, “family” : “Brum”, “given” : “Maria Carlota Borba”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Filho”, “given” : “Fu00e1bio Fernandes Dantas”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schnorr”, “given” : “Claudia Carolina”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bottega”, “given” : “Gustavo Borchardt”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rodrigues”, “given” : “Ticiana C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Diabetology & Metabolic Syndrome”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2015” }, “page” : “1-7”, “publisher” : “???”, “title” : “Shift work and its association with metabolic disorders”, “type” : “article-journal”, “volume” : “7” }, “uris” : “http://www.mendeley.com/documents/?uuid=7b266ff4-ad7c-448d-862d-482f430c258b” } , “mendeley” : { “formattedCitation” : “(Brum, Filho, Schnorr, Bottega, & Rodrigues, 2015)”, “manualFormatting” : “(Brum et al., 2015)”, “plainTextFormattedCitation” : “(Brum, Filho, Schnorr, Bottega, & Rodrigues, 2015)”, “previouslyFormattedCitation” : “(Brum, Filho, Schnorr, Bottega, & Rodrigues, 2015)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Brum et al., 2015); and more than 20% of all employees in industrial countries are shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1371/journal.pone.0120632”, “ISSN” : “1932-6203”, “author” : { “dropping-particle” : “”, “family” : “Guo”, “given” : “Yanjun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rong”, “given” : “Yi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Huang”, “given” : “Xiji”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lai”, “given” : “Hanpeng”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Luo”, “given” : “Xin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Zhang”, “given” : “Zhihong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Liu”, “given” : “Yuewei”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “He”, “given” : “Meian”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Wu”, “given” : “Tangchun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Chen”, “given” : “Weihong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Plos One”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2015” }, “page” : “e0120632”, “title” : “Shift Work and the Relationship with Metabolic Syndrome in Chinese Aged Workers”, “type” : “article-journal”, “volume” : “10” }, “uris” : “http://www.mendeley.com/documents/?uuid=4f37f5a9-d299-419a-90b6-e9be85a1b2af” } , “mendeley” : { “formattedCitation” : “(Guo et al., 2015)”, “plainTextFormattedCitation” : “(Guo et al., 2015)”, “previouslyFormattedCitation” : “(Guo et al., 2015)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Guo et al., 2015). The International Labor Office 1990 defines working in shifts as “a method of organization of working time in which workers succeed one another at the workplace so that the establishment can operate longer than the hours of work of individual workers” ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “ILO (International Labour Office)”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “May”, “issued” : { “date-parts” : “2004” }, “title” : “Shift work”, “type” : “article-journal” }, “uris” : “http://www.mendeley.com/documents/?uuid=dee6b7cd-505a-49c0-b480-888861aa7564” } , “mendeley” : { “formattedCitation” : “(ILO (International Labour Office), 2004)”, “manualFormatting” : “(ILO, 2004)”, “plainTextFormattedCitation” : “(ILO (International Labour Office), 2004)”, “previouslyFormattedCitation” : “(ILO (International Labour Office), 2004)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(ILO, 2004).

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The following categories of shift work were identified: regular evening schedules (beginning after 3 p.m., ending before midnight), regular night (beginning after 11 p.m., ending before 11 a.m.), rotating (day to evening and/or night), split (two or more distinct work periods each day), on call (no pre-arranged schedule), and irregular shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “0840-8750, 0840-8750”, “ISSN” : “08408750”, “PMID” : “47552728”, “abstract” : “More than a quarter of employed Canadians work something other than a regular daytime schedule-regular evenings or nights, rotating or split shifts, casual or on-call jobs or irregular shifts. This article focuses on shift work among full-time workers aged 19 to 64 and looks at where and among whom it is most prevalent. Work-life balance, role overload and other indicators of well-being are also examined. Adapted from the source document.”, “author” : { “dropping-particle” : “”, “family” : “Williams”, “given” : “Cara”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Statistics Canada”, “id” : “ITEM-1”, “issue” : “75”, “issued” : { “date-parts” : “2008” }, “page” : “5-16”, “title” : “Work-life balance of shift workers”, “type” : “article-journal”, “volume” : “Catalogue ” }, “uris” : “http://www.mendeley.com/documents/?uuid=8468927c-dbda-4c4a-9cc8-805a73bc6462” } , “mendeley” : { “formattedCitation” : “(Williams, 2008)”, “plainTextFormattedCitation” : “(Williams, 2008)”, “previouslyFormattedCitation” : “(Williams, 2008)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Williams, 2008). But generally shift work can be classified into two broad categories: rotating shift work; where the employee’s hours of work change (e.g., morning, afternoon, and night shift); and permanent shift work; where the work pattern may be constant but occupy unusual hours of the day ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1371/journal.pmed.1001138”, “ISSN” : “15491277”, “PMID” : “22162952”, “abstract” : “Mika Kivimaki and colleagues discuss new research that shows an association between shift work and the risk of developing type 2 diabetes among nurses.”, “author” : { “dropping-particle” : “”, “family” : “Kivimu00e4ki”, “given” : “Mika”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Batty”, “given” : “G. David”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hublin”, “given” : “Christer”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “PLoS Medicine”, “id” : “ITEM-1”, “issue” : “12”, “issued” : { “date-parts” : “2011” }, “page” : “1-3”, “title” : “Shift work as a risk factor for future type 2 diabetes: Evidence, mechanisms, implications, and future research directions”, “type” : “article-journal”, “volume” : “8” }, “uris” : “http://www.mendeley.com/documents/?uuid=98e541bf-183d-408f-aa38-6304f69de8e1” } , “mendeley” : { “formattedCitation” : “(Kivimu00e4ki, Batty, & Hublin, 2011)”, “manualFormatting” : “(Kivimu00e4ki and Batty, 2011)”, “plainTextFormattedCitation” : “(Kivimu00e4ki, Batty, & Hublin, 2011)”, “previouslyFormattedCitation” : “(Kivimu00e4ki, Batty, & Hublin, 2011)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Kivimäki and Batty, 2011).

Immediate disturbances associated with shift work include sleep disturbances and fatigue ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1111/j.1365-2796.2007.01766.x”, “ISBN” : “0954-6820 (Print)\r0954-6820 (Linking)”, “ISSN” : “09546820”, “PMID” : “17305651”, “abstract” : “OBJECTIVE: The major function of the circadian system is the internal cycling of physiological and metabolic events. The present study sought to explore the effect of rotating shift work schedule on leucocyte count and its relationship with risk factors of metabolic syndrome (MS). DESIGN AND PARTICIPANTS: From a population-based design, 1351 men of self-reported European ancestry were included in a cross-sectional study: 877 day workers were compared with 474 rotating shift workers. Medical history, health examination including anthropometric and arterial blood pressure measurements, a questionnaire on health-related behaviours and biochemical determinations was given to all participants. RESULTS: In comparison with day workers, rotating shift workers had elevated (mean +/- SE) body mass index (27.1 +/- 0.3 vs. 26.3 +/- 0.2, P < 0.0154), waist-hip ratio (0.95 +/- 0.01 vs. 0.93 +/- 0.01, P < 0.00024), diastolic arterial blood pressure (78 +/- 1 vs. 76 +/- 1, P < 0.033), fasting insulin (65.5 +/- 2.9 vs. 55.9 +/- 1.9 pmol L(-1), P < 0.017), Homeostasis Model Assessment index (2.12 +/- 0.11 vs. 1.77 +/- 0.07, P < 0.0027), triglycerides (1.71 +/- 0.1 vs. 1.5 +/- 0.1 mmol L(-1), P < 0.002), uric acid (292.7 +/- 2.8 vs. 282 +/- 3.4 micromol L(-1), P < 0.01) and leucocyte count (7030 +/- 84 vs. 6730 +/- 58, P < 0.0094). In multiple regression analysis, leucocyte count was correlated with rotating shift work independently of age, smoking, education and components of MS. CONCLUSION: The odds ratio for MS in rotating shift workers compared with day workers was 1.51 (95% CI 1.01-2.25), independently of age and physical activity. Increased leucocyte count, a biological marker of systemic inflammation, was associated with rotating shift work.”, “author” : { “dropping-particle” : “”, “family” : “Sookoian”, “given” : “S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gemma”, “given” : “C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fernu00e1ndez Gianotti”, “given” : “T.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Burgueu00f1o”, “given” : “a.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Alvarez”, “given” : “a.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gonzu00e1lez”, “given” : “C. D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pirola”, “given” : “C. J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Internal Medicine”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2007” }, “page” : “285-292”, “title” : “Effects of rotating shift work on biomarkers of metabolic syndrome and inflammation”, “type” : “article-journal”, “volume” : “261” }, “uris” : “http://www.mendeley.com/documents/?uuid=f8736c8c-30ad-4f2b-b6e7-742736e85e1d” } , “mendeley” : { “formattedCitation” : “(Sookoian et al., 2007)”, “plainTextFormattedCitation” : “(Sookoian et al., 2007)”, “previouslyFormattedCitation” : “(Sookoian et al., 2007)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Sookoian et al., 2007). Long term health problems that are also connected to shift work include heart diseases and cancer; the International Agency for Research on Cancer (IARC) in 2007 has concluded that “shift work that involves circadian disruption is probably carcinogenic to humans, group 2A” ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Erren”, “given” : “Thomas C”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Morfeld”, “given” : “Peter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Stork”, “given” : “Joachim”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Knauth”, “given” : “Peter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Von”, “given” : “Matthias J A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Breitstadt”, “given” : “Rolf”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mu00fcller”, “given” : “Uta”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Emmerich”, “given” : “Michael”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Piekarski”, “given” : “Claus”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Erren”, “given” : “C”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scand J Work Environ Health”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2009” }, “page” : “74 – 79”, “title” : “Shift work, chronodisruption and cancer?- the IARC 2007 challenge for research and prevention and 10 theses from the Cologne Colloquium 2008”, “type” : “article-journal”, “volume” : “35” }, “uris” : “http://www.mendeley.com/documents/?uuid=0574a869-e85a-4e4b-9722-e39e282c213e” } , “mendeley” : { “formattedCitation” : “(Erren et al., 2009)”, “plainTextFormattedCitation” : “(Erren et al., 2009)”, “previouslyFormattedCitation” : “(Erren et al., 2009)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Erren et al., 2009).

Shift work can also have adverse health effects through its potential impact on behavior, such as poorer quality diet, increased alcohol consumption or smoking as it was reported that shift workers are more likely than regular day workers to be smokers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Haus”, “given” : “Erhard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Stevens”, “given” : “Richard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandanavian journal for work and environmental health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “163 – 179”, “title” : “Shif work and cancer considerations on rationale, mechanism and epidemiology”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=a5f6f025-31ec-42a3-86c9-8ffcb5642667” } , “mendeley” : { “formattedCitation” : “(Costa, Haus, & Stevens, 2010)”, “manualFormatting” : “(Costa et al., 2010)”, “plainTextFormattedCitation” : “(Costa, Haus, & Stevens, 2010)”, “previouslyFormattedCitation” : “(Costa, Haus, & Stevens, 2010)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa et al., 2010).

Circadian rhythms are the body’s biological cycles that recur at 24-hour intervals, including sleep-wake patterns, body temperatures and hormone levels ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Haus”, “given” : “Erhard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Stevens”, “given” : “Richard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandanavian journal for work and environmental health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “163 – 179”, “title” : “Shif work and cancer considerations on rationale, mechanism and epidemiology”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=a5f6f025-31ec-42a3-86c9-8ffcb5642667” } , “mendeley” : { “formattedCitation” : “(Costa et al., 2010)”, “plainTextFormattedCitation” : “(Costa et al., 2010)”, “previouslyFormattedCitation” : “(Costa et al., 2010)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa et al., 2010). The major function of the circadian system is the internal cycling of physiological and metabolic events. Feeding behavior, lipid and carbohydrate metabolism and blood pressure are also subjected to daily variation ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1111/j.1365-2796.2007.01766.x”, “ISBN” : “0954-6820 (Print)\r0954-6820 (Linking)”, “ISSN” : “09546820”, “PMID” : “17305651”, “abstract” : “OBJECTIVE: The major function of the circadian system is the internal cycling of physiological and metabolic events. The present study sought to explore the effect of rotating shift work schedule on leucocyte count and its relationship with risk factors of metabolic syndrome (MS). DESIGN AND PARTICIPANTS: From a population-based design, 1351 men of self-reported European ancestry were included in a cross-sectional study: 877 day workers were compared with 474 rotating shift workers. Medical history, health examination including anthropometric and arterial blood pressure measurements, a questionnaire on health-related behaviours and biochemical determinations was given to all participants. RESULTS: In comparison with day workers, rotating shift workers had elevated (mean +/- SE) body mass index (27.1 +/- 0.3 vs. 26.3 +/- 0.2, P < 0.0154), waist-hip ratio (0.95 +/- 0.01 vs. 0.93 +/- 0.01, P < 0.00024), diastolic arterial blood pressure (78 +/- 1 vs. 76 +/- 1, P < 0.033), fasting insulin (65.5 +/- 2.9 vs. 55.9 +/- 1.9 pmol L(-1), P < 0.017), Homeostasis Model Assessment index (2.12 +/- 0.11 vs. 1.77 +/- 0.07, P < 0.0027), triglycerides (1.71 +/- 0.1 vs. 1.5 +/- 0.1 mmol L(-1), P < 0.002), uric acid (292.7 +/- 2.8 vs. 282 +/- 3.4 micromol L(-1), P < 0.01) and leucocyte count (7030 +/- 84 vs. 6730 +/- 58, P < 0.0094). In multiple regression analysis, leucocyte count was correlated with rotating shift work independently of age, smoking, education and components of MS. CONCLUSION: The odds ratio for MS in rotating shift workers compared with day workers was 1.51 (95% CI 1.01-2.25), independently of age and physical activity. Increased leucocyte count, a biological marker of systemic inflammation, was associated with rotating shift work.”, “author” : { “dropping-particle” : “”, “family” : “Sookoian”, “given” : “S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gemma”, “given” : “C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fernu00e1ndez Gianotti”, “given” : “T.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Burgueu00f1o”, “given” : “a.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Alvarez”, “given” : “a.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gonzu00e1lez”, “given” : “C. D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pirola”, “given” : “C. J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Internal Medicine”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2007” }, “page” : “285-292”, “title” : “Effects of rotating shift work on biomarkers of metabolic syndrome and inflammation”, “type” : “article-journal”, “volume” : “261” }, “uris” : “http://www.mendeley.com/documents/?uuid=f8736c8c-30ad-4f2b-b6e7-742736e85e1d” } , “mendeley” : { “formattedCitation” : “(Sookoian et al., 2007)”, “plainTextFormattedCitation” : “(Sookoian et al., 2007)”, “previouslyFormattedCitation” : “(Sookoian et al., 2007)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Sookoian et al., 2007).

The disruption of the circadian rhythm has been reported to lead not only to problems such as sleep disorders and exhaustion, but also to domestic life and social activity problems, as well as various health problems ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/2052-4374-25-33”, “ISBN” : “10.1186/2052-4374-25-33”, “ISSN” : “2052-4374”, “PMID” : “24472469”, “abstract” : “OBJECTIVE: This study aimed to determine identify any association between shift work and the metabolic syndrome by comparing the prevalence rates of the metabolic syndrome in shift work groups and daytime work groups for female workers.\n\nMETHODS: Based on data from health examinations carried out from April to December of 2012, we selected as our subjects 254 female workers from the Daegu area Dyeing Industrial Complex. We diagnosed the metabolic syndrome using the examination results, and information about age, whether or not they did shift work, job type, smoking habits, drinking habits, exercise habits, and past medical history was collected through self-administered questionnaire surveys and face-to-face interviews. The variables found in a univariate analysis to be significant in the occurrence of the metabolic syndrome – age, drinking habits, exercise habits, and shift work – were included in a logistic regression analysis of the risk of the metabolic syndrome for female workers.\n\nRESULTS: The prevalence rates of the metabolic syndrome for the total group of study subjects was 11.8%, for daytime workers was 2.8%, and for shift workers was 15.3%. A logistic regression analysis of the odds of the metabolic syndrome for female workers was conducted that included factors associated with the occurrence of the metabolic syndrome: age, drinking habits, exercise habits, and shift work. The results revealed that the odds ratio of the metabolic syndrome in the shift work group, 6.30 (95% CI 1.24-32.15), was significantly higher when compared with the daytime work group.\n\nCONCLUSION: Shift work appears to have an association with the metabolic syndrome in female workers. Accordingly, we believe that the attention of government agencies and business owners is needed together with the individual practice of health behaviors to manage the metabolic syndrome for the prevention of cardiovascular disease in female shift workers.”, “author” : { “dropping-particle” : “”, “family” : “Ye”, “given” : “Han Hui”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeong”, “given” : “Jae Uk”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeon”, “given” : “Man Joong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sakong”, “given” : “Joon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annals of occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “page” : “33”, “title” : “The Association between Shift Work and the Metabolic Syndrome in Female Workers.”, “type” : “article-journal”, “volume” : “25” }, “uris” : “http://www.mendeley.com/documents/?uuid=1c6e46ae-d8d1-4cc0-af02-e995027a42ca” } , “mendeley” : { “formattedCitation” : “(Ye, Jeong, Jeon, & Sakong, 2013)”, “manualFormatting” : “(Ye et al., 2013)”, “plainTextFormattedCitation” : “(Ye, Jeong, Jeon, & Sakong, 2013)”, “previouslyFormattedCitation” : “(Ye, Jeong, Jeon, & Sakong, 2013)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ye et al., 2013). Shift work is considered to be disruptive of normal diurnal biological rhythms ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Introduction: Rotating night shift work disrupts circadian rhythms and it has been associated with chronic conditions including cancers, cardiovascular diseases, obesity, metabolic syndrome and glucose dysregulation. Aim of work: the study aimed at determining the prevalence of glucose abnormalities among Abo-Korkas sugar factory workers and exploring the impact of rotating night shifts on glycemic state and control of diabetes. Materials and Methods: In a cross-sectional study a total of 330 male workers at Abo-Korkas sugar factory were randomly selected to fill out an interview questionnaire, have medical examination and be tested for fasting and post-prandial blood glucose level; with assessment of HbA1c (Hemoglobin A1c test) for those who were diagnosed as diabetics. Results: Our findings showed that 61 (18.4%) workers were diabetics, 7 of them were newly diagnosed diabetics. The prevalence of diabetes was significantly higher (p= 0.01) among former (33.3%) and current (15.7%) night shift than day-time workers (14.4%). The crude Odds Ratio (OR) for developing diabetes mellitus among the current and former shift workers were 1.1 (0.56-2.18) and 2.9 (1.39-6.31), respectively. Moreover, shift working significantly affected diabetes control (p= 0.04) with an OR= 3.83 (1.02-14.34). Conclusion: Rotating shift work especially night shifts have negative effects on health. It was found to be associated with developing type 2 diabetes mellitus and it hindered diabetes control among night shift diabetic workers. Preventive programs should be implemented for high risk Night shift working and its impact on development and control of diabetes mellitus in workers of Abo Korkas sugar factory, El Minia, Egypt (PDF Download Available). Available from: http://www.researchgate.net/publication/273441333_Night_shift_working_and_its_impact_on_development_and_control_of_diabetes_mellitus_in_workers_of_Abo_Korkas_sugar_factory_El_Minia_Egypt accessed Oct 10, 2015.”, “author” : { “dropping-particle” : “”, “family” : “Ghazawy”, “given” : “ER”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kamel”, “given” : “SM”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gamal”, “given” : “HM”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ewis”, “given” : “AA”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Egyptian journal of Occupational Medicine”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2014” }, “page” : “197”, “title” : “Night shift working and its impact on development and control of diabetes mellitus in workers of Abo Korkas sugar factory , El Minia ,”, “type” : “article-journal”, “volume” : “38” }, “uris” : “http://www.mendeley.com/documents/?uuid=7ad3ec26-3795-43e4-9633-314289200405” } , “mendeley” : { “formattedCitation” : “(Ghazawy, Kamel, Gamal, & Ewis, 2014)”, “manualFormatting” : “(Ghazawy et al., 2014) “, “plainTextFormattedCitation” : “(Ghazawy, Kamel, Gamal, & Ewis, 2014)”, “previouslyFormattedCitation” : “(Ghazawy, Kamel, Gamal, & Ewis, 2014)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ghazawy et al., 2014) and this is thought to be the main pathway for adverse health effects from shift work, particularly for work schedules that include night work ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Haus”, “given” : “Erhard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Stevens”, “given” : “Richard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandanavian journal for work and environmental health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “163 – 179”, “title” : “Shif work and cancer considerations on rationale, mechanism and epidemiology”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=a5f6f025-31ec-42a3-86c9-8ffcb5642667” } , “mendeley” : { “formattedCitation” : “(Costa et al., 2010)”, “manualFormatting” : “(Costa et al., 2010)”, “plainTextFormattedCitation” : “(Costa et al., 2010)”, “previouslyFormattedCitation” : “(Costa et al., 2010)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa et al., 2010).

Epidemiological studies have shown that rotating shift work has high propensity to metabolic and nutritional disorders and may be directly responsible for increased obesity, higher blood pressure levels, altered nutritional metabolism, insulin resistance, diabetes, dyslipidemias, gastrointestinal disorders and metabolic syndrome ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1136/oem.58.11.747”, “ISBN” : “1351-0711 (Print)\r1351-0711 (Linking)”, “ISSN” : “1351-0711”, “PMID” : “11600731”, “abstract” : “OBJECTIVES: To explore how metabolic risk factors for cardiovascular disease (CVD) differ between shift workers and day workers in a defined population. Shift work has been associated with an increased risk of CVD. Risk factors and causal pathways for this association are only partly known. METHODS: A working population of 27,485 people from the Vu00e4sterbotten intervention program (VIP) has been analysed. Cross sectional data, including blood sampling and questionnaires were collected in a health survey. RESULTS: Obesity was more prevalent among shift workers in all age strata of women, but only in two out of four age groups in men. Increased triglycerides (>1.7 mmol/l) were more common among two age groups of shift working women but not among men. Low concentrations of high density lipoprotein (HDL) cholesterol (men<0.9 and women<1.0 mmol/l) were present in the youngest age group of shift workers in both men and women. Impaired glucose tolerance was more often found among 60 year old women shift workers. Obesity and high triglycerides persisted as risk factors in shift working men and women after adjusting for age and socioeconomic factors, with an OR of 1.4 for obesity and 1.1 for high triglyceride concentrations. The relative risks for women working shifts versus days with one, two, and three metabolic variables were 1.06, 1.20, and 1.71, respectively. The corresponding relative risks for men were 0.99, 1.30, and 1.63, respectively. CONCLUSIONS: In this study, obesity, high triglycerides, and low concentrations of HDL cholesterol seem to cluster together more often in shift workers than in day workers, which might indicate an association between shift work and the metabolic syndrome.”, “author” : { “dropping-particle” : “”, “family” : “Karlsson”, “given” : “B”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Knutsson”, “given” : “a”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lindahl”, “given” : “B”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “11”, “issued” : { “date-parts” : “2001” }, “page” : “747-752”, “title” : “Is there an association between shift work and having a metabolic syndrome? Results from a population based study of 27,485 people.”, “type” : “article-journal”, “volume” : “58” }, “uris” : “http://www.mendeley.com/documents/?uuid=9ab3f242-d7db-4061-900b-2bfba9049e9b” } , “mendeley” : { “formattedCitation” : “(Karlsson, Knutsson, & Lindahl, 2001)”, “manualFormatting” : “(Karlsson et al., 2001; De Bacquer et al., 2009; Costa, 2010; Zimberg et al., 2012; Ghazawy et al., 2014s; Kawabe et al., 2014; )”, “plainTextFormattedCitation” : “(Karlsson, Knutsson, & Lindahl, 2001)”, “previouslyFormattedCitation” : “(Karlsson, Knutsson, & Lindahl, 2001)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Karlsson et al., 2001; De Bacquer et al., 2009; Costa, 2010; Zimberg et al., 2012; Ghazawy et al., 2014; Kawabe et al., 2014; Proper et al., 2016). Furthermore, other studies found that rotating shift workers had a significantly higher risk of death due to ischemic heart disease compared to day workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “OBJECTIVES: Previous studies have indicated an association between shiftwork and coronary heart disease. The increased risk could be due to job strain, which could act as a mediator of disease. There is also a possibility that interaction between shiftwork and job strain could occur that may induce or modify the development of disease. We conducted this study to explore the relation between shiftwork, job strain, and myocardial infarction. METHODS: 2006 cases with acute first time myocardial infarction were compared with 2642 controls without symptoms of myocardial infarction, and obtained from the same population that gave rise to the cases (population based case-control study). RESULTS: Myocardial infarction risk was associated with shiftwork both in men (odds ratio (OR) 1.3, 95% confidence interval (95% CI) 1.1 to 1.6) and women (OR 1.3, 95% CI 0.9 to 1.8). In the age group 45-55, the relative risk was 1.6 in men and 3.0 in women. The results cannot be explained by job strain, age, job education level, or smoking. No interaction was found between shiftwork and job strain. CONCLUSIONS: The findings indicate that shiftwork is associated with myocardial infarction in both men and women. The mechanism is unclear, but the relation cannot be explained by job strain, smoking, or job education level.”, “author” : { “dropping-particle” : “”, “family” : “Knutsson”, “given” : “A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hallquist”, “given” : “J”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Reuterwall”, “given” : “C”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Theorell”, “given” : “T”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Akerstedt”, “given” : “T”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “1999” }, “page” : “46-50”, “title” : “Shiftwork and myocardial infarction: a case-control study.”, “type” : “article-journal”, “volume” : “56” }, “uris” : “http://www.mendeley.com/documents/?uuid=0563823e-2dce-46cd-bab4-b118ab23d655” }, { “id” : “ITEM-2”, “itemData” : { “abstract” : “This study prospectively examined the association between shift work and the risk of ischemic heart disease among Japanese male workers. A baseline survey, which involved 110,792 inhabitants (age range: 40-79 years) from 45 areas throughout Japan, was conducted between 1988 and 1990. The causes of death were identified from death certificates. The analysis was restricted to 17,649 men (age range: 40-59 years) who were employed at the time of the baseline survey. All subjects were asked to indicate the most regular shift work that they had undertaken previously: day work, rotating-shift work, or fixed-night work. The Cox proportional hazards model was used to estimate the risks of shift work for ischemic heart disease. During the 233,869 person-years of follow-up, a total of 1,363 deaths were recorded, 86 of which were due to ischemic heart disease. Compared with the day workers, the rotating-shift workers had a significantly higher risk of death due to ischemic heart disease (relative risk = 2.32, 95% confidence interval: 1.37, 3.95; p = 0.002), whereas fixed-night work was not associated with ischemic heart disease (relative risk = 1.23, 95% confidence interval: 0.49, 3.10; p = 0.658). In addition, subjects with coronary risk factors, such as hypertension, overweight, habitual alcohol consumption, and smoking, were highly susceptible to the effect of rotating-shift work on the risk of death due to ischemic heart disease.”, “author” : { “dropping-particle” : “”, “family” : “Fujino”, “given” : “Yoshihisa”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Iso”, “given” : “Hiroyasu”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tamakoshi”, “given” : “Akiko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Inaba”, “given” : “Yutaka”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Koizumi”, “given” : “Akio”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kubo”, “given” : “Tatsuhiko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Yoshimura”, “given” : “Takesumi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “American Journal of Epidemiology”, “id” : “ITEM-2”, “issue” : “2”, “issued” : { “date-parts” : “2006” }, “page” : “128-135”, “title” : “A prospective cohort study of shift work and risk of ischemic heart disease in Japanese male workers”, “type” : “article-journal”, “volume” : “164” }, “uris” : “http://www.mendeley.com/documents/?uuid=d45f3676-d571-48d1-8a59-d8cdbdaeb5a1” }, { “id” : “ITEM-3”, “itemData” : { “abstract” : “In developing countries, shift work represents a considerable contingent workforce. Recently, studies have shown that overweight and obesity are more prevalent in shift workers than day workers. In addition, shift work has been associated with a higher propensity for the development of many metabolic disorders, such as insulin resistance, diabetes, dislipidemias and metabolic syndrome. Recent data have pointed that decrease of the sleep time, desynchronization of circadian rhythm and alteration of environmental aspects are the main factors related to such problems. Shortened or disturbed sleep is among the most common health-related effects of shift work. The plausible physiological and biological mechanisms are related to the activation of the autonomic nervous system, inflammation, changes in lipid and glucose metabolism, and related changes in the risk for atherosclerosis, metabolic syndrome, and type II diabetes. The present review will discuss the impact of shift work on obesity and metabolic disorders and how disruption of sleep and circadian misalignment may contribute to these metabolic dysfunctions.”, “author” : { “dropping-particle” : “”, “family” : “Zimberg”, “given” : “Ionu00e1 Zalcman”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fernandes Junior”, “given” : “Silvio A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Crispim”, “given” : “Cibele Aparecida”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tufik”, “given” : “Sergio”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mello”, “given” : “Marco Tulio”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” } , “container-title” : “Work”, “id” : “ITEM-3”, “issue” : “SUPPL.1”, “issued” : { “date-parts” : “2012” }, “page” : “4376-4383”, “title” : “Metabolic impact of shift work”, “type” : “paper-conference”, “volume” : “41” }, “uris” : “http://www.mendeley.com/documents/?uuid=d1020cd6-9d57-40af-b0c3-3b11f5e33cb5” } , “mendeley” : { “formattedCitation” : “(Fujino et al., 2006; Knutsson, Hallquist, Reuterwall, Theorell, & Akerstedt, 1999; Zimberg, Fernandes Junior, Crispim, Tufik, & De Mello, 2012)”, “manualFormatting” : “(Fujino et al., 2006; Knutsson et al., 1999; Zimberg et al., 2012)”, “plainTextFormattedCitation” : “(Fujino et al., 2006; Knutsson, Hallquist, Reuterwall, Theorell, & Akerstedt, 1999; Zimberg, Fernandes Junior, Crispim, Tufik, & De Mello, 2012)”, “previouslyFormattedCitation” : “(Fujino et al., 2006; Knutsson, Hallquist, Reuterwall, Theorell, & Akerstedt, 1999; Zimberg, Fernandes Junior, Crispim, Tufik, & De Mello, 2012)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Fujino et al., 2006; Zimberg et al., 2012).

The metabolic syndrome is a complex of interrelated risk factors, and is presently one of the most relevant public health risk factors, mainly for its association with type 2 diabetes and cardiovascular diseases ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5491/SHAW.2010.1.2.112”, “ISBN” : “2093-7997 (Electronic)\n2093-7911 (Linking)”, “ISSN” : “2093-7911”, “PMID” : “22953171”, “abstract” : “The paper gives an overview of the problems to be tackled nowadays by occupational health with regards to shift work as well as the main guidelines at organizational and medical levels on how to protect workers’ health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general populations, all of which involve more and more people in continuous assistance and control of work processes over the 24 hours in a day. The large increase of epidemiological and clinical studies on this issue document the severity of this risk factor on human health and well being, at both social and psychophysical levels, starting from a disruption of biological circadian rhythms and sleep/wake cycle and ending in several psychosomatic troubles and disorders, likely also including cancer, and extending to impairment of performance efficiency as well as family and social life. Appropriate interventions on the organization of shift schedules according to ergonomic criteria and careful health surveillance and social support for shift workers are important preventive and corrective measures that allow people to keep working without significant health impairment.”, “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Safety and Health at Work”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “112”, “publisher” : “Elsevier Masson SAS”, “title” : “Shift Work and Health: Current Problems and Preventive Actions”, “type” : “article-journal”, “volume” : “1” }, “uris” : “http://www.mendeley.com/documents/?uuid=466f1ca5-87e5-42bb-be92-e8b8cf0483fc” } , “mendeley” : { “formattedCitation” : “(Costa, 2010)”, “plainTextFormattedCitation” : “(Costa, 2010)”, “previouslyFormattedCitation” : “(Costa, 2010)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa, 2010).

Several clinical definitions have been proposed. The first criteria for definition for the diagnosis of metabolic syndrome was proposed by World Health Organization (WHO) in 1999 ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1002/(SICI)1096-9136(199807)15:7;539::AID-DIA668;3.0.CO;2-S”, “ISSN” : “07423071”, “PMID” : “9686693”, “abstract” : “The classification of diabetes mellitus and the tests used for its diagnosis were brought into order by the National Diabetes Data Group of the USA and the second World Health Organization Expert Committee on Diabetes Mellitus in 1979 and 1980. Apart from minor modifications by WHO in 1985, little has been changed since that time. There is however considerable new knowledge regarding the aetiology of different forms of diabetes as well as more information on the predictive value of different blood glucose values for the complications of diabetes. A WHO Consultation has therefore taken place in parallel with a report by an American Diabetes Association Expert Committee to re-examine diagnostic criteria and classification. The present document includes the conclusions of the former and is intended for wide distribution and discussion before final proposals are submitted to WHO for approval. The main changes proposed are as follows. The diagnostic fasting plasma (blood) glucose value has been lowered to ; or =7.0 mmol l(-1) (6.1 mmol l(-1)). Impaired Glucose Tolerance (IGT) is changed to allow for the new fasting level. A new category of Impaired Fasting Glycaemia (IFG) is proposed to encompass values which are above normal but below the diagnostic cut-off for diabetes (plasma ; or =6.1 to or =5.6 to ;6.1 mmol l(-1)). Gestational Diabetes Mellitus (GDM) now includes gestational impaired glucose tolerance as well as the previous GDM. The classification defines both process and stage of the disease. The processes include Type 1, autoimmune and non-autoimmune, with beta-cell destruction; Type 2 with varying degrees of insulin resistance and insulin hyposecretion; Gestational Diabetes Mellitus; and Other Types where the cause is known (e.g. MODY, endocrinopathies). It is anticipated that this group will expand as causes of Type 2 become known. Stages range from normoglycaemia to insulin required for survival. It is hoped that the new classification will allow better classification of individuals and lead to fewer therapeutic misjudgements.”, “author” : { “dropping-particle” : “”, “family” : “WHO”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “World Health”, “id” : “ITEM-1”, “issued” : { “date-parts” : “1999” }, “page” : “539-53”, “title” : “Definition , Diagnosis and Classification of Diabetes Mellitus and its Complications Part 1 : Diagnosis and Classification of”, “type” : “article-journal”, “volume” : “15” }, “uris” : “http://www.mendeley.com/documents/?uuid=2b9b6742-8558-45b4-9465-04ac028eab27” } , “mendeley” : { “formattedCitation” : “(WHO, 1999)”, “plainTextFormattedCitation” : “(WHO, 1999)”, “previouslyFormattedCitation” : “(WHO, 1999)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(WHO, 1999). European Group for the Study of Insulin Resistance (EGIR) was in the same year the next one ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Balkau”, “given” : “B”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Charles”, “given” : “MA.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “1999” }, “number-of-pages” : “16: 442 – 443”, “title” : “comment on who report european group”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=700d8e09-223f-48f6-bbd2-851b8d6c11c6” } , “mendeley” : { “formattedCitation” : “(Balkau ; Charles, 1999)”, “manualFormatting” : “(Balkau and Charles 1999)”, “plainTextFormattedCitation” : “(Balkau ; Charles, 1999)”, “previouslyFormattedCitation” : “(Balkau ; Charles, 1999)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Balkau and Charles 1999). The presence of insulin resistance was a prerequisite in both definitions.

National Cholesterol Education Program (NCEP) Adult Treatment Panel III in 2001 (ATP-III) does not obligatorily require impaired glucose regulation or insulin resistance as an essential component (ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1001/archinte.1991.00400060019005”, “ISSN” : “0003-9926”, “PMID” : “12485966”, “abstract” : “Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III, or ATP III) presents the National Cholesterol Education Program (NCEP) updated recommendations on cholesterol testing and management. The ATP III document is an evidence-based report that provides the scientific rationale for the recommendations contained in the Executive Summary. ATP III is constructed on the foundation of ATP I and ATP II, with low density lipoprotein (LDL) continuing to be identified as the primary target of cholesterol lowering therapy. New features of ATP III include: Aggressive treatment of persons who are at relatively high risk for coronary heart disease due to multiple risk factors Use of the lipoprotein profile as the first test for high cholesterol A new level at which low HDL (high density lipoprotein) becomes a major heart disease risk factor A new set of “Therapeutic Lifestyle Changes” to improve cholesterol levels An increased focus on a cluster of heart disease risk factors knows as “the metabolic syndrome” Increased attention to the treatment of high triglycerides”, “author” : { “dropping-particle” : “”, “family” : “National Cholesterol Education Program (NCEP) Expert Panel”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Archives of Internal Medicine”, “id” : “ITEM-1”, “issue” : “6”, “issued” : { “date-parts” : “2002” }, “number-of-pages” : “284”, “title” : “Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III)”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=775353c3-bb28-48a1-97b3-066b514d79db” } , “mendeley” : { “formattedCitation” : “(National Cholesterol Education Program (NCEP) Expert Panel, 2002)”, “manualFormatting” : “NCEP Expert Panel, 2002)”, “plainTextFormattedCitation” : “(National Cholesterol Education Program (NCEP) Expert Panel, 2002)”, “previouslyFormattedCitation” : “(National Cholesterol Education Program (NCEP) Expert Panel, 2002)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }NCEP Expert Panel, 2002). All the three groups agreed that the core components of the metabolic syndrome are: obesity, hypertension, insulin resistance and dyslipidemia ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.2478/v10001-010-0032-5”, “ISBN” : “1896-494X (Electronic)
1232-1087 (Linking)”, “ISSN” : “1232-1087”, “PMID” : “20934953”, “abstract” : “Shift work is affecting 20% to 25% employees and is becoming increasingly prevalent in contemporary life all over Europe and USA. It is associated with several health problems, such as e.g. metabolic syndrome, diabetes mellitus and cardiovascular disease. These diseases are possibly due to an impairment of biological rhythm. The metabolic syndrome is a complex of interrelated risk factors for cardiovascular disease and diabetes. Higher prevalence of the metabolic syndrome has been demonstrated among shift workers. Rotating shift work has an impact on each component of metabolic syndrome. Shift work might also have an impact on metabolic variables, and be a risk factor for type 2 diabetes. Only a few studies reported prevalence of impaired glucose metabolism and diabetes mellitus in relation to shift work. There is rather strong evidence in favour of association between shift work and coronary heart disease and that has been repeatedly demonstrated during over 20 years of research. Recent data increasingly reveal relations between shift work and plasma resistin, ghrelin, leptin and adiponectin.”, “author” : { “dropping-particle” : “”, “family” : “Szosland”, “given” : “Dorota”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International journal of occupational medicine and environmental health”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2010” }, “page” : “287-291”, “title” : “Shift work and metabolic syndrome, diabetes mellitus and ischaemic heart disease.”, “type” : “article-journal”, “volume” : “23” }, “uris” : “http://www.mendeley.com/documents/?uuid=c485a9ce-ceac-4e28-96b5-1899fda4f022” } , “mendeley” : { “formattedCitation” : “(Szosland, 2010)”, “plainTextFormattedCitation” : “(Szosland, 2010)”, “previouslyFormattedCitation” : “(Szosland, 2010)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Szosland, 2010).
In 2005 International Diabetes Federation (IDF) presented definition where visceral obesity was the necessary requirement ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “The molecular mechanisms involved in the development of type 2 diabetes are poorly understood. Starting from genome-wide genotype data for 1924 diabetic cases and 2938 population controls generated by the Wellcome Trust Case Control Consortium, we set out to detect replicated diabetes association signals through analysis of 3757 additional cases and 5346 controls and by integration of our findings with equivalent data from other international consortia. We detected diabetes susceptibility loci in and around the genes CDKAL1, CDKN2A/CDKN2B, and IGF2BP2 and confirmed the recently described associations at HHEX/IDE and SLC30A8. Our findings provide insight into the genetic architecture of type 2 diabetes, emphasizing the contribution of multiple variants of modest effect. The regions identified underscore the importance of pathways influencing pancreatic beta cell development and function in the etiology of type 2 diabetes.”, “author” : { “dropping-particle” : “”, “family” : “Alberti”, “given” : “K. George M M”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Zimmet”, “given” : “Paul”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Shaw”, “given” : “Jonathan”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Lancet”, “id” : “ITEM-1”, “issue” : “9491”, “issued” : { “date-parts” : “2005” }, “page” : “1059-1062”, “title” : “The metabolic syndrome – A new worldwide definition”, “type” : “article”, “volume” : “366” }, “uris” : “http://www.mendeley.com/documents/?uuid=2007704e-b67f-4f1b-9f09-9bf23da33a04” } , “mendeley” : { “formattedCitation” : “(Alberti, Zimmet, ; Shaw, 2005)”, “manualFormatting” : “(Alberti et al., 2005)”, “plainTextFormattedCitation” : “(Alberti, Zimmet, ; Shaw, 2005)”, “previouslyFormattedCitation” : “(Alberti, Zimmet, ; Shaw, 2005)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Alberti et al., 2005). They defined metabolic syndrome as a waist circumference ? 94 cm plus at least two of the following conditions: systolic blood pressure ? 130 mmHg and/or diastolic blood pressure ? 85 mmHg and/or using antihypertensive medication, HDL cholesterol < 40 mg/dl, non-fasting triglycerides ? 220 mg/dl and non-fasting glucose ? 120 mg/dl or type II diabetes ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1093/ije/dyn360”, “ISBN” : “1464-3685 (Electronic)”, “ISSN” : “1464-3685”, “PMID” : “19129266”, “abstract” : “BACKGROUND: Several studies have documented on the elevated cardiovascular risk among shift workers. In order to further explore this relation, we aimed at assessing the association between rotating shift work and the incidence of the metabolic syndrome (MetS). METHODS: In this population-based prospective study, 1529 employees from several large Belgian companies were followed for a median observation period of 6.6 years with respect to the onset of the MetS and its separate components. RESULTS: At baseline, 309 men (20.2%) were rotating shift workers. The MetS incidence rate in these shift workers (60.6 per 1000 person-years) was increased in comparison with day workers (37.2 per 1000 person-years) with an odds ratio (95% CI) of 1.77 (1.34-2.32). Multivariate adjustment for potential lifestyle and work-related confounders did only marginally affect the strength of the association. The risk for the development of MetS gradually increased independently with accumulated years of shift work. Rotating shift work not only had an impact on MetS as a cluster of conditions but on each of its individual components as well. CONCLUSIONS: Hence, prospective evidence was found that rotating shift work increases the risk for developing the MetS over a period of 6 years.”, “author” : { “dropping-particle” : “”, “family” : “Bacquer”, “given” : “D”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Risseghem”, “given” : “M”, “non-dropping-particle” : “Van”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Clays”, “given” : “E”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kittel”, “given” : “F”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Backer”, “given” : “G”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Braeckman”, “given” : “L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International journal of epidemiology”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2009” }, “page” : “848-854”, “title” : “Rotating shift work and the metabolic syndrome: a prospective study.”, “type” : “article-journal”, “volume” : “38” }, “uris” : “http://www.mendeley.com/documents/?uuid=0174b47f-e4a6-47d0-b7b8-2df6a00a4cb0” } , “mendeley” : { “formattedCitation” : “(De Bacquer et al., 2009)”, “plainTextFormattedCitation” : “(De Bacquer et al., 2009)”, “previouslyFormattedCitation” : “(De Bacquer et al., 2009)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(De Bacquer et al., 2009). In 2006 they updated their definition to produce a single, universally accepted diagnostic tool that is easy to use in clinical practice and an accessible, diagnostic tool suitable for worldwide use ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1159/000282084”, “ISBN” : “0003-9926 (Print) 0003-9926 (Linking)”, “ISSN” : “14219875”, “PMID” : “20460909”, “abstract” : “Over the last few years, the paradigm in hepatology has changed from focusing on a single liver disease to considering concurrent diseases, in particular obesity and related metabolic factors. Obesity has reached epidemic proportions globally and is associated with insulin resistance, steatosis and a low-grade systemic inflammatory state. These metabolic factors have a synergistic role in the natural history and treatment outcomes related to chronic liver disease. This is characterized best in chronic hepatitis C where steatosis and insulin resistance are caused by viral and metabolic effects. Non-alcoholic fatty liver disease and related metabolic abnormalities also exacerbate other diseases, such as alcoholic liver disease and haemochromatosis. In addition, there is growing evidence linking obesity and type 2 diabetes with hepatocellular carcinoma in subjects with chronic viral hepatitis. The pathogenesis of co-morbid disease may be related to increased oxidative stress, inflammatory injury and cell death, along with altered hepatocyte regeneration and repair. Hyperinsulinaemia and other metabolic factors may also have a direct role in the progression of liver injury. Data indicate that weight reduction improves steatosis and inflammation in patients with chronic hepatitis C. This has important clinical and therapeutic implications and suggests that obesity should be actively addressed in the management of patients with other chronic liver diseases.”, “author” : { “dropping-particle” : “”, “family” : “International Diabetes Federation”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “The IDF consensus worldwide definition of the metabolic syndrome”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2006” }, “page” : “1-7”, “title” : “The IDF consensus worldwide definition of the metabolic syndrome”, “type” : “article-journal”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=967b5632-9ea7-41c5-8a79-5b435c026da5” } , “mendeley” : { “formattedCitation” : “(International Diabetes Federation, 2006)”, “manualFormatting” : “(IDF, 2006)”, “plainTextFormattedCitation” : “(International Diabetes Federation, 2006)”, “previouslyFormattedCitation” : “(International Diabetes Federation, 2006)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(IDF, 2006).

With the gradual and constant increase in the number of shift workers worldwide, there is a growing interest in describing the metabolic processes and in understanding the mechanisms involved in disorders commonly observed in this population ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “In developing countries, shift work represents a considerable contingent workforce. Recently, studies have shown that overweight and obesity are more prevalent in shift workers than day workers. In addition, shift work has been associated with a higher propensity for the development of many metabolic disorders, such as insulin resistance, diabetes, dislipidemias and metabolic syndrome. Recent data have pointed that decrease of the sleep time, desynchronization of circadian rhythm and alteration of environmental aspects are the main factors related to such problems. Shortened or disturbed sleep is among the most common health-related effects of shift work. The plausible physiological and biological mechanisms are related to the activation of the autonomic nervous system, inflammation, changes in lipid and glucose metabolism, and related changes in the risk for atherosclerosis, metabolic syndrome, and type II diabetes. The present review will discuss the impact of shift work on obesity and metabolic disorders and how disruption of sleep and circadian misalignment may contribute to these metabolic dysfunctions.”, “author” : { “dropping-particle” : “”, “family” : “Zimberg”, “given” : “Ionu00e1 Zalcman”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fernandes Junior”, “given” : “Silvio A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Crispim”, “given” : “Cibele Aparecida”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tufik”, “given” : “Sergio”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mello”, “given” : “Marco Tulio”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” } , “container-title” : “Work”, “id” : “ITEM-1”, “issue” : “SUPPL.1”, “issued” : { “date-parts” : “2012” }, “page” : “4376-4383”, “title” : “Metabolic impact of shift work”, “type” : “paper-conference”, “volume” : “41” }, “uris” : “http://www.mendeley.com/documents/?uuid=d1020cd6-9d57-40af-b0c3-3b11f5e33cb5” } , “mendeley” : { “formattedCitation” : “(Zimberg et al., 2012)”, “plainTextFormattedCitation” : “(Zimberg et al., 2012)”, “previouslyFormattedCitation” : “(Zimberg et al., 2012)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Zimberg et al., 2012).
Metabolic syndrome is a serious health problem that increases the death rate from cardiovascular diseases and diabetes ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/2052-4374-25-33”, “ISBN” : “10.1186/2052-4374-25-33”, “ISSN” : “2052-4374”, “PMID” : “24472469”, “abstract” : “OBJECTIVE: This study aimed to determine identify any association between shift work and the metabolic syndrome by comparing the prevalence rates of the metabolic syndrome in shift work groups and daytime work groups for female workers.\n\nMETHODS: Based on data from health examinations carried out from April to December of 2012, we selected as our subjects 254 female workers from the Daegu area Dyeing Industrial Complex. We diagnosed the metabolic syndrome using the examination results, and information about age, whether or not they did shift work, job type, smoking habits, drinking habits, exercise habits, and past medical history was collected through self-administered questionnaire surveys and face-to-face interviews. The variables found in a univariate analysis to be significant in the occurrence of the metabolic syndrome – age, drinking habits, exercise habits, and shift work – were included in a logistic regression analysis of the risk of the metabolic syndrome for female workers.\n\nRESULTS: The prevalence rates of the metabolic syndrome for the total group of study subjects was 11.8%, for daytime workers was 2.8%, and for shift workers was 15.3%. A logistic regression analysis of the odds of the metabolic syndrome for female workers was conducted that included factors associated with the occurrence of the metabolic syndrome: age, drinking habits, exercise habits, and shift work. The results revealed that the odds ratio of the metabolic syndrome in the shift work group, 6.30 (95% CI 1.24-32.15), was significantly higher when compared with the daytime work group.\n\nCONCLUSION: Shift work appears to have an association with the metabolic syndrome in female workers. Accordingly, we believe that the attention of government agencies and business owners is needed together with the individual practice of health behaviors to manage the metabolic syndrome for the prevention of cardiovascular disease in female shift workers.”, “author” : { “dropping-particle” : “”, “family” : “Ye”, “given” : “Han Hui”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeong”, “given” : “Jae Uk”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeon”, “given” : “Man Joong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sakong”, “given” : “Joon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annals of occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “page” : “33”, “title” : “The Association between Shift Work and the Metabolic Syndrome in Female Workers.”, “type” : “article-journal”, “volume” : “25” }, “uris” : “http://www.mendeley.com/documents/?uuid=1c6e46ae-d8d1-4cc0-af02-e995027a42ca” } , “mendeley” : { “formattedCitation” : “(Ye et al., 2013)”, “plainTextFormattedCitation” : “(Ye et al., 2013)”, “previouslyFormattedCitation” : “(Ye et al., 2013)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ye et al., 2013). Moreover there is insufficient evidence regarding the association between shift work and metabolic syndrome ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/s13098-015-0041-4”, “ISSN” : “1758-5996”, “author” : { “dropping-particle” : “”, “family” : “Brum”, “given” : “Maria Carlota Borba”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Filho”, “given” : “Fu00e1bio Fernandes Dantas”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schnorr”, “given” : “Claudia Carolina”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bottega”, “given” : “Gustavo Borchardt”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rodrigues”, “given” : “Ticiana C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Diabetology ; Metabolic Syndrome”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2015” }, “page” : “1-7”, “publisher” : “???”, “title” : “Shift work and its association with metabolic disorders”, “type” : “article-journal”, “volume” : “7” }, “uris” : “http://www.mendeley.com/documents/?uuid=7b266ff4-ad7c-448d-862d-482f430c258b” } , “mendeley” : { “formattedCitation” : “(Brum et al., 2015)”, “plainTextFormattedCitation” : “(Brum et al., 2015)”, “previouslyFormattedCitation” : “(Brum et al., 2015)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Brum et al., 2015). In addition data regarding the impact of rotating shift work on metabolic syndrome among workers in Egypt is not available. So this study was conducted to find out the effect of rotating shift work on metabolic syndrome and its components among a group of Egyptian shift workers at an electricity distribution company.

AIM OF THE STUDY
The study aimed at clarifying the relation between rotating shift work and metabolic syndrome components for better health and well-being of rotating shift workers.

STUDY OBJECTIVES
To describe work schedules of rotating shift workers and day workers.
To assess clinical and laboratory components of metabolic syndrome which are (waist circumference, dyslipedimia, elevated fasting blood sugar and elevated blood pressure) among rotating shift workers and day workers.

To compare the risk of metabolic syndrome and its components among rotating shift workers and day workers.

STUDY QUESTION
Does rotating shift work have an effect on metabolic syndrome components?
STUDY HYPOTHESES
Alternative hypothesis
Rotating shift work has an effect on waist circumference.

Rotating shift work has an effect on blood pressure.

Rotating shift work has an effect on fasting blood sugar level.

Rotating shift work has an effect on triglycerides level.

Rotating shift work has an effect on high density lipoprotein level.

Null hypothesis
Rotating shift work has no effect on waist circumference.

Rotating shift work has no effect on blood pressure.

Rotating shift work has no effect on fasting blood sugar level.

Rotating shift work has no effect on triglycerides level.

Rotating shift work has no effect on high density lipoprotein level.

REVIEW OF LITERATURE
SHIFT WORK
Concepts and Definitions
The arrangement of working time is an important issue in work organization. Work arrangement is the basic factor connecting human capacities with production means. “Normal” working hours generally mean a working day with hours left for rest and recreation. Generally rest is a night time activity while work is a daytime activity. Other schedules either on shifts or with extended working hours which disturb the day-night work-sleep pattern are considered “abnormal”. These “abnormal” working hours are not a recent phenomenon. Ramazzini (1633–1714) noted that bakers, soldiers and innkeepers worked such hours. The commencement of the industrial revolution led to many workers working long hours until legislation was introduced to limit the worst changes of the new industrial based economy ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Harrington”, “given” : “J.M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Occupational and Environmental Medicine”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2001” }, “page” : “68-72”, “title” : “Health Effect of Shift Work and Extended Hours of Work”, “type” : “article-journal” }, “uris” : “http://www.mendeley.com/documents/?uuid=5e1ab785-c416-41b7-9601-3bec58bdc891” } , “mendeley” : { “formattedCitation” : “(;b;;b;Harrington;/b;;/b;, ;b;2001;/b;)”, “plainTextFormattedCitation” : “(Harrington, 2001)”, “previouslyFormattedCitation” : “(;b;;b;Harrington;/b;;/b;, ;b;2001;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Harrington, 2001).

Generally speaking shift work means any form of organizing work that differs from the normal daily work in which the operating time of a company is prolonged beyond the typical work day to cover the entire 24 hour period through shifting of different groups of worker ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9783319422848”, “abstract” : “The expanding use of shift work throughout the global economy is raising a variety of new questions, including those explored in the current volume. Is shift work an environmental demand that makes u201cbalancingu201d work and family more difficult, or is it a viable tool for alleviating inherent conflicts between work and family life? A casual perusal of the scholarly and popular literature will result in evidence supporting both positions, suggesting there is neither a simple nor a straightforward conclusion. In fact, the many dimensions and contours of u201cshift worku201d demand careful consideration before even attempting to answer the basic question, u201cis shift work a friend or foe of working adultsu2019 ability to meet their responsibilities in the domains of work and family?u201d. The overall goal of this chapter is to create a conceptual foundation for the content of this volume. To achieve this goal the chapter begins by outlining the meaning of u201cshift worku201d and alternative perspectives on combining work and family to help readers see that the concepts are both complex, making their linkages and potential interconnections exceedingly complicated. Next is a critical review of published research linking shift work with individualsu2019 ability to integrate work and family lives to help readers interpret the scientific literature. Finally, the chapter concludes with an agenda of high priority future research topics requiring attention to enable appropriate individual and collective responses to expanded reliance on shift work in the 21st century economy.”, “author” : { “dropping-particle” : “”, “family” : “Grzywacz”, “given” : “Joseph G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Social and Family Issues in Shift Work and Non Standard Working Hours”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “137 – 152”, “title” : “Shift Work and Its Implications for everyday Work and Family Life: A foundation and Summary”, “type” : “chapter” }, “uris” : “http://www.mendeley.com/documents/?uuid=4b93c033-889d-46e4-8e31-f99db0d67d50” } , “mendeley” : { “formattedCitation” : “(;b;;b;Grzywacz;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Grzywacz, 2016)”, “previouslyFormattedCitation” : “(;b;;b;Grzywacz;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Grzywacz, 2016). This definition follows the definition of the International Labor Office (ILO) 1990 which states that shift work is “a method of organization of working time in which workers succeed one another at the workplace so that the establishment can operate longer than the hours of work of individual workers” ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “International Labor Office (ILO)”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “WT- 8”, “issued” : { “date-parts” : “2004” }, “title” : “Shift work. Information sheet”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=dee6b7cd-505a-49c0-b480-888861aa7564” } , “mendeley” : { “formattedCitation” : “(;b;;b;International Labor Office (ILO);/b;;/b;, ;b;2004;/b;)”, “manualFormatting” : “(ILO, 2004)”, “plainTextFormattedCitation” : “(International Labor Office (ILO), 2004)”, “previouslyFormattedCitation” : “(;b;;b;International Labor Office (ILO);/b;;/b;, ;b;2004;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(ILO, 2004).
According to the European Directive (2003/88/EC of 4 November 2003), Shift work means “any method of organizing work in shifts whereby workers succeed each other at the same work stations according to a certain pattern, including a rotating pattern, and which may be continuous or discontinuous, entailing the need for workers to work at different times over a given period of days or weeks” ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/978-3-319-42286-2”, “ISBN” : “9783319422862”, “abstract” : “This chapter gives an overview of the health problems associated with shift work, and the main organizational guidelines on how to protect workersu2019 health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general population, involving more and more people in continuous assistance and control of the work processes over the 24 h. The strong increase of epidemiological studies on this issue demonstrates the seriousness of this risk factor for human health and well-being, at both social and psychophysical levels, starting from disruption of biological circadian rhythms and the sleep/wake cycle, ending in several psychosomatic troubles and disorders, probably including cancer, and passing through impairment of performance efficiency and family and social life. 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In 2009 the Australian Fair Work Act defines shift work as “work carried out with consecutive shifts of employees throughout the 24 h of each of at least six consecutive days without interruption except for breakdowns or meal breaks or due to unavoidable causes beyond the control of the employer”. The United States Centers for Disease Control and Prevention (CDC) defines shift work as “working outside the normal daylight hours; that is, outside the hours of around 7 am–6 pm” ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9783319422848”, “abstract” : “The expanding use of shift work throughout the global economy is raising a variety of new questions, including those explored in the current volume. Is shift work an environmental demand that makes u201cbalancingu201d work and family more difficult, or is it a viable tool for alleviating inherent conflicts between work and family life? A casual perusal of the scholarly and popular literature will result in evidence supporting both positions, suggesting there is neither a simple nor a straightforward conclusion. In fact, the many dimensions and contours of u201cshift worku201d demand careful consideration before even attempting to answer the basic question, u201cis shift work a friend or foe of working adultsu2019 ability to meet their responsibilities in the domains of work and family?u201d. The overall goal of this chapter is to create a conceptual foundation for the content of this volume. To achieve this goal the chapter begins by outlining the meaning of u201cshift worku201d and alternative perspectives on combining work and family to help readers see that the concepts are both complex, making their linkages and potential interconnections exceedingly complicated. Next is a critical review of published research linking shift work with individualsu2019 ability to integrate work and family lives to help readers interpret the scientific literature. 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The diverging emphases of all these definitions show one of the complexities of understanding the meaning of shift work; that is the origin of the problem. In the case of the European Union, the ILO, and the Australian Fair Work Commission, the origin of shift work is present in the work itself or the way the work is organized. From the side of these organizations, shift work is a part of the work: although an individual may choose a job that has shift work, shift work is not a personal selection, but rather something that is enforced upon workers. By contrast, the origin of shift work from the U.S. perspective is much vaguer because the definition focuses on when the work is performed. This makes the origin of shift work unclear as it could result from personal preference (for example a mother who works at night so she can be with her children at the daytime), an entrepreneurial trial of one business to get competitive benefit over another, or an obligation of workplace (e.g., hospitals need to provide 24/7 care), or some combinations of all these factors ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9783319422848”, “abstract” : “The expanding use of shift work throughout the global economy is raising a variety of new questions, including those explored in the current volume. Is shift work an environmental demand that makes u201cbalancingu201d work and family more difficult, or is it a viable tool for alleviating inherent conflicts between work and family life? A casual perusal of the scholarly and popular literature will result in evidence supporting both positions, suggesting there is neither a simple nor a straightforward conclusion. In fact, the many dimensions and contours of u201cshift worku201d demand careful consideration before even attempting to answer the basic question, u201cis shift work a friend or foe of working adultsu2019 ability to meet their responsibilities in the domains of work and family?u201d. The overall goal of this chapter is to create a conceptual foundation for the content of this volume. To achieve this goal the chapter begins by outlining the meaning of u201cshift worku201d and alternative perspectives on combining work and family to help readers see that the concepts are both complex, making their linkages and potential interconnections exceedingly complicated. Next is a critical review of published research linking shift work with individualsu2019 ability to integrate work and family lives to help readers interpret the scientific literature. Finally, the chapter concludes with an agenda of high priority future research topics requiring attention to enable appropriate individual and collective responses to expanded reliance on shift work in the 21st century economy.”, “author” : { “dropping-particle” : “”, “family” : “Grzywacz”, “given” : “Joseph G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Social and Family Issues in Shift Work and Non Standard Working Hours”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “137 – 152”, “title” : “Shift Work and Its Implications for everyday Work and Family Life: A foundation and Summary”, “type” : “chapter” }, “uris” : “http://www.mendeley.com/documents/?uuid=4b93c033-889d-46e4-8e31-f99db0d67d50” } , “mendeley” : { “formattedCitation” : “(;b;;b;Grzywacz;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Grzywacz, 2016)”, “previouslyFormattedCitation” : “(;b;;b;Grzywacz;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Grzywacz, 2016).

There are various shift systems adopted worldwide, each may have different impacts on workers’ health, depending on some factors as:
Table I. Factors defining shift type
The duration of the shift period: predominantly from 6 to 8–9 h, but it can be extended to 12 or be reduced to 4 h (in case of part-time work);
The interruption or not on week-end (semi-continuous or continuous systems);
The presence and frequency of working in the night time;
The number of shifts that take place all over the day: mainly 2 (morning and afternoon) or 3 shifts (including the night) of 7–9 h, or 4 shifts of six hours (morning, afternoon, evening, night);
The start and end times of each shift;
The direction of shift rotation: clockwise rotation or phase-delayed (Morning-Afternoon-Night), counter-clockwise rotation or phase-advanced (Afternoon-Morning-Night);
The speed of rotation among the shifts: rapid (every 1–3 days), intermediate (every 4–6 days), slow (7 or more days), null (in case of permanent shifts);
The regularity/irregularity and length of the whole shift cycle (from 5 days cycles up to 6 months cycles or more);
Distribution and number of rest days between shifts.

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Due to these variations there is an almost infinite number of different shift systems in operation and none of them is considered perfect ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789221260608”, “author” : { “dropping-particle” : “”, “family” : “Tucker”, “given” : “Philip”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Folkard”, “given” : “Simon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of Work and employment Series No. 31”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issue” : “31”, “issued” : { “date-parts” : “2012” }, “page” : “1-60”, “publisher” : “ILO”, “publisher-place” : “Geneva”, “title” : “Working time, health and safety: a research synthesis paper”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=a8c421e7-16d1-48bf-a620-7d0e2ba058fb” } , “mendeley” : { “formattedCitation” : “(;b;;b;Tucker;/b; and ;b;Folkard;/b;;/b;, ;b;2012;/b;)”, “plainTextFormattedCitation” : “(Tucker and Folkard, 2012)”, “previouslyFormattedCitation” : “(;b;;b;Tucker;/b; and ;b;Folkard;/b;;/b;, ;b;2012;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Tucker and Folkard, 2012). Despite these variations; some common categories of shift work are recognized including: regular evening schedules (beginning after 3 p.m., ending before midnight), regular night shift (beginning after 11 p.m., ending before 11 a.m.), rotating (day to evening and/or night), split (two or more distinct work periods each day), on call (no pre-arranged schedule), and irregular shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “0840-8750, 0840-8750”, “ISSN” : “08408750”, “PMID” : “47552728”, “abstract” : “More than a quarter of employed Canadians work something other than a regular daytime schedule-regular evenings or nights, rotating or split shifts, casual or on-call jobs or irregular shifts. This article focuses on shift work among full-time workers aged 19 to 64 and looks at where and among whom it is most prevalent. Work-life balance, role overload and other indicators of well-being are also examined. 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Other types of abnormal working schedules include week-end work,, compressed weeks, telework, part-time work, variable/flexible working time, and extended working hours (?12-h shifts) ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/978-3-319-42286-2”, “ISBN” : “9783319422862”, “abstract” : “This chapter gives an overview of the health problems associated with shift work, and the main organizational guidelines on how to protect workersu2019 health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general population, involving more and more people in continuous assistance and control of the work processes over the 24 h. 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The classical work day, starting at 7-8 a.m. ending at 5-6 p.m., Monday to Friday (Sunday to Thursday in Arab countries) , is now a condition affecting a small number of workers, that is 27% of employed and 8% of self-employed people ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/978-3-319-42286-2”, “ISBN” : “9783319422862”, “abstract” : “This chapter gives an overview of the health problems associated with shift work, and the main organizational guidelines on how to protect workersu2019 health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general population, involving more and more people in continuous assistance and control of the work processes over the 24 h. The strong increase of epidemiological studies on this issue demonstrates the seriousness of this risk factor for human health and well-being, at both social and psychophysical levels, starting from disruption of biological circadian rhythms and the sleep/wake cycle, ending in several psychosomatic troubles and disorders, probably including cancer, and passing through impairment of performance efficiency and family and social life. 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Males are involved in shift schedules more than females; this may be related to legal prohibition against night work among females in some countries. Nonetheless, there are substantial numbers of female shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “International Labor Office (ILO)”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “WT- 8”, “issued” : { “date-parts” : “2004” }, “title” : “Shift work. Information sheet”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=dee6b7cd-505a-49c0-b480-888861aa7564” } , “mendeley” : { “formattedCitation” : “(;b;;b;International Labor Office (ILO);/b;;/b;, ;b;2004;/b;)”, “manualFormatting” : “(ILO, 2004)”, “plainTextFormattedCitation” : “(International Labor Office (ILO), 2004)”, “previouslyFormattedCitation” : “(;b;;b;International Labor Office (ILO);/b;;/b;, ;b;2004;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(ILO, 2004). Gender difference may also be attributed to that women have more conflict than men, as they carry more responsibilities for their children in the home compared to men. Data showed that more males than females report incompatibility between their working hours and family life, social activities and other commitments. This is explained in part by a higher proportion of men working long and/or abnormal hours compared to women ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789221264293”, “ISSN” : “22268944”, “author” : { “dropping-particle” : “”, “family” : “Fagan”, “given” : “Colette”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lyonette”, “given” : “Clare”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Smith”, “given” : “Mark”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Saldau00f1a-tejeda”, “given” : “Abril”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Conditions of Work and Employment”, “id” : “ITEM-1”, “issue” : “32”, “issued” : { “date-parts” : “2012” }, “page” : “1-67”, “publisher” : “ILO”, “publisher-place” : “ILO, Geneva”, “title” : “The influence of working time arrangements on work-life integration or u2018 balance u2019: A review of the international evidence”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=3ca70d31-5d1f-4ac8-b99a-a2dbd022830f” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Fagan;/b; et al.;/b;;/b;, ;b;2012;/b;)”, “plainTextFormattedCitation” : “(Fagan et al., 2012)”, “previouslyFormattedCitation” : “(;b;;b;;b;Fagan;/b; et al.;/b;;/b;, ;b;2012;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Fagan et al., 2012).
Shift work is prevalent among both full time and part-time workers in all countries worldwide. Shift work is also more common among workers aged 18-29 years compared to other ages. subjects with a Bachelor’s degree or higher had a decreased tendency to work in shifts compared with workers who were less educated ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “0840-8750, 0840-8750”, “ISSN” : “08408750”, “PMID” : “47552728”, “abstract” : “More than a quarter of employed Canadians work something other than a regular daytime schedule-regular evenings or nights, rotating or split shifts, casual or on-call jobs or irregular shifts. This article focuses on shift work among full-time workers aged 19 to 64 and looks at where and among whom it is most prevalent. Work-life balance, role overload and other indicators of well-being are also examined. Adapted from the source document.”, “author” : { “dropping-particle” : “”, “family” : “Williams”, “given” : “Cara”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Statistics Canada”, “id” : “ITEM-1”, “issue” : “75”, “issued” : { “date-parts” : “2008” }, “page” : “5-16”, “title” : “Work-life balance of shift workers”, “type” : “article-journal”, “volume” : “Catalogue ” }, “uris” : “http://www.mendeley.com/documents/?uuid=8468927c-dbda-4c4a-9cc8-805a73bc6462” } , “mendeley” : { “formattedCitation” : “(;b;;b;Williams;/b;;/b;, ;b;2008;/b;)”, “plainTextFormattedCitation” : “(Williams, 2008)”, “previouslyFormattedCitation” : “(;b;;b;Williams;/b;;/b;, ;b;2008;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Williams, 2008). Some advantages and disadvantages of shift work to each of employers and employee were identified (table II).

Table II. Advantages and disadvantages of shift work
For the employer For the employee
Advantage
More intensive use of facilities and equipment through extended property operating time.

Increase in production to deal with higher demands or to cope with consumable goods.

Effective operation of continuous and semi-continuous production process.

Ideal use of energy or other resources during the night or other slack periods Increase in total earnings where premium wages are paid for certain types of shifts (e.g. night work).

Longer periods of free time if paid time off is granted instead of shift work payments.

May potentially save existing jobs and/or reduce temporary employment
Disadvantage
Additional administrative costs due to having more workers (because more shifts are in operation), higher labor costs due to shift premiums, provision of recreational facilities and training.

Difficulty and complexity of ensuring adequate supervision, especially at night.

Potential negative effects on workplace safety and health, especially at night. Potential negative effects on workers’ health and safety, especially where night work is involved. These potential effects include disruption of sleep, increased fatigue, cardiovascular and gastro-intestinal troubles, effects on reproductive health, increased risk of breast cancer (for women on night shifts).

Disruption of workers’ family and social life, especially due to “unsocial” and irregular hours of work.

Difficulties in transport to and from work, especially for night workers.

Work intensification, for example, through the suppression of breaks.

Reduced access to training or other opportunities for workers on non-day shifts.

(ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “International Labor Office (ILO)”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “WT- 8”, “issued” : { “date-parts” : “2004” }, “title” : “Shift work. Information sheet”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=dee6b7cd-505a-49c0-b480-888861aa7564” } , “mendeley” : { “formattedCitation” : “(;b;;b;International Labor Office (ILO);/b;;/b;, ;b;2004;/b;)”, “manualFormatting” : “ILO, 2004)”, “plainTextFormattedCitation” : “(International Labor Office (ILO), 2004)”, “previouslyFormattedCitation” : “(;b;;b;International Labor Office (ILO);/b;;/b;, ;b;2004;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }ILO, 2004).

Accurate data on the number of workers involved in shift work is difficult to collect due to the lack of accurate and updated statistics in many countries and due to differences in methods of data collection ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Shift work is a necessity for many organizations. Reasons for shift work are mainly to ensure continuous and optimized operations. Many studies on shift workers have concluded that it can lead to adverse physiological, social and psychological health effects. This study examines challenges associated with working shifts at a biscuits manufacturing factory. Results should be able to assist the employer in implementing effective interventions directed at limiting the negative effects of shift work on employees. This is a convergent parallel design multi method stud among 152 shift workers in a biscuits manufacturer located in Durban, KwaZulu Natal. An abbreviated and modified form of the validated SSI questionnaire was used (Barton et al. 1995). The questionnaire contained a battery of items designed to examine the relationship of health and personal adjustment to shift work. Owing to the exploratory nature of the study, a focus group methodology was also used and this allowed for in-depth qualitative research which catered for a more comprehensive understanding of the current shift work issues. A retrospective review of injury records of employees who sustained occupational injuries between 2012 and 2013 was also conducted. The sample comprised of 85 (56%) males and 63 (42%) females. Logistic regression was used to estimate the association between shift work and the likelihood of sleep disturbance, poor health outcomes and limited time for social and domestic activities, adjusting for age, sex, partner working, years working night shift, marital status, job class and years employed. Odds ratio (OR) for reported sleep disturbance was slightly higher among women (OR=1.65; 95% CI = 0.25; 10.84; p ; 0.05) compared to males, but this was not statistically significant. Longer shift work experience (i.e.11-20 years) was significantly associated with better health status (OR=0.18; 95%CI = 0.06; 0.46; p ; 0.05). Shift work experience (11 to 20 years) was also found to be significantly associated with limited time for both social (OR = 0.10; 95%CI = 0.03; 0.30) and domestic activities (OR= 0.25; 95% CI = 0.11; 0.57; p ; 0.05) (Table 4). Age had no effect on social and domestic activities, but those 40 years and above were more likely to have limited time for social and domestic activities (OR = iii 3.06; 95%CI =0.60; 15.60 and OR= 2.5; 95%CI=0.47; 13.06). Those with more shift work experience seemed to have more time for social and domestic activities compared to u2026”, “author” : { “dropping-particle” : “”, “family” : “Mhlongo”, “given” : “Philisiwe Kenlly (Faculty of Health Sciences)”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “publisher” : “Durban University of Technology”, “title” : “Adverse effects of shift work at a biscuits manufacturer”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=9f8d9a5d-5a0a-461e-ab55-2592866888e6” } , “mendeley” : { “formattedCitation” : “(;b;;b;Mhlongo;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Mhlongo, 2016)”, “previouslyFormattedCitation” : “(;b;;b;Mhlongo;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mhlongo, 2016). It is estimated that 20 – 25 % of total active adult population are working partly or entirely in rotating shifts or during the night and the prevalence is growing ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.2478/v10001-010-0032-5”, “ISBN” : “1896-494X (Electronic)
1232-1087 (Linking)”, “ISSN” : “1232-1087”, “PMID” : “20934953”, “abstract” : “Shift work is affecting 20% to 25% employees and is becoming increasingly prevalent in contemporary life all over Europe and USA. It is associated with several health problems, such as e.g. metabolic syndrome, diabetes mellitus and cardiovascular disease. These diseases are possibly due to an impairment of biological rhythm. The metabolic syndrome is a complex of interrelated risk factors for cardiovascular disease and diabetes. Higher prevalence of the metabolic syndrome has been demonstrated among shift workers. Rotating shift work has an impact on each component of metabolic syndrome. Shift work might also have an impact on metabolic variables, and be a risk factor for type 2 diabetes. Only a few studies reported prevalence of impaired glucose metabolism and diabetes mellitus in relation to shift work. There is rather strong evidence in favour of association between shift work and coronary heart disease and that has been repeatedly demonstrated during over 20 years of research. Recent data increasingly reveal relations between shift work and plasma resistin, ghrelin, leptin and adiponectin.”, “author” : { “dropping-particle” : “”, “family” : “Szosland”, “given” : “Dorota”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International journal of occupational medicine and environmental health”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2010” }, “page” : “287-291”, “title” : “Shift work and metabolic syndrome, diabetes mellitus and ischaemic heart disease.”, “type” : “article-journal”, “volume” : “23” }, “uris” : “http://www.mendeley.com/documents/?uuid=c485a9ce-ceac-4e28-96b5-1899fda4f022” } , “mendeley” : { “formattedCitation” : “(;b;;b;Szosland;/b;;/b;, ;b;2010;/b;)”, “plainTextFormattedCitation” : “(Szosland, 2010)”, “previouslyFormattedCitation” : “(;b;;b;Szosland;/b;;/b;, ;b;2010;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Szosland, 2010). In Australia the percent is lower where 16 % of working population worked in shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5694/mja13.10561”, “ISBN” : “1326-5377 (Electronic) 0025-729X (Linking)”, “ISSN” : “13265377”, “PMID” : “24138359”, “abstract” : “About 1.5 million Australians are shift workers. Shift work is associated with adverse health, safety and performance outcomes. Circadian rhythm misalignment, inadequate and poor-quality sleep, and sleep disorders such as sleep apnoea, insomnia and shift work disorder (excessive sleepiness and/or insomnia temporally associated with the work schedule) contribute to these associations. Falling asleep at work at least once a week occurs in 32%-36% of shift workers. Risk of occupational accidents is at least 60% higher for non-day shift workers. Shift workers also have higher rates of cardiometabolic diseases and mood disturbances. Road and workplace accidents related to excessive sleepiness, to which shift work is a significant contributor, are estimated to cost $71-$93 billion per annum in the United States. There is growing evidence that understanding the interindividual variability in sleep-wake responses to shift work will help detect and manage workers vulnerable to the health consequences of shift work. A range of approaches can be used to enhance alertness in shift workers, including screening and treating sleep disorders, melatonin treatment to promote sleep during the daytime, and avoidance of inappropriate use of sedatives and wakefulness-promoters such as modafinil and caffeine. Short naps, which minimise sleep inertia, are generally effective. Shifting the circadian pacemaker with appropriately timed melatonin and/or bright light may be used to facilitate adjustment to a shift work schedule in some situations, such as a long sequence of night work. It is important to manage the health risk of shift workers by minimising vascular risk factors through dietary and other lifestyle approaches.”, “author” : { “dropping-particle” : “”, “family” : “Rajaratnam”, “given” : “Shantha M.W.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Howard”, “given” : “Mark E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Grunstein”, “given” : “Ronald R.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Medical Journal of Australia”, “id” : “ITEM-1”, “issue” : “8”, “issued” : { “date-parts” : “2013” }, “page” : “S11-S15”, “title” : “Sleep loss and circadian disruption in shift work: Health burden and management”, “type” : “article-journal”, “volume” : “199” }, “uris” : “http://www.mendeley.com/documents/?uuid=6d0df266-f302-4f0d-97e5-898bfb2636d4” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Rajaratnam;/b; et al.;/b;;/b;, ;b;2013;/b;)”, “plainTextFormattedCitation” : “(Rajaratnam et al., 2013)”, “previouslyFormattedCitation” : “(;b;;b;;b;Rajaratnam;/b; et al.;/b;;/b;, ;b;2013;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Rajaratnam et al., 2013). In the Western countries, it is estimated to be 20% of workers are involved in shift work ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.smrv.2016.06.009”, “ISBN” : “1532-2955 (Electronic)\r1087-0792 (Linking)”, “ISSN” : “15322955”, “PMID” : “27568341”, “abstract” : “Prevalence and impact of metabolic disease is rising. In particular, overweight and obesity are at epidemic levels and are a leading health concern in the Western world. Shift work increases the risk of overweight and obesity, along with a number of additional metabolic diseases, including metabolic syndrome and type 2 diabetes (T2D). How shift work contributes to metabolic disease has not been fully elucidated. Short sleep duration is associated with metabolic disease and shift workers typically have shorter sleep durations. Short sleep durations have been shown to elicit a physiological stress response, and both physiological and psychological stress disrupt the healthy functioning of the intestinal gut microbiota. Recent findings have shown altered intestinal microbial communities and dysbiosis of the gut microbiota in circadian disrupted mice and jet lagged humans. We hypothesize that sleep and circadian disruption in humans alters the gut microbiota, contributing to an inflammatory state and metabolic disease associated with shift work. A research agenda for exploring the relationship between insufficient sleep, circadian misalignment and the gut microbiota is provided.”, “author” : { “dropping-particle” : “”, “family” : “Reynolds”, “given” : “Amy C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Paterson”, “given” : “Jessica L.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ferguson”, “given” : “Sally A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Stanley”, “given” : “Dragana”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Wright”, “given” : “Kenneth P.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dawson”, “given” : “Drew”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine Reviews”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2017” }, “page” : “3-9”, “publisher” : “Elsevier Ltd”, “title” : “The shift work and health research agenda: Considering changes in gut microbiota as a pathway linking shift work, sleep loss and circadian misalignment, and metabolic disease”, “type” : “article-journal”, “volume” : “34” }, “uris” : “http://www.mendeley.com/documents/?uuid=4bf3cfc7-38e5-4963-9b16-c51adfff12e0” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Reynolds;/b; et al.;/b;;/b;, ;b;2017;/b;)”, “plainTextFormattedCitation” : “(Reynolds et al., 2017)”, “previouslyFormattedCitation” : “(;b;;b;;b;Reynolds;/b; et al.;/b;;/b;, ;b;2017;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Reynolds et al., 2017). Data from Statistics Canada’s General Social Survey showed that in Canada in 2005 25.5% of full-time workers aged 19-64 years worked shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “0840-8750, 0840-8750”, “ISSN” : “08408750”, “PMID” : “47552728”, “abstract” : “More than a quarter of employed Canadians work something other than a regular daytime schedule-regular evenings or nights, rotating or split shifts, casual or on-call jobs or irregular shifts. This article focuses on shift work among full-time workers aged 19 to 64 and looks at where and among whom it is most prevalent. Work-life balance, role overload and other indicators of well-being are also examined. Adapted from the source document.”, “author” : { “dropping-particle” : “”, “family” : “Williams”, “given” : “Cara”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Statistics Canada”, “id” : “ITEM-1”, “issue” : “75”, “issued” : { “date-parts” : “2008” }, “page” : “5-16”, “title” : “Work-life balance of shift workers”, “type” : “article-journal”, “volume” : “Catalogue ” }, “uris” : “http://www.mendeley.com/documents/?uuid=8468927c-dbda-4c4a-9cc8-805a73bc6462” } , “mendeley” : { “formattedCitation” : “(;b;;b;Williams;/b;;/b;, ;b;2008;/b;)”, “plainTextFormattedCitation” : “(Williams, 2008)”, “previouslyFormattedCitation” : “(;b;;b;Williams;/b;;/b;, ;b;2008;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Williams, 2008). The highest percentage was among Americans where 29% of workers in the Unites States of America (USA) worked in alternating shifts as shown in data from the National Health Interview Survey Occupational Health Survey (2010) ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1002/ajim.22108”, “ISBN” : “0000000000000”, “ISSN” : “02713586”, “PMID” : “22911666”, “abstract” : “BACKGROUND Surveillance is needed to capture work organization characteristics and to identify their trends. METHODS Data from the 2010 National Health Interview Survey (NHIS) were used to calculate prevalence rates for four work organization characteristics (long work hours, non-standard work arrangements, temporary positions, and alternative shifts) overall, and by demographic characteristics, and industry and occupation of current/recent employment. RESULTS Data were available for 27,157 adults, of which 65% were current/recent workers. Among adults who worked in the past 12 months, 18.7% worked 48 hr or more per week, 7.2% worked 60 hr or more per week, 18.7% had non-standard work arrangements, 7.2% were in temporary positions, and 28.7% worked an alternative shift. CONCLUSIONS Prevalence rates of work organization characteristics are provided. These national estimates can be used to help occupational health professionals and employers to identify emerging occupational safety and health risks, allow researchers to examine associations with health, and use the data for benchmarking.”, “author” : { “dropping-particle” : “”, “family” : “Alterman”, “given” : “Toni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Luckhaupt”, “given” : “Sara E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dahlhamer”, “given” : “James M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ward”, “given” : “Brian W.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Calvert”, “given” : “Geoffrey M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “American Journal of Industrial Medicine”, “id” : “ITEM-1”, “issue” : “6”, “issued” : { “date-parts” : “2013” }, “page” : “647-659”, “title” : “Prevalence rates of work organization characteristics among workers in the U.S.: Data from the 2010 National Health Interview Survey”, “type” : “article-journal”, “volume” : “56” }, “uris” : “http://www.mendeley.com/documents/?uuid=c6323afa-28b2-4196-8f80-63fb8cedbda2” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Alterman;/b; et al.;/b;;/b;, ;b;2013;/b;)”, “plainTextFormattedCitation” : “(Alterman et al., 2013)”, “previouslyFormattedCitation” : “(;b;;b;;b;Alterman;/b; et al.;/b;;/b;, ;b;2013;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Alterman et al., 2013).
Occupations at Risk
Different types of occupations are engaged in shift work. Research showed that almost half of protective services (police, security and fire fighters) and food service workers work outside conventional hours and more than 25% of the transportation industry (train and bus drivers, truck drivers, pilots etc.) and healthcare (nurses, doctors, support staff) employees work shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Shift work is a necessity for many organizations. Reasons for shift work are mainly to ensure continuous and optimized operations. Many studies on shift workers have concluded that it can lead to adverse physiological, social and psychological health effects. This study examines challenges associated with working shifts at a biscuits manufacturing factory. Results should be able to assist the employer in implementing effective interventions directed at limiting the negative effects of shift work on employees. This is a convergent parallel design multi method stud among 152 shift workers in a biscuits manufacturer located in Durban, KwaZulu Natal. An abbreviated and modified form of the validated SSI questionnaire was used (Barton et al. 1995). The questionnaire contained a battery of items designed to examine the relationship of health and personal adjustment to shift work. Owing to the exploratory nature of the study, a focus group methodology was also used and this allowed for in-depth qualitative research which catered for a more comprehensive understanding of the current shift work issues. A retrospective review of injury records of employees who sustained occupational injuries between 2012 and 2013 was also conducted. The sample comprised of 85 (56%) males and 63 (42%) females. Logistic regression was used to estimate the association between shift work and the likelihood of sleep disturbance, poor health outcomes and limited time for social and domestic activities, adjusting for age, sex, partner working, years working night shift, marital status, job class and years employed. Odds ratio (OR) for reported sleep disturbance was slightly higher among women (OR=1.65; 95% CI = 0.25; 10.84; p ; 0.05) compared to males, but this was not statistically significant. Longer shift work experience (i.e.11-20 years) was significantly associated with better health status (OR=0.18; 95%CI = 0.06; 0.46; p ; 0.05). Shift work experience (11 to 20 years) was also found to be significantly associated with limited time for both social (OR = 0.10; 95%CI = 0.03; 0.30) and domestic activities (OR= 0.25; 95% CI = 0.11; 0.57; p ; 0.05) (Table 4). Age had no effect on social and domestic activities, but those 40 years and above were more likely to have limited time for social and domestic activities (OR = iii 3.06; 95%CI =0.60; 15.60 and OR= 2.5; 95%CI=0.47; 13.06). Those with more shift work experience seemed to have more time for social and domestic activities compared to u2026”, “author” : { “dropping-particle” : “”, “family” : “Mhlongo”, “given” : “Philisiwe Kenlly (Faculty of Health Sciences)”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “publisher” : “Durban University of Technology”, “title” : “Adverse effects of shift work at a biscuits manufacturer”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=9f8d9a5d-5a0a-461e-ab55-2592866888e6” } , “mendeley” : { “formattedCitation” : “(;b;;b;Mhlongo;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Mhlongo, 2016)”, “previouslyFormattedCitation” : “(;b;;b;Mhlongo;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mhlongo, 2016).

Figure I. Occupations with large frequency of shift workers (adopted from ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Shift work is a necessity for many organizations. Reasons for shift work are mainly to ensure continuous and optimized operations. Many studies on shift workers have concluded that it can lead to adverse physiological, social and psychological health effects. This study examines challenges associated with working shifts at a biscuits manufacturing factory. Results should be able to assist the employer in implementing effective interventions directed at limiting the negative effects of shift work on employees. This is a convergent parallel design multi method stud among 152 shift workers in a biscuits manufacturer located in Durban, KwaZulu Natal. An abbreviated and modified form of the validated SSI questionnaire was used (Barton et al. 1995). The questionnaire contained a battery of items designed to examine the relationship of health and personal adjustment to shift work. Owing to the exploratory nature of the study, a focus group methodology was also used and this allowed for in-depth qualitative research which catered for a more comprehensive understanding of the current shift work issues. A retrospective review of injury records of employees who sustained occupational injuries between 2012 and 2013 was also conducted. The sample comprised of 85 (56%) males and 63 (42%) females. Logistic regression was used to estimate the association between shift work and the likelihood of sleep disturbance, poor health outcomes and limited time for social and domestic activities, adjusting for age, sex, partner working, years working night shift, marital status, job class and years employed. Odds ratio (OR) for reported sleep disturbance was slightly higher among women (OR=1.65; 95% CI = 0.25; 10.84; p ; 0.05) compared to males, but this was not statistically significant. Longer shift work experience (i.e.11-20 years) was significantly associated with better health status (OR=0.18; 95%CI = 0.06; 0.46; p ; 0.05). Shift work experience (11 to 20 years) was also found to be significantly associated with limited time for both social (OR = 0.10; 95%CI = 0.03; 0.30) and domestic activities (OR= 0.25; 95% CI = 0.11; 0.57; p ; 0.05) (Table 4). Age had no effect on social and domestic activities, but those 40 years and above were more likely to have limited time for social and domestic activities (OR = iii 3.06; 95%CI =0.60; 15.60 and OR= 2.5; 95%CI=0.47; 13.06). Those with more shift work experience seemed to have more time for social and domestic activities compared to u2026”, “author” : { “dropping-particle” : “”, “family” : “Mhlongo”, “given” : “Philisiwe Kenlly (Faculty of Health Sciences)”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “publisher” : “Durban University of Technology”, “title” : “Adverse effects of shift work at a biscuits manufacturer”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=9f8d9a5d-5a0a-461e-ab55-2592866888e6” } , “mendeley” : { “formattedCitation” : “(;b;;b;Mhlongo;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Mhlongo, 2016)”, “previouslyFormattedCitation” : “(;b;;b;Mhlongo;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mhlongo, 2016).

Characteristics and Arrangements
Work pattern
Different aspects related to work pattern may affect the impact of shift work on health as the configuration of shift length and shift cycle, the direction of shift rotation, the speed of shift rotation, and the positioning of off days. Each of these criteria is illustrated in the normal or regular work schedule; that is, an 8-h period beginning around 8 am and ending around 5 pm spanning Monday through Friday (Sunday through Thursday in Arab countries) that does not change (so no shift rotation, consequently no variability in speed of shift change). Deviations from this standard along any dimension have been labeled “nonstandard”, ” irregular”, “abnormal:, “atypical”, and “unsocial” ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9783319422848”, “abstract” : “The expanding use of shift work throughout the global economy is raising a variety of new questions, including those explored in the current volume. Is shift work an environmental demand that makes u201cbalancingu201d work and family more difficult, or is it a viable tool for alleviating inherent conflicts between work and family life? A casual perusal of the scholarly and popular literature will result in evidence supporting both positions, suggesting there is neither a simple nor a straightforward conclusion. In fact, the many dimensions and contours of u201cshift worku201d demand careful consideration before even attempting to answer the basic question, u201cis shift work a friend or foe of working adultsu2019 ability to meet their responsibilities in the domains of work and family?u201d. The overall goal of this chapter is to create a conceptual foundation for the content of this volume. To achieve this goal the chapter begins by outlining the meaning of u201cshift worku201d and alternative perspectives on combining work and family to help readers see that the concepts are both complex, making their linkages and potential interconnections exceedingly complicated. Next is a critical review of published research linking shift work with individualsu2019 ability to integrate work and family lives to help readers interpret the scientific literature. Finally, the chapter concludes with an agenda of high priority future research topics requiring attention to enable appropriate individual and collective responses to expanded reliance on shift work in the 21st century economy.”, “author” : { “dropping-particle” : “”, “family” : “Grzywacz”, “given” : “Joseph G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Social and Family Issues in Shift Work and Non Standard Working Hours”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “137 – 152”, “title” : “Shift Work and Its Implications for everyday Work and Family Life: A foundation and Summary”, “type” : “chapter” }, “uris” : “http://www.mendeley.com/documents/?uuid=4b93c033-889d-46e4-8e31-f99db0d67d50” } , “mendeley” : { “formattedCitation” : “(<b><b>Grzywacz</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Grzywacz, 2016)”, “previouslyFormattedCitation” : “(<b><b>Grzywacz</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Grzywacz, 2016).

The first aspect related to work pattern is whether the shift schedule is a rotating or permanent one. It was reported that complete adaptation of the circadian pacemaker to night shift work would only occur in a small percentage (3%) of workers even if they work on a permanent night shift schedule. A partial entrainment to night work would occurs in about 25% of this population while the majority (72%) would not show any form of circadian adaptation ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.patbio.2014.08.001”, “ISBN” : “0369-8114”, “ISSN” : “17683114”, “PMID” : “25246026”, “abstract” : “Shift work comprises work schedules that extend beyond the typical “nine-to-five” workday, wherein schedules often comprise early work start, compressed work weeks with 12-hour shifts, and night work. According to recent American and European surveys, between 15 and 30% of adult workers are engaged in some type of shift work, with 19% of the European population reportedly working at least 2. hours between 22:00 and 05:00. The 2005 International Classification of Sleep Disorders estimates that a shift work sleep disorder can be found in 2-5% of workers. This disorder is characterized by excessive sleepiness and/or sleep disruption for at least one month in relation with the atypical work schedule. Individual tolerance to shift work remains a complex problem that is affected by the number of consecutive work hours and shifts, the rest periods, and the predictability of work schedules. Sleepiness usually occurs during night shifts and is maximal at the end of the night. Impaired vigilance and performance occur around times of increased sleepiness and can seriously compromise workers’ health and safety. Indeed, workers suffering from a shift work sleep-wake disorder can fall asleep involuntarily at work or while driving back home after a night shift. Working on atypical shifts has important socioeconomic impacts as it leads to an increased risk of accidents, workers’ impairment and danger to public safety, especially at night. The aim of the present review is to review the circadian and sleep-wake disturbances associated with shift work as well as their medical impacts.”, “author” : { “dropping-particle” : “”, “family” : “Boivin”, “given” : “D. B.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Boudreau”, “given” : “P.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Pathologie Biologie”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2014” }, “page” : “292-301”, “publisher” : “Elsevier Masson SAS”, “title” : “Impacts of shift work on sleep and circadian rhythms”, “type” : “article-journal”, “volume” : “62” }, “uris” : “http://www.mendeley.com/documents/?uuid=d45033ec-093d-441f-b9a3-4e57740cfaa2” } , “mendeley” : { “formattedCitation” : “(<b><b>Boivin</b> and <b>Boudreau</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Boivin and Boudreau, 2014)”, “previouslyFormattedCitation” : “(<b><b>Boivin</b> and <b>Boudreau</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Boivin and Boudreau, 2014).
A basic factor working against adaption to a nocturnal routine is that employees tend to return to a diurnal routine on their off days, reversing the process of circadian adaptation and resulting in workers having to start adaptation all over again after even just a few days off. Regarding workers on rotating schedules circadian adaptation to a nocturnal routine on the night shift possibly occurs very slowly, if at all occurred. No clear evidence exist showing that permanent night work is more beneficial than the rotating system. However, permanent night schedule may be good for individuals who have a late circadian phase and the readiness and possibility to live in a night-oriented rhythm also during days off ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.2900”, “ISBN” : “1795-990X (Electronic)\n0355-3140 (Linking)”, “ISSN” : “1795990X”, “PMID” : “20119631”, “abstract” : “In this narrative review, we examined what level of research evidence is available that shift workers’ sleep-wake disturbances can be minimized through ergonomic shift scheduling. We classified the pertinent studies conducted on real shift workers in field conditions by the type of shift system and study design (ie, whether the shift systems were modified or not – “treatment” versus “no treatment”). The results of the observational studies in which no changes to the shift system were made (ie, no treatment) showed that, irrespective of the shift system, night and early-morning shifts and quick returns are associated with short sleep and increases in sleepiness. The same is true for very long shifts (>16 hours) and extremely long weekly working hours (>55 hours). For all categories of shift systems, there was a lack of controlled intervention studies, limiting the possibility to provide solution-focused recommendations for shift scheduling. Most of the controlled intervention studies had been conducted on workers under regular 3-shift systems. These studies suggested that a change from slowly backward-rotating shifts to rapidly forward-rotating shifts is advantageous for alertness and, to some degree, sleep. We also found that a change from an 8- to 12-hour shift system does not necessarily result in impairments in the sleep-wake pattern. The level of research evidence was affected by many of the studies’ frequent methodological limitations in measuring sleep and sleepiness. In all, to have reliable and solution-focused recommendations for shift scheduling, methodologically sound controlled intervention studies are required in different categories of shift systems.”, “author” : { “dropping-particle” : “”, “family” : “Sallinen”, “given” : “Mikael”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kecklund”, “given” : “Gu00f6ran”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “121-133”, “title” : “Shift work, sleep, and sleepiness – Differences between shift schedules and systems”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=55be0f6f-5407-4f42-a8c1-39af2e9107c2” } , “mendeley” : { “formattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Sallinen and Kecklund, 2010)”, “previouslyFormattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Sallinen and Kecklund, 2010).

Speed of rotation means “the number of shifts of one type that are worked before the worker either changes to another type of shift or takes a day off”. Most research findings tend to prefer very rapidly rotating shift systems (i.e. ones that involve working 1 to 3 consecutive shifts of the same type) over more slowly rotating ones ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.2900”, “ISBN” : “1795-990X (Electronic)\n0355-3140 (Linking)”, “ISSN” : “1795990X”, “PMID” : “20119631”, “abstract” : “In this narrative review, we examined what level of research evidence is available that shift workers’ sleep-wake disturbances can be minimized through ergonomic shift scheduling. We classified the pertinent studies conducted on real shift workers in field conditions by the type of shift system and study design (ie, whether the shift systems were modified or not – “treatment” versus “no treatment”). The results of the observational studies in which no changes to the shift system were made (ie, no treatment) showed that, irrespective of the shift system, night and early-morning shifts and quick returns are associated with short sleep and increases in sleepiness. The same is true for very long shifts (>16 hours) and extremely long weekly working hours (>55 hours). For all categories of shift systems, there was a lack of controlled intervention studies, limiting the possibility to provide solution-focused recommendations for shift scheduling. Most of the controlled intervention studies had been conducted on workers under regular 3-shift systems. These studies suggested that a change from slowly backward-rotating shifts to rapidly forward-rotating shifts is advantageous for alertness and, to some degree, sleep. We also found that a change from an 8- to 12-hour shift system does not necessarily result in impairments in the sleep-wake pattern. The level of research evidence was affected by many of the studies’ frequent methodological limitations in measuring sleep and sleepiness. In all, to have reliable and solution-focused recommendations for shift scheduling, methodologically sound controlled intervention studies are required in different categories of shift systems.”, “author” : { “dropping-particle” : “”, “family” : “Sallinen”, “given” : “Mikael”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kecklund”, “given” : “Gu00f6ran”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “121-133”, “title” : “Shift work, sleep, and sleepiness – Differences between shift schedules and systems”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=55be0f6f-5407-4f42-a8c1-39af2e9107c2” } , “mendeley” : { “formattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Sallinen and Kecklund, 2010)”, “previouslyFormattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Sallinen and Kecklund, 2010). On the contrary, undesirable effects related to the number of mistakes, reaction time and concentration are most obvious in relation to the 1st to 3rd night shift, after which some adaptation to the night shift occurs. Sleep duration in between night shifts tend to increase with the number of consecutive nights. Thus there are sufficient causes to encourage the employees to work many consecutive nights in order to allow adaptation and thereby less turns in circadian rhythms because this may decrease the risk of accidents and increase overall sleep length ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1136/oem.60.11.e13”, “ISBN” : “1470-7926 (Electronic)\r1351-0711 (Linking)”, “ISSN” : “1351-0711”, “PMID” : “14573724”, “abstract” : “AIMS: To investigate factors that may contribute to performance adaptation during permanent night work. METHODS: Fifteen healthy subjects participated in an adaptation and baseline night sleep, directly followed by seven simulated eight-hour night shifts (2300 to 0700 hours). At the end of each shift they were taken outside and exposed to natural light for 20 minutes. They then slept from approximately 0800 hours until they naturally awoke. RESULTS: There was a significant increase in mean performance on a visual psychomotor vigilance task across the week. Daytime sleep quality and quantity were not negatively affected. Total sleep time (TST) for each of the daytime sleeps was reduced, resulting in an average cumulative sleep debt of 3.53 hours prior to the final night shift. TST for each of the daytime sleep periods did not significantly differ from the baseline night, nor did TST significantly vary across the week. There was a significant decrease in wake time after sleep onset and sleep onset latency across the week; sleep efficiency showed a trend towards greater efficiency across the consecutive daytime sleeps. Hours of wakefulness prior to each simulated night shift significantly varied across the week. The melatonin profile significantly shifted across the week. CONCLUSIONS: Results suggest that under optimal conditions, the sleep debt that accumulates during consecutive night shifts is relatively small and does not exacerbate decrements in night-time performance resulting from other factors. When sleep loss is minimised, adaptation of performance during consecutive night shifts can occur in conjunction with circadian adaptation.”, “author” : { “dropping-particle” : “”, “family” : “Lamond”, “given” : “N”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dorrian”, “given” : “J”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Roach”, “given” : “G D”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “McCulloch”, “given” : “K”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Holmes”, “given” : “a L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Burgess”, “given” : “H J”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fletcher”, “given” : “a”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dawson”, “given” : “D”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “11”, “issued” : { “date-parts” : “2003” }, “page” : “e13”, “title” : “The impact of a week of simulated night work on sleep, circadian phase, and performance.”, “type” : “article-journal”, “volume” : “60” }, “uris” : “http://www.mendeley.com/documents/?uuid=5f9b1937-3eb9-4531-9b35-73b91c31e71f” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Lamond</b> et al.</b></b>, <b>2003</b>)”, “plainTextFormattedCitation” : “(Lamond et al., 2003)”, “previouslyFormattedCitation” : “(<b><b><b>Lamond</b> et al.</b></b>, <b>2003</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Lamond et al., 2003).
However, the opposite suggestion that the number of consecutive nights should be as few as possible also has solid reasoning which is, negative metabolic effects start to appear after just one day without sleep. Other studies showed that sleep deprivation is accumulated, and that the circadian rhythms are displaced more. Slowly rotating shifts workers are more likely to experience significant circadian disruption, such that their circadian rhythms remain in a condition that is neither fully diurnal nor nocturnal, and therefore suffer disturbed sleep between shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1677/JOE-10-0077”, “ISBN” : “1479-6805 (Electronic)\r0022-0795 (Linking)”, “ISSN” : “00220795”, “PMID” : “20479040”, “abstract” : “Epidemiological studies have shown that shift workers are at a greater risk of developing cardiovascular disease which may, in part, be related to metabolic and hormonal changes. Partial sleep deprivation, a common consequence of rotating shift work, has been shown to affect glucose tolerance and insulin sensitivity. The current study investigated the effects of one night of total sleep deprivation, as a proxy for the first night shift, on postprandial glucose, insulin and lipid (triacylglycerols (TAGs) and non-esterified fatty acids (NEFAs)) responses under controlled laboratory conditions in shift workers and non-shift workers. Eleven experienced shift workers (35.7+/-7.2 years, mean+/-s.d.) who had worked in shifts for 8.7+/-5.25 years were matched with 13 non-shift workers who had worked for 32.8+/-6.4 years. After an adaptation night and a baseline sleep night, volunteers were kept awake for 30.5 h, followed by a nap (4 h) and recovery sleep. Blood samples were taken prior to and after a standard breakfast following baseline sleep, total sleep deprivation and recovery sleep. Basal TAG levels prior to the standard breakfast were significantly lower after sleep deprivation, indicating higher energy expenditure. Basal NEFA levels were significantly lower after recovery sleep. Postprandial insulin and TAG responses were significantly increased, and the NEFA response was decreased after recovery sleep, suggestive of insulin insensitivity. Although there were no overall significant differences between non-shift workers and shift workers, non-shift workers showed significantly higher basal insulin levels, lower basal NEFA levels, and an increased postprandial insulin and a decreased NEFA response after recovery sleep. In future, the reasons for these inter-group differences are to be investigated.”, “author” : { “dropping-particle” : “”, “family” : “Wehrens”, “given” : “Sophie M T”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hampton”, “given” : “Shelagh M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Finn”, “given” : “Rebecca E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Skene”, “given” : “Debra J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Endocrinology”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “205-215”, “title” : “Effect of total sleep deprivation on postprandial metabolic and insulin responses in shift workers and non-shift workers”, “type” : “article-journal”, “volume” : “206” }, “uris” : “http://www.mendeley.com/documents/?uuid=0d1650c2-a2c0-4619-a75a-9dcad778ec40” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Wehrens</b> et al.</b></b>, <b>2010</b>)”, “manualFormatting” : “(Wehrens et al., 2010”, “plainTextFormattedCitation” : “(Wehrens et al., 2010)”, “previouslyFormattedCitation” : “(<b><b><b>Wehrens</b> et al.</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Wehrens et al., 2010;ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9788790416607”, “author” : { “dropping-particle” : “”, “family” : “Jensen”, “given” : “Marie Aarrebo (Faculty of Health and Medical Sciences)”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “August”, “issued” : { “date-parts” : “2015” }, “number-of-pages” : “1 – 61”, “publisher” : “University of Copenhagen”, “title” : “working in the middle of the night.the physioogical effects of consecutive night shifts”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=9f419dea-c5b6-44ff-b45a-81bd0427b505” } , “mendeley” : { “formattedCitation” : “(<b><b>Jensen</b></b>, <b>2015</b>)”, “manualFormatting” : ” Jensen, 2015)”, “plainTextFormattedCitation” : “(Jensen, 2015)”, “previouslyFormattedCitation” : “(<b><b>Jensen</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” } Jensen, 2015).
Direction of rotation of rotating shift systems is also considered as an important factor contributing to shift work related problems. On rotating shift systems, shifting from one type of shift to another is followed by changing the timing of sleep and most other daily activity (e.g. meal times). An individual who switches from morning shift (e.g. 6 a.m. to 2 p.m.) to afternoon shifts (e.g. 2 p.m. to 10 p.m.) will probably go to bed and wake later in the day after the switch, while an individual who switches from afternoon to morning shifts will probably go to bed and wake up earlier after the switch ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.1228”, “ISBN” : “0355-3140”, “ISSN” : “03553140”, “PMID” : “18728909”, “abstract” : “OBJECTIVES: A controlled intervention study was conducted to evaluate the effects of two changes in shift characteristics on alertness and cardiovascular risk factors: a change in shift rotation (direction and speed) and a change in the flexibility of the shift system. METHODS: Altogether 84 male workers currently working in a backward-rotating shift system volunteered for the study. A total of 40 men changed to a rapidly forward-rotating shift system, 22 changed to a more flexible shift system, and 22 remained with the old shift system. Health effects were studied with the use of clinical measurements, blood tests, and questionnaires before and after the shift changes. Analyses of variance were used with repeated measures to study associations of cardiovascular risk factors and daytime sleepiness according to the change in shift systems. RESULTS: The mean number of days on which the workers reported sleepiness decreased in the group with the forward-rotating shift system when compared with that of the group on the old shift system (from 2.9 to 2.1 days/week, P=0.02). Systolic blood pressure decreased (from 142 to 136 mm Hg, P=0.049), and heart rate showed a declining trend (from 66 to 60 beats/minute, P=0.06) in the flexible shift system when the three groups were compared. CONCLUSIONS: The study indicates that a faster speed, together with a change to the forward direction, in shift rotation alleviates daytime sleepiness. Combining individual flexibility with company-based flexibility in a shift system may have favorable effects on shift workers’ blood pressure.”, “author” : { “dropping-particle” : “”, “family” : “Viitasalo”, “given” : “Katriina”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kuosma”, “given” : “Eeva”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Laitinen”, “given” : “Jaana”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hu00e4rmu00e4”, “given” : “Mikko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2008” }, “page” : “198-205”, “title” : “Effects of shift rotation and the flexibility of a shift system on daytime alertness and cardiovascular risk factors”, “type” : “article-journal”, “volume” : “34” }, “uris” : “http://www.mendeley.com/documents/?uuid=8430d0dd-2b35-48e8-8e92-6d187140b657” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Viitasalo</b> et al.</b></b>, <b>2008</b>)”, “plainTextFormattedCitation” : “(Viitasalo et al., 2008)”, “previouslyFormattedCitation” : “(<b><b><b>Viitasalo</b> et al.</b></b>, <b>2008</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Viitasalo et al., 2008).
Most people find it easier to delay sleep and waking than to advance them, and this is thought to reflect on the natural affinity of the biological clock to have a cycle slightly longer than 24 hours. So, from a circadian perspective, clockwise or forward rotating shift systems that comprise delaying the timing of one’s rhythms have been suggested to be preferable to anticlockwise or backward rotating ones that involve advancing the timing of circadian rhythms ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.2900”, “ISBN” : “1795-990X (Electronic)\n0355-3140 (Linking)”, “ISSN” : “1795990X”, “PMID” : “20119631”, “abstract” : “In this narrative review, we examined what level of research evidence is available that shift workers’ sleep-wake disturbances can be minimized through ergonomic shift scheduling. We classified the pertinent studies conducted on real shift workers in field conditions by the type of shift system and study design (ie, whether the shift systems were modified or not – “treatment” versus “no treatment”). The results of the observational studies in which no changes to the shift system were made (ie, no treatment) showed that, irrespective of the shift system, night and early-morning shifts and quick returns are associated with short sleep and increases in sleepiness. The same is true for very long shifts (;16 hours) and extremely long weekly working hours (;55 hours). For all categories of shift systems, there was a lack of controlled intervention studies, limiting the possibility to provide solution-focused recommendations for shift scheduling. Most of the controlled intervention studies had been conducted on workers under regular 3-shift systems. These studies suggested that a change from slowly backward-rotating shifts to rapidly forward-rotating shifts is advantageous for alertness and, to some degree, sleep. We also found that a change from an 8- to 12-hour shift system does not necessarily result in impairments in the sleep-wake pattern. The level of research evidence was affected by many of the studies’ frequent methodological limitations in measuring sleep and sleepiness. In all, to have reliable and solution-focused recommendations for shift scheduling, methodologically sound controlled intervention studies are required in different categories of shift systems.”, “author” : { “dropping-particle” : “”, “family” : “Sallinen”, “given” : “Mikael”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kecklund”, “given” : “Gu00f6ran”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “121-133”, “title” : “Shift work, sleep, and sleepiness – Differences between shift schedules and systems”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=55be0f6f-5407-4f42-a8c1-39af2e9107c2” } , “mendeley” : { “formattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Sallinen and Kecklund, 2010)”, “previouslyFormattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Sallinen and Kecklund, 2010).
Starting and ending time of the shift is also an important issue to be considered. Several studies have shown that worker who work on early morning shifts (e.g. starting before 7 a.m.) tend to have shorter sleep duration the night before the shift and are sleepier during the shift. This is apparently because they fail to compensate for an early waking up by going to bed sufficiently early the night before the shift ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.2900”, “ISBN” : “1795-990X (Electronic)\n0355-3140 (Linking)”, “ISSN” : “1795990X”, “PMID” : “20119631”, “abstract” : “In this narrative review, we examined what level of research evidence is available that shift workers’ sleep-wake disturbances can be minimized through ergonomic shift scheduling. We classified the pertinent studies conducted on real shift workers in field conditions by the type of shift system and study design (ie, whether the shift systems were modified or not – “treatment” versus “no treatment”). The results of the observational studies in which no changes to the shift system were made (ie, no treatment) showed that, irrespective of the shift system, night and early-morning shifts and quick returns are associated with short sleep and increases in sleepiness. The same is true for very long shifts (;16 hours) and extremely long weekly working hours (;55 hours). For all categories of shift systems, there was a lack of controlled intervention studies, limiting the possibility to provide solution-focused recommendations for shift scheduling. Most of the controlled intervention studies had been conducted on workers under regular 3-shift systems. These studies suggested that a change from slowly backward-rotating shifts to rapidly forward-rotating shifts is advantageous for alertness and, to some degree, sleep. We also found that a change from an 8- to 12-hour shift system does not necessarily result in impairments in the sleep-wake pattern. The level of research evidence was affected by many of the studies’ frequent methodological limitations in measuring sleep and sleepiness. In all, to have reliable and solution-focused recommendations for shift scheduling, methodologically sound controlled intervention studies are required in different categories of shift systems.”, “author” : { “dropping-particle” : “”, “family” : “Sallinen”, “given” : “Mikael”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kecklund”, “given” : “Gu00f6ran”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “121-133”, “title” : “Shift work, sleep, and sleepiness – Differences between shift schedules and systems”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=55be0f6f-5407-4f42-a8c1-39af2e9107c2” } , “mendeley” : { “formattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Sallinen and Kecklund, 2010)”, “previouslyFormattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Sallinen and Kecklund, 2010).
It might seem to be suitable to delay the start of morning shifts so as to reduce fatigue on that shift. However, if the morning-shift workers are replacing a group of night-shift workers, a considerable delay in the replacement time may cause sleep problems for the night-shift group. Just as morning-shift workers experience difficulty falling asleep in the early evening, so do night-shift workers experience more sleep problems when they try to sleep in the relatively “late” morning, after going back home from the night shift. Taking into consideration the trade-off between the sleep needs of those on the morning and night shifts, a shift change-over time of 7 a.m. has been suggested as an appropriate compromise ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789221260608”, “author” : { “dropping-particle” : “”, “family” : “Tucker”, “given” : “Philip”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Folkard”, “given” : “Simon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of Work and employment Series No. 31”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issue” : “31”, “issued” : { “date-parts” : “2012” }, “page” : “1-60”, “publisher” : “ILO”, “publisher-place” : “Geneva”, “title” : “Working time, health and safety: a research synthesis paper”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=a8c421e7-16d1-48bf-a620-7d0e2ba058fb” } , “mendeley” : { “formattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)”, “plainTextFormattedCitation” : “(Tucker and Folkard, 2012)”, “previouslyFormattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Tucker and Folkard, 2012).

Rest pattern
The basis of minimizing the accumulation of extreme fatigue and other problems of shift work is the provision of adequate opportunities for rest and recovery. There is no specific type of legal rest period that covers all dimensions of rest that a worker may need. Rather, there are four types of rest that are helpful in protecting the physical and mental wellbeing of workers: daily workplace rest breaks, daily rest (a period away from work, normally at night; i.e. quick returns between shifts), weekly rest (a day or days off, usually at the weekend), and annual leave ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Ghosheh”, “given” : “Naj”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of work and employment series; No. 78”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “1 – 23”, “publisher” : “ILO”, “publisher-place” : “Genenva”, “title” : “Remembering rest periods in law: Another tool to limit excessive working hours”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=360f31da-8391-4e15-bddb-850b09472a12” } , “mendeley” : { “formattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Ghosheh, 2016)”, “previouslyFormattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ghosheh, 2016).

Rest breaks; daily rest breaks at the workplace are needed to address the fatigue that can accumulate while working, especially in work that is either physically or mentally demanding. These breaks are provided for workers’ personal wellbeing and safety, as well as to guarantee workplace safety. They are an essential aspect of any work schedule and insufficient rest breaks during the day can be associated with augmented work-related stress ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Ghosheh”, “given” : “Naj”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of work and employment series; No. 78”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “1 – 23”, “publisher” : “ILO”, “publisher-place” : “Genenva”, “title” : “Remembering rest periods in law: Another tool to limit excessive working hours”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=360f31da-8391-4e15-bddb-850b09472a12” } , “mendeley” : { “formattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Ghosheh, 2016)”, “previouslyFormattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ghosheh, 2016).
A study in the United States performed to assess the effects of rest on time to injury and found that longer accumulated rest breaks resulted in longer time to injury compared with those who did not have rest breaks ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.3292”, “ISSN” : “03553140”, “PMID” : “22430076”, “abstract” : “Objectives: Rest breaks and other work-related temporal factors, such as time spent on task, influence the accumulation of fatigue, and thus impact occupational injury risk. The aim of this study was to investigate the effect of rest breaks on u201ctime to injuryu201d (the time between start of work and injury) for injured workers treated in a nationally representative sample of US emergency departments. Methods: Using the National Electronic Injury Surveillance System (NEISS), we identified 629 workers who had experienced a work-related ladder-fall. Of these, 306 were interviewed by telephone using a standardized questionnaire about the circumstances surrounding the injury. Survival analyses were used to estimate time to injury, and hazard ratios (HR) for time to injury were compared between workers who reported no rest break (reference) and workers who reported rest break(s) prior to the injury (accumulated break time categorized into 0, 1u201315, 16u201330, and >30 minutes). Age, gender, time of work start, injury time of day, and workload were included as covariates to control for demographic, circadian, and work-related factors, respectively. Results: A clear doseu2013response relation indicated that longer accumulated break time was associated with a significantly longer time to injury when compared to workers without rest breaks total break time 1u201315 minutes: HR 0.60, 95% confidence interval (95% CI) 0.44u20130.83; 16u201330 minutes: HR 0.50, 95% CI 0.33u20130.75; >30 minutes: HR 0.34, 95% CI 0.23u20130.51, adjusted for all covariates. Conclusions: The results showed that longer total rest break time allowed for a significantly prolonged time spent on task without an injury. These findings suggest that rest break design could be used as a tool to enhance fatigue management and workplace safety.”, “author” : { “dropping-particle” : “”, “family” : “Arlinghaus”, “given” : “Anna”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lombardi”, “given” : “David A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Courtney”, “given” : “Theodore K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Christiani”, “given” : “David C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Folkard”, “given” : “Simon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Perry”, “given” : “Melissa J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “6”, “issued” : { “date-parts” : “2012” }, “page” : “560-567”, “title” : “The effect of rest breaks on time to injury – A study on work-related ladder-fall injuries in the United States”, “type” : “article-journal”, “volume” : “38” }, “uris” : “http://www.mendeley.com/documents/?uuid=632cd1c3-7f30-43d3-af56-9b0e9d4eed3a” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Arlinghaus</b> et al.</b></b>, <b>2012</b>)”, “plainTextFormattedCitation” : “(Arlinghaus et al., 2012)”, “previouslyFormattedCitation” : “(<b><b><b>Arlinghaus</b> et al.</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Arlinghaus et al., 2012). Similarly, a research carried out in China found that workers who have rest breaks were able to work longer into their work shift without an injury than workers who had no rest break ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.3395”, “ISBN” : “0355-3140”, “ISSN” : “03553140”, “PMID” : “24162622”, “abstract” : “OBJECTIVE: The aim of the present study was to investigate the effects of the duration and timing of rest breaks on traumatic injury risk across a shift in a relatively large sample of hospitalized workers with severe work-related hand injury in the People’s Republic of China (PRC).\n\nMETHODS: Hospitalized workers from multiple industries with severe work-related traumatic hand injury were recruited from 11 hospitals in three industrially-developed cities in the PRC: Ningbo, Liuzhou, and Wuxi. Cox regression was used to compare time into the work shift of injury across categories of rest breaks, while evaluating several potential covariates including age, gender, work hours, work start time and duration, injury day and time, duration and quality of last sleep, alertness/sleepiness, job control, and several transient work-related factors. Effect modification by work shift start time was also evaluated.\n\nRESULTS: With four days of injury, 703 hospitalized workers completed a face-to-face interview. After adjusting for significant covariates, workers with rest breaks of 1-30, 31-60, and >60 minutes were able to work significantly (P<0.001) longer into their work shift without an injury (>5 hours) then those with no rest break. A significant interaction was also observed between rest break status and start time of the work shift.\n\nCONCLUSION: The results of this study suggest that rest breaks of any duration have a significant effect on delaying the onset of a work-related injury, which is modified by the time of day in which a shift begins.”, “author” : { “dropping-particle” : “”, “family” : “Lombardi”, “given” : “David A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jin”, “given” : “Kezhi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Courtney”, “given” : “Theodore K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Arlinghaus”, “given” : “Anna”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Folkard”, “given” : “Simon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Liang”, “given” : “Youxin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Perry”, “given” : “Melissa J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2014” }, “page” : “146-155”, “title” : “The effects of rest breaks, work shift start time, and sleep on the onset of severe injury among workers in the People’s Republic of China”, “type” : “article-journal”, “volume” : “40” }, “uris” : “http://www.mendeley.com/documents/?uuid=c88acf57-1ed1-4833-b677-f0c06d0f8111” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Lombardi</b> et al.</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Lombardi et al., 2014)”, “previouslyFormattedCitation” : “(<b><b><b>Lombardi</b> et al.</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Lombardi et al., 2014). Preferred activities at rest breaks and length of break time had effect on health symptoms and decreased workers emotional exhaustion, promoted job satisfaction, and organizational behavior ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1037/apl0000045”, “ISBN” : “0021-9010”, “ISSN” : “00219010”, “PMID” : “26375961”, “abstract” : “Surprisingly little research investigates employee breaks at work, and even less research provides prescriptive suggestions for better workday breaks in terms of when, where, and how break activities are most beneficial. Based on the effortu2013recovery model and using experience sampling methodology, we examined the characteristics of employee workday breaks with 95 employees across 5 workdays. In addition, we examined resources as a mediator between break characteristics and well-being. Multilevel analysis results indicated that activities that were preferred and earlier in the work shift related to more resource recovery following the break. We also found that resources mediated the influence of preferred break activities and time of break on health symptoms and that resource recovery benefited person-level outcomes of emotional exhaustion, job satisfaction, and organizational citizenship behavior. Finally, break length interacted with the number of breaks per day such that longer breaks and frequent short breaks were associated with more resources than infrequent short breaks. (PsycINFO Database Record (c) 2015 APA, all rights reserved)”, “author” : { “dropping-particle” : “”, “family” : “Hunter”, “given” : “Emily M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Wu”, “given” : “Cindy”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Applied Psychology”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2016” }, “page” : “302-311”, “title” : “Give me a Better break: Choosing workday break activities to maximize resource recovery”, “type” : “article”, “volume” : “101” }, “uris” : “http://www.mendeley.com/documents/?uuid=efaeef8e-eb0e-4a04-8177-01a4cd7aa8fa” } , “mendeley” : { “formattedCitation” : “(<b><b>Hunter</b> and <b>Wu</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Hunter and Wu, 2016)”, “previouslyFormattedCitation” : “(<b><b>Hunter</b> and <b>Wu</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Hunter and Wu, 2016).

Daily rests usually refer to the time off work between successive shifts or workdays. With the increasing use of shift work and overtime, it is essential to ensure that workers have enough time to leave work and to obtain a proper sleep period before returning to work ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Ghosheh”, “given” : “Naj”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of work and employment series; No. 78”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “1 – 23”, “publisher” : “ILO”, “publisher-place” : “Genenva”, “title” : “Remembering rest periods in law: Another tool to limit excessive working hours”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=360f31da-8391-4e15-bddb-850b09472a12” } , “mendeley” : { “formattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Ghosheh, 2016)”, “previouslyFormattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ghosheh, 2016). Short intervals between the end of one shift and the start of another commonly occur in backward rotating shift systems and are also common when the overall weekly working hours are long, they are called quick returns. Quick returns limit the opportunity for sleeping and performing other non-work activities between shifts, they are also associated with shorter sleeps, and excess fatigue on the following shift ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.3109/07420528.2016.1167725”, “ISBN” : “0742-0528”, “ISSN” : “15256073”, “PMID” : “27082143”, “abstract” : “Quick returns (intervals of <11 h between the end of one shift and the start of the next) are associated with short sleeps and fatigue on the subsequent shift. Recent evidence suggests that shift workers regard quick returns as being more problematic than night work. The current study explored quick returns and night work in terms of their impact on sleep, unwinding, recovery, exhaustion, satisfaction with work hours and work-family interference. Data from the 2006 cohort of Swedish nursing students within the national Longitudinal Analysis of Nursing Education (LANE) study were analysed (N = 1459). Respondents completed a questionnaire prior to graduation (response rate 69.2%) and 3 years after graduation (65.9%). The analyses examined associations between frequency of quick returns and night work and measures taken in year three, while adjusting for confounding factors (in year three and prior graduation). Frequency of quick returns was a significant predictor of poor sleep quality, short sleeps, unwinding, exhaustion, satisfaction with work hours and work-to-family interference, with higher frequency predicting more negative outcomes. Quick returns did not predict recovery after rest days. Frequency of night work did not predict any of the outcomes. In conclusion, quick returns were an important determinant of sleep, recovery and wellbeing, whereas night work did not show such an association.”, “author” : { “dropping-particle” : “”, “family” : “Dahlgren”, “given” : “Anna”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tucker”, “given” : “Philip”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gustavsson”, “given” : “Petter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rudman”, “given” : “Ann”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Chronobiology International”, “id” : “ITEM-1”, “issue” : “6”, “issued” : { “date-parts” : “2016” }, “page” : “759-767”, “title” : “Quick returns and night work as predictors of sleep quality, fatigue, worku2013family balance and satisfaction with work hours”, “type” : “article”, “volume” : “33” }, “uris” : “http://www.mendeley.com/documents/?uuid=e1af0abb-38ad-47b1-8e6f-6c6c19dafed2” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Dahlgren</b> et al.</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Dahlgren et al., 2016)”, “previouslyFormattedCitation” : “(<b><b><b>Dahlgren</b> et al.</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Dahlgren et al., 2016).
Weekly rest day/s; there is relatively little evidence regarding the optimal distribution of rest days within rotating shift system. A systematic review found that, in one study as 12-hour shift system involving 2 days on and 2 days off, resulted in a little higher alertness than one involving 4 days on, 4 days off; another one showed that alertness and performance were compromised on the first three days back at work following a single rest day compared to a period of two or three rest days ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.2900”, “ISBN” : “1795-990X (Electronic)\n0355-3140 (Linking)”, “ISSN” : “1795990X”, “PMID” : “20119631”, “abstract” : “In this narrative review, we examined what level of research evidence is available that shift workers’ sleep-wake disturbances can be minimized through ergonomic shift scheduling. We classified the pertinent studies conducted on real shift workers in field conditions by the type of shift system and study design (ie, whether the shift systems were modified or not – “treatment” versus “no treatment”). The results of the observational studies in which no changes to the shift system were made (ie, no treatment) showed that, irrespective of the shift system, night and early-morning shifts and quick returns are associated with short sleep and increases in sleepiness. The same is true for very long shifts (>16 hours) and extremely long weekly working hours (>55 hours). For all categories of shift systems, there was a lack of controlled intervention studies, limiting the possibility to provide solution-focused recommendations for shift scheduling. Most of the controlled intervention studies had been conducted on workers under regular 3-shift systems. These studies suggested that a change from slowly backward-rotating shifts to rapidly forward-rotating shifts is advantageous for alertness and, to some degree, sleep. We also found that a change from an 8- to 12-hour shift system does not necessarily result in impairments in the sleep-wake pattern. The level of research evidence was affected by many of the studies’ frequent methodological limitations in measuring sleep and sleepiness. In all, to have reliable and solution-focused recommendations for shift scheduling, methodologically sound controlled intervention studies are required in different categories of shift systems.”, “author” : { “dropping-particle” : “”, “family” : “Sallinen”, “given” : “Mikael”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kecklund”, “given” : “Gu00f6ran”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “121-133”, “title” : “Shift work, sleep, and sleepiness – Differences between shift schedules and systems”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=55be0f6f-5407-4f42-a8c1-39af2e9107c2” } , “mendeley” : { “formattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Sallinen and Kecklund, 2010)”, “previouslyFormattedCitation” : “(<b><b>Sallinen</b> and <b>Kecklund</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Sallinen and Kecklund, 2010).
Studies concluded that a one day of rest is never sufficient, two days usually are and that three or four are needed especially after periods of severely disturbed circadian rhythm (e.g. after working several night shifts). More generally, it seems possible that the ratio of work days to rest days that is important in allowing full recovery from a period of work, and that under normal circumstances it may be suitable to limit periods of successive work days to not more than six and to necessitate a minimum of two successive rest days ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789221260608”, “author” : { “dropping-particle” : “”, “family” : “Tucker”, “given” : “Philip”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Folkard”, “given” : “Simon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of Work and employment Series No. 31”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issue” : “31”, “issued” : { “date-parts” : “2012” }, “page” : “1-60”, “publisher” : “ILO”, “publisher-place” : “Geneva”, “title” : “Working time, health and safety: a research synthesis paper”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=a8c421e7-16d1-48bf-a620-7d0e2ba058fb” } , “mendeley” : { “formattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)”, “plainTextFormattedCitation” : “(Tucker and Folkard, 2012)”, “previouslyFormattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Tucker and Folkard, 2012).
Young doctors have noted that being on-call for work during weekends can lead to work-life imbalances ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789197874632”, “author” : { “dropping-particle” : “”, “family” : “Tucker”, “given” : “Philip”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bejerot”, “given” : “Eva”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “u00c5kerstedt”, “given” : “Tobjorn”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “number-of-pages” : “45”, “publisher-place” : “stockholm”, “title” : “Doctors u2019 work hours in Sweden : Their impact on sleep , health , work-family balance , patient safety and thoughts about work .”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=2af9e534-b066-482f-82c8-c3e1f92f8b6a” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Tucker</b> et al.</b></b>, <b>2013</b>)”, “plainTextFormattedCitation” : “(Tucker et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Tucker</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Tucker et al., 2013). There is inadequate research available on the association between worker fatigue and the implications of weekly rest days, but the available data indicate that weekly rest days can prove quite important for workers in relaxation and in physical awareness in the workplace. Weekly rest should generally fall during times that family and social events take place, as this allows workers appropriate rest as well as contributing to their work-life balance ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Ghosheh”, “given” : “Naj”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of work and employment series; No. 78”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “1 – 23”, “publisher” : “ILO”, “publisher-place” : “Genenva”, “title” : “Remembering rest periods in law: Another tool to limit excessive working hours”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=360f31da-8391-4e15-bddb-850b09472a12” } , “mendeley” : { “formattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Ghosheh, 2016)”, “previouslyFormattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ghosheh, 2016).

Annual leave refers to a period of days taken away from the workplace to rest and recreate. Annual leave for workers is a comparatively recent phenomenon which did not become prevalent until the 1950’s. The welfare of annual leave used to be limited to white collars, but has become more common for other types of workers too ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Ghosheh”, “given” : “Naj”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of work and employment series; No. 78”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “1 – 23”, “publisher” : “ILO”, “publisher-place” : “Genenva”, “title” : “Remembering rest periods in law: Another tool to limit excessive working hours”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=360f31da-8391-4e15-bddb-850b09472a12” } , “mendeley” : { “formattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Ghosheh, 2016)”, “previouslyFormattedCitation” : “(<b><b>Ghosheh</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ghosheh, 2016). Researchers have investigated the need for annual leave and have drawn some remarkable conclusions. Some medical studies have linked serious cardiovascular problems to a lack of vacations. Recent research has also concluded that employee health and wellbeing may improve during short vacations due to detachment from the workplace ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1002/smi.1434”, “ISBN” : “1532-2998”, “ISSN” : “15323005”, “PMID” : “22213478”, “abstract” : “It was investigated (1) whether employee health and well-being (H&W) improve during short vacations (4-5 days), (2) how long this improvement lasts after returning home and resuming work and (3) to what extent vacation activities and experiences explain health improvements during and after short vacations. Eighty workers reported their H&W 2 weeks before vacation (Pre), during vacation (Inter), on the day of return (Post 1) and on the third and 10th day after returning home (Post 2 and Post 3, respectively). The results showed improvements in H&W during short vacations (d=0.62), although this effect faded out rather quickly. Partial correlations and regression analyses showed that employees reported higher H&W during vacation, the more relaxed and psychologically detached they felt, the more time they spent on conversations with the partner, the more pleasure they derived from their vacation activities and the lower the number of negative incidents during vacation. Experiences of relaxation and detachment from work positively influenced H&W even after returning home. Working during vacation negatively influenced H&W after vacation. In conclusion, short vacations are an effective, although not very long lasting, ‘cure’ to improve employees’ H;W.”, “author” : { “dropping-particle” : “”, “family” : “Bloom”, “given” : “Jessica”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Geurts”, “given” : “Sabine A.E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kompier”, “given” : “Michiel A.J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Stress and Health”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2012” }, “page” : “305-318”, “title” : “Effects of short vacations, vacation activities and experiences on employee health and well-being”, “type” : “article-journal”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=8f9158a7-ada5-4397-b0dc-5c743c993049” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;De Bloom;/b; et al.;/b;;/b;, ;b;2012;/b;)”, “plainTextFormattedCitation” : “(De Bloom et al., 2012)”, “previouslyFormattedCitation” : “(;b;;b;;b;De Bloom;/b; et al.;/b;;/b;, ;b;2012;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(De Bloom et al., 2012).

Accessing annual leave in a way that allows for valuable rest may not always be straightforward. Two factors have substantial impact on workers’ ability to enjoy annual leave; the first is presenteeism, this occurs when a worker finishes his work but feels obliged to stay in the workplace so that the employer considers they are fully committed to the organization ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.jad.2015.03.034”, “ISBN” : “0165-0327”, “ISSN” : “15732517”, “PMID” : “25879720”, “abstract” : “Background Absence due to mental disease in the workplace has become a global public health problem. We aimed to evaluate the influence of presenteeism on depression and absence due to mental disease. Methods A prospective study of 1831 Japanese employees from all areas of Japan was conducted. Presenteeism and depression were measured by the validated Japanese version of the World Health Organization Health and Work Performance Questionnaire (WHO-HPQ) and the K6 scale, respectively. Absence due to mental disease across a 2-year follow up was surveyed through medical certificates obtained for work absence. Results After adjusting for age and gender, participants with higher rates of sickness absolute and relative presenteeism (the lowest tertile of the scores) were significantly more likely to be absent due to mental disease (OR=4.40, 95% CI: 1.65-11.73, and OR=3.31, 95% CI: 1.50-7.27). Subsequently, higher rates of sickness absolute or relative presenteeism were significantly associated with higher rates of depression (K6=13) one year later (OR=3.79, 95% CI: 2.48-5.81, and OR=2.89, 95% CI: 1.98-4.22). Limitations The number of females in the sample was relatively small. However, the rates of absence for females with and without mental illness did not significantly differ from those of men. Conclusions More sickness presenteeism scores were found to be related to higher rates of depression and absence due to mental disease in this large-scale cohort of Japanese workers. Measurement of presenteeism could be used to evaluate the risk for depression and absenteeism. Furthermore, our findings suggest that intervention to improve presenteeism would be effective in preventing depression and absence due to mental illness.”, “author” : { “dropping-particle” : “”, “family” : “Suzuki”, “given” : “Tomoko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Miyaki”, “given” : “Koichi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Song”, “given” : “Yixuan”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tsutsumi”, “given” : “Akizumi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kawakami”, “given” : “Norito”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Shimazu”, “given” : “Akihito”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Takahashi”, “given” : “Masaya”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Inoue”, “given” : “Akiomi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kurioka”, “given” : “Sumiko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Affective Disorders”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2015” }, “page” : “14-20”, “publisher” : “Elsevier”, “title” : “Relationship between sickness presenteeism (WHO-HPQ) with depression and sickness absence due to mental disease in a cohort of Japanese workers”, “type” : “article-journal”, “volume” : “180” }, “uris” : “http://www.mendeley.com/documents/?uuid=7166fe45-14b7-4588-8e51-fe3e69035364” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Suzuki;/b; et al.;/b;;/b;, ;b;2015;/b;)”, “plainTextFormattedCitation” : “(Suzuki et al., 2015)”, “previouslyFormattedCitation” : “(;b;;b;;b;Suzuki;/b; et al.;/b;;/b;, ;b;2015;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Suzuki et al., 2015). The second factor is a function of modern telecommunications; workers are not only under pressure to be visible in the workplace but to be accessible even when they are in vacation or rest away from the workplace. This factor may cause problems for daily and weekly rest, it can also affect a worker’s annual leave time. This combination of physical absence and mental connection can cause serious problems for workers, especially when they should be enjoying leisure time or time with friends and family ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1002/smi.1434”, “ISBN” : “1532-2998”, “ISSN” : “15323005”, “PMID” : “22213478”, “abstract” : “It was investigated (1) whether employee health and well-being (H;W) improve during short vacations (4-5 days), (2) how long this improvement lasts after returning home and resuming work and (3) to what extent vacation activities and experiences explain health improvements during and after short vacations. Eighty workers reported their H;W 2 weeks before vacation (Pre), during vacation (Inter), on the day of return (Post 1) and on the third and 10th day after returning home (Post 2 and Post 3, respectively). The results showed improvements in H;W during short vacations (d=0.62), although this effect faded out rather quickly. Partial correlations and regression analyses showed that employees reported higher H;W during vacation, the more relaxed and psychologically detached they felt, the more time they spent on conversations with the partner, the more pleasure they derived from their vacation activities and the lower the number of negative incidents during vacation. Experiences of relaxation and detachment from work positively influenced H;W even after returning home. Working during vacation negatively influenced H;W after vacation. In conclusion, short vacations are an effective, although not very long lasting, ‘cure’ to improve employees’ H&W.”, “author” : { “dropping-particle” : “”, “family” : “Bloom”, “given” : “Jessica”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Geurts”, “given” : “Sabine A.E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kompier”, “given” : “Michiel A.J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Stress and Health”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2012” }, “page” : “305-318”, “title” : “Effects of short vacations, vacation activities and experiences on employee health and well-being”, “type” : “article-journal”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=8f9158a7-ada5-4397-b0dc-5c743c993049” } , “mendeley” : { “formattedCitation” : “(<b><b><b>De Bloom</b> et al.</b></b>, <b>2012</b>)”, “plainTextFormattedCitation” : “(De Bloom et al., 2012)”, “previouslyFormattedCitation” : “(<b><b><b>De Bloom</b> et al.</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(De Bloom et al., 2012).

Susceptibility factors of shift work associated health effects
Many other factors may also affect the impact of work schedule on health. These factors include individual, organizational and situational factors (figure II). The individual factors encompass age, gender and personality traits (especially neuroticism and locus of control), as well as circadian preference, in particular the morningness – eveningness dimension. Some workers can tolerate shift work well, whereas others develop serious problems due to exposure to shift work. Trait vulnerability to sleep loss, circadian phase position (chronotype), and flexibility of sleep timing (natural ability to sleep and work at unusual times of day and at different locations) have been suggested as causes for individual differences, but conclusive evidence has not yet been presented (ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.smrv.2010.07.002”, “ISBN” : “1532-2955 (Electronic)\n1087-0792 (Linking)”, “ISSN” : “10870792”, “PMID” : “20851006”, “abstract” : “Shift work tolerance is a term describing the ability to adapt to shift work without adverse consequences. In this paper we systematically review literature published investigating the relation between individual differences such as age, gender, personality, morningness/eveningness as well as biological variables and different measures of shift work tolerance from 1998 till 2009. A total of 60 articles were included in this review, of which ten studies were classified as longitudinal, while the rest were classified as cross-sectional. Overall, the studies indicate that young age, male gender, low scores on morningness, high scores on flexibility and low scores on languidity, low scores on neuroticism, high scores on extraversion and internal locus of control and some genetic dispositions are related to higher shift work tolerance. More longitudinal studies, especially concerning personality, are needed to make conclusions about the predictive power of individual differences for shift work tolerance. u00a9 2010 Elsevier Ltd.”, “author” : { “dropping-particle” : “”, “family” : “Saksvik”, “given” : “Ingvild B.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bjorvatn”, “given” : “Bju00f8rn”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hetland”, “given” : “Hilde”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sandal”, “given” : “Gro M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pallesen”, “given” : “Stu00e5le”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine Reviews”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2011” }, “page” : “221-235”, “publisher” : “Elsevier Ltd”, “title” : “Individual differences in tolerance to shift work – A systematic review”, “type” : “article-journal”, “volume” : “15” }, “uris” : “http://www.mendeley.com/documents/?uuid=f6cf50eb-682f-42e8-9c87-6f8414acc45e” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Saksvik</b> et al.</b></b>, <b>2011</b>)”, “manualFormatting” : “Saksvik et al., 2011”, “plainTextFormattedCitation” : “(Saksvik et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Saksvik</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Saksvik et al., 2011).
Identifying individual determinants of shift work tolerance is therefore important for proper choice of individuals involved in shifts. Identification of these determinants can also help to establish a base for new research exploring different shift work systems and work conditions suitable for different individuals. It has been stated that it is a challenge to recognize intolerant shift workers, before or during the adaptation phase, and to examine whether additional support may enforce their adaptation or not ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.2486/indhealth.47.518”, “ISBN” : “1880-8026 (Electronic)\r0019-8366 (Linking)”, “ISSN” : “0019-8366”, “PMID” : “19834261”, “abstract” : “There are considerable individual differences in cognitive performance deficits resulting from extended work hours and shift work schedules. Recent progress in sleep and performance research has yielded new insights into the causes and consequences of these individual differences. Neurobiological processes of sleep/wake regulation underlie trait individual variability in vulnerability to performance impairment due to sleep loss. Trait vulnerability to sleep loss is observed in the laboratory and in the work environment, even in occupational settings where (self-)selection pressures are high. In general, individuals do not seem to accurately assess the magnitude of their own vulnerability. Methods for identifying workers who are most at risk of sleep loss-related errors and accidents would therefore be helpful to target fatigue countermeasure interventions at those needing them most. As yet, no reliable predictors of vulnerability to sleep loss have been identified, although candidate genetic predictors have been proposed. However, a Bayesian forecasting technique based on closed-loop feedback of measured performance has been developed for individualized prediction of future performance impairment during ongoing operations. Judiciously selecting or monitoring individuals in specific tasks or occupations, within legally and ethically acceptable boundaries, has the potential to improve operational performance and productivity, reduce errors and accidents, and save lives. Trait individual variability in responses to sleep loss represents a major complication in the application of one-size-fits-all hours of service regulations–favoring instead modern fatigue risk management strategies, because these allow flexibility to account for individual vulnerability or resilience to the performance consequences of extended work hours and shift work schedules.”, “author” : { “dropping-particle” : “”, “family” : “Donghen”, “given” : “Hans P.A.”, “non-dropping-particle” : “Van”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Belenky”, “given” : “Gregory”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Industrial Health”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2009” }, “page” : “518-526”, “title” : “Individual Differences in Vulnerability to Sleep Loss in the Work Environment”, “type” : “article-journal”, “volume” : “47” }, “uris” : “http://www.mendeley.com/documents/?uuid=f4ec87fa-b475-4427-a8b9-b3a1ee9071fc” } , “mendeley” : { “formattedCitation” : “(<b><b>Van Donghen</b> and <b>Belenky</b></b>, <b>2009</b>)”, “manualFormatting” : “(Van Donghen and Belenky, 2009”, “plainTextFormattedCitation” : “(Van Donghen and Belenky, 2009)”, “previouslyFormattedCitation” : “(<b><b>Van Donghen</b> and <b>Belenky</b></b>, <b>2009</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Van Donghen and Belenky, 2009; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.smrv.2010.07.002”, “ISBN” : “1532-2955 (Electronic)\n1087-0792 (Linking)”, “ISSN” : “10870792”, “PMID” : “20851006”, “abstract” : “Shift work tolerance is a term describing the ability to adapt to shift work without adverse consequences. In this paper we systematically review literature published investigating the relation between individual differences such as age, gender, personality, morningness/eveningness as well as biological variables and different measures of shift work tolerance from 1998 till 2009. A total of 60 articles were included in this review, of which ten studies were classified as longitudinal, while the rest were classified as cross-sectional. Overall, the studies indicate that young age, male gender, low scores on morningness, high scores on flexibility and low scores on languidity, low scores on neuroticism, high scores on extraversion and internal locus of control and some genetic dispositions are related to higher shift work tolerance. More longitudinal studies, especially concerning personality, are needed to make conclusions about the predictive power of individual differences for shift work tolerance. u00a9 2010 Elsevier Ltd.”, “author” : { “dropping-particle” : “”, “family” : “Saksvik”, “given” : “Ingvild B.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bjorvatn”, “given” : “Bju00f8rn”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hetland”, “given” : “Hilde”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sandal”, “given” : “Gro M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pallesen”, “given” : “Stu00e5le”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine Reviews”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2011” }, “page” : “221-235”, “publisher” : “Elsevier Ltd”, “title” : “Individual differences in tolerance to shift work – A systematic review”, “type” : “article-journal”, “volume” : “15” }, “uris” : “http://www.mendeley.com/documents/?uuid=f6cf50eb-682f-42e8-9c87-6f8414acc45e” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Saksvik</b> et al.</b></b>, <b>2011</b>)”, “manualFormatting” : “Saksvik et al., 2011”, “plainTextFormattedCitation” : “(Saksvik et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Saksvik</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Saksvik et al., 2011; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9073675103”, “author” : { “dropping-particle” : “”, “family” : “Lammers-van der Holst”, “given” : “H. 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Organizational differences are those associated with the special organization and are potentially equally applicable to all workers within the organization. They include factors such as the availability and quality of rest areas for breaks. They also include factors that may be considered “stressful”, such as the psychosocial conditions at the workplace, including support from colleagues and supervisors, and physical conditions such as noise, heat, vibration and unstable weather ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789221260608”, “author” : { “dropping-particle” : “”, “family” : “Tucker”, “given” : “Philip”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Folkard”, “given” : “Simon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of Work and employment Series No. 31”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issue” : “31”, “issued” : { “date-parts” : “2012” }, “page” : “1-60”, “publisher” : “ILO”, “publisher-place” : “Geneva”, “title” : “Working time, health and safety: a research synthesis paper”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=a8c421e7-16d1-48bf-a620-7d0e2ba058fb” } , “mendeley” : { “formattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)”, “plainTextFormattedCitation” : “(Tucker and Folkard, 2012)”, “previouslyFormattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Tucker and Folkard, 2012).
Situational differences affect the interaction between the individuals’ personal and professional lives and will determine the status of the individuals prior to the shift. The classic example of a situational factor is the time an individual takes to commute to and from work, which can have a major impact on, the extent to which sleep is shortened prior to a morning shift. Another situational difference is the type of activity that the individuals engage in during their rest periods. Theoretically people should be able to recover from any accumulative fatigue that may build up over successive shifts during their following rest periods. However, some workers may have a second occupation and others may have physically demanding leisure activities. The net result of these situational
differences may be increased levels of pre-shift fatigue at the beginning of a period of successive shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789221260608”, “author” : { “dropping-particle” : “”, “family” : “Tucker”, “given” : “Philip”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Folkard”, “given” : “Simon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of Work and employment Series No. 31”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issue” : “31”, “issued” : { “date-parts” : “2012” }, “page” : “1-60”, “publisher” : “ILO”, “publisher-place” : “Geneva”, “title” : “Working time, health and safety: a research synthesis paper”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=a8c421e7-16d1-48bf-a620-7d0e2ba058fb” } , “mendeley” : { “formattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)”, “plainTextFormattedCitation” : “(Tucker and Folkard, 2012)”, “previouslyFormattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Tucker and Folkard, 2012).

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Figure II. A theoretical model showing factors affecting the impact of work schedule on various health (ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789221260608”, “author” : { “dropping-particle” : “”, “family” : “Tucker”, “given” : “Philip”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Folkard”, “given” : “Simon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “collection-title” : “Conditions of Work and employment Series No. 31”, “container-title” : “Conditions of Work and Employment Series”, “id” : “ITEM-1”, “issue” : “31”, “issued” : { “date-parts” : “2012” }, “page” : “1-60”, “publisher” : “ILO”, “publisher-place” : “Geneva”, “title” : “Working time, health and safety: a research synthesis paper”, “type” : “entry-encyclopedia” }, “uris” : “http://www.mendeley.com/documents/?uuid=a8c421e7-16d1-48bf-a620-7d0e2ba058fb” } , “mendeley” : { “formattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)”, “manualFormatting” : “Tucker and Folkard, 2012)”, “plainTextFormattedCitation” : “(Tucker and Folkard, 2012)”, “previouslyFormattedCitation” : “(<b><b>Tucker</b> and <b>Folkard</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Tucker and Folkard, 2012).

Regulations and Legal Framework of Shift Work
Special arrangements and regulations for shift workers are not universal. Regulations often do not address all the needs of shift workers, and even if they do, efforts to meet those needs are rarely systematic. Some countries have extensive regulations and support services for shift workers, while others have almost none. In a few countries, there are comprehensive laws that cover a wide range of work issues as leisure facilities and housing facilities for workers. On the contrary, in the majority of countries, regulations dealing with irregular work schedules are limited to hours and wages. The most common regulation appears to be increased pay, while the second most common is fewer hours. Although most employers voluntarily give night workers higher wages than day workers, many countries have laws to ensure extra pay for night work. Some governments mandate shorter work hours for night work instead of higher wages. Unlike higher wages, shorter hours are directly protective, as they reduce the strain on night workers (U.S Congress, 1991).

Regulations controlling shift work are included within working hours’ regulations. The first ILO Convention “the Hours of Work Convention 1919 (No. 1)” was the 1st convention to establish the principles of ‘8 hours a day and 48 hours a week’ for the manufacturing sector. Numerous working time Conventions were subsequently adopted as “the Hours of Work (Commerce and Offices) Convention, 1930 (No. 30) which extended the 48-hour working week to workers in commerce and offices, and the Forty-Hour Week Convention, 1935 (No. 47) established a new standard of the 40-hour working week. The principle of a minimum of one-day weekly rest was introduced in the “Weekly Rest (Industry) Convention, 1921 (No. 14) and the Weekly Rest (Commerce and Offices) Convention, 1957 (No. 106)”. Conventions concerning night work and holidays with pay also followed. Although the ILO has no formal powers of enforcement, it can and does use unfavorable publicity to encourage nations to support the labor standards in conventions which they have ratified (Messenger et al., 2007).

Because the global picture for working time legislations is unclear, the ILO had developed “Conditions of Work and Employment Program” which began in 2004 to compile and translate national working time legislation and to include summaries of their content in an online Database of Working Time Laws. This is the most comprehensive available database on national working time laws. It covers the legislation of more than 100 countries and includes all the main elements of working regulation as working hours’ limits; rest periods; annual leave and public holidays; night work; overtime work; part-time work; and workers’ rights to change their working hours (Messenger et al., 2007).

Although 8 hours a day working time is adopted in many countries; sometimes extended working hours are unavoidable because of technological restrictions. Extended working hours means shifts longer than 8 hours (9, 10, 11 or 12-h/day) but this is generally combined with compressed working week (more hours worked/day, but less day worked/week) (Knauth, 2007). In these circumstances, many countries permit some worker (as shift or seasonal workers) to work longer than normal but employers must limit total work hours so that the average hours are equal to those of the average worker (McCann, 2005).
It was found that most workers strongly prefer rotating schedules to permanent night shifts. In response to this preference, many countries impose limits on the number of consecutive nights a person is permitted to work. Furthermore, most countries encourage rotating schedules usually on 1 week rotation. Finally, another point of concern is double shifts. Some countries permit double shifts (as India, Austria, Germany, the Netherlands and Panama), but more countries prohibit them. Many do so indirectly, by restricting the number of hours that can be worked consecutively. According to recent research, an extra-long break is advisable when shift workers are changing from a night to a day shift. At present, no country mandates this type of extra rest. Also, no country regulates the direction in which shifts rotate (i.e., forward or backward) (U.S Congress, 1991).

Apart from the issues of pay and hours, shift workers have a host of other concerns. These include obtaining adequate medical supervision, food, sleep, transportation, and entertainment. Shift workers can face health problems from continually operating out of synchrony with their biological rhythms. Factory canteens often close at night, and night workers must endure relatively poor food. Sleep during the day is more likely to be interrupted than sleep at night. Transportation and entertainment schedules are usually designed around standard daytime work schedules. France is unique in addressing these shift work associated problems where they established a multi-ministerial committee which has provided special arrangements for night workers for example noise and sunlight can impede sleep by day for night workers, so the French multi-ministerial committee has provided special arrangements for night workers’ housing. Not only do night workers get priority in obtaining nationally directed funding for housing, but they also receive 6 percent more money than other workers to soundproof and lightproof their houses. France’s multi-ministerial committee has also taken steps to arrange leisure activities for night workers (U.S Congress, 1991).

With regard to Egypt law No. 12 of the year 2003 promulgating labour law in book No. 2 (individual labour relationship), part 6 (organization of work), chapter 1 (working hours and break periods), article 80 states that in industrial establishments, the worker shall not be employed in actual labour for more than eight hours a day or forty eight hours a week not including the appropriated meal and rest hours. The Ministerial Decree No. 122 of 2003 provides that employers who have a continuous 24 hour operation (based on three shifts) can have its  employees work eight hours shifts rather than be bound by the five hour restriction. In addition, employers that operate a two shift operation may also have eight continuous daily working hours provided they obtain the written approval of the employees to work these shifts. In terms of overtime pay, Article 85 of the labor law, provides that overtime pay shall be more than the normal salary paid. The Labor Law sets out minimum rates for overtime pay and differentiates between overtime worked during the day and at night. Daytime overtime shall be compensated with an additional percentage of 35% of the normal working hours’ salary, while night-time overtime shall be compensated by 70% of the normal working hours’ salary (Part from Egypt labor law Appendix C).

EFFECTS OF SHIFT WORK
Shift work has negative impact on health that ranges from immediate effects to long term effects. Immediate disturbances include sleep disorders, fatigue, effects on mood and performance. Long term health problems include obesity, insulin resistance, type 2 diabetes (T2DM), dyslipidemia, cardiovascular diseases, metabolic syndrome (MS), gastrointestinal disorders and cancer. Circadian rhythm misalignment and chronic sleep deprivation are thought to be the main causes of many health problems related to shift work ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “In developing countries, shift work represents a considerable contingent workforce. Recently, studies have shown that overweight and obesity are more prevalent in shift workers than day workers. In addition, shift work has been associated with a higher propensity for the development of many metabolic disorders, such as insulin resistance, diabetes, dislipidemias and metabolic syndrome. Recent data have pointed that decrease of the sleep time, desynchronization of circadian rhythm and alteration of environmental aspects are the main factors related to such problems. Shortened or disturbed sleep is among the most common health-related effects of shift work. The plausible physiological and biological mechanisms are related to the activation of the autonomic nervous system, inflammation, changes in lipid and glucose metabolism, and related changes in the risk for atherosclerosis, metabolic syndrome, and type II diabetes. The present review will discuss the impact of shift work on obesity and metabolic disorders and how disruption of sleep and circadian misalignment may contribute to these metabolic dysfunctions.”, “author” : { “dropping-particle” : “”, “family” : “Zimberg”, “given” : “Ionu00e1 Zalcman”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fernandes Junior”, “given” : “Silvio A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Crispim”, “given” : “Cibele Aparecida”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tufik”, “given” : “Sergio”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mello”, “given” : “Marco Tulio”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” } , “container-title” : “Work”, “id” : “ITEM-1”, “issue” : “SUPPL.1”, “issued” : { “date-parts” : “2012” }, “page” : “4376-4383”, “title” : “Metabolic impact of shift work”, “type” : “paper-conference”, “volume” : “41” }, “uris” : “http://www.mendeley.com/documents/?uuid=d1020cd6-9d57-40af-b0c3-3b11f5e33cb5” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Zimberg</b> et al.</b></b>, <b>2012</b>)”, “manualFormatting” : “(Zimberg et al., 2012)”, “plainTextFormattedCitation” : “(Zimberg et al., 2012)”, “previouslyFormattedCitation” : “(<b><b><b>Zimberg</b> et al.</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Zimberg et al., 2012).

Circadian Rhythm and Sleep Deprivation
The rhythmic variations encountered in the human body differ in duration from milliseconds as in individual nerve cell to minutes or hours (ultradian rhythms) to 24 hours (circadian rhythms) and up to longer periods like the menstrual cycle in women, and seasonal (circannual rhythms) in both males and females. The rhythms most widely studied and most related to work physiology are the circadian rhythms ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/s10552-005-9015-4”, “ISBN” : “0957-5243 (Print)\n0957-5243 (Linking)”, “ISSN” : “0957-5243”, “PMID” : “16596302”, “abstract” : “Long-term epidemiologic studies on large numbers of night and rotating shift workers have suggested an increase in the incidence of breast and colon cancer in these populations. These studies suffer from poor definition and quantification of the work schedules of the exposed subjects. Against this background, the pathophysiology of phase shift and phase adaptation is reviewed. A phase shift as experienced in night and rotating shift work involves desynchronization at the molecular level in the circadian oscillators in the central nervous tissue and in most peripheral tissues of the body. There is a change in the coordination between oscillators with transient loss of control by the master-oscillator (the Suprachiasmatic Nucleus, SCN) in the hypothalamus. The implications of the pathophysiology of phase shift are discussed for long-term health effects and for the design of ergonomic work schedules minimizing the adverse health effects upon the worker.”, “author” : { “dropping-particle” : “”, “family” : “Haus”, “given” : “E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Smolensky”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Cancer Causes and Control”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2006” }, “page” : “489u2013500”, “title” : “Biological clocks and shift work: circadian dysregulation and potential long-term effects”, “type” : “article-journal”, “volume” : “17” }, “uris” : “http://www.mendeley.com/documents/?uuid=5bab3d0c-ce82-402d-8f92-5cee32bea020” } , “mendeley” : { “formattedCitation” : “(<b><b>Haus</b> and <b>Smolensky</b></b>, <b>2006</b>)”, “manualFormatting” : “(Haus and Smolensky, 2006)”, “plainTextFormattedCitation” : “(Haus and Smolensky, 2006)”, “previouslyFormattedCitation” : “(<b><b>Haus</b> and <b>Smolensky</b></b>, <b>2006</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Haus and Smolensky, 2006). These rhythms are the external manifestation of an internal timing system produced by a circadian clock that is synchronized by the day-night cycle ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/1740-3391-8-3”, “ISBN” : “1740-3391 (Electronic)\r1740-3391 (Linking)”, “ISSN” : “1740-3391”, “PMID” : “20353609”, “abstract” : “Circadian rhythms are daily oscillations of multiple biological processes directed by endogenous clocks. The circadian timing system comprises peripheral oscillators located in most tissues of the body and a central pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Circadian genes and the proteins produced by these genes constitute the molecular components of the circadian oscillator which form positive/negative feedback loops and generate circadian rhythms. The circadian regulation extends beyond clock genes to involve various clock-controlled genes (CCGs) including various cell cycle genes. Aberrant expression of circadian clock genes could have important consequences on the transactivation of downstream targets that control the cell cycle and on the ability of cells to undergo apoptosis. This may lead to genomic instability and accelerated cellular proliferation potentially promoting carcinogenesis. Different lines of evidence in mice and humans suggest that cancer may be a circadian-related disorder. The genetic or functional disruption of the molecular circadian clock has been found in various cancers including breast, ovarian, endometrial, prostate and hematological cancers. The acquisition of current data in circadian clock mechanism may help chronotherapy, which takes into consideration the biological time to improve treatments by devising new therapeutic approaches for treating circadian-related disorders, especially cancer.”, “author” : { “dropping-particle” : “”, “family” : “Rana”, “given” : “Sobia”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mahmood”, “given” : “Saqib”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Circadian Rhythms”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2010” }, “page” : “1-13”, “title” : “Circadian rhythm and its role in malignancy”, “type” : “article”, “volume” : “8” }, “uris” : “http://www.mendeley.com/documents/?uuid=227629d4-25f7-48a9-a5aa-a33635c2d0a8” } , “mendeley” : { “formattedCitation” : “(<b><b>Rana</b> and <b>Mahmood</b></b>, <b>2010</b>)”, “manualFormatting” : “(Rana and Mahmood, 2010)”, “plainTextFormattedCitation” : “(Rana and Mahmood, 2010)”, “previouslyFormattedCitation” : “(<b><b>Rana</b> and <b>Mahmood</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Rana and Mahmood, 2010).
Circadian clocks are “self-sustained biological oscillators that have a robust internal timing system. Circadian clocks allow an organism to cope with regular fluctuations in the environment (e.g. daylight, meal times). Circadian clocks also help organisms to adapt their behavior and physiology appropriately ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Ahern”, “given” : “Siobhu00e1n Anne”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “number-of-pages” : “66 – 72”, “publisher” : “(PhD thesis, School of Medical Sciences, University of Manchester, Manchester, United Kingdom)”, “title” : “The role of the clock in lipid metabolism”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=68304a00-db6b-4d28-a17e-f1ab84f68e1c” } , “mendeley” : { “formattedCitation” : “(<b><b>Ahern</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Ahern, 2016)”, “previouslyFormattedCitation” : “(<b><b>Ahern</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ahern, 2016). The endogenous circadian timing system optimally controls much of human physiology and behavior across the 24 hours day when it is appropriately aligned with the sleep/wake cycles. Each of circadian cycles and behavioral cycles include fasting/feeding cycle and sleep/wake cycle, endocrine metabolic and autonomic functions ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1073/pnas.0808180106”, “ISBN” : “1091-6490 (Electronic)\r0027-8424 (Linking)”, “ISSN” : “0027-8424”, “PMID” : “19255424”, “abstract” : “There is considerable epidemiological evidence that shift work is associated with increased risk for obesity, diabetes, and cardiovascular disease, perhaps the result of physiologic maladaptation to chronically sleeping and eating at abnormal circadian times. To begin to understand underlying mechanisms, we determined the effects of such misalignment between behavioral cycles (fasting/feeding and sleep/wake cycles) and endogenous circadian cycles on metabolic, autonomic, and endocrine predictors of obesity, diabetes, and cardiovascular risk. Ten adults (5 female) underwent a 10-day laboratory protocol, wherein subjects ate and slept at all phases of the circadian cycle-achieved by scheduling a recurring 28-h “day.” Subjects ate 4 isocaloric meals each 28-h “day.” For 8 days, plasma leptin, insulin, glucose, and cortisol were measured hourly, urinary catecholamines 2 hourly (totaling approximately 1,000 assays/subject), and blood pressure, heart rate, cardiac vagal modulation, oxygen consumption, respiratory exchange ratio, and polysomnographic sleep daily. Core body temperature was recorded continuously for 10 days to assess circadian phase. Circadian misalignment, when subjects ate and slept approximately 12 h out of phase from their habitual times, systematically decreased leptin (-17%, P < 0.001), increased glucose (+6%, P < 0.001) despite increased insulin (+22%, P = 0.006), completely reversed the daily cortisol rhythm (P < 0.001), increased mean arterial pressure (+3%, P = 0.001), and reduced sleep efficiency (-20%, P < 0.002). Notably, circadian misalignment caused 3 of 8 subjects (with sufficient available data) to exhibit postprandial glucose responses in the range typical of a prediabetic state. These findings demonstrate the adverse cardiometabolic implications of circadian misalignment, as occurs acutely with jet lag and chronically with shift work.”, “author” : { “dropping-particle” : “”, “family” : “Scheer”, “given” : “Frank a J L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hilton”, “given” : “Michael F”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mantzoros”, “given” : “Christos S”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Shea”, “given” : “Steven a”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Proceedings of the National Academy of Sciences of the United States of America”, “id” : “ITEM-1”, “issue” : “11”, “issued” : { “date-parts” : “2009” }, “page” : “4453-4458”, “title” : “Adverse metabolic and cardiovascular consequences of circadian misalignment.”, “type” : “article-journal”, “volume” : “106” }, “uris” : “http://www.mendeley.com/documents/?uuid=166679c9-3fa1-43aa-a803-9c627569288b” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Scheer</b> et al.</b></b>, <b>2009</b>)”, “plainTextFormattedCitation” : “(Scheer et al., 2009)”, “previouslyFormattedCitation” : “(<b><b><b>Scheer</b> et al.</b></b>, <b>2009</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Scheer et al., 2009).

Circadian rhythms are controlled by the master clock (pacemaker) that is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN pacemaker comprises multiple, autonomous single cell circadian oscillators, which are synchronized. Besides the master clock, there are also peripheral oscillators. Most tissues including extra-SCN brain regions and peripheral organs carry those peripheral circadian oscillators. These peripheral oscillators can function independently from the SCN ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/1740-3391-8-3”, “ISBN” : “1740-3391 (Electronic)\r1740-3391 (Linking)”, “ISSN” : “1740-3391”, “PMID” : “20353609”, “abstract” : “Circadian rhythms are daily oscillations of multiple biological processes directed by endogenous clocks. The circadian timing system comprises peripheral oscillators located in most tissues of the body and a central pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Circadian genes and the proteins produced by these genes constitute the molecular components of the circadian oscillator which form positive/negative feedback loops and generate circadian rhythms. The circadian regulation extends beyond clock genes to involve various clock-controlled genes (CCGs) including various cell cycle genes. Aberrant expression of circadian clock genes could have important consequences on the transactivation of downstream targets that control the cell cycle and on the ability of cells to undergo apoptosis. This may lead to genomic instability and accelerated cellular proliferation potentially promoting carcinogenesis. Different lines of evidence in mice and humans suggest that cancer may be a circadian-related disorder. The genetic or functional disruption of the molecular circadian clock has been found in various cancers including breast, ovarian, endometrial, prostate and hematological cancers. The acquisition of current data in circadian clock mechanism may help chronotherapy, which takes into consideration the biological time to improve treatments by devising new therapeutic approaches for treating circadian-related disorders, especially cancer.”, “author” : { “dropping-particle” : “”, “family” : “Rana”, “given” : “Sobia”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mahmood”, “given” : “Saqib”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Circadian Rhythms”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2010” }, “page” : “1-13”, “title” : “Circadian rhythm and its role in malignancy”, “type” : “article”, “volume” : “8” }, “uris” : “http://www.mendeley.com/documents/?uuid=227629d4-25f7-48a9-a5aa-a33635c2d0a8” } , “mendeley” : { “formattedCitation” : “(<b><b>Rana</b> and <b>Mahmood</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Rana and Mahmood, 2010)”, “previouslyFormattedCitation” : “(<b><b>Rana</b> and <b>Mahmood</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Rana and Mahmood, 2010).
Entrainment of the circadian clock to the environment is an important issue. Entrainment is the synchronization of endogenous oscillations to environmental cycles ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Ahern”, “given” : “Siobhu00e1n Anne”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “number-of-pages” : “66 – 72”, “publisher” : “(PhD thesis, School of Medical Sciences, University of Manchester, Manchester, United Kingdom)”, “title” : “The role of the clock in lipid metabolism”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=68304a00-db6b-4d28-a17e-f1ab84f68e1c” } , “mendeley” : { “formattedCitation” : “(<b><b>Ahern</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Ahern, 2016)”, “previouslyFormattedCitation” : “(<b><b>Ahern</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ahern, 2016). Entrainment is also defined as the process of determining both the circadian clock period (which is mostly 24 hours) and its phase. The phase means the offset of a circadian clock in relation to the standard 24 hour cycle. Generally, the period of the clock is genetically determined, however its phase is greatly affected by environmental stimuli as light ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1146/annurev-physiol-021115-105102”, “ISBN” : “978-0-8243-0378-5”, “ISSN” : “0066-4278”, “PMID” : “26208951”, “abstract” : “Disruption of circadian rhythms, provoked by artificial lighting at night, inconsistent sleep-wake schedules, and transmeridian air travel, is increasingly prevalent in modern society. Desynchrony of biological rhythms from environmental light cycles has dramatic consequences for human health. In particular, disrupting homeostatic oscillations in endocrine tissues and the hormones that these tissues regulate can have cascading effects on physiology and behavior. Accumulating evidence suggests that chronic disruption of circadian organization of endocrine function may lead to metabolic, reproductive, sleep, and mood disorders. This review discusses circadian control of endocrine systems and the consequences of distorting rhythmicity of these systems. Expected final online publication date for the Annual Review of Physiology Volume 78 is February 10, 2016. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.”, “author” : { “dropping-particle” : “”, “family” : “Bedrosian”, “given” : “Tracy A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annual Review of Physiology”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2016” }, “page” : “109-131”, “title” : “Endocrine Effects of Circadian Disruption”, “type” : “article-journal”, “volume” : “78” }, “uris” : “http://www.mendeley.com/documents/?uuid=616072d9-498f-48f4-bd31-28ec8fa26072” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Bedrosian</b> et al.</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Bedrosian et al., 2016)”, “previouslyFormattedCitation” : “(<b><b><b>Bedrosian</b> et al.</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Bedrosian et al., 2016). Entrainment allows human physiological functions to occur at optimal times of the day. Naturally the human circadian clock system promote energy intake, metabolism, physical activity, and cognition during the day time and promote sleep and related functions during the nighttime ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.cub.2013.06.039”, “ISBN” : “doi:10.1016/j.cub.2013.06.039”, “ISSN” : “09609822”, “PMID” : “23910656”, “abstract” : “The electric light is one of the most important human inventions. Sleep and other daily rhythms in physiology and behavior, however, evolved in the natural light-dark cycle 1, and electrical lighting is thought to have disrupted these rhythms. Yet how much the age of electrical lighting has altered the human circadian clock is unknown. Here we show that electrical lighting and the constructed environment is associated with reduced exposure to sunlight during the day, increased light exposure after sunset, and a delayed timing of the circadian clock as compared to a summer natural 14 hr 40 min:9 hr 20 min light-dark cycle camping. Furthermore, we find that after exposure to only natural light, the internal circadian clock synchronizes to solar time such that the beginning of the internal biological night occurs at sunset and the end of the internal biological night occurs before wake time just after sunrise. In addition, we find that later chronotypes show larger circadian advances when exposed to only natural light, making the timing of their internal clocks in relation to the light-dark cycle more similar to earlier chronotypes. These findings have important implications for understanding how modern light exposure patterns contribute to late sleep schedules and may disrupt sleep and circadian clocks. Video Abstract ?? 2013 Elsevier Ltd.”, “author” : { “dropping-particle” : “”, “family” : “Wright”, “given” : “Kenneth P.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “McHill”, “given” : “Andrew W.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Birks”, “given” : “Brian R.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Griffin”, “given” : “Brandon R.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rusterholz”, “given” : “Thomas”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Chinoy”, “given” : “Evan D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Current Biology”, “id” : “ITEM-1”, “issue” : “16”, “issued” : { “date-parts” : “2013” }, “page” : “1554-1558”, “publisher” : “Elsevier Ltd”, “title” : “Entrainment of the human circadian clock to the natural light-dark cycle”, “type” : “article-journal”, “volume” : “23” }, “uris” : “http://www.mendeley.com/documents/?uuid=aafadfb0-d5d8-442e-927e-0f4a127848d4” } , “mendeley” : { “formattedCitation” : “(<b><b><b>K. P. Wright</b> et al.</b></b>, <b>2013</b>)”, “manualFormatting” : “(Wright et al., 2013)”, “plainTextFormattedCitation” : “(K. P. Wright et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>K. P. Wright</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Wright et al., 2013).

Environmental zeitgebers are external factors whose function is to entrain biological rhythms. Any environmental cue that changes across the 24 h day can possibly serve as an entraining signal (zeitgeber: a German word meaning ‘time giver’) ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/S0092-8674(03)00076-X”, “ISBN” : “0092-8674 (Print)\r0092-8674 (Linking)”, “ISSN” : “00928674”, “PMID” : “12581517”, “abstract” : “Circadian clocks in a wide range of organisms are thought to consist of two interdependent transcriptional feedback loops. In Drosophila, the first loop has been well characterized and controls rhythmic period expression. In this issue of Cell, Cyran et al. (2003) define a role for a transcriptional activator and a repressor in the second feedback loop.”, “author” : { “dropping-particle” : “”, “family” : “Roenneberg”, “given” : “T.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kantermann”, “given” : “T.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Juda”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Vetter”, “given” : “C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Allebrandt”, “given” : “K.V.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Handbook of Experimental Pharmacology”, “edition” : “Circadian “, “editor” : { “dropping-particle” : “”, “family” : “Kramer”, “given” : “Achim”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Merrow”, “given” : “Martha”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2013” }, “number-of-pages” : “311 -331”, “publisher” : “springer”, “title” : “Light and the Human Circadian Clock”, “type” : “book”, “volume” : “117” }, “uris” : “http://www.mendeley.com/documents/?uuid=c71da2d6-75dc-49ae-9266-4bd3d4dfcf99” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Roenneberg</b> et al.</b></b>, <b>2013</b>)”, “plainTextFormattedCitation” : “(Roenneberg et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Roenneberg</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Roenneberg et al., 2013). Natural environmental inputs that entrain the circadian oscillator are generally divided into photic (light) and non-photic (exercise, social interaction) stimuli. These stimuli reach the SCN and peripheral clocks through very different pathways, but in each case the net result is rhythmic physiology and behavior that is optimally synchronized to the environment ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/B978-0-12-378610-4.00095-4”, “ISBN” : “9780123786104”, “author” : { “dropping-particle” : “”, “family” : “Mircsof”, “given” : “D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Brown”, “given” : “S.A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Encyclopedia of Sleep”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2013” }, “number-of-pages” : “435-441”, “publisher” : “Elsevier Inc.”, “title” : “The Influence of Light, Exercise, and Behavior upon Circadian Rhythms*”, “type” : “book”, “volume” : “1” }, “uris” : “http://www.mendeley.com/documents/?uuid=de2a6e2b-7ad9-42c0-b084-77fca19e77e8” } , “mendeley” : { “formattedCitation” : “(<b><b>Mircsof</b> and <b>Brown</b></b>, <b>2013</b>)”, “manualFormatting” : “(Mircsof and Brown, 2013)”, “plainTextFormattedCitation” : “(Mircsof and Brown, 2013)”, “previouslyFormattedCitation” : “(<b><b>Mircsof</b> and <b>Brown</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mircsof and Brown, 2013).
Light is considered the strongest Zeitgeber for the SCN. Every day, light exposure resets the phase of the endogenous circadian clock and the linked oscillations in physiology and behavior to exactly match the 24-h day. The effect of light on the SCN varies depending on the time at which it is perceived ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/B978-0-12-378610-4.00095-4”, “ISBN” : “9780123786104”, “author” : { “dropping-particle” : “”, “family” : “Mircsof”, “given” : “D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Brown”, “given” : “S.A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Encyclopedia of Sleep”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2013” }, “number-of-pages” : “435-441”, “publisher” : “Elsevier Inc.”, “title” : “The Influence of Light, Exercise, and Behavior upon Circadian Rhythms*”, “type” : “book”, “volume” : “1” }, “uris” : “http://www.mendeley.com/documents/?uuid=de2a6e2b-7ad9-42c0-b084-77fca19e77e8” } , “mendeley” : { “formattedCitation” : “(<b><b>Mircsof</b> and <b>Brown</b></b>, <b>2013</b>)”, “manualFormatting” : “(Mircsof and Brown, 2013)”, “plainTextFormattedCitation” : “(Mircsof and Brown, 2013)”, “previouslyFormattedCitation” : “(<b><b>Mircsof</b> and <b>Brown</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mircsof and Brown, 2013). In humans light is perceived by a photosensitive retinal ganglion cells (RGCs). These specialized RGCs depolarize in response to light and synapse directly onto SCN neurons. The photic information is then directly conveyed to the SCN clock through the retino-hypothalamic tract. Finally the photic information corrects the phase of the SCN oscillator every day to ensure circadian synchronization with geophysical time ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1146/annurev-physiol-021115-105102”, “ISBN” : “978-0-8243-0378-5”, “ISSN” : “0066-4278”, “PMID” : “26208951”, “abstract” : “Disruption of circadian rhythms, provoked by artificial lighting at night, inconsistent sleep-wake schedules, and transmeridian air travel, is increasingly prevalent in modern society. Desynchrony of biological rhythms from environmental light cycles has dramatic consequences for human health. In particular, disrupting homeostatic oscillations in endocrine tissues and the hormones that these tissues regulate can have cascading effects on physiology and behavior. Accumulating evidence suggests that chronic disruption of circadian organization of endocrine function may lead to metabolic, reproductive, sleep, and mood disorders. This review discusses circadian control of endocrine systems and the consequences of distorting rhythmicity of these systems. Expected final online publication date for the Annual Review of Physiology Volume 78 is February 10, 2016. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.”, “author” : { “dropping-particle” : “”, “family” : “Bedrosian”, “given” : “Tracy A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annual Review of Physiology”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2016” }, “page” : “109-131”, “title” : “Endocrine Effects of Circadian Disruption”, “type” : “article-journal”, “volume” : “78” }, “uris” : “http://www.mendeley.com/documents/?uuid=616072d9-498f-48f4-bd31-28ec8fa26072” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Bedrosian</b> et al.</b></b>, <b>2016</b>)”, “manualFormatting” : “(Bedrosian et al., 2016)”, “plainTextFormattedCitation” : “(Bedrosian et al., 2016)”, “previouslyFormattedCitation” : “(<b><b><b>Bedrosian</b> et al.</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Bedrosian et al., 2016).
Food is an essential external entraining signal for the circadian system. Limiting food intake to certain times of day can lead to expected increase in wakefulness, locomotion, body temperature, and glucocorticoid secretion ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1210/er.2013-1051”, “ISBN” : “0163-769X”, “ISSN” : “0163769X”, “PMID” : “24673196”, “abstract” : “Most organisms display endogenously produced u223cf24 h fluctuations in physiology and behavior, termed circadian rhythms. Circadian rhythms are driven by a transcriptional-translational feedback loop that is hierarchically expressed throughout the brain and body, with the suprachiasmatic nucleus of the hypothalamus serving as the master circadian oscillator at the top of the hierarchy. Appropriate circadian regulation is important for many homeostatic functions including energy regulation. Multiple genes involved in nutrient metabolism display rhythmic oscillations and metabolically related hormones such as glucagon, insulin, ghrelin, leptin, and corticosterone are released in a circadian fashion. Mice harboring mutations in circadian clock genes alter feeding behavior, endocrine signaling, and dietary fat absorption. Moreover, misalignment between behavioral and molecular circadian clocks can result in obesity in both rodents and humans. Importantly, circadian rhythms are most potently synchronized to the external environment by light information and exposure to light at night potentially disrupts circadian system function. Since the advent of electric lights around the turn of the 20th century, exposure to artificial and irregular light schedules has become commonplace. The increase in exposure to light at night parallels the global increase in the prevalence of obesity and metabolic disorders. In this review, we propose that exposure to light at night alters metabolic function through disruption of the circadian system. We first provide an introduction to the circadian system, with a specific emphasis on the effects of light on circadian rhythms. Next we address interactions between the circadian system and metabolism. Finally, we review current experimental and epidemiological work directly associating exposure to light at night and metabolism.”, “author” : { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Endocrine Reviews”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2014” }, “page” : “648-670”, “title” : “The effects of light at night on circadian clocks and metabolism”, “type” : “article-journal”, “volume” : “35” }, “uris” : “http://www.mendeley.com/documents/?uuid=90c7cda5-76f0-4c7a-870e-34cc4bc62c97” } , “mendeley” : { “formattedCitation” : “(<b><b>Fonken</b> and <b>Nelson</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Fonken and Nelson, 2014)”, “previouslyFormattedCitation” : “(<b><b>Fonken</b> and <b>Nelson</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Fonken and Nelson, 2014). Other non-photic cues such as exercise and behavior can also synchronize and entrain circadian rhythms. These cues act very potently on peripheral circadian oscillators, while the central clock remains light-driven under normal circumstances ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1152/physrev.00009.2009.”, “ISBN” : “1522-1210; 0031-9333”, “ISSN” : “1522-1210”, “PMID” : “20664079”, “abstract” : “Mammalian circadian rhythms are controlled by endogenous biological oscillators, including a master clock located in the hypothalamic suprachiasmatic nuclei (SCN). Since the period of this oscillation is of approximately 24 h, to keep synchrony with the environment, circadian rhythms need to be entrained daily by means of Zeitgeber (“time giver”) signals, such as the light-dark cycle. Recent advances in the neurophysiology and molecular biology of circadian rhythmicity allow a better understanding of synchronization. In this review we cover several aspects of the mechanisms for photic entrainment of mammalian circadian rhythms, including retinal sensitivity to light by means of novel photopigments as well as circadian variations in the retina that contribute to the regulation of retinal physiology. Downstream from the retina, we examine retinohypothalamic communication through neurotransmitter (glutamate, aspartate, pituitary adenylate cyclase-activating polypeptide) interaction with SCN receptors and the resulting signal transduction pathways in suprachiasmatic neurons, as well as putative neuron-glia interactions. Finally, we describe and analyze clock gene expression and its importance in entrainment mechanisms, as well as circadian disorders or retinal diseases related to entrainment deficits, including experimental and clinical treatments.”, “author” : { “dropping-particle” : “”, “family” : “Golombek”, “given” : “Diego a”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rosenstein”, “given” : “Ruth E”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Physiology Rev”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2010” }, “page” : “1063-1102”, “title” : “Physiology of Circadian Entrainment”, “type” : “article-journal”, “volume” : “90” }, “uris” : “http://www.mendeley.com/documents/?uuid=81802034-29f4-4769-9ef4-853e5f8a6f65” } , “mendeley” : { “formattedCitation” : “(<b><b>Golombek</b> and <b>Rosenstein</b></b>, <b>2010</b>)”, “manualFormatting” : “(Golombek and Rosenstein, 2010)”, “plainTextFormattedCitation” : “(Golombek and Rosenstein, 2010)”, “previouslyFormattedCitation” : “(<b><b>Golombek</b> and <b>Rosenstein</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Golombek and Rosenstein, 2010). There are also many factors that can act as internal cues for circadian clock. Internal zeitgebers include factors that fluctuate inside the body for example bloodstream, neuronal transmitters or body temperature ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/S0092-8674(03)00076-X”, “ISBN” : “0092-8674 (Print)\r0092-8674 (Linking)”, “ISSN” : “00928674”, “PMID” : “12581517”, “abstract” : “Circadian clocks in a wide range of organisms are thought to consist of two interdependent transcriptional feedback loops. In Drosophila, the first loop has been well characterized and controls rhythmic period expression. In this issue of Cell, Cyran et al. (2003) define a role for a transcriptional activator and a repressor in the second feedback loop.”, “author” : { “dropping-particle” : “”, “family” : “Roenneberg”, “given” : “T.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kantermann”, “given” : “T.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Juda”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Vetter”, “given” : “C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Allebrandt”, “given” : “K.V.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Handbook of Experimental Pharmacology”, “edition” : “Circadian “, “editor” : { “dropping-particle” : “”, “family” : “Kramer”, “given” : “Achim”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Merrow”, “given” : “Martha”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2013” }, “number-of-pages” : “311 -331”, “publisher” : “springer”, “title” : “Light and the Human Circadian Clock”, “type” : “book”, “volume” : “117” }, “uris” : “http://www.mendeley.com/documents/?uuid=c71da2d6-75dc-49ae-9266-4bd3d4dfcf99” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Roenneberg</b> et al.</b></b>, <b>2013</b>)”, “plainTextFormattedCitation” : “(Roenneberg et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Roenneberg</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Roenneberg et al., 2013).
Despite the presence of many external and internal zeitgebers; light is considered the most dominant zeitgeber. This light dominance is because light (and darkness) is responsible for all other environmental rhythms, and it is therefore the primary and most reliable source of information about time of day ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/S0092-8674(03)00076-X”, “ISBN” : “0092-8674 (Print)\r0092-8674 (Linking)”, “ISSN” : “00928674”, “PMID” : “12581517”, “abstract” : “Circadian clocks in a wide range of organisms are thought to consist of two interdependent transcriptional feedback loops. In Drosophila, the first loop has been well characterized and controls rhythmic period expression. In this issue of Cell, Cyran et al. (2003) define a role for a transcriptional activator and a repressor in the second feedback loop.”, “author” : { “dropping-particle” : “”, “family” : “Roenneberg”, “given” : “T.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kantermann”, “given” : “T.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Juda”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Vetter”, “given” : “C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Allebrandt”, “given” : “K.V.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Handbook of Experimental Pharmacology”, “edition” : “Circadian “, “editor” : { “dropping-particle” : “”, “family” : “Kramer”, “given” : “Achim”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Merrow”, “given” : “Martha”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2013” }, “number-of-pages” : “311 -331”, “publisher” : “springer”, “title” : “Light and the Human Circadian Clock”, “type” : “book”, “volume” : “117” }, “uris” : “http://www.mendeley.com/documents/?uuid=c71da2d6-75dc-49ae-9266-4bd3d4dfcf99” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Roenneberg</b> et al.</b></b>, <b>2013</b>)”, “plainTextFormattedCitation” : “(Roenneberg et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Roenneberg</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Roenneberg et al., 2013). The master clock in the SCN, it is highly sensitive to light information. On the contrary, peripheral oscillators may not respond to light-dark cycles and can be entrained commonly by non-photic stimuli such as variable chemical signals or to temperature cycles ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1177/0748730403253381”, “ISBN” : “9780123969712”, “ISSN” : “00000000”, “PMID” : “20148687”, “abstract” : “Peripheral cells from mammalian tissues, while perfectly capable of circadian rhythm generation, are not light sensitive and thus have to be entrained by nonphotic cues. Feeding time is the dominant zeitgeber for peripheral mammalian clocks: Daytime feeding of nocturnal laboratory rodents completely inverts the phase of circadian gene expression in many tissues, including liver, heart, kidney, and pancreas, but it has no effect on the SCN pacemaker. It is thus plausible that in intact animals, the SCN synchronizes peripheral clocks primarily through temporal feeding patterns that are imposed through behavioral restactivity cycles. In addition, body temperature rhythms, which are themselves dependent on both feeding patterns and rest-activity cycles, can sustain circadian, clock gene activity in vivo and in vitro. The SCN may also influence the phase of rhythmic gene expression in peripheral tissues through direct chemical pathways. In fact, many chemical signals induce circadian gene expression in tissue culture cells. Some of these have been shown to elicit phase shifts when injected into intact animals and are thus candidates for physiologically relevant timing cues. While the response of the SCN to light is strictly gated to respond only during the night, peripheral oscillators can be chemically phase shifted throughout the day. For example, injection of dexamethasone, a glucocorticoid receptor agonist, resets the phase of circadian liver gene expression during the entire 24-h day. Given the bewildering array of agents capable of influencing peripheral clocks, the identification of physiologically relevant agents used by the SCN to synchronize peripheral clocks will clearly be an arduous undertaking. Nevertheless, we feel that experimental systems by which this enticing problem can be tackled are now at hand”, “author” : { “dropping-particle” : “”, “family” : “Schibler”, “given” : “Ueli”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schibler”, “given” : “Ueli”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ripperger”, “given” : “Juergen”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ripperger”, “given” : “Juergen”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Brown”, “given” : “Steven a”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Brown”, “given” : “Steven a”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Biological Rhythms”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2003” }, “page” : “250-260”, “title” : “Peripheral Circadian Oscillators in Mammals: Time and Food”, “type” : “article”, “volume” : “18” }, “uris” : “http://www.mendeley.com/documents/?uuid=ad263810-b90e-4d67-a321-fc987d3607f0” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Schibler</b> et al.</b></b>, <b>2003</b>)”, “plainTextFormattedCitation” : “(Schibler et al., 2003)”, “previouslyFormattedCitation” : “(<b><b><b>Schibler</b> et al.</b></b>, <b>2003</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Schibler et al., 2003). The master clock synchronizes peripheral clocks in organs such as liver, heart, and kidney through direct and indirect ways. This synchronization makes an orchestrated coherent rhythm at the level of the organism to ensure temporally coordinated physiology ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/S0092-8674(02)01225-4”, “ISBN” : “0092-8674”, “ISSN” : “00928674”, “PMID” : “12507418”, “abstract” : “The mammalian circadian timing system is composed of almost as many individual clocks as there are cells. These countless oscillators have to be synchronized by a central pacemaker to coordinate temporal physiology and behavior. Recently, there has been some progress in understanding the relationship and communication mechanisms between central and peripheral clocks.”, “author” : { “dropping-particle” : “”, “family” : “Schibler”, “given” : “Ueli”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sassone-Corsi”, “given” : “Paolo”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Cell”, “id” : “ITEM-1”, “issue” : “7”, “issued” : { “date-parts” : “2002” }, “page” : “919-922”, “title” : “A web of circadian pacemakers”, “type” : “article-journal”, “volume” : “111” }, “uris” : “http://www.mendeley.com/documents/?uuid=31d06e57-84df-4d77-99a7-5b8bfb244b78” } , “mendeley” : { “formattedCitation” : “(<b><b>Schibler</b> and <b>Sassone-Corsi</b></b>, <b>2002</b>)”, “manualFormatting” : “(Schibler and Sassone-Corsi, 2002)”, “plainTextFormattedCitation” : “(Schibler and Sassone-Corsi, 2002)”, “previouslyFormattedCitation” : “(<b><b>Schibler</b> and <b>Sassone-Corsi</b></b>, <b>2002</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Schibler and Sassone-Corsi, 2002).
Entrainment may be direct or indirect. Direct entrainment may take place through cyclically secreted hormones and probably neuronal signals. Neuronal signals are transmitted to peripheral clocks via the peripheral nervous system. Indirect synchronization is achieved by controlling daily activity/rest cycles and consequently feeding time. Feeding (or starving) cycles are main stimuli for many, if not all, peripheral clocks. Food metabolites (as glucose) and hormones linked to feeding and starvation are probably the feeding-dependent entrainment signals. Activity cycles also affect body temperature rhythms, which are controlled in part by the SCN. Master clock then in turn can participate in the phase entrainment of peripheral clocks ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/S0092-8674(02)01225-4”, “ISBN” : “0092-8674”, “ISSN” : “00928674”, “PMID” : “12507418”, “abstract” : “The mammalian circadian timing system is composed of almost as many individual clocks as there are cells. These countless oscillators have to be synchronized by a central pacemaker to coordinate temporal physiology and behavior. Recently, there has been some progress in understanding the relationship and communication mechanisms between central and peripheral clocks.”, “author” : { “dropping-particle” : “”, “family” : “Schibler”, “given” : “Ueli”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sassone-Corsi”, “given” : “Paolo”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Cell”, “id” : “ITEM-1”, “issue” : “7”, “issued” : { “date-parts” : “2002” }, “page” : “919-922”, “title” : “A web of circadian pacemakers”, “type” : “article-journal”, “volume” : “111” }, “uris” : “http://www.mendeley.com/documents/?uuid=31d06e57-84df-4d77-99a7-5b8bfb244b78” } , “mendeley” : { “formattedCitation” : “(<b><b>Schibler</b> and <b>Sassone-Corsi</b></b>, <b>2002</b>)”, “manualFormatting” : “(Schibler and Sassone-Corsi, 2002)”, “plainTextFormattedCitation” : “(Schibler and Sassone-Corsi, 2002)”, “previouslyFormattedCitation” : “(<b><b>Schibler</b> and <b>Sassone-Corsi</b></b>, <b>2002</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Schibler and Sassone-Corsi, 2002).
Melatonin is a secretory product of the pineal gland. Melatonin plays an important role in entrainment. Melatonin activity is under circadian control via the SCN, where rhythmic melatonin secretion persists in constant darkness conditions, but melatonin rhythm is inhibited by light. Melatonin has many functions, for example it affects the immune system, the sleep-wake cycle, mood, and metabolism. Many causes of circadian disruption, also disrupt melatonin secretion ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1146/annurev-physiol-021115-105102”, “ISBN” : “978-0-8243-0378-5”, “ISSN” : “0066-4278”, “PMID” : “26208951”, “abstract” : “Disruption of circadian rhythms, provoked by artificial lighting at night, inconsistent sleep-wake schedules, and transmeridian air travel, is increasingly prevalent in modern society. Desynchrony of biological rhythms from environmental light cycles has dramatic consequences for human health. In particular, disrupting homeostatic oscillations in endocrine tissues and the hormones that these tissues regulate can have cascading effects on physiology and behavior. Accumulating evidence suggests that chronic disruption of circadian organization of endocrine function may lead to metabolic, reproductive, sleep, and mood disorders. This review discusses circadian control of endocrine systems and the consequences of distorting rhythmicity of these systems. Expected final online publication date for the Annual Review of Physiology Volume 78 is February 10, 2016. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.”, “author” : { “dropping-particle” : “”, “family” : “Bedrosian”, “given” : “Tracy A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annual Review of Physiology”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2016” }, “page” : “109-131”, “title” : “Endocrine Effects of Circadian Disruption”, “type” : “article-journal”, “volume” : “78” }, “uris” : “http://www.mendeley.com/documents/?uuid=616072d9-498f-48f4-bd31-28ec8fa26072” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Bedrosian</b> et al.</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Bedrosian et al., 2016)”, “previouslyFormattedCitation” : “(<b><b><b>Bedrosian</b> et al.</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Bedrosian et al., 2016). Melatonin protects the body from oxidative damage; elevate the efficiency of the electron transport chain in the mitochondria. In addition, melatonin acts as an endocrine regulator of nighttime blood pressure in healthy persons through contributing to its normal drop by 10–20% during sleep from its daytime mean level. Moreover, normal nighttime melatonin production reduces oxidative stress caused by arterial hypertension ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.3109/07420528.2012.709448”, “ISBN” : “3498681214”, “ISSN” : “07420528”, “PMID” : “23077971”, “abstract” : “Specific features of the 24-h blood pressure (BP) pattern are linked to progressive injury of target tissues and risk of cardiovascular disease (CVD) events. Several studies have consistently shown an association between blunted asleep BP decline and risk of fatal and nonfatal CVD events. Thus, there is growing focus on ways to properly control BP during nighttime sleep as well as during daytime activity. One strategy, termed chronotherapy, entails the timing of hypertension medications to endogenous circadian rhythm determinants of the 24-h BP pattern. Significant and clinically meaningful treatment-time differences in the beneficial and/or adverse effects of at least six different classes of hypertension medications, and their combinations, are now known. Generally, calcium channel blockers (CCBs) are more effective with bedtime than morning dosing, and for dihydropyridine derivatives bedtime dosing significantly reduces risk of peripheral edema. The renin-angiotensin-aldosterone system is highly circadian rhythmic and activates during nighttime sleep. Accordingly, evening/bedtime ingestion of the angiotensin-converting enzyme inhibitors (ACEIs) benazepril, captopril, enalapril, lisinopril, perindopril, quinapril, ramipril, spirapril, trandolapril, and zofenopril exerts more marked effect on the asleep than awake systolic (SBP) and diastolic (DBP) BP means. Likewise, the bedtime, in comparison with morning, ingestion schedule of the angiotensin-II receptor blockers (ARBs irbesartan, olmesartan, telmisartan, and valsartan exerts greater therapeutic effect on asleep BP, plus significant increase in the sleep-time relative BP decline, with the additional benefit, independent of drug terminal half-life, of converting the 24-h BP profile into a more normal dipping pattern. This is the case also for the bedtime versus upon-awakening regimen of combination ARB-CCB, ACEI-CCB, and ARB-diuretic medications. The chronotherapy of conventional hypertension medications constitutes a new and cost-effective strategy for enhancing the control of daytime and nighttime SBP and DBP levels, normalizing the dipping status of their 24-h patterning, and potentially reducing the risk of CVD events and end-organ injury, for example, of the blood vessels and tissues of the heart, brain, kidney, and retina.”, “author” : { “dropping-particle” : “”, “family” : “Hermida”, “given” : “Ramu00f3n C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ayala”, “given” : “Diana E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fernu00e1ndez”, “given” : “Josu00e9 R.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Moju00f3n”, “given” : “Artemio”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Smolensky”, “given” : “Michael H.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fabbian”, “given” : “Fabio”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Portaluppi”, “given” : “Francesco”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Chronobiology International”, “id” : “ITEM-1”, “issue” : “1-2”, “issued” : { “date-parts” : “2013” }, “page” : “280-314”, “title” : “Administration-Time Differences in Effects of Hypertension Medications on Ambulatory Blood Pressure Regulation”, “type” : “article”, “volume” : “30” }, “uris” : “http://www.mendeley.com/documents/?uuid=14948edf-abde-492c-91c8-1a061873e3a9” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Hermida</b> et al.</b></b>, <b>2013</b>)”, “plainTextFormattedCitation” : “(Hermida et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Hermida</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Hermida et al., 2013).

Also, melatonin is protective of the central nervous system; it reduces free-radical load, improves endothelial dysfunction, reduces inflammation, modulates the response to endotoxemia, and shifts the balance between sympathetic and parasympathetic drive in favor of the later ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.3109/07420528.2015.1072002”, “ISBN” : “0742-0528”, “ISSN” : “15256073”, “PMID” : “26374931”, “abstract” : “Routine exposure to artificial light at night (ALAN) in work, home, and community settings is linked with increased risk of breast and prostate cancer (BC, PC) in normally sighted women and men, the hypothesized biological rhythm mechanisms being frequent nocturnal melatonin synthesis suppression, circadian time structure (CTS) desynchronization, and sleep/wake cycle disruption with sleep deprivation. ALAN-induced perturbation of the CTS melatonin synchronizer signal is communicated maternally at the very onset of life and after birth via breast or artificial formula feedings. Nighttime use of personal computers, mobile phones, electronic tablets, televisions, and the like – now epidemic in adolescents and adults and highly prevalent in pre-school and school-aged children – is a new source of ALAN. However, ALAN exposure occurs concomitantly with almost complete absence of daytime sunlight, whose blue-violet (446-484 nm u03bb) spectrum synchronizes the CTS and whose UV-B (290-315 nm u03bb) spectrum stimulates vitamin D synthesis. Under natural conditions and clear skies, day/night and annual cycles of UV-B irradiation drive corresponding periodicities in vitamin D synthesis and numerous bioprocesses regulated by active metabolites augment and strengthen the biological time structure. Vitamin D insufficiency and deficiency are widespread in children and adults in developed and developing countries as a consequence of inadequate sunlight exposure. Past epidemiologic studies have focused either on exposure to too little daytime UV-B or too much ALAN, respectively, on vitamin D deficiency/insufficiency or melatonin suppression in relation to risk of cancer and other, e.g., psychiatric, hypertensive, cardiac, and vascular, so-called, diseases of civilization. The observed elevated incidence of medical conditions the two are alleged to influence through many complementary bioprocesses of cells, tissues, and organs led us to examine effects of the totality of the artificial light environment in which humans reside today. Never have chronobiologic or epidemiologic investigations comprehensively researched the potentially deleterious consequences of the combination of suppressed vitamin D plus melatonin synthesis due to life in today’s man-made artificial light environment, which in our opinion is long overdue.”, “author” : { “dropping-particle” : “”, “family” : “Smolensky”, “given” : “Michael H.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sackett-Lundeen”, “given” : “Linda L.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Portaluppi”, “given” : “Francesco”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Chronobiology International”, “id” : “ITEM-1”, “issue” : “8”, “issued” : { “date-parts” : “2015” }, “page” : “1029-1048”, “title” : “Nocturnal light pollution and underexposure to daytime sunlight: Complementary mechanisms of circadian disruption and related diseases”, “type” : “article-journal”, “volume” : “32” }, “uris” : “http://www.mendeley.com/documents/?uuid=184c74fc-fe9e-406b-9407-07a45b6b55ea” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Smolensky;/b; et al.;/b;;/b;, ;b;2015;/b;)”, “plainTextFormattedCitation” : “(Smolensky et al., 2015)”, “previouslyFormattedCitation” : “(;b;;b;;b;Smolensky;/b; et al.;/b;;/b;, ;b;2015;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Smolensky et al., 2015). In humans, 100 to 350 lux of light is enough to suppress melatonin levels. Exposure to just a 100 lux in the early night delays the melatonin rhythm. Melatonin suppression can take place by using a tablet, computer or e-reader before bedtime ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.apergo.2012.07.008”, “ISBN” : “1872-9126 (Electronic)\r0003-6870 (Linking)”, “ISSN” : “00036870”, “PMID” : “22850476”, “abstract” : “Exposure to light from self-luminous displays may be linked to increased risk for sleep disorders because these devices emit optical radiation at short wavelengths, close to the peak sensitivity of melatonin suppression. Thirteen participants experienced three experimental conditions in a within-subjects design to investigate the impact of self-luminous tablet displays on nocturnal melatonin suppression: 1) tablets-only set to the highest brightness, 2) tablets viewed through clear-lens goggles equipped with blue light-emitting diodes that provided 40 lux of 470-nm light at the cornea, and 3) tablets viewed through orange-tinted glasses (dark control; optical radiation ;525 nm ??? 0). Melatonin suppressions after 1-h and 2-h exposures to tablets viewed with the blue light were significantly greater than zero. Suppression levels after 1-h exposure to the tablets-only were not statistically different than zero; however, this difference reached significance after 2 h. Based on these results, display manufacturers can determine how their products will affect melatonin levels and use model predictions to tune the spectral power distribution of self-luminous devices to increase or to decrease stimulation to the circadian system. ?? 2012 Elsevier Ltd and The Ergonomics Society.”, “author” : { “dropping-particle” : “”, “family” : “Wood”, “given” : “Brittany”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rea”, “given” : “Mark S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Plitnick”, “given” : “Barbara”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Figueiro”, “given” : “Mariana G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Applied Ergonomics”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2013” }, “page” : “237-240”, “title” : “Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression”, “type” : “article”, “volume” : “44” }, “uris” : “http://www.mendeley.com/documents/?uuid=45049fd2-5161-48fd-b714-e1dd07f41157” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Wood;/b; et al.;/b;;/b;, ;b;2013;/b;)”, “manualFormatting” : “(Wood et al., 2013)”, “plainTextFormattedCitation” : “(Wood et al., 2013)”, “previouslyFormattedCitation” : “(;b;;b;;b;Wood;/b; et al.;/b;;/b;, ;b;2013;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Wood et al., 2013).
Glucocorticoids are particularly important in circadian disruption as they are both a primary output of, and a feedback signal for, the circadian system. The pattern of glucocorticoids secretion follows the light-dark cycle. In humans, plasma cortisol level peaks in the early morning, within 30 min of rising, and reach its lowest level near midnight. By peaking before or at the onset of the active phase, cortisol is believed to help prepare the body for waking up and activity ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1146/annurev-physiol-021115-105102”, “ISBN” : “978-0-8243-0378-5”, “ISSN” : “0066-4278”, “PMID” : “26208951”, “abstract” : “Disruption of circadian rhythms, provoked by artificial lighting at night, inconsistent sleep-wake schedules, and transmeridian air travel, is increasingly prevalent in modern society. Desynchrony of biological rhythms from environmental light cycles has dramatic consequences for human health. In particular, disrupting homeostatic oscillations in endocrine tissues and the hormones that these tissues regulate can have cascading effects on physiology and behavior. Accumulating evidence suggests that chronic disruption of circadian organization of endocrine function may lead to metabolic, reproductive, sleep, and mood disorders. This review discusses circadian control of endocrine systems and the consequences of distorting rhythmicity of these systems. Expected final online publication date for the Annual Review of Physiology Volume 78 is February 10, 2016. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.”, “author” : { “dropping-particle” : “”, “family” : “Bedrosian”, “given” : “Tracy A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annual Review of Physiology”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2016” }, “page” : “109-131”, “title” : “Endocrine Effects of Circadian Disruption”, “type” : “article-journal”, “volume” : “78” }, “uris” : “http://www.mendeley.com/documents/?uuid=616072d9-498f-48f4-bd31-28ec8fa26072” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Bedrosian;/b; et al.;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Bedrosian et al., 2016)”, “previouslyFormattedCitation” : “(;b;;b;;b;Bedrosian;/b; et al.;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Bedrosian et al., 2016). Notably, not only glucocorticoids levels fluctuate throughout the day, but also the sensitivity of the tissues and cells to their effect also swings. Fluctuations in the Tissue responsiveness can be attributed to rhythmic suppression of the glucocorticoid receptor ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1038/nature10700.Cryptochromes”, “author” : { “dropping-particle” : “”, “family” : “Lamia”, “given” : “Katja A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Papp”, “given” : “Stephanie J”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Yu”, “given” : “Ruth T”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Barish”, “given” : “Grant D”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Henriette”, “given” : “N”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jonker”, “given” : “Johan W”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Downes”, “given” : “Michael”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Evans”, “given” : “Ronald M”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Nature”, “id” : “ITEM-1”, “issue” : “7378”, “issued” : { “date-parts” : “2012” }, “page” : “552-556”, “title” : “Cryptochromes mediate rhythmic repression of the glucocorticoid receptor Katja”, “type” : “article-journal”, “volume” : “480” }, “uris” : “http://www.mendeley.com/documents/?uuid=64df3248-6347-4b24-80d5-d7b22f7c0e98” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Lamia;/b; et al.;/b;;/b;, ;b;2012;/b;)”, “plainTextFormattedCitation” : “(Lamia et al., 2012)”, “previouslyFormattedCitation” : “(;b;;b;;b;Lamia;/b; et al.;/b;;/b;, ;b;2012;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Lamia et al., 2012).
Daytime light levels in the workplace are inversely correlated with cortisol levels; workers exposed to lower levels of light in offices without windows have elevated nighttime cortisol concentrations. Shift work is also associated with disturbed cortisol rhythms. Moreover, it was shown that cortisol concentrations in night shift workers are higher during the day and lower during the night compared with cortisol concentrations in day shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.joca.2015.05.020.Osteoarthritic”, “ISBN” : “6176323479”, “ISSN” : “09652140”, “PMID” : “26780180”, “author” : { “dropping-particle” : “”, “family” : “Wright”, “given” : “KP Jr”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Drake”, “given” : “AL”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Frey”, “given” : “DJ”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fleshner”, “given” : “M”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Desouza”, “given” : “CA”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gronfier”, “given” : “C”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Czeisler”, “given” : “CA”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “10”, “issued” : { “date-parts” : “2016” }, “page” : “1780-1789”, “title” : “Influence of Sleep Deprivation and Circadian Misalignment on Cortisol, Inflammatory Markers, and Cytokine Balance”, “type” : “article-journal”, “volume” : “23” }, “uris” : “http://www.mendeley.com/documents/?uuid=c35edd45-a839-45f8-ad34-5edda9622e11” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;K. J. Wright;/b; et al.;/b;;/b;, ;b;2016;/b;)”, “manualFormatting” : “(Wright et al., 2016)”, “plainTextFormattedCitation” : “(K. J. Wright et al., 2016)”, “previouslyFormattedCitation” : “(;b;;b;;b;K. J. Wright;/b; et al.;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Wright et al., 2016).
Many metabolic hormones, including leptin, ghrelin, insulin, adiponectin, and glucagon, are released in a diurnal fashion. Importantly, the rhythmic pattern of nutrient sensitive hormones differs in part in response to environmental and behavioral factors such as timing of food intake ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1210/er.2013-1051”, “ISBN” : “0163-769X”, “ISSN” : “0163769X”, “PMID” : “24673196”, “abstract” : “Most organisms display endogenously produced u223cf24 h fluctuations in physiology and behavior, termed circadian rhythms. Circadian rhythms are driven by a transcriptional-translational feedback loop that is hierarchically expressed throughout the brain and body, with the suprachiasmatic nucleus of the hypothalamus serving as the master circadian oscillator at the top of the hierarchy. Appropriate circadian regulation is important for many homeostatic functions including energy regulation. Multiple genes involved in nutrient metabolism display rhythmic oscillations and metabolically related hormones such as glucagon, insulin, ghrelin, leptin, and corticosterone are released in a circadian fashion. Mice harboring mutations in circadian clock genes alter feeding behavior, endocrine signaling, and dietary fat absorption. Moreover, misalignment between behavioral and molecular circadian clocks can result in obesity in both rodents and humans. Importantly, circadian rhythms are most potently synchronized to the external environment by light information and exposure to light at night potentially disrupts circadian system function. Since the advent of electric lights around the turn of the 20th century, exposure to artificial and irregular light schedules has become commonplace. The increase in exposure to light at night parallels the global increase in the prevalence of obesity and metabolic disorders. In this review, we propose that exposure to light at night alters metabolic function through disruption of the circadian system. We first provide an introduction to the circadian system, with a specific emphasis on the effects of light on circadian rhythms. Next we address interactions between the circadian system and metabolism. Finally, we review current experimental and epidemiological work directly associating exposure to light at night and metabolism.”, “author” : { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Endocrine Reviews”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2014” }, “page” : “648-670”, “title” : “The effects of light at night on circadian clocks and metabolism”, “type” : “article-journal”, “volume” : “35” }, “uris” : “http://www.mendeley.com/documents/?uuid=90c7cda5-76f0-4c7a-870e-34cc4bc62c97” } , “mendeley” : { “formattedCitation” : “(;b;;b;Fonken;/b; and ;b;Nelson;/b;;/b;, ;b;2014;/b;)”, “plainTextFormattedCitation” : “(Fonken and Nelson, 2014)”, “previouslyFormattedCitation” : “(;b;;b;Fonken;/b; and ;b;Nelson;/b;;/b;, ;b;2014;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Fonken and Nelson, 2014). Also many hormones produced by the peripheral endocrine glands show different degrees of circadian control. Particularly the adrenal and reproductive systems demonstrate strong evidence of circadian rhythmicity. The 24 h fluctuations in these hormones have been shown to anticipate predictable daily events. The immune system is greatly controlled by the circadian system. Many aspects of immune functions show circadian rhythmicity, including immune cell trafficking, antigen presenting, Toll-like receptor function, cytokine gene expression, and lymphocyte proliferation. Rhythmicity of immune activity is both directly and indirectly dependent on circadian rhythms in endocrine factors ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1146/annurev-physiol-021115-105102”, “ISBN” : “978-0-8243-0378-5”, “ISSN” : “0066-4278”, “PMID” : “26208951”, “abstract” : “Disruption of circadian rhythms, provoked by artificial lighting at night, inconsistent sleep-wake schedules, and transmeridian air travel, is increasingly prevalent in modern society. Desynchrony of biological rhythms from environmental light cycles has dramatic consequences for human health. In particular, disrupting homeostatic oscillations in endocrine tissues and the hormones that these tissues regulate can have cascading effects on physiology and behavior. Accumulating evidence suggests that chronic disruption of circadian organization of endocrine function may lead to metabolic, reproductive, sleep, and mood disorders. This review discusses circadian control of endocrine systems and the consequences of distorting rhythmicity of these systems. Expected final online publication date for the Annual Review of Physiology Volume 78 is February 10, 2016. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.”, “author” : { “dropping-particle” : “”, “family” : “Bedrosian”, “given” : “Tracy A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annual Review of Physiology”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2016” }, “page” : “109-131”, “title” : “Endocrine Effects of Circadian Disruption”, “type” : “article-journal”, “volume” : “78” }, “uris” : “http://www.mendeley.com/documents/?uuid=616072d9-498f-48f4-bd31-28ec8fa26072” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Bedrosian;/b; et al.;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Bedrosian et al., 2016)”, “previouslyFormattedCitation” : “(;b;;b;;b;Bedrosian;/b; et al.;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Bedrosian et al., 2016).

Individual rhythms are synchronized to diurnal activity by the ambient light/dark cycle and social routine. These rhythms must undergo phase readjustment when forced to follow a new activity/sleep schedule as with night work or geographic transposition across different time zones. The central and peripheral oscillators will adhere to the new schedule, but this occurs over a number of transient cycles of adaptation to the changed phase of the environmental synchronizer. During the time of adaptation, there is disruption of the usual sequence and biological order of the numerous rhythmic events with some clock genes responding faster than others. The result is an internal phase desynchronization within the oscillator mechanism ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/s10552-005-9015-4”, “ISBN” : “0957-5243 (Print)\n0957-5243 (Linking)”, “ISSN” : “0957-5243”, “PMID” : “16596302”, “abstract” : “Long-term epidemiologic studies on large numbers of night and rotating shift workers have suggested an increase in the incidence of breast and colon cancer in these populations. These studies suffer from poor definition and quantification of the work schedules of the exposed subjects. Against this background, the pathophysiology of phase shift and phase adaptation is reviewed. A phase shift as experienced in night and rotating shift work involves desynchronization at the molecular level in the circadian oscillators in the central nervous tissue and in most peripheral tissues of the body. There is a change in the coordination between oscillators with transient loss of control by the master-oscillator (the Suprachiasmatic Nucleus, SCN) in the hypothalamus. The implications of the pathophysiology of phase shift are discussed for long-term health effects and for the design of ergonomic work schedules minimizing the adverse health effects upon the worker.”, “author” : { “dropping-particle” : “”, “family” : “Haus”, “given” : “E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Smolensky”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Cancer Causes and Control”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2006” }, “page” : “489u2013500”, “title” : “Biological clocks and shift work: circadian dysregulation and potential long-term effects”, “type” : “article-journal”, “volume” : “17” }, “uris” : “http://www.mendeley.com/documents/?uuid=5bab3d0c-ce82-402d-8f92-5cee32bea020” } , “mendeley” : { “formattedCitation” : “(;b;;b;Haus;/b; and ;b;Smolensky;/b;;/b;, ;b;2006;/b;)”, “plainTextFormattedCitation” : “(Haus and Smolensky, 2006)”, “previouslyFormattedCitation” : “(;b;;b;Haus;/b; and ;b;Smolensky;/b;;/b;, ;b;2006;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Haus and Smolensky, 2006).

The circadian oscillators in the anterior region of the SCN adapt faster than those in the posterior region. Also the adaptation of the central oscillators in the hypothalamus precedes that in the peripheral tissues, which follow at a slower rate and are temporarily lost to the hypothalamic control. The internal desynchronization within the individual oscillators augments the desynchronization between central and peripheral oscillators. The overall effect of this phase shift is that the affected subject experiences an alteration at several levels of its internal timing system during the transitional period of adjustment ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/s10552-005-9015-4”, “ISBN” : “0957-5243 (Print)\n0957-5243 (Linking)”, “ISSN” : “0957-5243”, “PMID” : “16596302”, “abstract” : “Long-term epidemiologic studies on large numbers of night and rotating shift workers have suggested an increase in the incidence of breast and colon cancer in these populations. These studies suffer from poor definition and quantification of the work schedules of the exposed subjects. Against this background, the pathophysiology of phase shift and phase adaptation is reviewed. A phase shift as experienced in night and rotating shift work involves desynchronization at the molecular level in the circadian oscillators in the central nervous tissue and in most peripheral tissues of the body. There is a change in the coordination between oscillators with transient loss of control by the master-oscillator (the Suprachiasmatic Nucleus, SCN) in the hypothalamus. The implications of the pathophysiology of phase shift are discussed for long-term health effects and for the design of ergonomic work schedules minimizing the adverse health effects upon the worker.”, “author” : { “dropping-particle” : “”, “family” : “Haus”, “given” : “E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Smolensky”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Cancer Causes and Control”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2006” }, “page” : “489u2013500”, “title” : “Biological clocks and shift work: circadian dysregulation and potential long-term effects”, “type” : “article-journal”, “volume” : “17” }, “uris” : “http://www.mendeley.com/documents/?uuid=5bab3d0c-ce82-402d-8f92-5cee32bea020” } , “mendeley” : { “formattedCitation” : “(;b;;b;Haus;/b; and ;b;Smolensky;/b;;/b;, ;b;2006;/b;)”, “manualFormatting” : “(Haus and Smolensky, 2006)”, “plainTextFormattedCitation” : “(Haus and Smolensky, 2006)”, “previouslyFormattedCitation” : “(;b;;b;Haus;/b; and ;b;Smolensky;/b;;/b;, ;b;2006;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Haus and Smolensky, 2006).
Circadian rhythm disruption is the condition when the endogenous circadian rhythms (~24 h) are not in synchrony with each other or with the environment. This “desynchrony” takes place when behaviors such as sleep, wake and meals are not at appropriate times relative to the timing of the central circadian clock, and/or relative to the external environment, especially the light-dark cycle ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “:10.1016/j.jsmc.2015.07.005”, “ISBN” : “0000000000000”, “ISSN” : “1527-5418”, “PMID” : “24655651”, “abstract” : “Synapses are highly plastic and are modified by changes in patterns of neural activity or sensory experience. Plasticity of cortical excitatory synapses is thought to be important for learning and memory, leading to alterations in sensory representations and cognitive maps. However, these changes must be coordinated across other synapses within local circuits to preserve neural coding schemes and the organization of excitatory and inhibitory inputs, i.e., excitatory-inhibitory balance. Recent studies indicate that inhibitory synapses are also plastic and are controlled directly by a large number of neuromodulators, particularly during episodes of learning. Many modulators transiently alter excitatory-inhibitory balance by decreasing inhibition, and thus disinhibition has emerged as a major mechanism by which neuromodulation might enable long-term synaptic modifications naturally. This review examines the relationships between neuromodulation and synaptic plasticity, focusing on the induction of long-term changes that collectively enhance cortical excitatory-inhibitory balance for improving perception and behavior. Keywords”, “author” : { “dropping-particle” : “”, “family” : “Reutrakul”, “given” : “Sirimon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Knutson”, “given” : “Kristen L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine Clinics journal”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2015” }, “page” : “455-468”, “title” : “Consequences of Circadian Disruption on Cardiometabolic Health”, “type” : “article-journal”, “volume” : “10” }, “uris” : “http://www.mendeley.com/documents/?uuid=2b847882-6e9a-4c9a-923d-7fb6ea3410d5” } , “mendeley” : { “formattedCitation” : “(;b;;b;Reutrakul;/b; and ;b;Knutson;/b;;/b;, ;b;2015;/b;)”, “plainTextFormattedCitation” : “(Reutrakul and Knutson, 2015)”, “previouslyFormattedCitation” : “(;b;;b;Reutrakul;/b; and ;b;Knutson;/b;;/b;, ;b;2015;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Reutrakul and Knutson, 2015). Exposure to light in the late night and early morning advances the phase of the clock (activity starts earlier on the next day) and exposure to light in the evening and early night delays the clock (activity starts later on the next day). Light exposure can shift the SCN clock in both directions ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/B978-0-12-378610-4.00095-4”, “ISBN” : “9780123786104”, “author” : { “dropping-particle” : “”, “family” : “Mircsof”, “given” : “D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Brown”, “given” : “S.A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Encyclopedia of Sleep”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2013” }, “number-of-pages” : “435-441”, “publisher” : “Elsevier Inc.”, “title” : “The Influence of Light, Exercise, and Behavior upon Circadian Rhythms*”, “type” : “book”, “volume” : “1” }, “uris” : “http://www.mendeley.com/documents/?uuid=de2a6e2b-7ad9-42c0-b084-77fca19e77e8” } , “mendeley” : { “formattedCitation” : “(;b;;b;Mircsof;/b; and ;b;Brown;/b;;/b;, ;b;2013;/b;)”, “manualFormatting” : “(Mircsof and Brown, 2013)”, “plainTextFormattedCitation” : “(Mircsof and Brown, 2013)”, “previouslyFormattedCitation” : “(;b;;b;Mircsof;/b; and ;b;Brown;/b;;/b;, ;b;2013;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mircsof and Brown, 2013).
Two different theories have been emerged to discuss this phenomenon. The 1st theory states that; light might affect directly and uniformly the availability of a clock protein. Depending upon whether the cell is synthesizing this clock protein (at one time of the cycle) or to degrade it (at the opposite time), relative clock phase will advance or delay. The 2nd one says; light might stimulate alternative signaling cascades at different times of day which can affect the clock in different ways ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/B978-0-12-378610-4.00095-4”, “ISBN” : “9780123786104”, “author” : { “dropping-particle” : “”, “family” : “Mircsof”, “given” : “D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Brown”, “given” : “S.A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Encyclopedia of Sleep”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2013” }, “number-of-pages” : “435-441”, “publisher” : “Elsevier Inc.”, “title” : “The Influence of Light, Exercise, and Behavior upon Circadian Rhythms*”, “type” : “book”, “volume” : “1” }, “uris” : “http://www.mendeley.com/documents/?uuid=de2a6e2b-7ad9-42c0-b084-77fca19e77e8” } , “mendeley” : { “formattedCitation” : “(;b;;b;Mircsof;/b; and ;b;Brown;/b;;/b;, ;b;2013;/b;)”, “manualFormatting” : “(Mircsof and Brown, 2013)”, “plainTextFormattedCitation” : “(Mircsof and Brown, 2013)”, “previouslyFormattedCitation” : “(;b;;b;Mircsof;/b; and ;b;Brown;/b;;/b;, ;b;2013;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mircsof and Brown, 2013).
Extensive evidence confirms that circadian disruption alters metabolically related hormones; these hormonal alterations make individuals susceptible to obesity and other metabolic disorders ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1210/er.2013-1051”, “ISBN” : “0163-769X”, “ISSN” : “0163769X”, “PMID” : “24673196”, “abstract” : “Most organisms display endogenously produced u223cf24 h fluctuations in physiology and behavior, termed circadian rhythms. Circadian rhythms are driven by a transcriptional-translational feedback loop that is hierarchically expressed throughout the brain and body, with the suprachiasmatic nucleus of the hypothalamus serving as the master circadian oscillator at the top of the hierarchy. Appropriate circadian regulation is important for many homeostatic functions including energy regulation. Multiple genes involved in nutrient metabolism display rhythmic oscillations and metabolically related hormones such as glucagon, insulin, ghrelin, leptin, and corticosterone are released in a circadian fashion. Mice harboring mutations in circadian clock genes alter feeding behavior, endocrine signaling, and dietary fat absorption. Moreover, misalignment between behavioral and molecular circadian clocks can result in obesity in both rodents and humans. Importantly, circadian rhythms are most potently synchronized to the external environment by light information and exposure to light at night potentially disrupts circadian system function. Since the advent of electric lights around the turn of the 20th century, exposure to artificial and irregular light schedules has become commonplace. The increase in exposure to light at night parallels the global increase in the prevalence of obesity and metabolic disorders. In this review, we propose that exposure to light at night alters metabolic function through disruption of the circadian system. We first provide an introduction to the circadian system, with a specific emphasis on the effects of light on circadian rhythms. Next we address interactions between the circadian system and metabolism. Finally, we review current experimental and epidemiological work directly associating exposure to light at night and metabolism.”, “author” : { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Endocrine Reviews”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2014” }, “page” : “648-670”, “title” : “The effects of light at night on circadian clocks and metabolism”, “type” : “article-journal”, “volume” : “35” }, “uris” : “http://www.mendeley.com/documents/?uuid=90c7cda5-76f0-4c7a-870e-34cc4bc62c97” } , “mendeley” : { “formattedCitation” : “(;b;;b;Fonken;/b; and ;b;Nelson;/b;;/b;, ;b;2014;/b;)”, “plainTextFormattedCitation” : “(Fonken and Nelson, 2014)”, “previouslyFormattedCitation” : “(;b;;b;Fonken;/b; and ;b;Nelson;/b;;/b;, ;b;2014;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Fonken and Nelson, 2014). Circadian disruption causes many lifestyle and behavioral changes that may further affect metabolism. Most remarkably, circadian disruption can lead to mismatch between the internal biological clock and timing of food intake. Unusual mealtimes due to shift schedules and social jet lag may add to metabolic disturbances ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.physbeh.2014.01.001”, “ISBN” : “1873-507X (Electronic)\r0031-9384 (Linking)”, “ISSN” : “1873507X”, “PMID” : “24467926”, “abstract” : “Recent studies link energy regulation to the circadian clock at the behavioral, physiological and molecular levels, emphasizing that the timing of food intake itself may have a significant role in obesity. In this regards, there is emerging literature in animals demonstrating a relationship between the timing of feeding and weight regulation. Unusual feeding time can produce a disruption of the circadian system which might produce unhealthy consequences in humans. In a longitudinal study, we recently showed that the timing of the main meal was predictive of weight loss during a 20-week dietary intervention and that this effect was independent from total 24-h caloric intake. The importance of caloric distribution across the day on weight loss therapy was supported by a recent 12-week experimental study showing that subjects assigned to high caloric intake during breakfast lost significantly more weight than those assigned to high caloric intake during the dinner. Furthermore, one of the most influential discoveries relevant for this area of research in the last years is the presence of an active circadian clock in different organs related to food intake. This is the case for stomach, intestine, pancreas or liver. New data also suggest that there is a temporal component in the regulation of adipose tissue functions. Thus, a specific temporal order in the daily patterns of adipose tissue genes appears to be crucial for adipose tissue to exclusively either accumulate fat or to mobilize fat at the proper time. Taking into account that feeding is the source of energy for adipose tissue, the time of feeding, particularly for high-energy content meals, may be decisive, and changes in this timing could have metabolic consequences for the development of obesity and for weight loss.”, “author” : { “dropping-particle” : “”, “family” : “Garaulet”, “given” : “Marta”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gu00f3mez-Abellu00e1n”, “given” : “Purificaciu00f3n”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Physiology ; behavior”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2014” }, “page” : “44-50”, “title” : “Timing of food intake and obesity: a novel association”, “type” : “article”, “volume” : “134” }, “uris” : “http://www.mendeley.com/documents/?uuid=64d498fd-ad92-47ae-ad61-10913297dfda” } , “mendeley” : { “formattedCitation” : “(;b;;b;Garaulet;/b; and ;b;Gu00f3mez-Abellu00e1n;/b;;/b;, ;b;2014;/b;)”, “manualFormatting” : “(Garaulet and Gu00f3mez-Abellu00e1n, 2014)”, “plainTextFormattedCitation” : “(Garaulet and Gu00f3mez-Abellu00e1n, 2014)”, “previouslyFormattedCitation” : “(;b;;b;Garaulet;/b; and ;b;Gu00f3mez-Abellu00e1n;/b;;/b;, ;b;2014;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Garaulet and Gómez-Abellán, 2014). Large epidemiological studies have suggested a direct relationship between obesity and exposure to artificial light at night. For example, in a study of 100,000 women in the United Kingdom, the odds ratio of obesity (assessed by BMI, waist-hip ratio, and waist circumference) increased with increased exposure to light at night. This association was related only to light exposure at night and was not related to any other factors as sleep duration, cigarette smoking, or physical activity ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1093/aje/kwu117”, “ISBN” : “1476-6256 (Electronic) 0002-9262 (Linking)”, “ISSN” : “14766256”, “PMID” : “24875371”, “abstract” : “There has been a worldwide epidemic of obesity in recent decades. In animal studies, there is convincing evidence that light exposure causes weight gain, even when calorie intake and physical activity are held constant. Disruption of sleep and circadian rhythms by exposure to light at night (LAN) might be one mechanism contributing to the rise in obesity, but it has not been well-investigated in humans. Using multinomial logistic regression, we examined the association between exposure to LAN and obesity in questionnaire data from over 100,000 women in the Breakthrough Generations Study, a cohort study of women aged 16 years or older who were living in the United Kingdom and recruited during 2003-2012. The odds of obesity, measured using body mass index, waist:hip ratio, waist:height ratio, and waist circumference, increased with increasing levels of LAN exposure (P ; 0.001), even after adjustment for potential confounders such as sleep duration, alcohol intake, physical activity, and current smoking. We found a significant association between LAN exposure and obesity which was not explained by potential confounders we could measure. While the possibility of residual confounding cannot be excluded, the pattern is intriguing, accords with the results of animal experiments, and warrants further investigation.”, “author” : { “dropping-particle” : “”, “family” : “McFadden”, “given” : “Emily”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jones”, “given” : “Michael E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schoemaker”, “given” : “Minouk J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ashworth”, “given” : “Alan”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Swerdlow”, “given” : “Anthony J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “American Journal of Epidemiology”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2014” }, “page” : “245-250”, “title” : “The relationship between obesity and exposure to light at night: Cross-sectional analyses of over 100,000 women in the breakthrough generations study”, “type” : “article-journal”, “volume” : “180” }, “uris” : “http://www.mendeley.com/documents/?uuid=7b37753e-cb7b-43c4-9377-e0506462da8b” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;McFadden;/b; et al.;/b;;/b;, ;b;2014;/b;)”, “manualFormatting” : “(McFadden et al., 2014)”, “plainTextFormattedCitation” : “(McFadden et al., 2014)”, “previouslyFormattedCitation” : “(;b;;b;;b;McFadden;/b; et al.;/b;;/b;, ;b;2014;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(McFadden et al., 2014).
The relation between exposure to light at nighttime and cancer is the most extensively studied connection between circadian disruption and an inflammatory condition. An association between cancer and circadian disruption is supported by epidemiological, clinical, and basic researches. These researches has led the World Health Organization to declare shift work a probable carcinogen (class 2A, International Agency for Research on Cancer) ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789283212980 (pbk.)\n9283212983 (pbk.)\n1017-1606 ;”, “ISSN” : “10171606”, “PMID” : “21381544”, “abstract” : “This volume of the IARC Monographs provides evaluations of the carcinogenicity of shiftwork, painting and firefighting. Shiftwork is estimated to involve about 15-20% of the total working population. It is most prevalent among workers in the health care, transportation, communication, leisure and hospitality sectors. Shiftwork involving work at night is the most disruptive for the circadian clock. Painters are potentially exposed to the chemicals found in paint products during their application and removal, and may also be exposed to other workplace hazards, such as asbestos or crystalline silica dust. Firefighters may be exposed at different intensity levels depending on crew assignment, tasks, and/or the time spent at fires. All fires generate a very large number of toxic combustion products, including known, probable or possible carcinogens. An IARC Monographs Working Group reviewed epidemiological evidence, animal bioassays where appropriate, and mechanistic and other relevant data to reach conclusions as to the carcinogenic hazard of these three exposure circumstances to humans.”, “author” : { “dropping-particle” : “”, “family” : “International Agency for Research on Cancer (IARC)”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “IARC monographs working group on the evaluation of carcinogenic risks to humans / World Health Organization, International Agency for Research on Cancer”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2010” }, “number-of-pages” : “764”, “publisher-place” : “Lyon – France”, “title” : “Painting, firefighting, and shiftwork.”, “type” : “report”, “volume” : “98” }, “uris” : “http://www.mendeley.com/documents/?uuid=1b992c4d-0681-4fcb-95c6-125ac64da4be” } , “mendeley” : { “formattedCitation” : “(;b;;b;International Agency for Research on Cancer (IARC);/b;;/b;, ;b;2010;/b;)”, “manualFormatting” : “(IARC, 2010)”, “plainTextFormattedCitation” : “(International Agency for Research on Cancer (IARC), 2010)”, “previouslyFormattedCitation” : “(;b;;b;International Agency for Research on Cancer (IARC);/b;;/b;, ;b;2010;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(IARC, 2010). Circadian disruption is associated with increased risk for several inflammatory pathologies. This risk is attributed to disruption in immune functions which follow circadian control. Moreover, both melatonin and glucocorticoids have potent anti-inflammatory actions, so disrupting melatonin and glucocorticoids rhythmicity leads to loss of this action. It was shown that even acute circadian misalignment decreases circulating cortisol levels and increases inflammatory cytokines ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1146/annurev-physiol-021115-105102”, “ISBN” : “978-0-8243-0378-5”, “ISSN” : “0066-4278”, “PMID” : “26208951”, “abstract” : “Disruption of circadian rhythms, provoked by artificial lighting at night, inconsistent sleep-wake schedules, and transmeridian air travel, is increasingly prevalent in modern society. Desynchrony of biological rhythms from environmental light cycles has dramatic consequences for human health. In particular, disrupting homeostatic oscillations in endocrine tissues and the hormones that these tissues regulate can have cascading effects on physiology and behavior. Accumulating evidence suggests that chronic disruption of circadian organization of endocrine function may lead to metabolic, reproductive, sleep, and mood disorders. This review discusses circadian control of endocrine systems and the consequences of distorting rhythmicity of these systems. Expected final online publication date for the Annual Review of Physiology Volume 78 is February 10, 2016. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.”, “author” : { “dropping-particle” : “”, “family” : “Bedrosian”, “given” : “Tracy A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annual Review of Physiology”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2016” }, “page” : “109-131”, “title” : “Endocrine Effects of Circadian Disruption”, “type” : “article-journal”, “volume” : “78” }, “uris” : “http://www.mendeley.com/documents/?uuid=616072d9-498f-48f4-bd31-28ec8fa26072” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Bedrosian;/b; et al.;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Bedrosian et al., 2016)”, “previouslyFormattedCitation” : “(;b;;b;;b;Bedrosian;/b; et al.;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Bedrosian et al., 2016).
In shift work normally diurnal rhythms of behavioral and physiological cycles are voluntarily shifted to abnormal phases of the light-dark cycle. This shift results in a misalignment among internal behavioral/ physiological rhythms as well as a misalignment between internal rhythms and the external day/night cycle. So shift work is generally accompanied by chronic misalignment between the endogenous circadian timing system and the behavioral cycles ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “In developing countries, shift work represents a considerable contingent workforce. Recently, studies have shown that overweight and obesity are more prevalent in shift workers than day workers. In addition, shift work has been associated with a higher propensity for the development of many metabolic disorders, such as insulin resistance, diabetes, dislipidemias and metabolic syndrome. Recent data have pointed that decrease of the sleep time, desynchronization of circadian rhythm and alteration of environmental aspects are the main factors related to such problems. Shortened or disturbed sleep is among the most common health-related effects of shift work. The plausible physiological and biological mechanisms are related to the activation of the autonomic nervous system, inflammation, changes in lipid and glucose metabolism, and related changes in the risk for atherosclerosis, metabolic syndrome, and type II diabetes. The present review will discuss the impact of shift work on obesity and metabolic disorders and how disruption of sleep and circadian misalignment may contribute to these metabolic dysfunctions.”, “author” : { “dropping-particle” : “”, “family” : “Zimberg”, “given” : “Ionu00e1 Zalcman”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fernandes Junior”, “given” : “Silvio A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Crispim”, “given” : “Cibele Aparecida”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tufik”, “given” : “Sergio”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mello”, “given” : “Marco Tulio”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” } , “container-title” : “Work”, “id” : “ITEM-1”, “issue” : “SUPPL.1”, “issued” : { “date-parts” : “2012” }, “page” : “4376-4383”, “title” : “Metabolic impact of shift work”, “type” : “paper-conference”, “volume” : “41” }, “uris” : “http://www.mendeley.com/documents/?uuid=d1020cd6-9d57-40af-b0c3-3b11f5e33cb5” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Zimberg;/b; et al.;/b;;/b;, ;b;2012;/b;)”, “plainTextFormattedCitation” : “(Zimberg et al., 2012)”, “previouslyFormattedCitation” : “(;b;;b;;b;Zimberg;/b; et al.;/b;;/b;, ;b;2012;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Zimberg et al., 2012).
A person sleeps better at night and performs better during the day. Sleep is known to be an important factor for individual’s health and functional capacity. A loss of sleep has been shown to result in disturbances in many basic body functions, such as glucose metabolism ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1055/s-2005-872944”, “ISBN” : “0947-7349 (Print)\r0947-7349 (Linking)”, “ISSN” : “0947-7349 (Print) 0947-7349 (Linking)”, “PMID” : “16320152”, “abstract” : “Emerging evidence suggests that short duration of sleep and sleep disturbances increase the risk of developing diabetes. The mechanism of this presumed adverse influence of sleep loss on glucose metabolism is not well understood yet. However, in diabetes research and diabetes care, the multitude of influences of sleep and sleep loss on glucose regulation has been largely neglected so far. Here, we provide a short overview of the current epidemiological and experimental evidence for a potential contribution of sleep loss to the development of diabetes.”, “author” : { “dropping-particle” : “”, “family” : “Schultes”, “given” : “B”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schmid”, “given” : “S”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Peters”, “given” : “A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Born”, “given” : “J”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fehm”, “given” : “H L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Exp Clin Endocrinol Diabetes”, “id” : “ITEM-1”, “issue” : “10”, “issued” : { “date-parts” : “2005” }, “page” : “563-567”, “title” : “Sleep loss and the development of diabetes: a review of current evidence”, “type” : “article”, “volume” : “113” }, “uris” : “http://www.mendeley.com/documents/?uuid=e530aeb3-5b29-4eb7-bdfb-0932a901cac4” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Schultes;/b; et al.;/b;;/b;, ;b;2005;/b;)”, “plainTextFormattedCitation” : “(Schultes et al., 2005)”, “previouslyFormattedCitation” : “(;b;;b;;b;Schultes;/b; et al.;/b;;/b;, ;b;2005;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Schultes et al., 2005), hormones excretions and metabolic process ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/S1389-9457(08)70013-3”, “ISBN” : “1389-9457”, “ISSN” : “13899457”, “PMID” : “18929315”, “abstract” : “Reduced sleep duration and quality appear to be endemic in modern society. Curtailment of the bedtime period to minimum tolerability is thought to be efficient and harmless by many. It has been known for several decades that sleep is a major modulator of hormonal release, glucose regulation and cardiovascular function. In particular, slow wave sleep (SWS), thought to be the most restorative sleep stage, is associated with decreased heart rate, blood pressure, sympathetic nervous activity and cerebral glucose utilization, compared with wakefulness. During SWS, the anabolic growth hormone is released while the stress hormone cortisol is inhibited. In recent years, laboratory and epidemiologic evidence have converged to indicate that sleep loss may be a novel risk factor for obesity and type 2 diabetes. The increased risk of obesity is possibly linked to the effect of sleep loss on hormones that play a major role in the central control of appetite and energy expenditure, such as leptin and ghrelin. Reduced leptin and increased ghrelin levels correlate with increases in subjective hunger when individuals are sleep restricted rather than well rested. Given the evidence, sleep curtailment appears to be an important, yet modifiable, risk factor for the metabolic syndrome, diabetes and obesity. The marked decrease in average sleep duration in the last 50 years coinciding with the increased prevalence of obesity, together with the observed adverse effects of recurrent partial sleep deprivation on metabolism and hormonal processes, may have important implications for public health. u00a9 2008 Elsevier B.V. All rights reserved.”, “author” : { “dropping-particle” : “”, “family” : “Cauter”, “given” : “Eve”, “non-dropping-particle” : “Van”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Spiegel”, “given” : “Karine”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tasali”, “given” : “Esra”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Leproult”, “given” : “Rachel”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine”, “id” : “ITEM-1”, “issue” : “SUPPL. 1”, “issued” : { “date-parts” : “2008” }, “page” : “1-11”, “title” : “Metabolic consequences of sleep and sleep loss”, “type” : “article-journal”, “volume” : “9” }, “uris” : “http://www.mendeley.com/documents/?uuid=139fca2f-9d58-4845-a5ea-218c689795ac” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Van Cauter;/b; et al.;/b;;/b;, ;b;2008;/b;)”, “plainTextFormattedCitation” : “(Van Cauter et al., 2008)”, “previouslyFormattedCitation” : “(;b;;b;;b;Van Cauter;/b; et al.;/b;;/b;, ;b;2008;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Van Cauter et al., 2008), pro-inflammatory cytokines production, the functions of the autonomous nervous and immune systems ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1371/journal.pone.0004589”, “ISBN” : “1932-6203 (Electronic)\n1932-6203 (Linking)”, “ISSN” : “19326203”, “PMID” : “19240794”, “abstract” : “BACKGROUND: Sleep restriction, leading to deprivation of sleep, is common in modern 24-h societies and is associated with the development of health problems including cardiovascular diseases. Our objective was to investigate the immunological effects of prolonged sleep restriction and subsequent recovery sleep, by simulating a working week and following recovery weekend in a laboratory environment.\n\nMETHODS AND FINDINGS: After 2 baseline nights of 8 hours time in bed (TIB), 13 healthy young men had only 4 hours TIB per night for 5 nights, followed by 2 recovery nights with 8 hours TIB. 6 control subjects had 8 hours TIB per night throughout the experiment. Heart rate, blood pressure, salivary cortisol and serum C-reactive protein (CRP) were measured after the baseline (BL), sleep restriction (SR) and recovery (REC) period. Peripheral blood mononuclear cells (PBMC) were collected at these time points, counted and stimulated with PHA. Cell proliferation was analyzed by thymidine incorporation and cytokine production by ELISA and RT-PCR. CRP was increased after SR (145% of BL; p;0.05), and continued to increase after REC (231% of BL; p;0.05). Heart rate was increased after REC (108% of BL; p;0.05). The amount of circulating NK-cells decreased (65% of BL; p;0.005) and the amount of B-cells increased (121% of BL; p;0.005) after SR, but these cell numbers recovered almost completely during REC. Proliferation of stimulated PBMC increased after SR (233% of BL; p;0.05), accompanied by increased production of IL-1beta (137% of BL; p;0.05), IL-6 (163% of BL; p;0.05) and IL-17 (138% of BL; p;0.05) at mRNA level. After REC, IL-17 was still increased at the protein level (119% of BL; p;0.05).\n\nCONCLUSIONS: 5 nights of sleep restriction increased lymphocyte activation and the production of proinflammatory cytokines including IL-1beta IL-6 and IL-17; they remained elevated after 2 nights of recovery sleep, accompanied by increased heart rate and serum CRP, 2 important risk factors for cardiovascular diseases. Therefore, long-term sleep restriction may lead to persistent changes in the immune system and the increased production of IL-17 together with CRP may increase the risk of developing cardiovascular diseases.”, “author” : { “dropping-particle” : “”, “family” : “Leeuwen”, “given” : “Van”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Wessel”, “given” : “MA”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lehto”, “given” : “Maili”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Karisola”, “given” : “Piia”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lindholm”, “given” : “Harri”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Luukkonen”, “given” : “Ritva”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sallinen”, “given” : “Mikael”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hu00e4rmu00e4”, “given” : “Mikko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Porkka-Heiskanen”, “given” : “Tarja”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Alenius”, “given” : “Harri”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “PLoS ONE”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2009” }, “title” : “Sleep restriction increases the risk of developing cardiovascular diseases by augmenting proinflammatory responses through IL-17 and CRP”, “type” : “article-journal”, “volume” : “4” }, “uris” : “http://www.mendeley.com/documents/?uuid=73ccc642-a2f6-405a-8171-75182334b627” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Leeuwen;/b; et al.;/b;;/b;, ;b;2009;/b;)”, “plainTextFormattedCitation” : “(Leeuwen et al., 2009)”, “previouslyFormattedCitation” : “(;b;;b;;b;Leeuwen;/b; et al.;/b;;/b;, ;b;2009;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Leeuwen et al., 2009). Sleep deprivation is also considered a physiological stressor and a metabolic challenge that is often associated with increased production of cortisol and stress ratings. Sleep loss is also reported to elevate blood levels of inflammatory proteins and may be reflective of impaired physiological function and disease processes ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.joca.2015.05.020.Osteoarthritic”, “ISBN” : “6176323479”, “ISSN” : “09652140”, “PMID” : “26780180”, “author” : { “dropping-particle” : “”, “family” : “Wright”, “given” : “KP Jr”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Drake”, “given” : “AL”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Frey”, “given” : “DJ”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fleshner”, “given” : “M”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Desouza”, “given” : “CA”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gronfier”, “given” : “C”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Czeisler”, “given” : “CA”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “10”, “issued” : { “date-parts” : “2016” }, “page” : “1780-1789”, “title” : “Influence of Sleep Deprivation and Circadian Misalignment on Cortisol, Inflammatory Markers, and Cytokine Balance”, “type” : “article-journal”, “volume” : “23” }, “uris” : “http://www.mendeley.com/documents/?uuid=c35edd45-a839-45f8-ad34-5edda9622e11” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;K. J. Wright;/b; et al.;/b;;/b;, ;b;2016;/b;)”, “manualFormatting” : “(Wright et al., 2016)”, “plainTextFormattedCitation” : “(K. J. Wright et al., 2016)”, “previouslyFormattedCitation” : “(;b;;b;;b;K. J. Wright;/b; et al.;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Wright et al., 2016).

In light of these findings, it is not shocking that short habitual sleep is associated with an increased risk of many health problems, for example, coronary heart disease. Sleep restriction has also been shown to be injurious to alertness and cognitive functions, which are the basics of human mental functional capacity. Such effects at least partly explain why disturbed sleep puts an individual at an greater risk of occupational accidents ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.2900”, “ISBN” : “1795-990X (Electronic)\n0355-3140 (Linking)”, “ISSN” : “1795990X”, “PMID” : “20119631”, “abstract” : “In this narrative review, we examined what level of research evidence is available that shift workers’ sleep-wake disturbances can be minimized through ergonomic shift scheduling. We classified the pertinent studies conducted on real shift workers in field conditions by the type of shift system and study design (ie, whether the shift systems were modified or not – “treatment” versus “no treatment”). The results of the observational studies in which no changes to the shift system were made (ie, no treatment) showed that, irrespective of the shift system, night and early-morning shifts and quick returns are associated with short sleep and increases in sleepiness. The same is true for very long shifts (>16 hours) and extremely long weekly working hours (>55 hours). For all categories of shift systems, there was a lack of controlled intervention studies, limiting the possibility to provide solution-focused recommendations for shift scheduling. Most of the controlled intervention studies had been conducted on workers under regular 3-shift systems. These studies suggested that a change from slowly backward-rotating shifts to rapidly forward-rotating shifts is advantageous for alertness and, to some degree, sleep. We also found that a change from an 8- to 12-hour shift system does not necessarily result in impairments in the sleep-wake pattern. The level of research evidence was affected by many of the studies’ frequent methodological limitations in measuring sleep and sleepiness. In all, to have reliable and solution-focused recommendations for shift scheduling, methodologically sound controlled intervention studies are required in different categories of shift systems.”, “author” : { “dropping-particle” : “”, “family” : “Sallinen”, “given” : “Mikael”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kecklund”, “given” : “Gu00f6ran”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “121-133”, “title” : “Shift work, sleep, and sleepiness – Differences between shift schedules and systems”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=55be0f6f-5407-4f42-a8c1-39af2e9107c2” } , “mendeley” : { “formattedCitation” : “(;b;;b;Sallinen;/b; and ;b;Kecklund;/b;;/b;, ;b;2010;/b;)”, “plainTextFormattedCitation” : “(Sallinen and Kecklund, 2010)”, “previouslyFormattedCitation” : “(;b;;b;Sallinen;/b; and ;b;Kecklund;/b;;/b;, ;b;2010;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Sallinen and Kecklund, 2010).
Altered sleep duration is an example of a quantitative sleep irregularity. There is evidence to suggest that reduced sleep duration per se can exert important metabolic effects. Decreased amount of sleep is associated with increased body weight and obesity, such that obese subjects show a nearly inverse linear relationship between body weight and sleep time ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Gangwisch”, “given” : “James E”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Malaspina”, “given” : “Dolores”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Boden-albala”, “given” : “Bernadette”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Heymsfield”, “given” : “Steven B”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep”, “id” : “ITEM-1”, “issue” : “10”, “issued” : { “date-parts” : “2005” }, “page” : “1289-1296”, “title” : “inadequate sleep as a risk factor for obesity::Analysis of NHANES”, “type” : “article-journal”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=1b285a64-86bd-49f1-a79c-ba6d6f151127” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Gangwisch;/b; et al.;/b;;/b;, ;b;2005;/b;)”, “plainTextFormattedCitation” : “(Gangwisch et al., 2005)”, “previouslyFormattedCitation” : “(;b;;b;;b;Gangwisch;/b; et al.;/b;;/b;, ;b;2005;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Gangwisch et al., 2005). Sleep deprivation has been shown to elevate blood pressure and may be independently associated with an increased risk for hypertension ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1161/01.HYP.0000217362.34748.e0”, “ISBN” : “1524-4563 (Electronic)\r0194-911X (Linking)”, “ISSN” : “0194911X”, “PMID” : “16585410”, “abstract” : “Depriving healthy subjects of sleep has been shown to acutely increase blood pressure and sympathetic nervous system activity. Prolonged short sleep durations could lead to hypertension through extended exposure to raised 24-hour blood pressure and heart rate, elevated sympathetic nervous system activity, and increased salt retention. Such forces could lead to structural adaptations and the entrainment of the cardiovascular system to operate at an elevated pressure equilibrium. Sleep disorders are associated with cardiovascular disease, but we are not aware of any published prospective population studies that have shown a link between short sleep duration and the incidence of hypertension in subjects without apparent sleep disorders. We assessed whether short sleep duration would increase the risk for hypertension incidence by conducting longitudinal analyses of the first National Health and Nutrition Examination Survey (n=4810) using Cox proportional hazards models and controlling for covariates. Hypertension incidence (n=647) was determined by physician diagnosis, hospital record, or cause of death over the 8- to 10-year follow-up period between 1982 and 1992. Sleep durations of ; or =5 hours per night were associated with a significantly increased risk of hypertension (hazard ratio, 2.10; 95% CI, 1.58 to 2.79) in subjects between the ages of 32 and 59 years, and controlling for the potential confounding variables only partially attenuated this relationship. The increased risk continued to be significant after controlling for obesity and diabetes, which was consistent with the hypothesis that these variables would act as partial mediators. Short sleep duration could, therefore, be a significant risk factor for hypertension.”, “author” : { “dropping-particle” : “”, “family” : “Gangwisch”, “given” : “James E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Heymsfield”, “given” : “Steven B.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Boden-Albala”, “given” : “Bernadette”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Buijs”, “given” : “Ruud M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kreier”, “given” : “Felix”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pickering”, “given” : “Thomas G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rundle”, “given” : “Andrew G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Zammit”, “given” : “Gary K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Malaspina”, “given” : “Dolores”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Hypertension”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2006” }, “page” : “833-839”, “title” : “Short sleep duration as a risk factor for hypertension: Analyses of the first National Health and Nutrition Examination Survey”, “type” : “article-journal”, “volume” : “47” }, “uris” : “http://www.mendeley.com/documents/?uuid=9e00c286-039d-403c-9d7d-3bfc2a33b12c” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Gangwisch;/b; et al.;/b;;/b;, ;b;2006;/b;)”, “plainTextFormattedCitation” : “(Gangwisch et al., 2006)”, “previouslyFormattedCitation” : “(;b;;b;;b;Gangwisch;/b; et al.;/b;;/b;, ;b;2006;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Gangwisch et al., 2006). Sleep deprivation increase vulnerability to oxidative stress but this finding is still controversial and tissue specific ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Gopalakrishnan”, “given” : “Anupama”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ji”, “given” : “Li Li”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Cirelli”, “given” : “Chiara”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2004” }, “page” : “27-35”, “title” : “Sleep Deprivation and Cellular Responses to Oxidative Stress”, “type” : “article-journal”, “volume” : “27” }, “uris” : “http://www.mendeley.com/documents/?uuid=37fc082c-c503-4f57-80c5-d0e1f4fad21f” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Gopalakrishnan;/b; et al.;/b;;/b;, ;b;2004;/b;)”, “manualFormatting” : “(Gopalakrishnan et al., 2004”, “plainTextFormattedCitation” : “(Gopalakrishnan et al., 2004)”, “previouslyFormattedCitation” : “(;b;;b;;b;Gopalakrishnan;/b; et al.;/b;;/b;, ;b;2004;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Gopalakrishnan et al., 2004; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1152/ajpregu.00565.2004”, “ISBN” : “0363-6119 (Print)”, “ISSN” : “0363-6119”, “PMID” : “15472007”, “abstract” : “Sleep deprivation in humans is widely believed to impair health, and sleep is thought to have powerful restorative properties. The specific physical and biochemical factors and processes mediating these outcomes, however, are poorly elucidated. Sleep deprivation in the animal model produces a condition that eventually becomes highly lethal, lacks specific localization, and is reversible with sleep, implying mediation by a biochemical abnormality. Metabolic and immunological consequences of sleep deprivation point to a high potential for antioxidant imbalance. The objective, therefore, was to study glutathione content in the liver, heart, and lung, because glutathione is considered a major free radical scavenger that reflects the degree to which a tissue has been oxidatively challenged. We also investigated major enzymatic antioxidants, including catalase and glutathione peroxidase, as well as indexes of glutathione recycling. Catalase activity and glutathione content, which normally are tightly regulated, were both decreased in liver by 23-36% by 5 and 10 days of sleep deprivation. Such levels are associated with impaired health in other animal models of oxidative stress-associated disease. The decreases were accompanied by markers of generalized cell injury and absence of responses by the other enzymatic antioxidants under study. Enzymatic activities in the heart indicated an increased rate of oxidative pentose phosphate pathway activity during sleep deprivation. Recovery sleep normalized antioxidant content in liver and enhanced enzymatic antioxidant activities in both the liver and the heart. The present results link uncompensated oxidative stress to health effects induced by sleep deprivation and provide evidence that restoration of antioxidant balance is a property of recovery sleep.”, “author” : { “dropping-particle” : “”, “family” : “Everson”, “given” : “C A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Laatsch”, “given” : “C D”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hogg”, “given” : “N”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “American Journal of Physiology. Regulatory Integrative and Comparative Physiology”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2005” }, “page” : “R374-383”, “title” : “Antioxidant defense responses to sleep loss and sleep recovery”, “type” : “article-journal”, “volume” : “288” }, “uris” : “http://www.mendeley.com/documents/?uuid=a96c0ffa-e656-40c7-9c9d-aea4ffcc2add” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Everson;/b; et al.;/b;;/b;, ;b;2005;/b;)”, “manualFormatting” : “Everson et al., 2005)”, “plainTextFormattedCitation” : “(Everson et al., 2005)”, “previouslyFormattedCitation” : “(;b;;b;;b;Everson;/b; et al.;/b;;/b;, ;b;2005;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Everson et al., 2005). Sleep deprivation has been stated as an independent risk factor for diabetes ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Yaggi”, “given” : “H. Klar”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Araujo”, “given” : “Andre B.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mckinlay”, “given” : “J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Diabetes Care”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2006” }, “page” : “657-661”, “title” : “Sleep Duration as a Risk Factor for the Development of Type 2 Diabetes”, “type” : “article-journal”, “volume” : “29” }, “uris” : “http://www.mendeley.com/documents/?uuid=cf77fe49-b5d6-443b-933b-39cd76cad770” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Yaggi;/b; et al.;/b;;/b;, ;b;2006;/b;)”, “manualFormatting” : “(Yaggi et al., 2006”, “plainTextFormattedCitation” : “(Yaggi et al., 2006)”, “previouslyFormattedCitation” : “(;b;;b;;b;Yaggi;/b; et al.;/b;;/b;, ;b;2006;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Yaggi et al., 2006; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.sleep.2008.09.016”, “ISSN” : “13899457”, “abstract” : “Objective: To examine the long-term relationship between sleep duration and type 2 diabetes or impaired glucose tolerance (IGT). Methods: Body composition measurements and self-reported sleep duration were determined in a longitudinal sample of 276 individuals aged 21 to 64 years followed for a mean of 6 years. Risk factors of type 2 diabetes/IGT over the follow-up were determined and relative risks (RRs) calculated for the development of type 2 diabetes/IGT by sleep duration group. Results: Independent risk factors of type 2 diabetes/IGT over the follow-up included age, obesity, sleep duration, and glucose/insulin homeostasis indicators. Using adults with 7-8 h of sleep as a reference, the adjusted RR for the development of type 2 diabetes/IGT was 2.78 (1.61-4.12) for those with u22646 h of sleep and 2.54 (1.42-3.53) for those with u22659 h of sleep. These elevated RRs remained significant after adjustment for body mass index, waist circumference or percent body fat. Conclusion: Short and long sleeping times are associated with a higher risk of developing type 2 diabetes/IGT, independent of several covariates. These results suggest that sleep duration may represent a novel risk factor for type 2 diabetes/IGT. u00a9 2009 Elsevier B.V. All rights reserved.”, “author” : { “dropping-particle” : “”, “family” : “Chaput”, “given” : “Jean Philippe”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Despru00e9s”, “given” : “Jean Pierre”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bouchard”, “given” : “Claude”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Astrup”, “given” : “Arne”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tremblay”, “given” : “Angelo”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine”, “id” : “ITEM-1”, “issue” : “8”, “issued” : { “date-parts” : “2009” }, “page” : “919-924”, “publisher” : “Elsevier B.V.”, “title” : “Sleep duration as a risk factor for the development of type 2 diabetes or impaired glucose tolerance: Analyses of the Quebec Family Study”, “type” : “article-journal”, “volume” : “10” }, “uris” : “http://www.mendeley.com/documents/?uuid=5f3623ee-8129-4818-a6cf-00b1af7c5934” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Chaput;/b; et al.;/b;;/b;, ;b;2009;/b;)”, “manualFormatting” : “Chaput et al., 2009)”, “plainTextFormattedCitation” : “(Chaput et al., 2009)”, “previouslyFormattedCitation” : “(;b;;b;;b;Chaput;/b; et al.;/b;;/b;, ;b;2009;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Chaput et al., 2009). The concept that sleep disturbances exert negative metabolic effects may help in explaining the increasing prevalence of MS and insulin resistance in the general population and may have important implications for population based approaches to fight the increasing epidemic of metabolic and cardiovascular diseases ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1113/expphysiol.2006.033787”, “abstract” : “The metabolic syndrome represents a clustering of several interrelated risk factors of metabolic origin that are thought to increase cardiovascular risk. It is still uncertainwhether this clustering results from multiple underlying risk factors or whether it has a single cause. One metabolic abnormality that may underlie several clinical characteristics of the metabolic syndrome is insulin resistance. This review discusses the evidence that sleep disturbances (obstructive sleep apnoea, sleep deprivation and shift work) may independently lead to the development of both insulin resistance and individual clinical components of the metabolic syndrome. The converse may also be true, in that metabolic abnormalities associated with the metabolic syndromeandinsulin resistancemaypotentially exacerbate sleep disorders.Thenotion that sleep disturbances exert detrimental metabolic effects may help explain the increasing prevalence of the metabolic syndromeand insulin resistance inthe generalpopulation andmayhaveimportant implications for population-based approaches to combat the increasing epidemic of metabolic and cardiovascular disease.”, “author” : { “dropping-particle” : “”, “family” : “Wolk”, “given” : “Robert”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Somers”, “given” : “Virend k”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Experimental Physiology”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2007” }, “page” : “67 – 78”, “title” : “sleep and metabolic syndrome”, “type” : “article-journal”, “volume” : “92.1” }, “uris” : “http://www.mendeley.com/documents/?uuid=72fecc28-4c8b-4bcc-8a0f-8e76b2890f49” } , “mendeley” : { “formattedCitation” : “(;b;;b;Wolk;/b; and ;b;Somers;/b;;/b;, ;b;2007;/b;)”, “plainTextFormattedCitation” : “(Wolk and Somers, 2007)”, “previouslyFormattedCitation” : “(;b;;b;Wolk;/b; and ;b;Somers;/b;;/b;, ;b;2007;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Wolk and Somers, 2007).

Inadequate sleep is a common feature of shiftwork. Generally, shift workers get less average sleep during the week compared with regular day workers. Shiftwork is characterized by changes in biological rhythms, cumulative circadian phase delay, variation in photo-period and napping. Most of the sleep loss involves stage 2 and rapid eye movement (REM) sleep, whereas slow wave sleep (SWS) is unaffected. The most troublesome acute symptoms are difficulty getting to sleep, shortened sleep and somnolence during working hours that continues into successive days of shift ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1093/occmed/kqg046”, “ISBN” : “1087-0792”, “ISSN” : “09627480”, “PMID” : “15310506”, “abstract” : “This paper reviews the effects of shift work and finds strong, acute effects on sleep and alertness in relation to night and morning work. The effects seem, however, to linger and also affect days off. The level of the disturbances is similar to that seen in clinical insomnia and may be responsible for considerable human and economical costs due to fatigue related accidents and reduced productivity. The mechanism behind the disturbances is the sleep interfering properties of the circadian system during day sleep and the corresponding sleep promoting properties during night work. Various strategies may be used to counteract the effects of shift work, such as napping, sufficient recovery time between shifts, clockwise rotation, etc. Still it does not seem possible to more eliminate the effects – only to reduce them.”, “author” : { “dropping-particle” : “”, “family” : “u00c5kerstedt”, “given” : “Torbju00f6rn”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational Medicine”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2003” }, “page” : “89-94”, “title” : “Shift work and disturbed sleep/wakefulness”, “type” : “article-journal”, “volume” : “53” }, “uris” : “http://www.mendeley.com/documents/?uuid=010ba495-f8c1-4b94-b729-3875b29317c0” } , “mendeley” : { “formattedCitation” : “(;b;;b;u00c5kerstedt;/b;;/b;, ;b;2003;/b;)”, “plainTextFormattedCitation” : “(u00c5kerstedt, 2003)”, “previouslyFormattedCitation” : “(;b;;b;u00c5kerstedt;/b;;/b;, ;b;2003;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Åkerstedt, 2003). It is concluded that working on atypical schedules, outside of the conventional daytime hours, leads to a substantial increase of sleepiness and sleep complaints ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.patbio.2014.08.001”, “ISBN” : “0369-8114”, “ISSN” : “17683114”, “PMID” : “25246026”, “abstract” : “Shift work comprises work schedules that extend beyond the typical “nine-to-five” workday, wherein schedules often comprise early work start, compressed work weeks with 12-hour shifts, and night work. According to recent American and European surveys, between 15 and 30% of adult workers are engaged in some type of shift work, with 19% of the European population reportedly working at least 2. hours between 22:00 and 05:00. The 2005 International Classification of Sleep Disorders estimates that a shift work sleep disorder can be found in 2-5% of workers. This disorder is characterized by excessive sleepiness and/or sleep disruption for at least one month in relation with the atypical work schedule. Individual tolerance to shift work remains a complex problem that is affected by the number of consecutive work hours and shifts, the rest periods, and the predictability of work schedules. Sleepiness usually occurs during night shifts and is maximal at the end of the night. Impaired vigilance and performance occur around times of increased sleepiness and can seriously compromise workers’ health and safety. Indeed, workers suffering from a shift work sleep-wake disorder can fall asleep involuntarily at work or while driving back home after a night shift. Working on atypical shifts has important socioeconomic impacts as it leads to an increased risk of accidents, workers’ impairment and danger to public safety, especially at night. The aim of the present review is to review the circadian and sleep-wake disturbances associated with shift work as well as their medical impacts.”, “author” : { “dropping-particle” : “”, “family” : “Boivin”, “given” : “D. B.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Boudreau”, “given” : “P.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Pathologie Biologie”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2014” }, “page” : “292-301”, “publisher” : “Elsevier Masson SAS”, “title” : “Impacts of shift work on sleep and circadian rhythms”, “type” : “article-journal”, “volume” : “62” }, “uris” : “http://www.mendeley.com/documents/?uuid=d45033ec-093d-441f-b9a3-4e57740cfaa2” } , “mendeley” : { “formattedCitation” : “(;b;;b;Boivin;/b; and ;b;Boudreau;/b;;/b;, ;b;2014;/b;)”, “plainTextFormattedCitation” : “(Boivin and Boudreau, 2014)”, “previouslyFormattedCitation” : “(;b;;b;Boivin;/b; and ;b;Boudreau;/b;;/b;, ;b;2014;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Boivin and Boudreau, 2014).
Night shift workers often complain also of decreased sleep quality, and symptoms of insomnia. Compared to regular day workers and evening shift workers; night workers whether on a permanent or rotating schedules, are associated with the most prominent sleep disruption. Melatonin level starts to rise in the evening, reaches its peak in the middle of the night, and then slowly declines to reach low undetectable levels at the end of the morning. Thus, sleepiness at nighttime in normal subjects can be attributed to melatonin peak secretion. On the contrary night shift workers will habitually be awake during their nocturnal melatonin peak and will go to bed at a time of day that is characterized by low melatonin levels, this reverses the normal sleep-wake cycle and makes the worker sleepy during the work shift and difficulty fall asleep during the day and this leads to sleep disturbances ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.patbio.2014.08.001”, “ISBN” : “0369-8114”, “ISSN” : “17683114”, “PMID” : “25246026”, “abstract” : “Shift work comprises work schedules that extend beyond the typical “nine-to-five” workday, wherein schedules often comprise early work start, compressed work weeks with 12-hour shifts, and night work. According to recent American and European surveys, between 15 and 30% of adult workers are engaged in some type of shift work, with 19% of the European population reportedly working at least 2. hours between 22:00 and 05:00. The 2005 International Classification of Sleep Disorders estimates that a shift work sleep disorder can be found in 2-5% of workers. This disorder is characterized by excessive sleepiness and/or sleep disruption for at least one month in relation with the atypical work schedule. Individual tolerance to shift work remains a complex problem that is affected by the number of consecutive work hours and shifts, the rest periods, and the predictability of work schedules. Sleepiness usually occurs during night shifts and is maximal at the end of the night. Impaired vigilance and performance occur around times of increased sleepiness and can seriously compromise workers’ health and safety. Indeed, workers suffering from a shift work sleep-wake disorder can fall asleep involuntarily at work or while driving back home after a night shift. Working on atypical shifts has important socioeconomic impacts as it leads to an increased risk of accidents, workers’ impairment and danger to public safety, especially at night. The aim of the present review is to review the circadian and sleep-wake disturbances associated with shift work as well as their medical impacts.”, “author” : { “dropping-particle” : “”, “family” : “Boivin”, “given” : “D. B.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Boudreau”, “given” : “P.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Pathologie Biologie”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2014” }, “page” : “292-301”, “publisher” : “Elsevier Masson SAS”, “title” : “Impacts of shift work on sleep and circadian rhythms”, “type” : “article-journal”, “volume” : “62” }, “uris” : “http://www.mendeley.com/documents/?uuid=d45033ec-093d-441f-b9a3-4e57740cfaa2” } , “mendeley” : { “formattedCitation” : “(;b;;b;Boivin;/b; and ;b;Boudreau;/b;;/b;, ;b;2014;/b;)”, “plainTextFormattedCitation” : “(Boivin and Boudreau, 2014)”, “previouslyFormattedCitation” : “(;b;;b;Boivin;/b; and ;b;Boudreau;/b;;/b;, ;b;2014;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Boivin and Boudreau, 2014).

It has been recognized for a long time that individuals differ significantly in their responses to extended working hours and shift work schedules. It has been suggested that individual-specific characteristics of sleep/wake regulation may be involved in inter-individual differences in tolerance to shift work. As mentioned above individual trait affect their tolerance to shift work but more studies need to be performed to provide strong evidence ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.2486/indhealth.47.518”, “ISBN” : “1880-8026 (Electronic)\r0019-8366 (Linking)”, “ISSN” : “0019-8366”, “PMID” : “19834261”, “abstract” : “There are considerable individual differences in cognitive performance deficits resulting from extended work hours and shift work schedules. Recent progress in sleep and performance research has yielded new insights into the causes and consequences of these individual differences. Neurobiological processes of sleep/wake regulation underlie trait individual variability in vulnerability to performance impairment due to sleep loss. Trait vulnerability to sleep loss is observed in the laboratory and in the work environment, even in occupational settings where (self-)selection pressures are high. In general, individuals do not seem to accurately assess the magnitude of their own vulnerability. Methods for identifying workers who are most at risk of sleep loss-related errors and accidents would therefore be helpful to target fatigue countermeasure interventions at those needing them most. As yet, no reliable predictors of vulnerability to sleep loss have been identified, although candidate genetic predictors have been proposed. However, a Bayesian forecasting technique based on closed-loop feedback of measured performance has been developed for individualized prediction of future performance impairment during ongoing operations. Judiciously selecting or monitoring individuals in specific tasks or occupations, within legally and ethically acceptable boundaries, has the potential to improve operational performance and productivity, reduce errors and accidents, and save lives. Trait individual variability in responses to sleep loss represents a major complication in the application of one-size-fits-all hours of service regulations–favoring instead modern fatigue risk management strategies, because these allow flexibility to account for individual vulnerability or resilience to the performance consequences of extended work hours and shift work schedules.”, “author” : { “dropping-particle” : “”, “family” : “Donghen”, “given” : “Hans P.A.”, “non-dropping-particle” : “Van”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Belenky”, “given” : “Gregory”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Industrial Health”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2009” }, “page” : “518-526”, “title” : “Individual Differences in Vulnerability to Sleep Loss in the Work Environment”, “type” : “article-journal”, “volume” : “47” }, “uris” : “http://www.mendeley.com/documents/?uuid=f4ec87fa-b475-4427-a8b9-b3a1ee9071fc” } , “mendeley” : { “formattedCitation” : “(<b><b>Van Donghen</b> and <b>Belenky</b></b>, <b>2009</b>)”, “manualFormatting” : “(Van Donghen and Belenky, 2009”, “plainTextFormattedCitation” : “(Van Donghen and Belenky, 2009)”, “previouslyFormattedCitation” : “(<b><b>Van Donghen</b> and <b>Belenky</b></b>, <b>2009</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Van Donghen and Belenky, 2009; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1111/j.1479-8425.2010.00432.x”, “ISBN” : “1479-8425”, “ISSN” : “14469235”, “abstract” : “Abstract Shift-work seriously affects the health and well-being of millions of people worldwide, and the number of shift workers is constantly rising (currently approximately 20% of the workforce). While some effects are acute, others lead to chronic syndromes that persist after retirement. Though health problems in shift workers are well established, we still do not properly understand the causal mechanisms underlying shift-work’s effects on health. One reason may be the heterogeneity in shift-work research design and methodology, rendering comparison between studies difficult or even impossible. Shift-work also involves a multitude of interacting factors, and we do not yet fully understand many of these interactions. Interindividual differences between workers are central predictors for health. Among these, individual differences in internal time (chronotype) should play a key role in a worker’s ability to adjust to shift-work. While the importance of chronotype is receiving increased attention in chronobiology, it is still being largely ignored by shift-work studies, particularly by those performed in the field. Shift-work research would greatly benefit from increased attention to circadian components in real-life shift-work situations. Here, we summarize the current state of shift-work research in an attempt to address the reasons as to why we still do not clearly understand the links between shift-work and health. The aim of shift-work research should ultimately be to improve health and well-being (including social issues) in shift workers by means of improved work schedules. Society as a whole would benefit from such improvements u2013 the individual worker, the health system, and industry.”, “author” : { “dropping-particle” : “”, “family” : “Kantermann”, “given” : “Thomas”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Juda”, “given” : “Myriam”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Vetter”, “given” : “Cu00e9line”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Roenneberg”, “given” : “Till”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep and Biological Rhythms”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “95-105”, “title” : “Shift-work research: Where do we stand, where should we go?”, “type” : “article-journal”, “volume” : “8” }, “uris” : “http://www.mendeley.com/documents/?uuid=59a60b20-ef3c-43f8-929c-002f72c755d1” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Kantermann</b> et al.</b></b>, <b>2010</b>)”, “manualFormatting” : “Kantermann et al., 2010”, “plainTextFormattedCitation” : “(Kantermann et al., 2010)”, “previouslyFormattedCitation” : “(<b><b><b>Kantermann</b> et al.</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Kantermann et al., 2010; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9073675103”, “author” : { “dropping-particle” : “”, “family” : “Lammers-van der Holst”, “given” : “H. M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “sleep-wake”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “88-100”, “title” : “Individual differences in shift work tolerance”, “type” : “article-journal”, “volume” : “27” }, “uris” : “http://www.mendeley.com/documents/?uuid=cbd8741c-85f1-4d91-9f8a-db09be18da17” } , “mendeley” : { “formattedCitation” : “(<b><b>Lammers-van der Holst</b></b>, <b>2016</b>)”, “manualFormatting” : “Lammers-van der Holst, 2016)”, “plainTextFormattedCitation” : “(Lammers-van der Holst, 2016)”, “previouslyFormattedCitation” : “(<b><b>Lammers-van der Holst</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Lammers-van der Holst, 2016).

Mental and Psychosocial
Shift work has become a lifestyle for most people. Due to their irregular working hours, shift workers spend less time with their families on their off days because they are often too tired to enjoy recreational and social activities. Lack of sleep makes people irritable and simple everyday issues can lead to arguments. Theses irritability and frequent arguments makes personal relationships and family life stressful. Shift workers can also often feel isolated from their social lives ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Shift work is a necessity for many organizations. Reasons for shift work are mainly to ensure continuous and optimized operations. Many studies on shift workers have concluded that it can lead to adverse physiological, social and psychological health effects. This study examines challenges associated with working shifts at a biscuits manufacturing factory. Results should be able to assist the employer in implementing effective interventions directed at limiting the negative effects of shift work on employees. This is a convergent parallel design multi method stud among 152 shift workers in a biscuits manufacturer located in Durban, KwaZulu Natal. An abbreviated and modified form of the validated SSI questionnaire was used (Barton et al. 1995). The questionnaire contained a battery of items designed to examine the relationship of health and personal adjustment to shift work. Owing to the exploratory nature of the study, a focus group methodology was also used and this allowed for in-depth qualitative research which catered for a more comprehensive understanding of the current shift work issues. A retrospective review of injury records of employees who sustained occupational injuries between 2012 and 2013 was also conducted. The sample comprised of 85 (56%) males and 63 (42%) females. Logistic regression was used to estimate the association between shift work and the likelihood of sleep disturbance, poor health outcomes and limited time for social and domestic activities, adjusting for age, sex, partner working, years working night shift, marital status, job class and years employed. Odds ratio (OR) for reported sleep disturbance was slightly higher among women (OR=1.65; 95% CI = 0.25; 10.84; p < 0.05) compared to males, but this was not statistically significant. Longer shift work experience (i.e.11-20 years) was significantly associated with better health status (OR=0.18; 95%CI = 0.06; 0.46; p < 0.05). Shift work experience (11 to 20 years) was also found to be significantly associated with limited time for both social (OR = 0.10; 95%CI = 0.03; 0.30) and domestic activities (OR= 0.25; 95% CI = 0.11; 0.57; p < 0.05) (Table 4). Age had no effect on social and domestic activities, but those 40 years and above were more likely to have limited time for social and domestic activities (OR = iii 3.06; 95%CI =0.60; 15.60 and OR= 2.5; 95%CI=0.47; 13.06). Those with more shift work experience seemed to have more time for social and domestic activities compared to u2026”, “author” : { “dropping-particle” : “”, “family” : “Mhlongo”, “given” : “Philisiwe Kenlly (Faculty of Health Sciences)”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “publisher” : “Durban University of Technology”, “title” : “Adverse effects of shift work at a biscuits manufacturer”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=9f8d9a5d-5a0a-461e-ab55-2592866888e6” } , “mendeley” : { “formattedCitation” : “(<b><b>Mhlongo</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Mhlongo, 2016)”, “previouslyFormattedCitation” : “(<b><b>Mhlongo</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mhlongo, 2016). Evidence shows that shift work can have indirect negative effect on social life. Shift work can lead to increased family problems, decreased social support and psychosocial stress ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISSN” : “18140351”, “abstract” : “This cross sectional study identified the common impacts of shift work on the health and social lives of security guards in the town of Madang. The study used face to face interviews and questionnaires to collect data from the managers and security guards. Both male and female security guards of three different security firms were involved in the study. Results showed that the most common health effects associated with shift work was sleeping disorder (52%), followed by fatigue (22%), stress (15%) and eating disorder (11%). The most common action taken by individual guards in managing the mentioned health conditions was a visit to the hospital. This study further discovered that social activities of security guards working on shifts were disturbed whereby 46% had less or limited time for other activities, 35% experienced behavioural changes, 11% encountered disharmony and 7% suffered broken marriages. In light of the findings of this study, recommendations are made for the National Department of Health (NDoH) and the Labour Department to review policies and legislations in the area of Occupational Health and Safety specifically dealing with shift work. ABSTRACT FROM AUTHOR”, “author” : { “dropping-particle” : “”, “family” : “Begani”, “given” : “Rose Kamaga”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Begani”, “given” : “Alphonse Zuivani”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “So’on”, “given” : “Vincent”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pokasui”, “given” : “Kinangase”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Contemporary PNG Studies”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2013” }, “page” : “98-116”, “title” : “Impact of shift work amongst security guards in Madang.”, “type” : “article-journal”, “volume” : “18” }, “uris” : “http://www.mendeley.com/documents/?uuid=a1ad2fe6-f64b-4362-8ec4-d78a4eabe38a” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Begani</b> et al.</b></b>, <b>2013</b>)”, “plainTextFormattedCitation” : “(Begani et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Begani</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Begani et al., 2013). Due to shift schedules, it is difficult to participate in family life. It was reported that irregular shift schedules also interfere with the coordination of family timetables, depending on the family composition (e.g. number of members and age of children), personal duties (e.g. housework) and the accessibility to community services (e.g. transportation, shop hours). A relationship was found between shift work and decreased partner satisfaction and increased divorce rates ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/978-3-319-42286-2”, “ISBN” : “9783319422862”, “abstract” : “This chapter gives an overview of the health problems associated with shift work, and the main organizational guidelines on how to protect workersu2019 health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general population, involving more and more people in continuous assistance and control of the work processes over the 24 h. The strong increase of epidemiological studies on this issue demonstrates the seriousness of this risk factor for human health and well-being, at both social and psychophysical levels, starting from disruption of biological circadian rhythms and the sleep/wake cycle, ending in several psychosomatic troubles and disorders, probably including cancer, and passing through impairment of performance efficiency and family and social life. Appropriate interventions on the organization of shift schedules according to ergonomic criteria, on the one hand, and a careful health surveillance and social support to shift workers, on the other hand, are important preventive and corrective measures able to allow people to keep working without significant health and social impairment.”, “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Social and Family Issues in Shift Work and Non Standard Working Hours”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “19 – 35”, “title” : “introduction to problems of shift work”, “type” : “chapter” }, “uris” : “http://www.mendeley.com/documents/?uuid=874a938e-65eb-4202-a8b5-6f6ab71f6b21” } , “mendeley” : { “formattedCitation” : “(<b><b>Costa</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Costa, 2016)”, “previouslyFormattedCitation” : “(<b><b>Costa</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa, 2016).

A study conducted in South Africa found that work demands of night nurses due to shift work had a negative impact on family responsibilities. Studied nurses worked 12 h shifts and they stated that they had limited time to spend with their families due to their schedule. They felt that their long working hours contributed to the moody and irritable feelings, which usually produced family conflicts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Background: Nurses have an increased risk for non-communicable diseases (NCDs), along with a high prevalence of obesity, poor eating habits and insufficient physical activity. The aim of this study was to determine the health concerns, health priorities and barriers to living a healthy lifestyle among nurses and hospital management staff from public hospitals in the Western Cape Metropole, South Africa. Methods: Participants were purposively sampled (n = 103), and included management personnel (n = 9), night shift (n = 57) and day-shift nurses (n = 36). Twelve focus groups (FGDs) were conducted with nursing staff to obtain insight into nursesu2019 health concerns, lifestyle behaviours and worksite health promotion programmes (WHPPs). Seven key informant interviews (KII) were conducted with management personnel, to gain their perspective on health promotion in the worksite. Thematic analysis was used to analyse the data with the assistance of Atlas.ti Qualitative Data Analysis Software. Results: Night shift nurses frequently identified weight gain and living with NCDs such as hypertension as their main health concerns. Being overweight was perceived to have a negative impact on work performance. All nurses identified backache and exposure to tuberculosis (TB) as occupation-related health concerns, and both management and nurses frequently reported a stressful working environment. Nurses frequently mentioned lack of time to prepare healthy meals due to long working hours and being overtired from work. The hospital environment was perceived to have a negative influence on the nursesu2019 lifestyle behaviours, including food service that offered predominantly unhealthy foods. The most commonly delivered WHPPs included independent counselling services, an online employee wellness programme offered by the Department of Health and wellness days in which clinical measures, such as blood glucose were measured. Nurses identified a preference for WHPPs that provided access to fitness facilities or support groups. Conclusions: Public hospitals are a stressful work environment and shift work places an additional strain on nurses. The risk of NCDs and exposure to infectious disease remains a concern in this working population. Our findings highlight the need for WHPPs that support nurses in managing stress and transforming the work environment to facilitate healthy lifestyles.”, “author” : { “dropping-particle” : “”, “family” : “Phiri”, “given” : “Lindokuhle P”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Draper”, “given” : “Catherine E”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “V”, “family” : “Lambert”, “given” : “Estelle”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kolbe-alexander”, “given” : “Tracy L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “BMC Nursing”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2014” }, “page” : “13 – 38”, “title” : “Nurses u2019 lifestyle behaviours , health priorities and barriers to living a healthy lifestyle : a qualitative descriptive study”, “type” : “article-journal” }, “uris” : “http://www.mendeley.com/documents/?uuid=6c3f6ee2-2127-48ec-969b-2cbdb65e18fa” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Phiri</b> et al.</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Phiri et al., 2014)”, “previouslyFormattedCitation” : “(<b><b><b>Phiri</b> et al.</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Phiri et al., 2014). On the other side, shift workers may be enforced to learn how to use daytime periods more positively; this provides more flexibility to those who enjoy solitary activities or for women who give a greater priority to family and house duties than to personal activities. As a consequence, it is found that working in shifts can be voluntarily preferred choice by some workers as it provides them more opportunities to use daytime hours to fulfill private needs (e.g. access to public offices, banks), or to enjoy longer intervals of free time in-between shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/978-3-319-42286-2”, “ISBN” : “9783319422862”, “abstract” : “This chapter gives an overview of the health problems associated with shift work, and the main organizational guidelines on how to protect workersu2019 health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general population, involving more and more people in continuous assistance and control of the work processes over the 24 h. The strong increase of epidemiological studies on this issue demonstrates the seriousness of this risk factor for human health and well-being, at both social and psychophysical levels, starting from disruption of biological circadian rhythms and the sleep/wake cycle, ending in several psychosomatic troubles and disorders, probably including cancer, and passing through impairment of performance efficiency and family and social life. Appropriate interventions on the organization of shift schedules according to ergonomic criteria, on the one hand, and a careful health surveillance and social support to shift workers, on the other hand, are important preventive and corrective measures able to allow people to keep working without significant health and social impairment.”, “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Social and Family Issues in Shift Work and Non Standard Working Hours”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “19 – 35”, “title” : “introduction to problems of shift work”, “type” : “chapter” }, “uris” : “http://www.mendeley.com/documents/?uuid=874a938e-65eb-4202-a8b5-6f6ab71f6b21” } , “mendeley” : { “formattedCitation” : “(<b><b>Costa</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Costa, 2016)”, “previouslyFormattedCitation” : “(<b><b>Costa</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa, 2016). It should be noted that this longer free time accrues not only from the shift system, but also from the decreased duration of sleep experienced by shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Shift work is a necessity for many organizations. Reasons for shift work are mainly to ensure continuous and optimized operations. Many studies on shift workers have concluded that it can lead to adverse physiological, social and psychological health effects. This study examines challenges associated with working shifts at a biscuits manufacturing factory. Results should be able to assist the employer in implementing effective interventions directed at limiting the negative effects of shift work on employees. This is a convergent parallel design multi method stud among 152 shift workers in a biscuits manufacturer located in Durban, KwaZulu Natal. An abbreviated and modified form of the validated SSI questionnaire was used (Barton et al. 1995). The questionnaire contained a battery of items designed to examine the relationship of health and personal adjustment to shift work. Owing to the exploratory nature of the study, a focus group methodology was also used and this allowed for in-depth qualitative research which catered for a more comprehensive understanding of the current shift work issues. A retrospective review of injury records of employees who sustained occupational injuries between 2012 and 2013 was also conducted. The sample comprised of 85 (56%) males and 63 (42%) females. Logistic regression was used to estimate the association between shift work and the likelihood of sleep disturbance, poor health outcomes and limited time for social and domestic activities, adjusting for age, sex, partner working, years working night shift, marital status, job class and years employed. Odds ratio (OR) for reported sleep disturbance was slightly higher among women (OR=1.65; 95% CI = 0.25; 10.84; p < 0.05) compared to males, but this was not statistically significant. Longer shift work experience (i.e.11-20 years) was significantly associated with better health status (OR=0.18; 95%CI = 0.06; 0.46; p < 0.05). Shift work experience (11 to 20 years) was also found to be significantly associated with limited time for both social (OR = 0.10; 95%CI = 0.03; 0.30) and domestic activities (OR= 0.25; 95% CI = 0.11; 0.57; p < 0.05) (Table 4). Age had no effect on social and domestic activities, but those 40 years and above were more likely to have limited time for social and domestic activities (OR = iii 3.06; 95%CI =0.60; 15.60 and OR= 2.5; 95%CI=0.47; 13.06). Those with more shift work experience seemed to have more time for social and domestic activities compared to u2026”, “author” : { “dropping-particle” : “”, “family” : “Mhlongo”, “given” : “Philisiwe Kenlly (Faculty of Health Sciences)”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “publisher” : “Durban University of Technology”, “title” : “Adverse effects of shift work at a biscuits manufacturer”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=9f8d9a5d-5a0a-461e-ab55-2592866888e6” } , “mendeley” : { “formattedCitation” : “(<b><b>Mhlongo</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Mhlongo, 2016)”, “previouslyFormattedCitation” : “(<b><b>Mhlongo</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mhlongo, 2016).

Shift work and mental health show mutual relationship where both affect each other. Regarding the effect of shift work on mental health, there is a suggested relation between the demands of modern work life and the increased rates of psychological and psychosomatic disorders. Work-related conditions play an increasingly important role in psychological and mental well-being ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/s00702-012-0800-4”, “ISBN” : “1435-1463 (Electronic)\r0300-9564 (Linking)”, “ISSN” : “03009564”, “PMID” : “22488445”, “abstract” : “Occupational engagement is a pre-requisite for continuous income\nopportunities. Among the changing social circumstances work-related\nconditions play an increasingly eminent role in psychological and mental\nwell-being. The public discusses the question of a possible association\nbetween the demands of modern work life and the increases of\npsychological, psychosomatic and cardiovascular disorders. Given the\nsocioeconomic implications of psychiatric and psychosomatic suffering in\nthe general population, there is a need to further elucidate the causes\nof their increasing incidence. From a medical point of view, any\norganization of work disrupting the phased circadian rhythms for\nbio-psycho-social processes and functioning of the individual are\ninteresting against the background of clock genes and certain biological\nfunctions that are organized in a circadian fashion. The authors review\nthe influence of shift work as a form of systematic desynchronization of\ninner clock systems on the endocrine, the physical, and the mental\nlevel. The significance of the findings in the field is discussed along\nwith future directions of conclusive research.”, “author” : { “dropping-particle” : “”, “family” : “Vogel”, “given” : “Matthias”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Braungardt”, “given” : “Tanja”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Meyer”, “given” : “Wolfgang”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schneider”, “given” : “Wolfgang”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Neural Transmission”, “id” : “ITEM-1”, “issue” : “10”, “issued” : { “date-parts” : “2012” }, “page” : “1121-1132”, “title” : “The effects of shift work on physical and mental health”, “type” : “article-journal”, “volume” : “119” }, “uris” : “http://www.mendeley.com/documents/?uuid=1511cc76-9356-4014-bf39-7115c2ca77f6” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Vogel</b> et al.</b></b>, <b>2012</b>)”, “plainTextFormattedCitation” : “(Vogel et al., 2012)”, “previouslyFormattedCitation” : “(<b><b><b>Vogel</b> et al.</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Vogel et al., 2012).
Driesen et al confirmed the relationship between shift work and depressive complaints, mostly defined as ”depressive mood” ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.3158”, “ISBN” : “0355-3140”, “ISSN” : “03553140”, “PMID” : “21526329”, “abstract” : “The aim of this study was to examine longitudinally the mutual relationship between shift work and depressive complaints.”, “author” : { “dropping-particle” : “”, “family” : “Driesen”, “given” : “Karolien”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jansen”, “given” : “Nicole W.H.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Amelsvoort”, “given” : “Ludovic G.P.M.”, “non-dropping-particle” : “van”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kant”, “given” : “Ijmert”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2011” }, “page” : “402-410”, “title” : “The mutual relationship between shift work and depressive complaints – aprospective cohort study”, “type” : “article-journal”, “volume” : “37” }, “uris” : “http://www.mendeley.com/documents/?uuid=bfa0389e-aa5c-4c1f-82f9-67b7db05e7f9” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Driesen</b> et al.</b></b>, <b>2011</b>)”, “plainTextFormattedCitation” : “(Driesen et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Driesen</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Driesen et al., 2011). In another study conducted by Bara and Arber; the results discovered that men who had worked nights for ? 4 years were more than twice the risk of reporting mental health problems compared to men who had never worked nights. For women, the results were more extensive where women who worked rotating shifts for ? 4 years were more than twice the risk of reporting mental health problems compared with women who did not work rotating shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.1344”, “ISBN” : “0355-3140 (Print)\r0355-3140 (Linking)”, “ISSN” : “1795990X”, “PMID” : “19688143”, “abstract” : “OBJECTIVE: Our objective was to examine the impact of shift work on mental health at the population level. We expected that this impact would depend on duration of exposure, type of shift work, and gender. METHODS: We analyzed longitudinal data (1995-2005) from the British Household Panel Survey. From the 2005 wave, we selected a subsample of people aged 21-73 years who had been followed annually from 1995 to 2005. We used responses in 2005 to the General Health Questionnaire (GHQ, 12-item) and self-reported anxiety/depression as dependent variables. Controlling for age, marital status, education, number of years working in six occupational categories (1995-2005), and baseline mental health, we performed nested logistic regression models to examine the effect of the duration of night work and varied shift patterns on mental health for men and women. RESULTS: Undertaking night work for > or =4 years in men was associated with an increased risk of having a GHQ score reflecting mental ill health and reporting anxiety/depression odds ratios (OR) 2.58, 95% confidence interval (95% CI) 1.22-5.48; OR 6.08, 95% CI 2.06-17.92, respectively. Women were significantly more likely to report anxiety/depression (OR 2.58, 95% CI 1.53-4.35 ) and to have a GHQ score reflecting mental ill health (OR 4.17, 95% CI 1.45-11.98), after working varied shift patterns for 2-3 years, and >/=4 years, respectively. CONCLUSIONS: Different types of shift work had a differential impact on mental health, but this impact varied according to gender. Women’s mental health was more adversely affected by varied shift patterns, while night work had a greater negative impact on men’s mental health.”, “author” : { “dropping-particle” : “”, “family” : “Bara”, “given” : “Ana Claudia”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Arber”, “given” : “Sara”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2009” }, “page” : “361-367”, “title” : “Working shifts and mental health – Findings from the British Household Panel Survey (1995-2005)”, “type” : “article-journal”, “volume” : “35” }, “uris” : “http://www.mendeley.com/documents/?uuid=4724ffc1-75c7-4a7f-b606-3a61673aa5fb” } , “mendeley” : { “formattedCitation” : “(<b><b>Bara</b> and <b>Arber</b></b>, <b>2009</b>)”, “plainTextFormattedCitation” : “(Bara and Arber, 2009)”, “previouslyFormattedCitation” : “(<b><b>Bara</b> and <b>Arber</b></b>, <b>2009</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Bara and Arber, 2009).
Studies investigating shift work among health professionals demonstrated that nurses show higher prevalence of somatization and anxiety-scores than the general population ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “The present study was conducted to determine the prevalence of mental disorders among shift work hospital nurses in Shiraz. One thousand one hundred and ninety five nurses from 12 general hospitals were investigated by Persian version of General Health Questionnaire-28 (GHQ-28) as screen tool. Using a checklist, structured observations were made to assess working environment. Selecting a score of 6 in GHQ-28 as cut-off point, 45.4% of nurses were found to suffer from mental disorders and this was more common among females. Similarly, anxiety and somatic symptoms were more prevalent than other types of mental disorders (43.2 and 34.5%, respectively). The prevalence of depression and social dysfunction were 11.2 and 79.5%, respectively. Shift work was significantly associated with anxiety (p < 0.05). Likewise, marital status was significantly associated with depression and social dysfunction (p < 0.001). It was concluded that the mental health pattern in hospital nurses was similar to that of general Iranian population as the referent population. However, the prevalence rates of social dysfunction, somatisation and anxiety symptoms among the nurses were higher than the referent population.”, “author” : { “dropping-particle” : “”, “family” : “Ardekani”, “given” : “ZZ”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kakooei”, “given” : “H”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ayattollahi”, “given” : “SM”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Choobineh”, “given” : “A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Seraji”, “given” : “GN.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “pakistan journal of biological science”, “id” : “ITEM-1”, “issue” : “12”, “issued” : { “date-parts” : “2008” }, “page” : “1605-9”, “title” : “Prevalence of mental disorders among shift work hospital nurses in Shiraz, Iran.”, “type” : “article-journal”, “volume” : “11” }, “uris” : “http://www.mendeley.com/documents/?uuid=dcf070a7-d83c-478a-a074-1fce3530bbc8” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Ardekani</b> et al.</b></b>, <b>2008</b>)”, “plainTextFormattedCitation” : “(Ardekani et al., 2008)”, “previouslyFormattedCitation” : “(<b><b><b>Ardekani</b> et al.</b></b>, <b>2008</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ardekani et al., 2008). Selvi and his colleagues compared nurses working at daytime with those working in shifts regarding their psychiatric symptoms. They found that working in night shifts was associated with significantly higher scores regarding somatization, obsessive–compulsive, interpersonal sensitivity, anxiety and paranoid symptoms ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5350/DAJPN2010230403t”, “ISSN” : “10188681”, “author” : { “dropping-particle” : “”, “family” : “Selvi”, “given” : “Yavuz”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “u00d6zdemir”, “given” : “Pu0131nar Gu00fczel”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “u00d6zdemir”, “given” : “Osman”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Aydu0131n”, “given” : “Adem”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Beu015firou011flu”, “given” : “Lu00fctfullah”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Dusunen Adam: The Journal of Psychiatry and Neurological Sciences”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2010” }, “page” : “238-243”, “title” : “Influence of night shift work on psychologic state and quality of life in health workers”, “type” : “article-journal”, “volume” : “23” }, “uris” : “http://www.mendeley.com/documents/?uuid=91ec6244-ede4-4a96-81c4-9cc49289867e” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Selvi</b> et al.</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Selvi et al., 2010)”, “previouslyFormattedCitation” : “(<b><b><b>Selvi</b> et al.</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Selvi et al., 2010). There is a claimed association between shift work and psychological distress, depression, anxiety and burnout. The authors proposed that shift work may get in the way of participating in family life because of fatigue and scheduling, which may increase the risk of depression ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1080/02678370802564272”, “ISBN” : “02678373”, “ISSN” : “02678373”, “PMID” : “35639724”, “abstract” : “With significant segments of the working population involved in shiftwork, there is the possibility of serious health outcomes. There are two possible pathways to ill health. In the biological pathway the bodyu2019s circadian rhythms are affected, leading to physiological disturbances and the inability to cope. By contrast, the aim of this study is to elucidate a social pathway by which shiftwork may lead to mental ill health. It examines the mediating influence of work-to-family conflict in the association between shiftwork and depression. Gender differences are also investigated. The sample included 2,931 Canadian respondents with a spouse and at least one child living at home. Close to 28% of respondents were involved in some form of shiftwork. Structural equation modelling supported partial mediation through work-to-family conflict. Further analyses found that mediation was supported in sub-samples of male and female respondents. The results, however, suggest that the experience of shiftwork is quite similar for men and women as no significant differences were found between mediating models. Overall, the findings support the social explanation of the effect of shiftwork on mental health, but they do not rule out other social or biological pathways.”, “author” : { “dropping-particle” : “”, “family” : “Haines”, “given” : “Victor Y.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Marchand”, “given” : “Alain”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rousseau”, “given” : “Vincent”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Demers”, “given” : “Andree”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Work and Stress”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2008” }, “page” : “341-356”, “title” : “The mediating role of work-to-family conflict in the relationship between shiftwork and depression”, “type” : “article”, “volume” : “22” }, “uris” : “http://www.mendeley.com/documents/?uuid=e020ac1a-5da6-48d3-8668-cda4ea531b5b” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Haines</b> et al.</b></b>, <b>2008</b>)”, “plainTextFormattedCitation” : “(Haines et al., 2008)”, “previouslyFormattedCitation” : “(<b><b><b>Haines</b> et al.</b></b>, <b>2008</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Haines et al., 2008).
About 26% of rotating shift workers develops a disorder called “shift work sleep-wake disorder” or “shift work disorder” (SWD). The disorder is recognized by persistent and severe sleep disruption during the sleep time and/or excessive sleepiness during the wake period. The condition is a direct consequence of the mismatch between the internal timing of the circadian rhythm and the external work-related sleep-wake schedule. Besides sleep-wake complaints, shift workers also report poorer mental health and lower quality of life. Shift work disorder is marked by chronic and severe sleep-wake disturbances that is attributed to failure to sufficiently adjust to shiftwork ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.sleep.2015.09.007”, “ISBN” : “0000000000000”, “ISSN” : “1527-5418”, “PMID” : “24655651”, “abstract” : “Objectivesu2014To investigate premorbid sleep reactivity as a vulnerability to incident shift work disorder and related changes in depression and anxiety following a transition to a rotating shifts work schedule. Methodsu2014This is a longitudinal study with two waves of data collection. The community-based sample included normal sleeping non-shift workers (N=96; 62.5% female; 47.9u00b113.3 yo) without a lifetime history of insomnia or baseline excessive daytime sleepiness who transitioned to rotating shift work one year later. Participants reported demographic characteristics, trait sleep reactivity on the Ford Insomnia Response to Stress Test, depression symptoms on the Quick Inventory of Depression Symptomatology, and anxiety symptoms on the Beck Anxiety Inventory. Shift work disorder was determined based on significant sleep disturbance and/or excessive sleepiness in the context of working a rotating shifts schedule. Resultsu2014Analyses revealed that the odds were over five times greater for highly sleep reactive individuals to develop shift work disorder after transitioning to rotating shifts (OR=5.59, p=.04). Nearly 90% of shift work disorder sufferers were accurately identified as high risk at 1-y prior to disease onset. Furthermore, individuals who developed SWD reported greater increases in symptoms of depression and anxiety. Finally, analyses revealed significant indirect effects wherein high sleep reactivity increased risk for SWD, which led to greater severity of anxiety and depression symptoms. Conclusionsu2014The FIRST accurately identifies a focused target population in which the premorbid psychobiological processes complicit in SWD onset and progression, as well as shift work-related depression and anxiety changes, can be better investigated, thus improving future preventative efforts.”, “author” : { “dropping-particle” : “”, “family” : “Kalmbach”, “given” : “David A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pillai”, “given” : “Vivek”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Cheng”, “given” : “Philip”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Arnedt”, “given” : “J Todd”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Drake”, “given” : “Christopher L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine”, “id” : “ITEM-1”, “issue” : “12”, “issued” : { “date-parts” : “2015” }, “page” : “1532- 1538”, “title” : “Shift Work Disorder, Depression, and Anxiety in the Transition to Rotating Shifts: The Role of Sleep Reactivity”, “type” : “article-journal”, “volume” : “16” }, “uris” : “http://www.mendeley.com/documents/?uuid=075b0928-0ca6-46fe-898c-e5db2d4cf2f9” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Kalmbach</b> et al.</b></b>, <b>2015</b>)”, “plainTextFormattedCitation” : “(Kalmbach et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Kalmbach</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Kalmbach et al., 2015). According to The National Sleep Foundation 2005 Sleep in America poll , compared to their day shift colleagues, shift workers also more commonly suffer from insomnia and excessive daytime sleepiness ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “National Sleep Foundation”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2005” }, “title” : “Shift Work & Sleep – National Sleep Foundation”, “type” : “article” }, “uris” : “http://www.mendeley.com/documents/?uuid=1062522e-7b62-4e35-b4e5-503c41c6dd68” } , “mendeley” : { “formattedCitation” : “(<b><b>National Sleep Foundation</b></b>, <b>2005</b>)”, “plainTextFormattedCitation” : “(National Sleep Foundation, 2005)”, “previouslyFormattedCitation” : “(<b><b>National Sleep Foundation</b></b>, <b>2005</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(National Sleep Foundation, 2005).

An identified trait characteristic that predicts individual tolerance to shift work is diurnal preference, or morningness versus eveningness. This trait has been related to a polymorphism of the clock gene, PERIOD3. Individuals with morningness preference (who have the homozygotic PERIOD35/5 polymorphism) are less tolerant circadian disruption and sleep loss associated with shift work. Much of the research on sequelae of diurnal preference and the PERIOD3 gene following a circadian challenge are greatly concerned with the degree to which sleep deprivation disrupts wake functioning ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.smrv.2009.07.002”, “ISBN” : “1532-2955 (Electronic) 1087-0792 (Linking)”, “ISSN” : “10870792”, “PMID” : “19716732”, “abstract” : “Circadian rhythmicity and sleep homeostasis contribute to sleep phenotypes and sleep-wake disorders, some of the genetic determinants of which are emerging. Approximately 10% of the population are homozygous for the 5-repeat allele (PER35/5) of a variable number tandem repeat polymorphism in the clock gene PERIOD3 (PER3). We review recent data on the effects of this polymorphism on sleep-wake regulation. PER35/5are more likely to show morning preference, whereas homozygosity for the four-repeat allele (PER34/4) associates with evening preferences. The association between sleep timing and the circadian rhythms of melatonin and PER3 RNA in leukocytes is stronger in PER35/5than in PER34/4. EEG alpha activity in REM sleep, theta/alpha activity during wakefulness and slow wave activity in NREM sleep are elevated in PER35/5. PER35/5show a greater cognitive decline, and a greater reduction in fMRI-assessed brain responses to an executive task, in response to total sleep deprivation. These effects are most pronounced during the late circadian night/early morning hours, i.e., approximately 0-4 h after the crest of the melatonin rhythm. We interpret the effects of the PER3 polymorphism within the context of a conceptual model in which higher homeostatic sleep pressure in PER35/5through feedback onto the circadian pacemaker modulates the amplitude of diurnal variation in performance. These findings highlight the interrelatedness of circadian rhythmicity and sleep homeostasis. u00a9 2009 Elsevier Ltd. All rights reserved.”, “author” : { “dropping-particle” : “”, “family” : “Dijk”, “given” : “Derk Jan”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Archer”, “given” : “Simon N.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine Reviews”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2010” }, “page” : “151-160”, “publisher” : “Elsevier Ltd”, “title” : “PERIOD3, circadian phenotypes, and sleep homeostasis”, “type” : “article-journal”, “volume” : “14” }, “uris” : “http://www.mendeley.com/documents/?uuid=98d02d70-97a2-4951-acdb-3cbedb52a3e4” } , “mendeley” : { “formattedCitation” : “(<b><b>Dijk</b> and <b>Archer</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Dijk and Archer, 2010)”, “previouslyFormattedCitation” : “(<b><b>Dijk</b> and <b>Archer</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Dijk and Archer, 2010).
Work Performance and Safety Issues
Sleepiness during work, sleep disturbances at nighttime, chronic fatigue and fluctuations of alertness and vigilance are basic individual factors in the occurrence human errors, and consequent work accidents and injuries. Individual factors interact with organizational factors, such as conditions of work environment, job demands, workload, and time pressure. Among shift workers both circadian disruption and sleep deprivation can lead to high levels of fatigue and sleepiness during the work periods. As a consequence, higher risk of performance impairment, inducing errors and accidents, both at the work place and during commuting to and from work occur with shift work ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/978-3-319-42286-2”, “ISBN” : “9783319422862”, “abstract” : “This chapter gives an overview of the health problems associated with shift work, and the main organizational guidelines on how to protect workersu2019 health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general population, involving more and more people in continuous assistance and control of the work processes over the 24 h. The strong increase of epidemiological studies on this issue demonstrates the seriousness of this risk factor for human health and well-being, at both social and psychophysical levels, starting from disruption of biological circadian rhythms and the sleep/wake cycle, ending in several psychosomatic troubles and disorders, probably including cancer, and passing through impairment of performance efficiency and family and social life. Appropriate interventions on the organization of shift schedules according to ergonomic criteria, on the one hand, and a careful health surveillance and social support to shift workers, on the other hand, are important preventive and corrective measures able to allow people to keep working without significant health and social impairment.”, “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Social and Family Issues in Shift Work and Non Standard Working Hours”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “19 – 35”, “title” : “introduction to problems of shift work”, “type” : “chapter” }, “uris” : “http://www.mendeley.com/documents/?uuid=874a938e-65eb-4202-a8b5-6f6ab71f6b21” } , “mendeley” : { “formattedCitation” : “(<b><b>Costa</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Costa, 2016)”, “previouslyFormattedCitation” : “(<b><b>Costa</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa, 2016). Dembe et al. concluded that “night, evening, rotating and irregular shifts all were associated with an increased risk of occupational injury or illness compared with regular day time shifts” ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.1004”, “ISBN” : “0355-3140”, “ISSN” : “03553140”, “PMID” : “16804627”, “abstract” : “OBJECTIVES: This study assessed the extent to which working various types of nonstandard shift schedules (eg, night and evening shifts) is associated with the risk of occupational injuries or illnesses. METHODS: Multivariate analyses were conducted using data from 13 years (1987 to 2000) of the National Longitudinal Survey of Youth (NLSY) encompassing 110 236 job records and over 82 000 person-years of work experience. Cox proportional hazard regression techniques were used to derive hazard ratios comparing the relative risk of suffering a work-related injury among people working night, evening, rotating, split, and irregular shifts to the risks for those working conventional day shifts, after adjustment for age, gender, occupation, industry, and region. Incidence rates were normalized using a common denominator of 100 person-years of “at-risk time” to obtain valid comparisons. RESULTS: All of the nonstandard shift schedules, except split shifts, were found to have a higher risk for occupational injuries and illnesses than conventional day shifts. After control for the selected covariates, the calculated hazard ratios were 1.43 for evening shifts 95% confidence interval (95% CI) 1.26-1.62, 1.36 for rotating shifts (95% CI 1.17-1.58), 1.30 for night shifts (95% CI 1.12-1.52), 1.15 for irregular shifts (1.03-1.30), and 1.06 for split shifts (0.71-1.58). CONCLUSIONS: These findings suggest that nonstandard shifts are not more risky merely because of the concentration of hazardous jobs in those types of schedules or because of underlying differences in the characteristics of employees working nonstandard shifts. The results point to the need to extend targeted injury prevention programs not only to people working night shifts, but also to those who work evenings.”, “author” : { “dropping-particle” : “”, “family” : “Dembe”, “given” : “Allard E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Erickson”, “given” : “J. Bianca”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Delbos”, “given” : “Rachel G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Banks”, “given” : “Steven M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2006” }, “page” : “232-240”, “title” : “Nonstandard shift schedules and the risk of job-related injuries”, “type” : “article-journal”, “volume” : “32” }, “uris” : “http://www.mendeley.com/documents/?uuid=b279d72a-408f-403f-abb2-34dc8869b634” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Dembe</b> et al.</b></b>, <b>2006</b>)”, “plainTextFormattedCitation” : “(Dembe et al., 2006)”, “previouslyFormattedCitation” : “(<b><b><b>Dembe</b> et al.</b></b>, <b>2006</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Dembe et al., 2006).

It was found that a 12 h shift workers had a double risk of accident compared with an 8-h shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.3109/07420528.2014.957309”, “ISBN” : “0742-0528”, “ISSN” : “15256073”, “PMID” : “25216205”, “abstract” : “ISSN: 0742-0528 (Print) 1525-6073 (Online) Journal homepage: http://www.tandfonline.com/loi/icbi20 We compared two ”3 u00c2 8” shift rotas with backward rotation and quick return (morning and night shift in the same day) in a 5-or 6-day shift cycle, and a ”2 u00c2 12” shift rota with forward rotation in a 5-d shift cycle. A total of 294 nurses (72.6% women, mean age 33.8) were examined in a survey on work-related stress, including the Standard Shiftwork Index. Ten nurses per each shift roster recorded their activity and rest periods by actigraphy, rated sleepiness and sleep quality, and collected salivary cortisol throughout the whole shift cycle. Nurses engaged in the ”2 u00c2 12” rota showed lower levels of sleep disturbances and, according to actigraphy, sleep duration was more balanced and less fragmented than in the ”3 u00c2 8” rosters. The counter-clockwise shift rotation and quick return of ”3 u00c2 8” schedules reduce possibility of sleep and recovery. The insertion of a morning shift before the day with quick return increases night sleep by about 1 h. Nurses who take a nap during the night shift require 40% less sleep in the morning after. The ”2 u00c2 12” clockwise roster, in spite of 50% increased length of shift, allows a better recovery and more satisfying leisure times, thanks to longer intervals between work periods. Sleepiness increased more during the night than day shifts in all rosters, but without significant difference between 8-h and 12-h rosters. However, the significantly higher level at the start of the night shift in the ”3 u00c2 8” rotas points out that the fast backward rotation with quick return puts the subjects in less efficient operational conditions. Some personal characteristics, such as morningness, lability to overcome drowsiness, flexibility of sleeping habits and age were significantly associated to sleep disturbances in nurses engaged in the ”3 u00c2 8” rotas, but not in the ”2 u00c2 12” schedule.”, “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Anelli”, “given” : “Matteo M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Castellini”, “given” : “Giovanna”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fustinoni”, “given” : “Silvia”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Neri”, “given” : “Luca”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Chronobiology International”, “id” : “ITEM-1”, “issue” : “10”, “issued” : { “date-parts” : “2014” }, “page” : “1169-1178”, “title” : “Stress and sleep in nurses employed in “3 u00d7 8” and “2 u00d7 12″ fast rotating shift schedules”, “type” : “article”, “volume” : “31” }, “uris” : “http://www.mendeley.com/documents/?uuid=3adaedbb-f36d-46c7-bff0-9779f2a0fc60” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Costa</b> et al.</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Costa et al., 2014)”, “previouslyFormattedCitation” : “(<b><b><b>Costa</b> et al.</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa et al., 2014). Also a recent survey of more than 75,000 US workers over a 4-year period confirmed a higher risk of injury strictly related to a progressive increase of working hours and reduction of sleep duration ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.3395”, “ISBN” : “0355-3140”, “ISSN” : “03553140”, “PMID” : “24162622”, “abstract” : “OBJECTIVE: The aim of the present study was to investigate the effects of the duration and timing of rest breaks on traumatic injury risk across a shift in a relatively large sample of hospitalized workers with severe work-related hand injury in the People’s Republic of China (PRC).\n\nMETHODS: Hospitalized workers from multiple industries with severe work-related traumatic hand injury were recruited from 11 hospitals in three industrially-developed cities in the PRC: Ningbo, Liuzhou, and Wuxi. Cox regression was used to compare time into the work shift of injury across categories of rest breaks, while evaluating several potential covariates including age, gender, work hours, work start time and duration, injury day and time, duration and quality of last sleep, alertness/sleepiness, job control, and several transient work-related factors. Effect modification by work shift start time was also evaluated.\n\nRESULTS: With four days of injury, 703 hospitalized workers completed a face-to-face interview. After adjusting for significant covariates, workers with rest breaks of 1-30, 31-60, and >60 minutes were able to work significantly (P<0.001) longer into their work shift without an injury (>5 hours) then those with no rest break. A significant interaction was also observed between rest break status and start time of the work shift.\n\nCONCLUSION: The results of this study suggest that rest breaks of any duration have a significant effect on delaying the onset of a work-related injury, which is modified by the time of day in which a shift begins.”, “author” : { “dropping-particle” : “”, “family” : “Lombardi”, “given” : “David A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jin”, “given” : “Kezhi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Courtney”, “given” : “Theodore K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Arlinghaus”, “given” : “Anna”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Folkard”, “given” : “Simon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Liang”, “given” : “Youxin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Perry”, “given” : “Melissa J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment and Health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2014” }, “page” : “146-155”, “title” : “The effects of rest breaks, work shift start time, and sleep on the onset of severe injury among workers in the People’s Republic of China”, “type” : “article-journal”, “volume” : “40” }, “uris” : “http://www.mendeley.com/documents/?uuid=c88acf57-1ed1-4833-b677-f0c06d0f8111” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Lombardi</b> et al.</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Lombardi et al., 2014)”, “previouslyFormattedCitation” : “(<b><b><b>Lombardi</b> et al.</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Lombardi et al., 2014). Fortson (2004) concluded that the human biological clock does not work efficiently in the early hours of the morning, and, as a consequence, short-term memory, reaction time and visual vigilance may be impaired. According to “population-attributable risk” calculations, shift work may be responsible for 6-7% of workplace injuries. This study also showed another factor that may add to increased injuries among night workers which is usually lower levels of supervision and co-worker support during irregular work schedules ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Fortson”, “given” : “Kenneth N”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “monthly labor review”, “id” : “ITEM-1”, “issue” : “9”, “issued” : { “date-parts” : “2004” }, “page” : “18-25”, “title” : “The diurnal pattern of on-the-job injuries”, “type” : “article-journal”, “volume” : “127” }, “uris” : “http://www.mendeley.com/documents/?uuid=58aefead-2415-4426-928f-1fe96857893b” } , “mendeley” : { “formattedCitation” : “(<b><b>Fortson</b></b>, <b>2004</b>)”, “plainTextFormattedCitation” : “(Fortson, 2004)”, “previouslyFormattedCitation” : “(<b><b>Fortson</b></b>, <b>2004</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Fortson, 2004). In 2014 a study conducted among Western Cape nurses found that increased prevalence of reporting needle stick injuries during night shift, and most of them occurred during the early hours of the morning when nurses were usually fatigued ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Background: Nurses have an increased risk for non-communicable diseases (NCDs), along with a high prevalence of obesity, poor eating habits and insufficient physical activity. The aim of this study was to determine the health concerns, health priorities and barriers to living a healthy lifestyle among nurses and hospital management staff from public hospitals in the Western Cape Metropole, South Africa. Methods: Participants were purposively sampled (n = 103), and included management personnel (n = 9), night shift (n = 57) and day-shift nurses (n = 36). Twelve focus groups (FGDs) were conducted with nursing staff to obtain insight into nursesu2019 health concerns, lifestyle behaviours and worksite health promotion programmes (WHPPs). Seven key informant interviews (KII) were conducted with management personnel, to gain their perspective on health promotion in the worksite. Thematic analysis was used to analyse the data with the assistance of Atlas.ti Qualitative Data Analysis Software. Results: Night shift nurses frequently identified weight gain and living with NCDs such as hypertension as their main health concerns. Being overweight was perceived to have a negative impact on work performance. All nurses identified backache and exposure to tuberculosis (TB) as occupation-related health concerns, and both management and nurses frequently reported a stressful working environment. Nurses frequently mentioned lack of time to prepare healthy meals due to long working hours and being overtired from work. The hospital environment was perceived to have a negative influence on the nursesu2019 lifestyle behaviours, including food service that offered predominantly unhealthy foods. The most commonly delivered WHPPs included independent counselling services, an online employee wellness programme offered by the Department of Health and wellness days in which clinical measures, such as blood glucose were measured. Nurses identified a preference for WHPPs that provided access to fitness facilities or support groups. Conclusions: Public hospitals are a stressful work environment and shift work places an additional strain on nurses. The risk of NCDs and exposure to infectious disease remains a concern in this working population. Our findings highlight the need for WHPPs that support nurses in managing stress and transforming the work environment to facilitate healthy lifestyles.”, “author” : { “dropping-particle” : “”, “family” : “Phiri”, “given” : “Lindokuhle P”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Draper”, “given” : “Catherine E”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “V”, “family” : “Lambert”, “given” : “Estelle”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kolbe-alexander”, “given” : “Tracy L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “BMC Nursing”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2014” }, “page” : “13 – 38”, “title” : “Nurses u2019 lifestyle behaviours , health priorities and barriers to living a healthy lifestyle : a qualitative descriptive study”, “type” : “article-journal” }, “uris” : “http://www.mendeley.com/documents/?uuid=6c3f6ee2-2127-48ec-969b-2cbdb65e18fa” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Phiri</b> et al.</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Phiri et al., 2014)”, “previouslyFormattedCitation” : “(<b><b><b>Phiri</b> et al.</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Phiri et al., 2014).

Effects on Body Systems
Cardiovascular system
Among the different causes of mortality; deaths attributable to cardiovascular diseases (CVDs) are the most prevalent worldwide. In 2015 CVDs were responsible for 17.7 million deaths (accounting for 45% of all deaths due to non-communicable diseases), and estimates suggest they will still rank first in 2030 (ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “ISBN 978-92-4-156548-6”, “ISBN” : “9789241565394”, “abstract” : “Overview More than 50 SDG indicators, across more than 10 goals, have been selected to measure health outcomes, direct determinants of health or health-service provision. These health-related indicators may be grouped into the following seven thematic areas: u2022 reproductive, maternal, newborn and child health u2022 infectious diseases u2022 noncommunicable diseases and mental health u2022 injuries and violence u2022 universal health coverage and health systems u2022 environmental risks u2022 health risks and disease outbreaks. Available data indicate that despite the progress made during the MDG era major challenges remain in terms of reducing maternal and child mortality, improving nutrition, and making further progress in the battle against communicable diseases such as HIV/AIDS, tuberculosis (TB), malaria, neglected tropical diseases and hepatitis. Furthermore, the results of situation analyses provide clear evidence of the crucial importance of addressing NCDs and their risk factors u2013 such as tobacco use, mental health problems, road traffic injuries and environmental conditions u2013 within the sustainable development agenda. In many countries, weak health systems remain an obstacle to progress and result in deficiencies in coverage for even the most basic health services, as well as poor preparedness for health emergencies. Based on the latest available data, the global and regional situation in relation to the above seven thematic areas is summarized below. Country-specific findings by indicator, where available, are presented graphically in Annex A and in tabular form in Annex B. 2.1 Reproductive, maternal, newborn and child health”, “author” : { “dropping-particle” : “”, “family” : “World Health Statistics”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Geneva: World Health Organization”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2017” }, “number-of-pages” : “29-35”, “title” : “World Health Statistics. Status of the health-related SDGs”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=3a9d402b-fa45-4931-8411-7b78a781af78” } , “mendeley” : { “formattedCitation” : “(<b><b>World Health Statistics</b></b>, <b>2017</b>)”, “manualFormatting” : “World Health Statistics, 2017)”, “plainTextFormattedCitation” : “(World Health Statistics, 2017)”, “previouslyFormattedCitation” : “(<b><b>World Health Statistics</b></b>, <b>2017</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }World Health Statistics, 2017). Some occupational factors are now assumed to be related to CVDs. Among these factors, the management of work schedules (shift work) is becoming a progressively important one ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.acvd.2011.09.004”, “ISBN” : “1875-2136”, “ISSN” : “18752136”, “PMID” : “22152516”, “abstract” : “Cardiovascular diseases remain a major public health problem. The involvement of several occupational factors has recently been discussed, notably the organization of work schedules, e.g. shift work. To analyse the progress of knowledge on the relationship between cardiovascular risk factors and shift work. A review of English-language literature dealing with the link between cardiovascular factors and shift workers (published during 2000-2010) was conducted. Studies published in the past 10 years tend to document an impact of shift work on blood pressure, lipid profile (triglyceride levels), metabolic syndrome and, possibly, body mass index. However, the consequences on glucose metabolism are unclear. These results are not yet firmly established, but are supported by strong hypotheses. Some advice could reasonably be proposed to guide the clinical practitioner. ?? 2011 Elsevier Masson SAS. All rights reserved.”, “author” : { “dropping-particle” : “”, “family” : “Esquirol”, “given” : “Yolande”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Perret”, “given” : “Bertrand”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ruidavets”, “given” : “Jean Bernard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Marquie”, “given” : “Jean Claude”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dienne”, “given” : “Eloi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Niezborala”, “given” : “Michel”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ferrieres”, “given” : “Jean”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Archives of Cardiovascular Diseases”, “id” : “ITEM-1”, “issue” : “12”, “issued” : { “date-parts” : “2011” }, “page” : “636-668”, “publisher” : “Elsevier Masson SAS”, “title” : “Shift work and cardiovascular risk factors: New knowledge from the past decade”, “type” : “article-journal”, “volume” : “104” }, “uris” : “http://www.mendeley.com/documents/?uuid=4bc56eba-58ba-4875-9f45-09f98976d807” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Esquirol</b> et al.</b></b>, <b>2011</b>)”, “plainTextFormattedCitation” : “(Esquirol et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Esquirol</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Esquirol et al., 2011).
Several complex pathophysiological hypotheses support the effect of shift work on CVDs including: disruption of circadian rhythms, sleep disturbances, behavioral factors (diet, alcohol and tobacco) and occupational stress as well as other CVD risk factors that are related to shift work as dyslipidemia, obesity and DM ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.acvd.2011.09.004”, “ISBN” : “1875-2136”, “ISSN” : “18752136”, “PMID” : “22152516”, “abstract” : “Cardiovascular diseases remain a major public health problem. The involvement of several occupational factors has recently been discussed, notably the organization of work schedules, e.g. shift work. To analyse the progress of knowledge on the relationship between cardiovascular risk factors and shift work. A review of English-language literature dealing with the link between cardiovascular factors and shift workers (published during 2000-2010) was conducted. Studies published in the past 10 years tend to document an impact of shift work on blood pressure, lipid profile (triglyceride levels), metabolic syndrome and, possibly, body mass index. However, the consequences on glucose metabolism are unclear. These results are not yet firmly established, but are supported by strong hypotheses. Some advice could reasonably be proposed to guide the clinical practitioner. ?? 2011 Elsevier Masson SAS. All rights reserved.”, “author” : { “dropping-particle” : “”, “family” : “Esquirol”, “given” : “Yolande”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Perret”, “given” : “Bertrand”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ruidavets”, “given” : “Jean Bernard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Marquie”, “given” : “Jean Claude”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dienne”, “given” : “Eloi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Niezborala”, “given” : “Michel”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ferrieres”, “given” : “Jean”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Archives of Cardiovascular Diseases”, “id” : “ITEM-1”, “issue” : “12”, “issued” : { “date-parts” : “2011” }, “page” : “636-668”, “publisher” : “Elsevier Masson SAS”, “title” : “Shift work and cardiovascular risk factors: New knowledge from the past decade”, “type” : “article-journal”, “volume” : “104” }, “uris” : “http://www.mendeley.com/documents/?uuid=4bc56eba-58ba-4875-9f45-09f98976d807” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Esquirol</b> et al.</b></b>, <b>2011</b>)”, “plainTextFormattedCitation” : “(Esquirol et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Esquirol</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Esquirol et al., 2011). It was suggested that circadian misalignment by itself elevates sleep blood pressure (which is a better predictor of adverse cardiovascular events and all-cause mortality than wake blood pressure) and inflammatory markers. These findings may help explaining why shift work increases hypertension and CVDs risk ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1073/pnas.1516953113”, “ISBN” : “1091-6490 (Electronic)\r0027-8424 (Linking)”, “ISSN” : “0027-8424”, “PMID” : “26858430”, “abstract” : “Shift work is a risk factor for hypertension, inflammation, and cardiovascular disease. This increased risk cannot be fully explained by classic risk factors. One of the key features of shift workers is that their behavioral and environmental cycles are typically misaligned relative to their endogenous circadian system. However, there is little information on the impact of acute circadian misalignment on cardiovascular disease risk in humans. Here we show-by using two 8-d laboratory protocols-that short-term circadian misalignment (12-h inverted behavioral and environmental cycles for three days) adversely affects cardiovascular risk factors in healthy adults. Circadian misalignment increased 24-h systolic blood pressure (SBP) and diastolic blood pressure (DBP) by 3.0 mmHg and 1.5 mmHg, respectively. These results were primarily explained by an increase in blood pressure during sleep opportunities (SBP, +5.6 mmHg; DBP, +1.9 mmHg) and, to a lesser extent, by raised blood pressure during wake periods (SBP, +1.6 mmHg; DBP, +1.4 mmHg). Circadian misalignment decreased wake cardiac vagal modulation by 8-15%, as determined by heart rate variability analysis, and decreased 24-h urinary epinephrine excretion rate by 7%, without a significant effect on 24-h urinary norepinephrine excretion rate. Circadian misalignment increased 24-h serum interleukin-6, C-reactive protein, resistin, and tumor necrosis factor-u03b1 levels by 3-29%. We demonstrate that circadian misalignment per se increases blood pressure and inflammatory markers. Our findings may help explain why shift work increases hypertension, inflammation, and cardiovascular disease risk.”, “author” : { “dropping-particle” : “”, “family” : “Morris”, “given” : “Christopher J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Purvis”, “given” : “Taylor E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hu”, “given” : “Kun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Scheer”, “given” : “Frank A. J. L.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Proceedings of the National Academy of Sciences of the United States of America”, “id” : “ITEM-1”, “issue” : “10”, “issued” : { “date-parts” : “2016” }, “page” : “E1402-1414”, “title” : “Circadian misalignment increases cardiovascular disease risk factors in humans”, “type” : “article-journal”, “volume” : “113” }, “uris” : “http://www.mendeley.com/documents/?uuid=c29c10bb-ec5e-4683-ac78-322668e89b5d” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Morris</b> et al.</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Morris et al., 2016)”, “previouslyFormattedCitation” : “(<b><b><b>Morris</b> et al.</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Morris et al., 2016).

Gastrointestinal system
Eating habits of shift workers differ from those of day workers. The overall caloric intake consumed by shift workers mayn’t change significantly, but they have different timing and frequency of eating (i.e. nibbling). The food quality and composition eaten by shift workers are also different (e.g. more consumption of pre-packed foods and soft drinks; more carbohydrates and fats in many cases), and meals often being taken cold and during short breaks. Shift workers are more prone to stomach discomfort, indigestion, constipation and may be ulcers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Shift work is a necessity for many organizations. Reasons for shift work are mainly to ensure continuous and optimized operations. Many studies on shift workers have concluded that it can lead to adverse physiological, social and psychological health effects. This study examines challenges associated with working shifts at a biscuits manufacturing factory. Results should be able to assist the employer in implementing effective interventions directed at limiting the negative effects of shift work on employees. This is a convergent parallel design multi method stud among 152 shift workers in a biscuits manufacturer located in Durban, KwaZulu Natal. An abbreviated and modified form of the validated SSI questionnaire was used (Barton et al. 1995). The questionnaire contained a battery of items designed to examine the relationship of health and personal adjustment to shift work. Owing to the exploratory nature of the study, a focus group methodology was also used and this allowed for in-depth qualitative research which catered for a more comprehensive understanding of the current shift work issues. A retrospective review of injury records of employees who sustained occupational injuries between 2012 and 2013 was also conducted. The sample comprised of 85 (56%) males and 63 (42%) females. Logistic regression was used to estimate the association between shift work and the likelihood of sleep disturbance, poor health outcomes and limited time for social and domestic activities, adjusting for age, sex, partner working, years working night shift, marital status, job class and years employed. Odds ratio (OR) for reported sleep disturbance was slightly higher among women (OR=1.65; 95% CI = 0.25; 10.84; p < 0.05) compared to males, but this was not statistically significant. Longer shift work experience (i.e.11-20 years) was significantly associated with better health status (OR=0.18; 95%CI = 0.06; 0.46; p < 0.05). Shift work experience (11 to 20 years) was also found to be significantly associated with limited time for both social (OR = 0.10; 95%CI = 0.03; 0.30) and domestic activities (OR= 0.25; 95% CI = 0.11; 0.57; p < 0.05) (Table 4). Age had no effect on social and domestic activities, but those 40 years and above were more likely to have limited time for social and domestic activities (OR = iii 3.06; 95%CI =0.60; 15.60 and OR= 2.5; 95%CI=0.47; 13.06). Those with more shift work experience seemed to have more time for social and domestic activities compared to u2026”, “author” : { “dropping-particle” : “”, “family” : “Mhlongo”, “given” : “Philisiwe Kenlly (Faculty of Health Sciences)”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “publisher” : “Durban University of Technology”, “title” : “Adverse effects of shift work at a biscuits manufacturer”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=9f8d9a5d-5a0a-461e-ab55-2592866888e6” } , “mendeley” : { “formattedCitation” : “(<b><b>Mhlongo</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Mhlongo, 2016)”, “previouslyFormattedCitation” : “(<b><b>Mhlongo</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mhlongo, 2016).

Gastrointestinal problems are among the most frequently reported health problems among shift workers; it is estimated that gastrointestinal disorders are two to five times more common among night shift workers compared with those who are not working at night ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1093/occmed/kqg045”, “ISBN” : “0962-7480 (Print)\n0962-7480 (Linking)”, “ISSN” : “09627480”, “PMID” : “12637591”, “abstract” : “In modern society, more and more people work during ‘non-standard’ working hours, including shift and night work, which are recognized risk factors for health, safety and social well-being. Suitable preventive and protective measures are required to mitigate the adverse effects and ensure that the worker can cope satisfactorily. These are based mainly on the organization of shift schedules according to ergonomic criteria and on specific medical surveillance. Occupational medicine has to consider very carefully the several factors (psycho-physiological, pathological and social) that can influence tolerance and/or maladaptation.”, “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational Medicine”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2003” }, “page” : “83-88”, “title” : “Shift work and occupational medicine: An overview”, “type” : “article-journal”, “volume” : “53” }, “uris” : “http://www.mendeley.com/documents/?uuid=ddcac3bc-046e-4ed7-8bd4-64e2fa13b306” } , “mendeley” : { “formattedCitation” : “(<b><b>Costa</b></b>, <b>2003</b>)”, “plainTextFormattedCitation” : “(Costa, 2003)”, “previouslyFormattedCitation” : “(<b><b>Costa</b></b>, <b>2003</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa, 2003). Gastrointestinal troubles mostly encountered by shift workers can vary from changes in bowel habits (mainly constipation); indigestion; flatulence and heart burn up to more severe disorders such as peptic ulcer, gastroduodenitis and irritable bowel syndrome (Costa, 2010) Furthermore, Helicobacter Pylori infection was found to be more prevalent in shift workers compared with day workers, which means that shift work hampers the natural gastric defense (ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1136/oem.2006.027367”, “ISBN” : “1470-7926 (Electronic)\r1351-0711 (Linking)”, “ISSN” : “13510711”, “PMID” : “17050745”, “abstract” : “To evaluate whether shift work is associated with an increased rate of peptic ulcer in H pylori infected workers.”, “author” : { “dropping-particle” : “”, “family” : “Pietroiusti”, “given” : “A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Forlini”, “given” : “A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Magrini”, “given” : “A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Galante”, “given” : “A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Coppeta”, “given” : “L.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gemma”, “given” : “G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Romeo”, “given” : “E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bergamaschi”, “given” : “A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational and Environmental Medicine”, “id” : “ITEM-1”, “issue” : “11”, “issued” : { “date-parts” : “2006” }, “page” : “773-775”, “title” : “Shift work increases the frequency of duodenal ulcer in H pylori infected workers”, “type” : “article-journal”, “volume” : “63” }, “uris” : “http://www.mendeley.com/documents/?uuid=64c86e1a-be17-4756-a9a1-1bee06c243a2” } , “mendeley” : { “formattedCitation” : “(<b><b><b>A. Pietroiusti</b> et al.</b></b>, <b>2006</b>)”, “manualFormatting” : “Pietroiusti et al., 2006)”, “plainTextFormattedCitation” : “(A. Pietroiusti et al., 2006)”, “previouslyFormattedCitation” : “(<b><b><b>A. Pietroiusti</b> et al.</b></b>, <b>2006</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Pietroiusti et al., 2006).
Reproductive system
Shift work also has an impact on the reproductive health of women. Studies have linked shift work with unfavorable pregnancy outcomes as spontaneous abortion, preterm labor, preeclampsia and low birth weight ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Shift work is a necessity for many organizations. Reasons for shift work are mainly to ensure continuous and optimized operations. Many studies on shift workers have concluded that it can lead to adverse physiological, social and psychological health effects. This study examines challenges associated with working shifts at a biscuits manufacturing factory. Results should be able to assist the employer in implementing effective interventions directed at limiting the negative effects of shift work on employees. This is a convergent parallel design multi method stud among 152 shift workers in a biscuits manufacturer located in Durban, KwaZulu Natal. An abbreviated and modified form of the validated SSI questionnaire was used (Barton et al. 1995). The questionnaire contained a battery of items designed to examine the relationship of health and personal adjustment to shift work. Owing to the exploratory nature of the study, a focus group methodology was also used and this allowed for in-depth qualitative research which catered for a more comprehensive understanding of the current shift work issues. A retrospective review of injury records of employees who sustained occupational injuries between 2012 and 2013 was also conducted. The sample comprised of 85 (56%) males and 63 (42%) females. Logistic regression was used to estimate the association between shift work and the likelihood of sleep disturbance, poor health outcomes and limited time for social and domestic activities, adjusting for age, sex, partner working, years working night shift, marital status, job class and years employed. Odds ratio (OR) for reported sleep disturbance was slightly higher among women (OR=1.65; 95% CI = 0.25; 10.84; p < 0.05) compared to males, but this was not statistically significant. Longer shift work experience (i.e.11-20 years) was significantly associated with better health status (OR=0.18; 95%CI = 0.06; 0.46; p < 0.05). Shift work experience (11 to 20 years) was also found to be significantly associated with limited time for both social (OR = 0.10; 95%CI = 0.03; 0.30) and domestic activities (OR= 0.25; 95% CI = 0.11; 0.57; p < 0.05) (Table 4). Age had no effect on social and domestic activities, but those 40 years and above were more likely to have limited time for social and domestic activities (OR = iii 3.06; 95%CI =0.60; 15.60 and OR= 2.5; 95%CI=0.47; 13.06). Those with more shift work experience seemed to have more time for social and domestic activities compared to u2026”, “author” : { “dropping-particle” : “”, “family” : “Mhlongo”, “given” : “Philisiwe Kenlly (Faculty of Health Sciences)”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “publisher” : “Durban University of Technology”, “title” : “Adverse effects of shift work at a biscuits manufacturer”, “type” : “thesis” }, “uris” : “http://www.mendeley.com/documents/?uuid=9f8d9a5d-5a0a-461e-ab55-2592866888e6” } , “mendeley” : { “formattedCitation” : “(<b><b>Mhlongo</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Mhlongo, 2016)”, “previouslyFormattedCitation” : “(<b><b>Mhlongo</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mhlongo, 2016). Shift work was also related to irregular menstrual cycles including short or long-term cycles and both irregularities are associated with reduced women’s productivity. Menstrual dysfunction decreases the quality of life, increases absenteeism rates, and puts significant costs to the industry ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5539/gjhs.v5n3p163”, “ISSN” : “1916-9744”, “author” : { “dropping-particle” : “”, “family” : “Attarchi”, “given” : “Mirsaeed”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Darkhi”, “given” : “Hamidreza”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Khodarahmian”, “given” : “Mahshad”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dolati”, “given” : “Mandana”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kashanian”, “given” : “Maryam”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ghaffari”, “given” : “Mostafa”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mirzamohammadi”, “given” : “Elham”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mohammadi”, “given” : “Saber”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Global Journal of Health Science”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2013” }, “page” : “163-172”, “title” : “Characteristics of Menstrual Cycle in Shift Workers”, “type” : “article-journal”, “volume” : “5” }, “uris” : “http://www.mendeley.com/documents/?uuid=b4492133-aa89-4f9e-946a-6259f899cb97” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Attarchi</b> et al.</b></b>, <b>2013</b>)”, “plainTextFormattedCitation” : “(Attarchi et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Attarchi</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Attarchi et al., 2013). It was suggested that women exhibit daily rhythms in the timing of reproductive cycle events and patterns of hormone secretion. The pre-ovulatory luteinizing hormone (LH) surge acrophase typically occurs between midnight and 8 am. So shift work disturbs the rhythmic pattern of female hormones ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2010/813764”, “ISBN” : “1687-8345 (Electronic)\r1687-8337 (Linking)”, “ISSN” : “16878337”, “PMID” : “20224815”, “abstract” : “Circadian rhythms and “clock gene” expression are involved in successful reproductive cycles, mating, and pregnancy. Alterations or disruptions of biological rhythms, as commonly occurs in shift work, jet lag, sleep deprivation, or clock gene knock out models, are linked to significant disruptions in reproductive function. These impairments include altered hormonal secretion patterns, reduced conception rates, increased miscarriage rates and an increased risk of breast cancer. Female health may be particularly susceptible to the impact of desynchronizing work schedules as perturbed hormonal rhythms can further influence the expression patterns of clock genes. Estrogen modifies clock gene expression in the uterus, ovaries, and suprachiasmatic nucleus, the site of the primary circadian clock mechanism. Further work investigating clock genes, light exposure, ovarian hormones, and reproductive function will be critical for indentifying how these factors interact to impact health and susceptibility to disease.”, “author” : { “dropping-particle” : “”, “family” : “Mahoney”, “given” : “Megan M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International Journal of Endocrinology”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2010” }, “title” : “Shift work, jet lag, and female reproduction”, “type” : “article-journal”, “volume” : “2010” }, “uris” : “http://www.mendeley.com/documents/?uuid=67e08716-3cc7-48a9-94c3-6d383efe3b1d” } , “mendeley” : { “formattedCitation” : “(<b><b>Mahoney</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Mahoney, 2010)”, “previouslyFormattedCitation” : “(<b><b>Mahoney</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Mahoney, 2010).

Some studies showed that women shift workers have lower fertility rates than their day counterparts not only because of the interference on the hormonal rhythms, but also for a personal choice of avoiding or limiting pregnancies or new babies. The latter choice is due to the more complex and difficult organization of their life caused by the conflicts between irregular work schedules and home commitments ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/978-3-319-42286-2”, “ISBN” : “9783319422862”, “abstract” : “This chapter gives an overview of the health problems associated with shift work, and the main organizational guidelines on how to protect workersu2019 health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general population, involving more and more people in continuous assistance and control of the work processes over the 24 h. The strong increase of epidemiological studies on this issue demonstrates the seriousness of this risk factor for human health and well-being, at both social and psychophysical levels, starting from disruption of biological circadian rhythms and the sleep/wake cycle, ending in several psychosomatic troubles and disorders, probably including cancer, and passing through impairment of performance efficiency and family and social life. Appropriate interventions on the organization of shift schedules according to ergonomic criteria, on the one hand, and a careful health surveillance and social support to shift workers, on the other hand, are important preventive and corrective measures able to allow people to keep working without significant health and social impairment.”, “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Social and Family Issues in Shift Work and Non Standard Working Hours”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “19 – 35”, “title” : “introduction to problems of shift work”, “type” : “chapter” }, “uris” : “http://www.mendeley.com/documents/?uuid=874a938e-65eb-4202-a8b5-6f6ab71f6b21” } , “mendeley” : { “formattedCitation” : “(<b><b>Costa</b></b>, <b>2016</b>)”, “plainTextFormattedCitation” : “(Costa, 2016)”, “previouslyFormattedCitation” : “(<b><b>Costa</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa, 2016).

Cancer
Recently, several studies showed an increased incidence or prevalence of cancer, especially breast cancer, among shift workers. Shiftwork that involves circadian disruption is classified by the International Agency for Research on Cancer (IARC) as a probable carcinogen (group 2A) for humans, evidence is strongest for breast cancer which is the most common cancer affecting females ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “9789283212980 (pbk.)\n9283212983 (pbk.)\n1017-1606 ;”, “ISSN” : “10171606”, “PMID” : “21381544”, “abstract” : “This volume of the IARC Monographs provides evaluations of the carcinogenicity of shiftwork, painting and firefighting. Shiftwork is estimated to involve about 15-20% of the total working population. It is most prevalent among workers in the health care, transportation, communication, leisure and hospitality sectors. Shiftwork involving work at night is the most disruptive for the circadian clock. Painters are potentially exposed to the chemicals found in paint products during their application and removal, and may also be exposed to other workplace hazards, such as asbestos or crystalline silica dust. Firefighters may be exposed at different intensity levels depending on crew assignment, tasks, and/or the time spent at fires. All fires generate a very large number of toxic combustion products, including known, probable or possible carcinogens. An IARC Monographs Working Group reviewed epidemiological evidence, animal bioassays where appropriate, and mechanistic and other relevant data to reach conclusions as to the carcinogenic hazard of these three exposure circumstances to humans.”, “author” : { “dropping-particle” : “”, “family” : “International Agency for Research on Cancer (IARC)”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “IARC monographs working group on the evaluation of carcinogenic risks to humans / World Health Organization, International Agency for Research on Cancer”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2010” }, “number-of-pages” : “764”, “publisher-place” : “Lyon – France”, “title” : “Painting, firefighting, and shiftwork.”, “type” : “report”, “volume” : “98” }, “uris” : “http://www.mendeley.com/documents/?uuid=1b992c4d-0681-4fcb-95c6-125ac64da4be” } , “mendeley” : { “formattedCitation” : “(<b><b>International Agency for Research on Cancer (IARC)</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(International Agency for Research on Cancer (IARC), 2010)”, “previouslyFormattedCitation” : “(<b><b>International Agency for Research on Cancer (IARC)</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(IARC, 2010). More limited observations are seen in other studies, some of which posed a warning also for cancers of the prostate and colorectal, endometrium cancers, and non-Hodgkin’s lymphoma ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Haus”, “given” : “Erhard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Stevens”, “given” : “Richard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandanavian journal for work and environmental health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “163 – 179”, “title” : “Shif work and cancer considerations on rationale, mechanism and epidemiology”, “type” : “article-journal”, “volume” : “36” }, “uris” : “http://www.mendeley.com/documents/?uuid=a5f6f025-31ec-42a3-86c9-8ffcb5642667” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Costa</b> et al.</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Costa et al., 2010)”, “previouslyFormattedCitation” : “(<b><b><b>Costa</b> et al.</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa et al., 2010).

A potential effect of circadian disruption on prostate can-
cer incidence has been re cently suggested (evidence reviewed
in Sigurdardottir et al. 2012).

6
Night shift work, the main
cause of circadian disruption, is one of the most widespread
occupational exposures in the industrialized part of the
world
A potential effect of circadian disruption on prostate can-
cer incidence has been re cently suggested
Chronotype is an individual characteristic that describes the circadian phase and correlates with diurnal preference (i.e. the individual preference for morning or evening activity) ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1002/ijc.29400”, “ISBN” : “0020-7136”, “ISSN” : “10970215”, “PMID” : “25530021”, “abstract” : “Night shift work has been classified as a probable human carcinogen based on experimental studies and limited human evidence on breast cancer. Evidence on other common cancers, such as prostate cancer, is scarce. Chronotype is an individual characteristic that may relate to night work adaptation. We evaluated night shift work with relation to prostate cancer, taking into account chronotype and disease severity in a population based case-control study in Spain. We included 1,095 prostate cancer cases and 1,388 randomly selected population controls. We collected detailed information on shift schedules (permanent vs. rotating, time schedules, duration, frequency), using lifetime occupational history. Sociodemographic and lifestyle factors were assessed by face-to-face interviews and chronotype through a validated questionnaire. We used unconditional logistic regression analysis adjusting for potential confounders. Subjects who had worked at least for one year in night shift work had a slightly higher prostate cancer risk Odds Ratio (OR) 1.14; 95%CI 0.94, 1.37 compared with never night workers; this risk increased with longer duration of exposure (u2265 28 years: OR 1.37; 95%CI 1.05, 1.81; p-trendu2009=u20090.047). Risks were more pronounced for high risk tumors D’Amico classification, Relative Risk Ratio (RRR) 1.40; 95%CI 1.05, 1.86, particularly among subjects with longer duration of exposure (u226528 years: RRR 1.63; 95%CI 1.08, 2.45; p-trendu2009=u20090.027). Overall risk was higher among subjects with an evening chronotype, but also increased in morning chronotypes after long-term night work. In this large population based study, we found an association between night shift work and prostate cancer particularly for tumors with worse prognosis.”, “author” : { “dropping-particle” : “”, “family” : “Papantoniou”, “given” : “Kyriaki”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Castau00f1o-Vinyals”, “given” : “Gemma”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Espinosa”, “given” : “Ana”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Aragonu00e9s”, “given” : “Nuria”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pu00e9rez-Gu00f5mez”, “given” : “Beatriz”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Burgos”, “given” : “Javier”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gu00f5mez-Acebo”, “given” : “Inu00e9s”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Llorca”, “given” : “Javier”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Peiru00f5”, “given” : “Rosana”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jimenez-Moleu00f5n”, “given” : “Jose Juan”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Arredondo”, “given” : “Francisco”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tardu00f5n”, “given” : “Adonina”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pollan”, “given” : “Marina”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kogevinas”, “given” : “Manolis”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International Journal of Cancer”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2015” }, “page” : “1147-1157”, “title” : “Night shift work, chronotype and prostate cancer risk in the MCC-Spain case-control study”, “type” : “article-journal”, “volume” : “137” }, “uris” : “http://www.mendeley.com/documents/?uuid=90176aa4-5c36-4643-885e-94998cee8e49” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Papantoniou;/b; et al.;/b;;/b;, ;b;2015;/b;)”, “plainTextFormattedCitation” : “(Papantoniou et al., 2015)”, “previouslyFormattedCitation” : “(;b;;b;;b;Papantoniou;/b; et al.;/b;;/b;, ;b;2015;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Papantoniou et al., 2015). Few studies have assessed chronotype in connection with night shift work and breast cancer risk ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “2011100240”, “author” : { “dropping-particle” : “”, “family” : “Hansen”, “given” : “Johnni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lassen”, “given” : “Christina F”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational and Environmental Medicine”, “id” : “ITEM-1”, “issue” : “8”, “issued” : { “date-parts” : “2012” }, “page” : “551-556”, “title” : “Nested case – control study of night shift work and breast cancer risk among women in the Danish military”, “type” : “article-journal”, “volume” : “69” }, “uris” : “http://www.mendeley.com/documents/?uuid=c22c79de-a278-48c2-8f9a-6c880ce1905f” } , “mendeley” : { “formattedCitation” : “(;b;;b;J. Hansen;/b; and ;b;Lassen;/b;;/b;, ;b;2012;/b;)”, “manualFormatting” : “(Hansen and Lassen, 2012”, “plainTextFormattedCitation” : “(J. Hansen and Lassen, 2012)”, “previouslyFormattedCitation” : “(;b;;b;J. Hansen;/b; and ;b;Lassen;/b;;/b;, ;b;2012;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Hansen and Lassen, 2012 ; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.3109/07420528.2013.809359”, “abstract” : “The aim of this study was to examine the relation between chronotype and breast cancer risk. We analyzed the association between chronotype (definite morning type, probable morning type, probable evening type, definite evening type, or neither morning nor evening type) and breast cancer risk among 72 517 women in the Nurses’ Health Study II (NHS II). Chronotype was self-reported in 2009, and 1834 breast cancer cases were confirmed among participants between 1989 and 2007; a 2-yr lag period was imposed to account for possible circadian disruptions related to breast cancer diagnosis. Age- and multivariable-adjusted logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Participants who self-reported as neither morning nor evening type had a 27% increased risk of breast cancer (multivariable-adjusted OR = 1.27, 95% CI = 1.04-1.56), compared with definite morning types. None of the other chronotypes were significantly associated with breast cancer risk (multivariable-adjusted OR = 0.99, 95% CI = 0.87-1.12 for probable morning versus definite morning types; OR = 0.96, 95% CI = 0.84-1.09 for probable evening versus definite morning types; and OR = 1.15, 95% CI = 0.98-1.34 for definite evening versus definite morning types). Overall, chronotype was not associated with breast cancer risk in our study. A modestly increased risk among neither morning nor evening types may indicate circadian disruption as a potentially underlying mechanism; however, more studies are needed to confirm our results. u00a9 Informa Healthcare USA, Inc.”, “author” : { “dropping-particle” : “”, “family” : “Ramin”, “given” : “C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Devore”, “given” : “E.E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pierre-Paul”, “given” : “J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Duffy”, “given” : “J.F.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hankinson”, “given” : “S.E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schernhammer”, “given” : “E.S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Chronobiology International”, “id” : “ITEM-1”, “issue” : “9”, “issued” : { “date-parts” : “2013” }, “page” : “1181-1186”, “title” : “Chronotype and breast cancer risk in a cohort of US nurses”, “type” : “article-journal”, “volume” : “30” }, “uris” : “http://www.mendeley.com/documents/?uuid=1c93e4bb-d197-43ee-bfdd-962b2e046033” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Ramin</b> et al.</b></b>, <b>2013</b>)”, “manualFormatting” : “Ramin et al., 2013)”, “plainTextFormattedCitation” : “(Ramin et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Ramin</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Ramin et al., 2013).

METABOLIC SYNDROME AND SHIFT WORK
Epidemiology of Metabolic Syndrome
“Syndrome X”, the name given to a cluster of cardiovascular disease risk factors by Reaven ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Reaven”, “given” : “Gerald M”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “diabetes”, “id” : “ITEM-1”, “issue” : “12”, “issued” : { “date-parts” : “1988” }, “page” : “1595 – 1607”, “title” : “Role of Insulin Resistance in Human Disease”, “type” : “article-journal”, “volume” : “37” }, “uris” : “http://www.mendeley.com/documents/?uuid=96c38af6-4a65-4476-b3e6-56a895a4c5b6” } , “mendeley” : { “formattedCitation” : “(<b><b>Reaven</b></b>, <b>1988</b>)”, “plainTextFormattedCitation” : “(Reaven, 1988)”, “previouslyFormattedCitation” : “(<b><b>Reaven</b></b>, <b>1988</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Reaven, 1988). After that, the term metabolic syndrome and diagnostic criteria was first proposed by the World Health Organization (WHO) in 1999 ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1002/(SICI)1096-9136(199807)15:7<539::AID-DIA668>3.0.CO;2-S”, “ISSN” : “07423071”, “PMID” : “9686693”, “abstract” : “The classification of diabetes mellitus and the tests used for its diagnosis were brought into order by the National Diabetes Data Group of the USA and the second World Health Organization Expert Committee on Diabetes Mellitus in 1979 and 1980. Apart from minor modifications by WHO in 1985, little has been changed since that time. There is however considerable new knowledge regarding the aetiology of different forms of diabetes as well as more information on the predictive value of different blood glucose values for the complications of diabetes. A WHO Consultation has therefore taken place in parallel with a report by an American Diabetes Association Expert Committee to re-examine diagnostic criteria and classification. The present document includes the conclusions of the former and is intended for wide distribution and discussion before final proposals are submitted to WHO for approval. The main changes proposed are as follows. The diagnostic fasting plasma (blood) glucose value has been lowered to > or =7.0 mmol l(-1) (6.1 mmol l(-1)). Impaired Glucose Tolerance (IGT) is changed to allow for the new fasting level. A new category of Impaired Fasting Glycaemia (IFG) is proposed to encompass values which are above normal but below the diagnostic cut-off for diabetes (plasma > or =6.1 to or =5.6 to <6.1 mmol l(-1)). Gestational Diabetes Mellitus (GDM) now includes gestational impaired glucose tolerance as well as the previous GDM. The classification defines both process and stage of the disease. The processes include Type 1, autoimmune and non-autoimmune, with beta-cell destruction; Type 2 with varying degrees of insulin resistance and insulin hyposecretion; Gestational Diabetes Mellitus; and Other Types where the cause is known (e.g. MODY, endocrinopathies). It is anticipated that this group will expand as causes of Type 2 become known. Stages range from normoglycaemia to insulin required for survival. It is hoped that the new classification will allow better classification of individuals and lead to fewer therapeutic misjudgements.”, “author” : { “dropping-particle” : “”, “family” : “World Health Organization (WHO)”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “World Health”, “id” : “ITEM-1”, “issued” : { “date-parts” : “1999” }, “page” : “539-53”, “title” : “Definition , Diagnosis and Classification of Diabetes Mellitus and its Complications Part 1 : Diagnosis and Classification of”, “type” : “article-journal”, “volume” : “15” }, “uris” : “http://www.mendeley.com/documents/?uuid=2b9b6742-8558-45b4-9465-04ac028eab27” } , “mendeley” : { “formattedCitation” : “(<b><b>World Health Organization (WHO)</b></b>, <b>1999</b>)”, “manualFormatting” : “(WHO, 1999)”, “plainTextFormattedCitation” : “(World Health Organization (WHO), 1999)”, “previouslyFormattedCitation” : “(<b><b>World Health Organization (WHO)</b></b>, <b>1999</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(WHO, 1999). In the same year the European Group for the study of Insulin Resistance (EGIR) published another definition for MS ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1046/j.1464-5491.1999.00059.x”, “author” : { “dropping-particle” : “”, “family” : “Balkau”, “given” : “B”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Charles”, “given” : “MA.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Diabetic medicine”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “1999” }, “page” : “442 – 443”, “publisher-place” : “Pisa, Italy”, “title” : “comment on who report european group”, “type” : “article-journal”, “volume” : “16” }, “uris” : “http://www.mendeley.com/documents/?uuid=700d8e09-223f-48f6-bbd2-851b8d6c11c6” } , “mendeley” : { “formattedCitation” : “(<b><b>Balkau</b> and <b>Charles</b></b>, <b>1999</b>)”, “plainTextFormattedCitation” : “(Balkau and Charles, 1999)”, “previouslyFormattedCitation” : “(<b><b>Balkau</b> and <b>Charles</b></b>, <b>1999</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Balkau and Charles, 1999). Later, in 2001, the US National Cholesterol Education Program Adult Treatment Panel (NCEP-ATP) III highlighted the importance of the MS for management of cardiovascular diseases and proposed standards for the diagnosis of MS. These standards for MS diagnosis required three or more of the following criteria to be met: abdominal obesity, hypertriglyceridemia, low HDL, elevated blood pressure, and impaired glucose tolerance (ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1001/archinte.1991.00400060019005”, “ISSN” : “0003-9926”, “PMID” : “12485966”, “abstract” : “Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III, or ATP III) presents the National Cholesterol Education Program (NCEP) updated recommendations on cholesterol testing and management. The ATP III document is an evidence-based report that provides the scientific rationale for the recommendations contained in the Executive Summary. ATP III is constructed on the foundation of ATP I and ATP II, with low density lipoprotein (LDL) continuing to be identified as the primary target of cholesterol lowering therapy. New features of ATP III include: Aggressive treatment of persons who are at relatively high risk for coronary heart disease due to multiple risk factors Use of the lipoprotein profile as the first test for high cholesterol A new level at which low HDL (high density lipoprotein) becomes a major heart disease risk factor A new set of “Therapeutic Lifestyle Changes” to improve cholesterol levels An increased focus on a cluster of heart disease risk factors knows as “the metabolic syndrome” Increased attention to the treatment of high triglycerides”, “author” : { “dropping-particle” : “”, “family” : “National Cholesterol Education Program (NCEP) Expert Panel”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Archives of Internal Medicine”, “id” : “ITEM-1”, “issue” : “6”, “issued” : { “date-parts” : “2002” }, “number-of-pages” : “284”, “title” : “Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III)”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=775353c3-bb28-48a1-97b3-066b514d79db” } , “mendeley” : { “formattedCitation” : “(<b><b>National Cholesterol Education Program (NCEP) Expert Panel</b></b>, <b>2002</b>)”, “manualFormatting” : “NCEP Expert Panel, 2002)”, “plainTextFormattedCitation” : “(National Cholesterol Education Program (NCEP) Expert Panel, 2002)”, “previouslyFormattedCitation” : “(<b><b>National Cholesterol Education Program (NCEP) Expert Panel</b></b>, <b>2002</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }NCEP Expert Panel, 2002).
In 2005, the International Diabetes Federation (IDF) offered new diagnostic criteria that modified the NCEP-ATP III. They noted the high relation to insulin resistance, and suggested abdominal obesity (a simple clinical measurement) as a diagnostic prerequisite (ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1159/000282084”, “ISBN” : “0003-9926 (Print) 0003-9926 (Linking)”, “ISSN” : “14219875”, “PMID” : “20460909”, “abstract” : “Over the last few years, the paradigm in hepatology has changed from focusing on a single liver disease to considering concurrent diseases, in particular obesity and related metabolic factors. Obesity has reached epidemic proportions globally and is associated with insulin resistance, steatosis and a low-grade systemic inflammatory state. These metabolic factors have a synergistic role in the natural history and treatment outcomes related to chronic liver disease. This is characterized best in chronic hepatitis C where steatosis and insulin resistance are caused by viral and metabolic effects. Non-alcoholic fatty liver disease and related metabolic abnormalities also exacerbate other diseases, such as alcoholic liver disease and haemochromatosis. In addition, there is growing evidence linking obesity and type 2 diabetes with hepatocellular carcinoma in subjects with chronic viral hepatitis. The pathogenesis of co-morbid disease may be related to increased oxidative stress, inflammatory injury and cell death, along with altered hepatocyte regeneration and repair. Hyperinsulinaemia and other metabolic factors may also have a direct role in the progression of liver injury. Data indicate that weight reduction improves steatosis and inflammation in patients with chronic hepatitis C. This has important clinical and therapeutic implications and suggests that obesity should be actively addressed in the management of patients with other chronic liver diseases.”, “author” : { “dropping-particle” : “”, “family” : “IDF”, “given” : “International Diabetes Fedration”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “The IDF consensus worldwide definition of the metabolic syndrome”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2006” }, “page” : “1-7”, “title” : “The IDF consensus worldwide definition of the metabolic syndrome”, “type” : “article”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=967b5632-9ea7-41c5-8a79-5b435c026da5” } , “mendeley” : { “formattedCitation” : “(<b><b>IDF</b></b>, <b>2006</b>)”, “manualFormatting” : “IDF, 2006)”, “plainTextFormattedCitation” : “(IDF, 2006)”, “previouslyFormattedCitation” : “(<b><b>IDF</b></b>, <b>2006</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }IDF, 2006). In addition, in 2005 also, the American Heart Association/ National Heart Lung and Blood Institute (AHA/NGLBI) modified NCEP-ATP III criterion for impaired fasting glucose and the use of medication as a risk factor ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1161/CIRCULATIONAHA.105.169404”, “ISBN” : “8006116083”, “ISSN” : “00097322”, “PMID” : “16157765”, “abstract” : “The metabolic syndrome has received increased attention in the past few years. This statement from the American Heart Association (AHA) and the National Heart, Lung, and Blood Institute (NHLBI) is intended to provide up-to-date guidance for professionals on the diagnosis and management of the metabolic syndrome in adults.\n\nThe metabolic syndrome is a constellation of interrelated risk factors of metabolic originu2014 metabolic risk factors u2014that appear to directly promote the development of atherosclerotic cardiovascular disease (ASCVD).1 Patients with the metabolic syndrome also are at increased risk for developing type 2 diabetes mellitus. Another set of conditions, the underlying risk factors , give rise to the metabolic risk factors. In the past few years, several expert groups have attempted to set forth simple diagnostic criteria to be used in clinical practice to identify patients who manifest the multiple components of the metabolic syndrome. These criteria have varied somewhat in specific elements, but in general they include a combination of both underlying and metabolic risk factors.\n\nThe most widely recognized of the metabolic risk factors are atherogenic dyslipidemia, elevated blood pressure, and elevated plasma glucose. Individuals with these characteristics commonly manifest a prothrombotic state and a pro-inflammatory state as well. Atherogenic dyslipidemia consists of an aggregation of lipoprotein abnormalities including elevated serum triglyceride and apolipoprotein B (apoB), increased small LDL particles, and a reduced level of HDL cholesterol (HDL-C). The metabolic syndrome is often referred to as if it were a discrete entity with a single cause. Available data suggest that it truly is a syndrome, ie, a grouping of ASCVD risk factors, but one that probably has more than one cause. Regardless of cause, the syndrome identifies individuals at an elevated risk for ASCVD. The magnitude of the increased risk can vary according to which components of the syndrome are u2026”, “author” : { “dropping-particle” : “”, “family” : “Grundy”, “given” : “Scott M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Cleeman”, “given” : “James I.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Daniels”, “given” : “Stephen R.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Donato”, “given” : “Karen A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Eckel”, “given” : “Robert H.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Franklin”, “given” : “Barry A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gordon”, “given” : “David J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Krauss”, “given” : “Ronald M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Savage”, “given” : “Peter J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Smith”, “given” : “Sidney C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Spertus”, “given” : “John A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Costa”, “given” : “Fernando”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Circulation”, “id” : “ITEM-1”, “issue” : “17”, “issued” : { “date-parts” : “2005” }, “page” : “2735-2752”, “title” : “Diagnosis and management of the metabolic syndrome: An American Heart Association/National Heart, Lung, and Blood Institute scientific statement”, “type” : “article-journal”, “volume” : “112” }, “uris” : “http://www.mendeley.com/documents/?uuid=123605be-63c8-40db-a00c-2780bfc3de1e” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Grundy</b> et al.</b></b>, <b>2005</b>)”, “plainTextFormattedCitation” : “(Grundy et al., 2005)”, “previouslyFormattedCitation” : “(<b><b><b>Grundy</b> et al.</b></b>, <b>2005</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Grundy et al., 2005).
Lately, other abnormalities as chronic pro-inflammatory and pro-thrombotic states, non-alcoholic fatty liver and sleep apnea have been added to the entity of the MS, making the definition more complicated. In addition to the different components and clinical consequences of MS, there is still no universally accepted pathogenic mechanism or clearly defined diagnostic criteria. Moreover, there is still an argument about whether this entity represents a true syndrome or is a combination of risk factors that put the individual at specific risk ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/1741-7015-9-48”, “ISBN” : “1741-7015 (Electronic)\r1741-7015 (Linking)”, “ISSN” : “1741-7015”, “PMID” : “21542944”, “abstract” : “Metabolic syndrome (MetS) is a complex disorder defined by a cluster of interconnected factors that increase the risk of cardiovascular atherosclerotic diseases and diabetes mellitus type 2. Currently, several different definitions of MetS exist, causing substantial confusion as to whether they identify the same individuals or represent a surrogate of risk factors. Recently, a number of other factors besides those traditionally used to define MetS that are also linked to the syndrome have been identified. In this review, we critically consider existing definitions and evolving information, and conclude that there is still a need to develop uniform criteria to define MetS, so as to enable comparisons between different studies and to better identify patients at risk. As the application of the MetS model has not been fully validated in children and adolescents as yet, and because of its alarmingly increasing prevalence in this population, we suggest that diagnosis, prevention and treatment in this age group should better focus on established risk factors rather than the diagnosis of MetS.”, “author” : { “dropping-particle” : “”, “family” : “Kassi”, “given” : “Eva”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pervanidou”, “given” : “Panagiota”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kaltsas”, “given” : “Gregory”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Chrousos”, “given” : “George”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “BMC Medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2011” }, “page” : “48”, “title” : “Metabolic syndrome: definitions and controversies”, “type” : “article-journal”, “volume” : “9” }, “uris” : “http://www.mendeley.com/documents/?uuid=590bd2ae-b9ac-4da3-ae84-1bdf86c7cc95” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Kassi</b> et al.</b></b>, <b>2011</b>)”, “plainTextFormattedCitation” : “(Kassi et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Kassi</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Kassi et al., 2011).
Metabolic syndrome is defined by a constellation of an interrelated physiological, biochemical, clinical risk factors. This collection of unhealthy body measurements and abnormal laboratory test results include atherogenic form of dyslipidemia, hypertension, glucose intolerance, pro-inflammatory and pro-thrombotic states. The MS is a major and growing public health and clinical challenge all over the world. Urbanization, excess energy intake, increasing rates of obesity and sedentary life habits, all favor the increase in prevalence of MS. Metabolic syndrome confers a 5 fold greater risk of T2DM, 2 fold increased risk of developing CVDs, 2 – 4 fold increased risk of stroke, 3 – 4 fold increased risk of myocardial infarction (MI), and 2 fold the risk of mortality from such an event compared with those without the syndrome ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2014/943162”, “ISBN” : “2090-8016 (Print)\r2090-0597 (Linking)”, “ISSN” : “20900597”, “PMID” : “24711954”, “abstract” : “<p> Metabolic syndrome is defined by a constellation of interconnected physiological, biochemical, clinical, and metabolic factors that directly increases the risk of cardiovascular disease, type 2 diabetes mellitus, and all cause mortality. Insulin resistance, visceral adiposity, atherogenic dyslipidemia, endothelial dysfunction, genetic susceptibility, elevated blood pressure, hypercoagulable state, and chronic stress are the several factors which constitute the syndrome. Chronic inflammation is known to be associated with visceral obesity and insulin resistance which is characterized by production of abnormal adipocytokines such as tumor necrosis factor <italic>u03b1</italic> , interleukin-1 (IL-1), IL-6, leptin, and adiponectin. The interaction between components of the clinical phenotype of the syndrome with its biological phenotype (insulin resistance, dyslipidemia, etc.) contributes to the development of a proinflammatory state and further a chronic, subclinical vascular inflammation which modulates and results in atherosclerotic processes. Lifestyle modification remains the initial intervention of choice for such population. Modern lifestyle modification therapy combines specific recommendations on diet and exercise with behavioural strategies. Pharmacological treatment should be considered for those whose risk factors are not adequately reduced with lifestyle changes. This review provides summary of literature related to the syndromeu2019s definition, epidemiology, underlying pathogenesis, and treatment approaches of each of the risk factors comprising metabolic syndrome. </p>”, “author” : { “dropping-particle” : “”, “family” : “Kaur”, “given” : “Jaspinder”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Cardiology Research and Practice”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2014” }, “title” : “A comprehensive review on metabolic syndrome”, “type” : “article-journal”, “volume” : “2014” }, “uris” : “http://www.mendeley.com/documents/?uuid=7b69eb00-792c-4788-bd27-0f34a33adbd2” } , “mendeley” : { “formattedCitation” : “(<b><b>Kaur</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Kaur, 2014)”, “previouslyFormattedCitation” : “(<b><b>Kaur</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Kaur, 2014).
Table III shows most of the common definitions and diagnostic criteria of MS.

Table III. Different criteria for diagnosing metabolic syndrome.

Clinical measure WHO (1998) EGIR (1999) ATPIII (2001) AACE (2003) IDF (2005)
Insulin resistance IGT, IFG, T2DM, or lowered insulin sensitivitya
Plus any two of the following Plasma insulin > 75th percentile
Plus any two of the following None, but any 3 of the following 5 features IGT or IFG
plus any of
the following
None
Body weight Men: waist to hip ratio > 0.90;
Women: waist to hip ratio > 0.85 and/or BMI > 30 WC ?94 cm in men or ?80 cm in women WC ?102 cm in men or ?88 cm in women BMI ?25 kg/m2 Increased WC
(population specific)
plus any 2 of the
following
Lipids TGs ? 150 mg/dl and/or HDL-C < 35 mg/dl in men or < 39 mg/dl in women TGs ?150 mg/dL and/or HDL-C TGs ?150 mg/dL HDL-C TGs ? 150 mg/dL and
HDL-C <40 mg/dL in
men or <50 mg/dL in
women TGs ?150mg/dL or on TGs Rx.

HDL-C < 40 mg/dL in
men or < 50 mg/dL in women or on HDL-C Rx
Blood pressure ?140/90 mm Hg ?140/90 mm Hg or on hypertension Rx ?130/85mmHg ?130/85mmHg ?130mmHg systolic
or ?85 mm Hg
diastolic or on
hypertension Rx
Glucose IGT, IFG or T2DM IGT or IFG (but not diabetes) >110mg/dL (includes
Diabetes) IGT or IFG (but not
diabetes) ?100mg/dL (includes
diabetes)b
Other Microalbuminuria: Urinary excretion rate of >20 mg/min or albumin: creatinine ratio of >30 mg/g. Other features of
insulin resistancec a) Insulin sensitivity measured under hyperinsulinemic euglycemic conditions, glucose uptake below lowest quartile for background population under investigation.
b) In 2003, the American Diabetes Association (ADA) changed the criteria for IFG tolerance from >110 mg/dl to >100 mg/dl.
c) Includes family history of type 2 diabetes mellitus, polycystic ovary syndrome, sedentary lifestyle, advancing age, and ethnic groups susceptible to type 2 diabetes mellitus
AACE: American Association of Clinical Endocrinologist; BMI: body mass index; HDL-C: high density lipoprotein cholesterol; IFG: impaired fasting glucose; IGT: impaired glucose tolerance; Rx: receiving treatment; TGs: triglycerides; T2DM: type 2 diabetes mellitus; WC: waist circumference ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2014/943162”, “ISBN” : “2090-8016 (Print)\r2090-0597 (Linking)”, “ISSN” : “20900597”, “PMID” : “24711954”, “abstract” : “<p> Metabolic syndrome is defined by a constellation of interconnected physiological, biochemical, clinical, and metabolic factors that directly increases the risk of cardiovascular disease, type 2 diabetes mellitus, and all cause mortality. Insulin resistance, visceral adiposity, atherogenic dyslipidemia, endothelial dysfunction, genetic susceptibility, elevated blood pressure, hypercoagulable state, and chronic stress are the several factors which constitute the syndrome. Chronic inflammation is known to be associated with visceral obesity and insulin resistance which is characterized by production of abnormal adipocytokines such as tumor necrosis factor <italic>u03b1</italic> , interleukin-1 (IL-1), IL-6, leptin, and adiponectin. The interaction between components of the clinical phenotype of the syndrome with its biological phenotype (insulin resistance, dyslipidemia, etc.) contributes to the development of a proinflammatory state and further a chronic, subclinical vascular inflammation which modulates and results in atherosclerotic processes. Lifestyle modification remains the initial intervention of choice for such population. Modern lifestyle modification therapy combines specific recommendations on diet and exercise with behavioural strategies. Pharmacological treatment should be considered for those whose risk factors are not adequately reduced with lifestyle changes. This review provides summary of literature related to the syndromeu2019s definition, epidemiology, underlying pathogenesis, and treatment approaches of each of the risk factors comprising metabolic syndrome. </p>”, “author” : { “dropping-particle” : “”, “family” : “Kaur”, “given” : “Jaspinder”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Cardiology Research and Practice”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2014” }, “title” : “A comprehensive review on metabolic syndrome”, “type” : “article-journal”, “volume” : “2014” }, “uris” : “http://www.mendeley.com/documents/?uuid=7b69eb00-792c-4788-bd27-0f34a33adbd2” } , “mendeley” : { “formattedCitation” : “(<b><b>Kaur</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Kaur, 2014)”, “previouslyFormattedCitation” : “(<b><b>Kaur</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Kaur, 2014).

Worldwide prevalence of MS ranges from <10% up to 84%, depending on the studied area, urban or rural environment, composition (age, gender, race, and ethnicity) of the population studied, and the used definition of the syndrome ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.ecl.2004.03.005”, “author” : { “dropping-particle” : “”, “family” : “Cameron AJ, Shaw JE”, “given” : “Zimmet PZ”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Endocrinol Metabolic”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2004” }, “page” : “351u201375”, “title” : “The Metabolic Syndrome Prevalence in Worldwide Populations”, “type” : “article-journal”, “volume” : “33” }, “uris” : “http://www.mendeley.com/documents/?uuid=9d539c35-5044-4d90-a464-cf59abee5f2b”, “http://www.mendeley.com/documents/?uuid=4d20f96e-c1f6-4aac-81fc-0f62d00d11ba” } , “mendeley” : { “formattedCitation” : “(<b><b>Cameron AJ, Shaw JE</b></b>, <b>2004</b>)”, “manualFormatting” : “(Cameron et al., 2004;”, “plainTextFormattedCitation” : “(Cameron AJ, Shaw JE, 2004)”, “previouslyFormattedCitation” : “(<b><b>Cameron AJ, Shaw JE</b></b>, <b>2004</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Cameron et al., 2004; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Desroches”, “given” : “Sophie”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lamarche”, “given” : “Benou00eet”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Physiologie appliquu00e9e, nutrition et mu00e9tabolisme”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2007” }, “page” : “23-32”, “title” : “The evolving definitions and increasing prevalence of the metabolic syndrome”, “type” : “article”, “volume” : “32” }, “uris” : “http://www.mendeley.com/documents/?uuid=433da558-6047-4a25-b154-0304c8c62f43”, “http://www.mendeley.com/documents/?uuid=fc04f329-f08b-4f35-b4e7-f80c2ec95dc5” } , “mendeley” : { “formattedCitation” : “(<b><b>Desroches</b> and <b>Lamarche</b></b>, <b>2007</b>)”, “manualFormatting” : “Desroches and Lamarche, 2007;”, “plainTextFormattedCitation” : “(Desroches and Lamarche, 2007)”, “previouslyFormattedCitation” : “(<b><b>Desroches</b> and <b>Lamarche</b></b>, <b>2007</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Desroches and Lamarche, 2007; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1097/MAJ.0b013e318065c3a1”, “ISBN” : “0002-9629”, “ISSN” : “00029629”, “PMID” : “17570989”, “abstract” : “The insulin resistance/metabolic syndrome is characterized by the variable co-existence of hyperinsulinemia, obesity, dyslipidemia (small dense low-density lipoprotein, hypertriglyceridemia, and decreased high-density lipoprotein cholesterol), and hypertension. The pathogenesis of the syndrome has multiple origins. However, obesity and sedentary lifestyle coupled with diet and still largely unknown genetic factors clearly interact to produce the syndrome. This multifactorial and complex trait of metabolic syndrome leads to increased risk of cardiovascular disease. The scope of this review is to examine the differences in prevalence of the metabolic syndrome in various groups (eg, according to age, sex, ethnicity, social status, or presence of obesity) that could help with the better understanding of the pathogenesis of this syndrome. This review also considers the impact of metabolic syndrome on cardiovascular disease.”, “author” : { “dropping-particle” : “”, “family” : “Kolovou”, “given” : “Genovefa D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Anagnostopoulou”, “given” : “Katherine K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Salpea”, “given” : “Klelia D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mikhailidis”, “given” : “Dimitri P.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “The American Journal of the Medical Sciences”, “id” : “ITEM-1”, “issue” : “6”, “issued” : { “date-parts” : “2007” }, “page” : “362-371”, “title” : “The Prevalence of Metabolic Syndrome in Various Populations”, “type” : “article”, “volume” : “333” }, “uris” : “http://www.mendeley.com/documents/?uuid=aa641b92-f43b-4e82-8e80-282279e901bd”, “http://www.mendeley.com/documents/?uuid=c56aae24-297b-41c3-9b51-5635da3c9c17” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Kolovou</b> et al.</b></b>, <b>2007</b>)”, “manualFormatting” : “Kolovou et al., 2007)”, “plainTextFormattedCitation” : “(Kolovou et al., 2007)”, “previouslyFormattedCitation” : “(<b><b><b>Kolovou</b> et al.</b></b>, <b>2007</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Kolovou et al., 2007). In general, the IDF estimated that one-quarter of the world’s adult population has the MS ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1159/000282084”, “ISBN” : “0003-9926 (Print) 0003-9926 (Linking)”, “ISSN” : “14219875”, “PMID” : “20460909”, “abstract” : “Over the last few years, the paradigm in hepatology has changed from focusing on a single liver disease to considering concurrent diseases, in particular obesity and related metabolic factors. Obesity has reached epidemic proportions globally and is associated with insulin resistance, steatosis and a low-grade systemic inflammatory state. These metabolic factors have a synergistic role in the natural history and treatment outcomes related to chronic liver disease. This is characterized best in chronic hepatitis C where steatosis and insulin resistance are caused by viral and metabolic effects. Non-alcoholic fatty liver disease and related metabolic abnormalities also exacerbate other diseases, such as alcoholic liver disease and haemochromatosis. In addition, there is growing evidence linking obesity and type 2 diabetes with hepatocellular carcinoma in subjects with chronic viral hepatitis. The pathogenesis of co-morbid disease may be related to increased oxidative stress, inflammatory injury and cell death, along with altered hepatocyte regeneration and repair. Hyperinsulinaemia and other metabolic factors may also have a direct role in the progression of liver injury. Data indicate that weight reduction improves steatosis and inflammation in patients with chronic hepatitis C. This has important clinical and therapeutic implications and suggests that obesity should be actively addressed in the management of patients with other chronic liver diseases.”, “author” : { “dropping-particle” : “”, “family” : “IDF”, “given” : “International Diabetes Fedration”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “The IDF consensus worldwide definition of the metabolic syndrome”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2006” }, “page” : “1-7”, “title” : “The IDF consensus worldwide definition of the metabolic syndrome”, “type” : “article”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=967b5632-9ea7-41c5-8a79-5b435c026da5” } , “mendeley” : { “formattedCitation” : “(<b><b>IDF</b></b>, <b>2006</b>)”, “manualFormatting” : “(IDF, 2006)”, “plainTextFormattedCitation” : “(IDF, 2006)”, “previouslyFormattedCitation” : “(<b><b>IDF</b></b>, <b>2006</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(IDF, 2006). Higher socioeconomic status, sedentary lifestyle, and increased body mass index (BMI) were significantly associated with MS ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.ecl.2004.03.005”, “author” : { “dropping-particle” : “”, “family” : “Cameron AJ, Shaw JE”, “given” : “Zimmet PZ”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Endocrinol Metabolic”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2004” }, “page” : “351u201375”, “title” : “The Metabolic Syndrome Prevalence in Worldwide Populations”, “type” : “article-journal”, “volume” : “33” }, “uris” : “http://www.mendeley.com/documents/?uuid=4d20f96e-c1f6-4aac-81fc-0f62d00d11ba”, “http://www.mendeley.com/documents/?uuid=9d539c35-5044-4d90-a464-cf59abee5f2b” } , “mendeley” : { “formattedCitation” : “(<b><b>Cameron AJ, Shaw JE</b></b>, <b>2004</b>)”, “manualFormatting” : “(Cameron et al., 2004)”, “plainTextFormattedCitation” : “(Cameron AJ, Shaw JE, 2004)”, “previouslyFormattedCitation” : “(<b><b>Cameron AJ, Shaw JE</b></b>, <b>2004</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Cameron et al., 2004). The coincidence of several factors elevates cardiovascular risk more than the risk associated with each factor alone. The risk also increases as the number of MS components exists.

By 2030, reducing premature mortality from non-communicable diseases through prevention and treatment is one of the targets of the third goal of sustainable developmental goals (SDGs). So prevention of diabetes, metabolic syndrome and cardiovascular diseases are considered an issue of concern to achieve this goal ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “URL” : “https://sustainabledevelopment.un.org/sdg3”, “author” : { “dropping-particle” : “”, “family” : “United Nations”, “given” : “(UN)”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sustainable developmental goals”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2018” }, “title” : “sustainable developmental goals (Goal 3)”, “type” : “webpage” }, “uris” : “http://www.mendeley.com/documents/?uuid=02ab9699-ba55-4e45-95b8-ae4782c08918” } , “mendeley” : { “formattedCitation” : “(<b><b>United Nations</b></b>, <b>2018</b>)”, “plainTextFormattedCitation” : “(United Nations, 2018)”, “previouslyFormattedCitation” : “(<b><b>United Nations</b></b>, <b>2018</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(United Nations, 2018).

Pathophysiology of Metabolic Syndrome
Metabolic syndrome is a state of chronic low grade inflammation as a result of complex interaction between genetic and environmental factors. Genetic susceptibility, insulin resistance, visceral obesity, atherogenic dyslipidemia, endothelial dysfunction, elevated blood pressure, hypercoagulable status, and chronic stress are the several factors which comprise the syndrome. Figure III shows pathophysiology of MS ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2014/943162”, “ISBN” : “2090-8016 (Print)\r2090-0597 (Linking)”, “ISSN” : “20900597”, “PMID” : “24711954”, “abstract” : “<p> Metabolic syndrome is defined by a constellation of interconnected physiological, biochemical, clinical, and metabolic factors that directly increases the risk of cardiovascular disease, type 2 diabetes mellitus, and all cause mortality. Insulin resistance, visceral adiposity, atherogenic dyslipidemia, endothelial dysfunction, genetic susceptibility, elevated blood pressure, hypercoagulable state, and chronic stress are the several factors which constitute the syndrome. Chronic inflammation is known to be associated with visceral obesity and insulin resistance which is characterized by production of abnormal adipocytokines such as tumor necrosis factor <italic>u03b1</italic> , interleukin-1 (IL-1), IL-6, leptin, and adiponectin. The interaction between components of the clinical phenotype of the syndrome with its biological phenotype (insulin resistance, dyslipidemia, etc.) contributes to the development of a proinflammatory state and further a chronic, subclinical vascular inflammation which modulates and results in atherosclerotic processes. Lifestyle modification remains the initial intervention of choice for such population. Modern lifestyle modification therapy combines specific recommendations on diet and exercise with behavioural strategies. Pharmacological treatment should be considered for those whose risk factors are not adequately reduced with lifestyle changes. This review provides summary of literature related to the syndromeu2019s definition, epidemiology, underlying pathogenesis, and treatment approaches of each of the risk factors comprising metabolic syndrome. </p>”, “author” : { “dropping-particle” : “”, “family” : “Kaur”, “given” : “Jaspinder”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Cardiology Research and Practice”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2014” }, “title” : “A comprehensive review on metabolic syndrome”, “type” : “article-journal”, “volume” : “2014” }, “uris” : “http://www.mendeley.com/documents/?uuid=7b69eb00-792c-4788-bd27-0f34a33adbd2” } , “mendeley” : { “formattedCitation” : “(<b><b>Kaur</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Kaur, 2014)”, “previouslyFormattedCitation” : “(<b><b>Kaur</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Kaur, 2014)

3149600265430Genetics
Thrifty genotype
Thrifty phenotype
00Genetics
Thrifty genotype
Thrifty phenotype
403860265430Environmental ?
Physical inactivity
Smoking
Energy dense food
Stress
00Environmental ?
Physical inactivity
Smoking
Energy dense food
Stress

221297522288500
26181053956050026181051422400077343014224000
2618105160020001736090440055Adipose tissue hyperplasia and hypertrophy
00Adipose tissue hyperplasia and hypertrophy
Positive energy balance

330644519812000155638516891000
237744022288500314960015875Altered release of adipokines
00Altered release of adipokines
61785515875Altered free fatty acid metabolism
00Altered free fatty acid metabolism

61785526987500194691026987500452818526924000331216026987500617855269240003979545819150013995408191500420687536449000302069536449000
420751022669500 Leptin Factor VII
3020060762000 AT II Factor V
331216077470004505325774700042094158890003020060571500 Aldosterone PAI-I
40640-32385Portal free fatty acids
00Portal free fatty acids
1398905-32385Insulin resistance,
hyperinsulinemia
00Insulin resistance,
hyperinsulinemia
2785745-32385Activate RAAS and SNS
00Activate RAAS and SNS
4049395-32385Oxidative stress
Endothelial dysfunction
00Oxidative stress
Endothelial dysfunction

40640299085Lipoprotein synthesis
Glucagonogenesis
00Lipoprotein synthesis
Glucagonogenesis
46545509461500338010594615002007870946150067627594615004049395299085Pro-inflammatory state
Pro-thrombotic state
00Pro-inflammatory state
Pro-thrombotic state
2760345299085Sodium reabsorption vasoconstriction
00Sodium reabsorption vasoconstriction
1398905299085Impairs ? cell function of pancreas
00Impairs ? cell function of pancreas

4049395137160Hypercoaggulable state
00Hypercoaggulable state
2760345137160Hypertension
00Hypertension
1412240137160Hyperglycemia
Overt T2DM
00Hyperglycemia
Overt T2DM
40640137160Dyslipidemia
00Dyslipidemia

2708910342900006178553422650046539151771650033794701771650061722017716500200723517716500
101663519050Metabolic syndrome
00Metabolic syndrome

2216150509778000482346042710100031496004271010001398905427101000-488315427101000476440534829750031496003482975001398905348297500-488315348297500Figure III. Pathophysiology of metabolic syndrome (ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2014/943162”, “ISBN” : “2090-8016 (Print)\r2090-0597 (Linking)”, “ISSN” : “20900597”, “PMID” : “24711954”, “abstract” : “<p> Metabolic syndrome is defined by a constellation of interconnected physiological, biochemical, clinical, and metabolic factors that directly increases the risk of cardiovascular disease, type 2 diabetes mellitus, and all cause mortality. Insulin resistance, visceral adiposity, atherogenic dyslipidemia, endothelial dysfunction, genetic susceptibility, elevated blood pressure, hypercoagulable state, and chronic stress are the several factors which constitute the syndrome. Chronic inflammation is known to be associated with visceral obesity and insulin resistance which is characterized by production of abnormal adipocytokines such as tumor necrosis factor <italic>u03b1</italic> , interleukin-1 (IL-1), IL-6, leptin, and adiponectin. The interaction between components of the clinical phenotype of the syndrome with its biological phenotype (insulin resistance, dyslipidemia, etc.) contributes to the development of a proinflammatory state and further a chronic, subclinical vascular inflammation which modulates and results in atherosclerotic processes. Lifestyle modification remains the initial intervention of choice for such population. Modern lifestyle modification therapy combines specific recommendations on diet and exercise with behavioural strategies. Pharmacological treatment should be considered for those whose risk factors are not adequately reduced with lifestyle changes. This review provides summary of literature related to the syndromeu2019s definition, epidemiology, underlying pathogenesis, and treatment approaches of each of the risk factors comprising metabolic syndrome. </p>”, “author” : { “dropping-particle” : “”, “family” : “Kaur”, “given” : “Jaspinder”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Cardiology Research and Practice”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2014” }, “title” : “A comprehensive review on metabolic syndrome”, “type” : “article-journal”, “volume” : “2014” }, “uris” : “http://www.mendeley.com/documents/?uuid=7b69eb00-792c-4788-bd27-0f34a33adbd2” } , “mendeley” : { “formattedCitation” : “(<b><b>Kaur</b></b>, <b>2014</b>)”, “manualFormatting” : “Kaur, 2014)”, “plainTextFormattedCitation” : “(Kaur, 2014)”, “previouslyFormattedCitation” : “(<b><b>Kaur</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Kaur, 2014).

Shift Work, Metabolic Syndrome and Its Components
With the gradual and progressive increase in the number of shift workers worldwide, there is a growing interest in describing the metabolic processes and understanding the mechanisms involved in health problems commonly encountered in this population ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “In developing countries, shift work represents a considerable contingent workforce. Recently, studies have shown that overweight and obesity are more prevalent in shift workers than day workers. In addition, shift work has been associated with a higher propensity for the development of many metabolic disorders, such as insulin resistance, diabetes, dislipidemias and metabolic syndrome. Recent data have pointed that decrease of the sleep time, desynchronization of circadian rhythm and alteration of environmental aspects are the main factors related to such problems. Shortened or disturbed sleep is among the most common health-related effects of shift work. The plausible physiological and biological mechanisms are related to the activation of the autonomic nervous system, inflammation, changes in lipid and glucose metabolism, and related changes in the risk for atherosclerosis, metabolic syndrome, and type II diabetes. The present review will discuss the impact of shift work on obesity and metabolic disorders and how disruption of sleep and circadian misalignment may contribute to these metabolic dysfunctions.”, “author” : { “dropping-particle” : “”, “family” : “Zimberg”, “given” : “Ionu00e1 Zalcman”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fernandes Junior”, “given” : “Silvio A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Crispim”, “given” : “Cibele Aparecida”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tufik”, “given” : “Sergio”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mello”, “given” : “Marco Tulio”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” } , “container-title” : “Work”, “id” : “ITEM-1”, “issue” : “SUPPL.1”, “issued” : { “date-parts” : “2012” }, “page” : “4376-4383”, “title” : “Metabolic impact of shift work”, “type” : “paper-conference”, “volume” : “41” }, “uris” : “http://www.mendeley.com/documents/?uuid=d1020cd6-9d57-40af-b0c3-3b11f5e33cb5” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Zimberg</b> et al.</b></b>, <b>2012</b>)”, “plainTextFormattedCitation” : “(Zimberg et al., 2012)”, “previouslyFormattedCitation” : “(<b><b><b>Zimberg</b> et al.</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Zimberg et al., 2012). In a meta-analysis conducted by Wang and his colleagues, it was stated that there was a significant positive dose response relationship between duration of night shift work and the risk of MS. Moreover, the study also mentioned the gender differences between shift work and MS ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1093/occmed/kqr001”, “ISBN” : “1471-8405 (Electronic)\n0962-7480 (Linking)”, “ISSN” : “09627480”, “PMID” : “21355031”, “author” : { “dropping-particle” : “”, “family” : “Wang”, “given” : “X. S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Armstrong”, “given” : “M. E G”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Cairns”, “given” : “B. J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Key”, “given” : “T. J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Travis”, “given” : “R. C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational Medicine”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2011” }, “page” : “78-89”, “title” : “Shift work and chronic disease: The epidemiological evidence”, “type” : “article-journal”, “volume” : “61” }, “uris” : “http://www.mendeley.com/documents/?uuid=7cde413c-1e22-40b6-873f-e7675fa4c897” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Wang</b> et al.</b></b>, <b>2011</b>)”, “plainTextFormattedCitation” : “(Wang et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Wang</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Wang et al., 2011).

Pietroiusti et al found strong association between night shift work and MS ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1136/oem.2009.046797”, “ISBN” : “1351-0711\r1470-7926”, “ISSN” : “1351-0711”, “PMID” : “19737731”, “abstract” : “OBJECTIVE: Night-shift work is associated with ischaemic cardiovascular disorders. It is not currently known whether it may be causally linked to metabolic syndrome (MS), a risk condition for ischaemic cardiovascular disorders. The syndrome presents with visceral obesity associated with mild alterations in glucidic and lipidic homeostasis, and in blood pressure. The aim of this study was to assess whether a causal relationship exists between night-shift work and the development of MS. METHODS: Male and female nurses performing night shifts, free from any component of MS at baseline, were evaluated annually for the development of the disorder during a 4-year follow-up. Male and female nurses performing daytime work only, visited during the same time period, represented the control group. RESULTS: The cumulative incidence of MS was 9.0% (36/402) among night-shift workers, and 1.8% (6/336) among daytime workers (relative risk (RR) 5.0, 95% CI -2.1 to 14.6). The annual rate of incidence of MS was 2.9% in night-shift workers and 0.5% in daytime workers. Kaplan-Meier survival curves of the two groups were significantly different (log-rank test; p<0.001). Multiple Cox regression analysis (forward selection method based on likelihood ratio) showed that among selected variables (age, gender, smoking, alcohol intake, familiar history, physical activity, and work schedule) the only predictors of occurrence of MS were sedentariness (hazard ratio (HR) 2.92; 95% CI 1.64 to 5.18; p = 0.017), and night-shift work (HR 5.10; 95% CI 2.15 to 12.11; p<0.001). CONCLUSIONS: The risk of developing MS is strongly associated with night-shift work in nurses. Medical counselling should be promptly instituted in night-shift workers with the syndrome, and in case of persistence or progression, a change in work schedule should be considered.”, “author” : { “dropping-particle” : “”, “family” : “Pietroiusti”, “given” : “a”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Neri”, “given” : “A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Somma”, “given” : “G”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Coppeta”, “given” : “L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Iavicoli”, “given” : “I”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bergamaschi”, “given” : “A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Magrini”, “given” : “A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2009” }, “page” : “54-57”, “title” : “Incidence of metabolic syndrome among night-shift healthcare workers.”, “type” : “article-journal”, “volume” : “67” }, “uris” : “http://www.mendeley.com/documents/?uuid=7f6caaf4-5a67-4b8a-a8e9-41243286a749” } , “mendeley” : { “formattedCitation” : “(<b><b><b> a Pietroiusti</b> et al.</b></b>, <b>2009</b>)”, “manualFormatting” : “(Pietroiusti et al., 2009)”, “plainTextFormattedCitation” : “( a Pietroiusti et al., 2009)”, “previouslyFormattedCitation” : “(<b><b><b> a Pietroiusti</b> et al.</b></b>, <b>2009</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Pietroiusti et al., 2009). A study by Guo et al. established the association between shift work and MS, and also the connection with each component of MS according to shift work duration. The study found an increased ORs for elevated blood pressure, waist circumference and glucose levels with the duration of shift work, but it did not found significantly elevated ORs in low HDL and increased triglycerides ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1371/journal.pone.0120632”, “ISSN” : “1932-6203”, “author” : { “dropping-particle” : “”, “family” : “Guo”, “given” : “Yanjun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rong”, “given” : “Yi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Huang”, “given” : “Xiji”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lai”, “given” : “Hanpeng”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Luo”, “given” : “Xin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Zhang”, “given” : “Zhihong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Liu”, “given” : “Yuewei”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “He”, “given” : “Meian”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Wu”, “given” : “Tangchun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Chen”, “given” : “Weihong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Plos One”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2015” }, “page” : “e0120632”, “title” : “Shift Work and the Relationship with Metabolic Syndrome in Chinese Aged Workers”, “type” : “article-journal”, “volume” : “10” }, “uris” : “http://www.mendeley.com/documents/?uuid=4f37f5a9-d299-419a-90b6-e9be85a1b2af” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Guo</b> et al.</b></b>, <b>2015</b>)”, “plainTextFormattedCitation” : “(Guo et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Guo</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Guo et al., 2015). A five year follow-up study carried out in Taiwan found that rotating shift work had significant harmful effects on health that leads to an increased risk of MS. After the follow up period, workers who initially had one or two risk factors for MS were 4.6 and 12.7 times, respectively, increased risk to develop the condition ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1080/074205202929029”, “author” : { “dropping-particle” : “”, “family” : “Lin”, “given” : “Yu-Cheng”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hiao”, “given” : “Tun-jen”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Chen”, “given” : “Pau-chung”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Chronobiology International”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2009” }, “page” : “740-55”, “title” : “persistent rotating shift work expoure accelerates development of metabolic syndrome among middle aged female employees: a five year follow up”, “type” : “article-journal”, “volume” : “26” }, “uris” : “http://www.mendeley.com/documents/?uuid=b87e27fd-5e41-41d9-a4ed-f7552a345760” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Y.-C. 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In 2015; a study suggested that metabolic syndrome component count (MSCC) (which is a summation of the numbers of MS 5 components for an individual or a worker group), and metabolic syndrome component density (MSCD) (which is the arithmetic mean value of MSCC for a worker) can potentially be a good indicator of the general metabolic health status of a group of workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Lin”, “given” : “Yu-cheng”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hsieh”, “given” : “I-chun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Chen”, “given” : “Pau-chung”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International journal of occupational medicine and environmental health”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2015” }, “page” : “675-688”, “title” : “Utilizing the metabolic syndrome component count in workers u2019 health surveillance : an example of day-time vs . Day-night rotating shift workers”, “type” : “article-journal”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=1c443c07-3ae8-4af6-9a07-158f5ef4e32f” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Y. Lin</b> et al.</b></b>, <b>2015</b>)”, “manualFormatting” : “(Lin et al., 2015)”, “plainTextFormattedCitation” : “(Y. Lin et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Y. Lin</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Lin et al., 2015).

Circadian misalignment of metabolically related hormones has been considered the major risk factors for all metabolic abnormalities that cause MS. The link between clock genes and metabolism are evident in humans and disruption of these genes cause metabolic disturbances ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1210/er.2013-1051”, “ISBN” : “0163-769X”, “ISSN” : “0163769X”, “PMID” : “24673196”, “abstract” : “Most organisms display endogenously produced u223cf24 h fluctuations in physiology and behavior, termed circadian rhythms. Circadian rhythms are driven by a transcriptional-translational feedback loop that is hierarchically expressed throughout the brain and body, with the suprachiasmatic nucleus of the hypothalamus serving as the master circadian oscillator at the top of the hierarchy. Appropriate circadian regulation is important for many homeostatic functions including energy regulation. Multiple genes involved in nutrient metabolism display rhythmic oscillations and metabolically related hormones such as glucagon, insulin, ghrelin, leptin, and corticosterone are released in a circadian fashion. Mice harboring mutations in circadian clock genes alter feeding behavior, endocrine signaling, and dietary fat absorption. Moreover, misalignment between behavioral and molecular circadian clocks can result in obesity in both rodents and humans. Importantly, circadian rhythms are most potently synchronized to the external environment by light information and exposure to light at night potentially disrupts circadian system function. Since the advent of electric lights around the turn of the 20th century, exposure to artificial and irregular light schedules has become commonplace. The increase in exposure to light at night parallels the global increase in the prevalence of obesity and metabolic disorders. In this review, we propose that exposure to light at night alters metabolic function through disruption of the circadian system. We first provide an introduction to the circadian system, with a specific emphasis on the effects of light on circadian rhythms. Next we address interactions between the circadian system and metabolism. Finally, we review current experimental and epidemiological work directly associating exposure to light at night and metabolism.”, “author” : { “dropping-particle” : “”, “family” : “Fonken”, “given” : “Laura K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nelson”, “given” : “Randy J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Endocrine Reviews”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2014” }, “page” : “648-670”, “title” : “The effects of light at night on circadian clocks and metabolism”, “type” : “article-journal”, “volume” : “35” }, “uris” : “http://www.mendeley.com/documents/?uuid=90c7cda5-76f0-4c7a-870e-34cc4bc62c97” } , “mendeley” : { “formattedCitation” : “(<b><b>Fonken</b> and <b>Nelson</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Fonken and Nelson, 2014)”, “previouslyFormattedCitation” : “(<b><b>Fonken</b> and <b>Nelson</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Fonken and Nelson, 2014).  Sleep deprivation and abnormal sleep times are also studied as independent risk factors for metabolic disorders among shift workers. Several studies have assessed the relation between sleep duration and metabolic dysfunction leading to metabolic syndrome components and finally MS development ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “0161-8105”, “ISSN” : “0161-8105”, “PMID” : “18517034”, “abstract” : “STUDY OBJECTIVE: Short and long sleep duration have been linked to various risk factors for cardiovascular disease. In the present study, we evaluated the relationship between sleep duration and presence of the metabolic syndrome, which is a cluster of physiologically interrelated risk factors for cardiometabolic disease.\n\nDESIGN/SETTING: Cross-sectional community-based cohort study.\n\nPARTICIPANTS: One thousand two hundred fourteen participants from the Adult Health and Behavior Project registry (aged 30 to 54 years).\n\nMEASUREMENTS: Participants were divided into 4 groups based upon their reported sleep duration. The metabolic syndrome was defined according to the American Heart Association/National Heart Lung and Blood Institute’s criteria. Logistic regression was used to test the hypothesis that sleep duration is a significant correlate of the metabolic syndrome and its components.\n\nRESULTS: The observed metabolic syndrome rate (22%) was similar to that of published health statistics for American adults. After covariate adjustment, the odds for having the metabolic syndrome increased by more than 45% in both short and long sleepers, compared with those sleeping 7 to 8 hours per night. Sleep duration was also associated individually with abdominal obesity, elevated fasting glucose, and hypertriglyceridemia. After further adjustment for use of antihypertensive medication, prevalence of the metabolic syndrome and its components remained elevated in short sleepers only.\n\nCONCLUSION: These data suggest that sleep duration is a significant correlate of the metabolic syndrome. Additional studies are needed to evaluate temporal relationships among these measures, the behavioral and physiologic mechanisms that link the two, and their impact on subsequent cardiometabolic disease.”, “author” : { “dropping-particle” : “”, “family” : “Hall”, “given” : “Martica”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Muldoon”, “given” : “Matthew”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jennings”, “given” : “J Richard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Buysse”, “given” : “Daniel”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Flory”, “given” : “Janine”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Manuck”, “given” : “Stephen”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2008” }, “page” : “635-43”, “title” : “Self-reported sleep duration is associated with the metabolic syndrome in midlife adults.”, “type” : “article-journal”, “volume” : “31” }, “uris” : “http://www.mendeley.com/documents/?uuid=4f836617-6606-4f69-aa27-044df63442a3” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Hall</b> et al.</b></b>, <b>2008</b>)”, “manualFormatting” : “(Hall et al., 2008”, “plainTextFormattedCitation” : “(Hall et al., 2008)”, “previouslyFormattedCitation” : “(<b><b><b>Hall</b> et al.</b></b>, <b>2008</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Hall et al., 2008; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1113/expphysiol.2006.033787”, “ISBN” : “0971-5916 (Print)\n0971-5916 (Linking)”, “ISSN” : “09715916”, “PMID” : “20308746”, “abstract” : “Sleep is an essential part of our daily living, and sleep disturbances may intervene with the biological and physiological processes in human body leading to the development of metabolic dysfunction. Short sleep duration and poor sleep quality have adverse effects on metabolism and hormonal processes, contributing to increased cardiovascular risk. Obstructive sleep apnoea is a chronic condition characterized by repetitive upper airway collapse during sleep, causing intermittent hypoxaemia, recurrent arousals and sleep fragmentation. Sleep disturbances can increase sympathetic activity, provoke systemic inflammation and oxidative stress, and impair vascular endothelial function. Obstructive sleep apnoea is increasingly recognized to be an independent cardiovascular risk factor. There is intense research interest in the association between obstructive sleep apnoea and the metabolic syndrome – the constellation of inter-related metabolic derangements including central obesity, hypertension, insulin resistance and dyslipidaemia, which appears to directly promote the development of atherosclerosis. The underlying pathophysiologic pathways or mechanistic links between obstructive sleep apnoea and metabolic syndrome have not been well delineated. This article reviews the current knowledge of the relationship between sleep disturbances, sleep-disordered breathing and the metabolic syndrome in adults.”, “author” : { “dropping-particle” : “”, “family” : “Lam”, “given” : “Jamie C.M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mary”, “given” : “S. M.I.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Indian Journal of Medical Research”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “206-216”, “title” : “Sleep & the metabolic syndrome”, “type” : “article-journal”, “volume” : “131” }, “uris” : “http://www.mendeley.com/documents/?uuid=941cdc76-8070-40c0-a6b7-c2a71990abd0” } , “mendeley” : { “formattedCitation” : “(<b><b>Lam</b> and <b>Mary</b></b>, <b>2010</b>)”, “manualFormatting” : “Lam and Mary, 2010”, “plainTextFormattedCitation” : “(Lam and Mary, 2010)”, “previouslyFormattedCitation” : “(<b><b>Lam</b> and <b>Mary</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Lam and Mary, 2010; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.2147/DMSO.S16147”, “ISSN” : “1178-7007”, “author” : { “dropping-particle” : “”, “family” : “Nakamura”, “given” : “Yasuyuki”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Katano”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nakamura”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Murakami”, “given” : “Y”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tanaka”, “given” : “T”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Takebayashi”, “given” : “Toru”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Okayama”, “given” : “Akira”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Miura”, “given” : “K”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Okamura”, “given” : “T”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ueshima”, “given” : “H”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2011” }, “page” : “119”, “title” : “Relationship between sleep duration and clustering of metabolic syndrome diagnostic components”, “type” : “article-journal” }, “uris” : “http://www.mendeley.com/documents/?uuid=46996884-b361-4425-9ab1-fe01216dc5b5” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Nakamura</b> et al.</b></b>, <b>2011</b>)”, “manualFormatting” : “Nakamura et al., 2011”, “plainTextFormattedCitation” : “(Nakamura et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Nakamura</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Nakamura et al., 2011; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “8232860820”, “author” : { “dropping-particle” : “”, “family” : “Lee”, “given” : “Bo Gyeong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kim”, “given” : “Jae Yeon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Son”, “given” : “Sun Ah”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ham”, “given” : “Dong Min”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kyung”, “given” : “Ok”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “journal of korean academic nuring”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2015” }, “page” : “420-428”, “title” : “Factors associated with Self-Rated Health in Metabolic Syndrome and Relationship between Sleep Duration and Metabolic Syndrome Risk Factors”, “type” : “article-journal”, “volume” : “45” }, “uris” : “http://www.mendeley.com/documents/?uuid=f5d68b52-5033-45b8-aab3-4751447d9120” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Lee</b> et al.</b></b>, <b>2015</b>)”, “manualFormatting” : “Lee et al., 2015)”, “plainTextFormattedCitation” : “(Lee et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Lee</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Lee et al., 2015). Figure IV shows different mechanisms that link between sleep deprivation and MS.

Despite the presence of various studies and systematic reviews that assessed that relation between shift work and MS, the evidence obtained is inconclusive. This inconsistency may be due to the deficiency of high methodological quality studies and inconsistency in their findings and because evidence is insufficient in assessing the relation between shift work and other metabolic risk factors. Evidence needs to be strengthened by more high quality studies that take into consideration details of shift schedule and other confounding factors ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/s13098-015-0041-4”, “ISSN” : “1758-5996”, “author” : { “dropping-particle” : “”, “family” : “Brum”, “given” : “Maria Carlota Borba”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Filho”, “given” : “Fu00e1bio Fernandes Dantas”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schnorr”, “given” : “Claudia Carolina”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bottega”, “given” : “Gustavo Borchardt”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rodrigues”, “given” : “Ticiana C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Diabetology & Metabolic Syndrome”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2015” }, “page” : “1-7”, “publisher” : “???”, “title” : “Shift work and its association with metabolic disorders”, “type” : “article-journal”, “volume” : “7” }, “uris” : “http://www.mendeley.com/documents/?uuid=7b266ff4-ad7c-448d-862d-482f430c258b” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Brum</b> et al.</b></b>, <b>2015</b>)”, “manualFormatting” : “(Brum et al., 2015”, “plainTextFormattedCitation” : “(Brum et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Brum</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Brum et al., 2015; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.amepre.2015.11.013”, “abstract” : “Context Although the metabolic health effects of shift work have been extensively studied, a systematic synthesis of the available research is lacking. This review aimed to systematically summarize the available evidence of longitudinal studies linking shift work with metabolic risk factors. Evidence acquisition A systematic literature search was performed in 2015. Studies were included if (1) they had a longitudinal design; (2) shift work was studied as the exposure; and (3) the outcome involved a metabolic risk factor, including anthropometric, blood glucose, blood lipid, or blood pressure measures. Evidence synthesis Eligible studies were assessed for their methodologic quality in 2015. A best-evidence synthesis was used to draw conclusions per outcome. Thirty-nine articles describing 22 studies were included. Strong evidence was found for a relation between shift work and increased body weight/BMI, risk for overweight, and impaired glucose tolerance. For the remaining outcomes, there was insufficient evidence. Conclusions Shift work seems to be associated with body weight gain, risk for overweight, and impaired glucose tolerance. Overall, lack of high-methodologic quality studies and inconsistency in findings led to insufficient evidence in assessing the relation between shift work and other metabolic risk factors. To strengthen the evidence, more high-quality longitudinal studies that provide more information on the shift work schedule (e.g., frequency of night shifts, duration in years) are needed. Further, research to the (mediating) role of lifestyle behaviors in the health effects of shift work is recommended, as this may offer potential for preventive strategies. u00a9 2016 American Journal of Preventive Medicine.”, “author” : { “dropping-particle” : “”, “family” : “Proper”, “given” : “K I”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Langenberg”, “given” : “D”, “non-dropping-particle” : “Van De”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rodenburg”, “given” : “W”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Vermeulen”, “given” : “R C H”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Beek”, “given” : “A J”, “non-dropping-particle” : “Van Der”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Steeg”, “given” : “H”, “non-dropping-particle” : “Van”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kerkhof”, “given” : “L W M”, “non-dropping-particle” : “Van”, “parse-names” : false, “suffix” : “” } , “container-title” : “American Journal of Preventive Medicine”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2016” }, “page” : “e147-e157”, “title” : “The relationship between shift work and metabolic risk factors: A systematic review of longitudinal studies”, “type” : “article-journal”, “volume” : “50” }, “uris” : “http://www.mendeley.com/documents/?uuid=55aedf3b-75ef-4bef-ab99-3627727edc82” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Proper</b> et al.</b></b>, <b>2016</b>)”, “manualFormatting” : “Proper et al., 2016)”, “plainTextFormattedCitation” : “(Proper et al., 2016)”, “previouslyFormattedCitation” : “(<b><b><b>Proper</b> et al.</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Proper et al., 2016).

-65341523899001560195260985Sleep loss or deprivation
00Sleep loss or deprivation

2654300580390003141345531495001635760305435000-52705404685500462534030543500047523401310005003837940697230Altered circadian rhythm
00Altered circadian rhythm
3088640198437500321119528111450039350952441575Hypertension
00Hypertension
17405352811145002654935238315500144780131000500370141536004500111379045720000163576053149500-527051310005001447802587625Insulin resistance or diabetes
00Insulin resistance or diabetes
-228600697230Inflammation
00Inflammation
32785051310005Reduced energy use
00Reduced energy use
20923251699260Increased appetite
00Increased appetite
7696201310005Altered glucose metabolism
00Altered glucose metabolism
20923252646045Obesity
00Obesity

Figure IV. Association between shift work and metabolic syndrome ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1113/expphysiol.2006.033787”, “ISBN” : “0971-5916 (Print)\n0971-5916 (Linking)”, “ISSN” : “09715916”, “PMID” : “20308746”, “abstract” : “Sleep is an essential part of our daily living, and sleep disturbances may intervene with the biological and physiological processes in human body leading to the development of metabolic dysfunction. Short sleep duration and poor sleep quality have adverse effects on metabolism and hormonal processes, contributing to increased cardiovascular risk. Obstructive sleep apnoea is a chronic condition characterized by repetitive upper airway collapse during sleep, causing intermittent hypoxaemia, recurrent arousals and sleep fragmentation. Sleep disturbances can increase sympathetic activity, provoke systemic inflammation and oxidative stress, and impair vascular endothelial function. Obstructive sleep apnoea is increasingly recognized to be an independent cardiovascular risk factor. There is intense research interest in the association between obstructive sleep apnoea and the metabolic syndrome – the constellation of inter-related metabolic derangements including central obesity, hypertension, insulin resistance and dyslipidaemia, which appears to directly promote the development of atherosclerosis. The underlying pathophysiologic pathways or mechanistic links between obstructive sleep apnoea and metabolic syndrome have not been well delineated. This article reviews the current knowledge of the relationship between sleep disturbances, sleep-disordered breathing and the metabolic syndrome in adults.”, “author” : { “dropping-particle” : “”, “family” : “Lam”, “given” : “Jamie C.M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mary”, “given” : “S. M.I.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Indian Journal of Medical Research”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2010” }, “page” : “206-216”, “title” : “Sleep & the metabolic syndrome”, “type” : “article-journal”, “volume” : “131” }, “uris” : “http://www.mendeley.com/documents/?uuid=941cdc76-8070-40c0-a6b7-c2a71990abd0” } , “mendeley” : { “formattedCitation” : “(<b><b>Lam</b> and <b>Mary</b></b>, <b>2010</b>)”, “manualFormatting” : “(Lam and Mary, 2010)”, “plainTextFormattedCitation” : “(Lam and Mary, 2010)”, “previouslyFormattedCitation” : “(<b><b>Lam</b> and <b>Mary</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Lam and Mary, 2010).

Obesity
Nowadays, obesity is considered one of the leading causes of morbidity and mortality in industrialized countries. A shocking 1.9 billion adults which represents 39% of the global adult population are estimated to be overweight, with 600 million (13%) of these individuals are considered obese ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “world health organization (WHO)”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Who”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2018” }, “title” : “WHO | Obesity and overweight”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=f6c15790-b772-4a2e-8300-a9914397242d” } , “mendeley” : { “formattedCitation” : “(<b><b>world health organization (WHO)</b></b>, <b>2018</b>)”, “manualFormatting” : “(WHO, 2018)”, “plainTextFormattedCitation” : “(world health organization (WHO), 2018)”, “previouslyFormattedCitation” : “(<b><b>world health organization (WHO)</b></b>, <b>2018</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(WHO, 2018). In addition to the recognized risks as unhealthy diet and sedentarism, shift and night work have been associated with weight gain as well. Many factors associated with night and shift work are suggested to be related to pathophysiology of obesity. These factors include short sleep duration and long working hours, reduction of practicing physical activity (shift and night work decrease the opportunities of physical activity practice) ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2015/826249”, “ISBN” : “1687-8337 (Print)\r1687-8337 (Linking)”, “ISSN” : “1687-8337”, “PMID” : “25892993”, “abstract” : “<p>The objective of this review was to investigate the impact of shift and night work on metabolic processes and the role of alterations in the sleep-wake cycle and feeding times and environmental changes in the occurrence of metabolic disorders. The literature review was performed by searching three electronic databases for relevant studies published in the last 10 years. The methodological quality of each study was assessed, and best-evidence synthesis was applied to draw conclusions. The literature has shown changes in concentrations of melatonin, cortisol, ghrelin, and leptin among shift workers. Melatonin has been implicated for its role in the synthesis and action of insulin. The action of this hormone also regulates the expression of transporter glucose type 4 or triggers phosphorylation of the insulin receptor. Therefore, a reduction in melatonin can be associated with an increase in insulin resistance and a propensity for the development of diabetes. Moreover, shift work can negatively affect sleep and contribute to sedentarism, unhealthy eating habits, and stress. Recent studies on metabolic processes have increasingly revealed their complexity. Physiological changes induced in workers who invert their activity-rest cycle to fulfill work hours include disruptions in metabolic processes.</p>”, “author” : { “dropping-particle” : “”, “family” : “Ulhu00f4a”, “given” : “M. A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Marqueze”, “given” : “E. C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Burgos”, “given” : “L. G. A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Moreno”, “given” : “C. R. C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International Journal of Endocrinology”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2015” }, “page” : “1-11”, “title” : “Shift Work and Endocrine Disorders”, “type” : “article-journal”, “volume” : “2015” }, “uris” : “http://www.mendeley.com/documents/?uuid=3bc3c285-793f-45be-98b2-7bb45b6a4d6e” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Ulhu00f4a</b> et al.</b></b>, <b>2015</b>)”, “plainTextFormattedCitation” : “(Ulhu00f4a et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Ulhu00f4a</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ulhôa et al., 2015).
Moreover, among night and shift workers, the overall frequency of meal is typically decreased while night-time snacks tend to increase. Both the quality and quantity of foods consumed are influenced by shift or night work and traditional meals at home stopped. Also, nocturnal digestion is less effective due to circadian rhythmicity. Desynchronization can affect metabolism and control of body weight, supporting the development of obesity. It is suggested that in humans timing of food intake can predict BMI even after control of confounders as sleep timing and duration. People who have more meals after 8:00 PM tend to have greater BMI ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2015/826249”, “ISBN” : “1687-8337 (Print)\r1687-8337 (Linking)”, “ISSN” : “1687-8337”, “PMID” : “25892993”, “abstract” : “<p>The objective of this review was to investigate the impact of shift and night work on metabolic processes and the role of alterations in the sleep-wake cycle and feeding times and environmental changes in the occurrence of metabolic disorders. The literature review was performed by searching three electronic databases for relevant studies published in the last 10 years. The methodological quality of each study was assessed, and best-evidence synthesis was applied to draw conclusions. The literature has shown changes in concentrations of melatonin, cortisol, ghrelin, and leptin among shift workers. Melatonin has been implicated for its role in the synthesis and action of insulin. The action of this hormone also regulates the expression of transporter glucose type 4 or triggers phosphorylation of the insulin receptor. Therefore, a reduction in melatonin can be associated with an increase in insulin resistance and a propensity for the development of diabetes. Moreover, shift work can negatively affect sleep and contribute to sedentarism, unhealthy eating habits, and stress. Recent studies on metabolic processes have increasingly revealed their complexity. Physiological changes induced in workers who invert their activity-rest cycle to fulfill work hours include disruptions in metabolic processes.</p>”, “author” : { “dropping-particle” : “”, “family” : “Ulhu00f4a”, “given” : “M. A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Marqueze”, “given” : “E. C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Burgos”, “given” : “L. G. A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Moreno”, “given” : “C. R. C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International Journal of Endocrinology”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2015” }, “page” : “1-11”, “title” : “Shift Work and Endocrine Disorders”, “type” : “article-journal”, “volume” : “2015” }, “uris” : “http://www.mendeley.com/documents/?uuid=3bc3c285-793f-45be-98b2-7bb45b6a4d6e” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Ulhu00f4a</b> et al.</b></b>, <b>2015</b>)”, “plainTextFormattedCitation” : “(Ulhu00f4a et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Ulhu00f4a</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ulhôa et al., 2015).
Studies showed a relationship between night shift work and the development of obesity, and provide evidence that night work may be related to central adiposity. The prevalence of overweight and obesity in shift workers were also found to be higher compared to non-shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Morikawa”, “given” : “Yuko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nakagawa”, “given” : “Hideaki”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Miura”, “given” : “Katsuyuki”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Soyama”, “given” : “Yoshiyuki”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kido”, “given” : “Teruhiko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Naruse”, “given” : “Yuchi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Suwazono”, “given” : “Yasushi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nogawa”, “given” : “Koji”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian journal of work, environment & health”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2007” }, “page” : “45 – 50”, “title” : “Health Effect of shift work on body mass index and metabolic parameters”, “type” : “article-journal”, “volume” : “33” }, “uris” : “http://www.mendeley.com/documents/?uuid=66a45b81-e708-4b03-858b-7b0cc6e89681” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Morikawa</b> et al.</b></b>, <b>2007</b>)”, “manualFormatting” : “(Morikawa et al., 2007;”, “plainTextFormattedCitation” : “(Morikawa et al., 2007)”, “previouslyFormattedCitation” : “(<b><b><b>Morikawa</b> et al.</b></b>, <b>2007</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Morikawa et al., 2007;ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1371/journal.pone.0133761”, “ISBN” : “1932-6203”, “ISSN” : “19326203”, “PMID” : “26196859”, “abstract” : “BACKGROUND: Mounting epidemiological evidence suggests that night shift work may contribute to the etiology of increased body weight. The present study aimed to examine association between rotating night shift work and body mass index (BMI), and abdominal adiposity respectively among nurses and midwives.\n\nMETHODS: A cross-sectional study was conducted among 724 female nurses and midwives, aged 40-60 years (354 rotating night shift and 370 daytime workers) in u0141u00f3du017a, Poland, between 2008 and 2011. Information about occupational history and potential confounders was collected during personal interviews. Anthropometric measurements of body weight, height, waist (WC) and hip (HC) circumference were made, and body mass index (BMI), waist to hip ratio (WHR) and waist to height ratio (WHtR) were calculated. GLM regression models and multinomial logit regression models were fitted to explore the association between night shift work and anthropometric parameters, with adjustment for age, body silhouette at age 20, current smoking status, packyears, marital status, and menopausal hormone therapy use.\n\nRESULTS: Cumulative night shift work showed significant associations with BMI, WC, HC and WHtR, with BMI increasing by 0.477 kg/m2 per 1000 night duties and by 0.432 kg/m2 per 10000 night shift hours, WC increasing respectively by 1.089 cm and 0.99 cm, and HC by 0.72 cm and WHtR by 0.007 cm for both metrics. Both current and cumulative night work was associated with obesity (BMIu226530kg/m2), with OR=3.9 (95%CI:1.5-9.9), in women reporting eight or more night shifts per month.\n\nCONCLUSION: The results of the study support the previously reported relations between night shift work and development of obesity.”, “author” : { “dropping-particle” : “”, “family” : “Peplonska”, “given” : “Beata”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bukowska”, “given” : “Agnieszka”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sobala”, “given” : “Wojciech”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “PLoS ONE”, “id” : “ITEM-1”, “issue” : “7”, “issued” : { “date-parts” : “2015” }, “page” : “1-13”, “title” : “Association of rotating night shift work with BMI and abdominal obesity among nurses and midwives”, “type” : “article-journal”, “volume” : “10” }, “uris” : “http://www.mendeley.com/documents/?uuid=8eee1b6b-e3b2-4a44-9568-d9b0f6897d3a” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Peplonska</b> et al.</b></b>, <b>2015</b>)”, “manualFormatting” : ” Peplonska et al., 2015)”, “plainTextFormattedCitation” : “(Peplonska et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Peplonska</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” } Peplonska et al., 2015). Studies assessed the relation between sleep deprivation and obesity; they reported that prevalence of obesity was significantly higher in male workers who sleep ; 5 hours compared to day workers who sleep ; 5 hour. This finding concluded that short sleep durations (;5 h) accelerated the onset of obesity in shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.sleep.2010.09.007”, “ISSN” : “13899457”, “PMID” : “21377926”, “abstract” : “Objective: The objective of this longitudinal epidemiological study was to investigate the association of risk factors for cardiovascular illness with sleep duration and shift work. Methods: This study used data obtained at medical checkups conducted in 1999 and 2006 for the employees of a local government organization in Japan (covering 21,693 male employees and 2109 female employees). The medical checkup data included (1) body measurements, (2) blood test parameters, and (3) replies to a self-administered questionnaire (inquiring about sleep duration, with or without shift work, etc.). On the basis of these data, we conducted multiple logistic regression analyses to study the association between the risk of new-onset obesity, hypertension, hyperglycemia, hypertriglyceridemia, and hypo-high density lipoprotein (HDL) cholesterolemia and shift work as well as sleep duration. Results: Among the male subjects who were engaged in shift work, the relative risk of new-onset obesity for those with a sleep duration of less than 5. h was 1.30 (95% CI, 1.14-1.49) higher than for those with sleep duration of 5-7. h. Furthermore, analysis using both engagement in shift work and sleep duration as dependent variables showed that the relative risks of new-onset obesity for those with a sleep duration of less than 5. h were 1.20 (95% CI, 1.09-1.32) for men and 1.7 (95% CI, 1.11-2.87) for women. Conclusions: Short sleep duration is associated with onset of obesity. u00a9 2011 Elsevier B.V.”, “author” : { “dropping-particle” : “”, “family” : “Itani”, “given” : “Osamu”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kaneita”, “given” : “Yoshitaka”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Murata”, “given” : “Atsushi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Yokoyama”, “given” : “Eise”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ohida”, “given” : “Takashi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2011” }, “page” : “341-345”, “publisher” : “Elsevier B.V.”, “title” : “Association of onset of obesity with sleep duration and shift work among Japanese adults”, “type” : “article-journal”, “volume” : “12” }, “uris” : “http://www.mendeley.com/documents/?uuid=773fa27a-d787-406a-950f-77ec798d2875” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Itani</b> et al.</b></b>, <b>2011</b>)”, “manualFormatting” : “(Itani et al., 2011;”, “plainTextFormattedCitation” : “(Itani et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Itani</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Itani et al., 2011;ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1017/S1368980013002838”, “ISBN” : “1475-2727 (Electronic)\r1368-9800 (Linking)”, “ISSN” : “14752727”, “PMID” : “24168892”, “abstract” : “OBJECTIVE: The objective of our study was to explore the association between sleep deprivation and obesity among shift workers.\n\nDESIGN: A cross-sectional study was conducted. Obesity was defined as BMI u226530 kg/m2. Time of sleep was categorized as: >5 h of continuous sleep/d; u22645 h of continuous sleep/d with some additional rest (sleep deprivation level I); and u22645 h of continuous sleep/d without any additional rest (sleep deprivation level II). Sociodemographic, parental and behavioural variables were evaluated by means of a standardized pre-tested questionnaire. Potential confounding factors were controlled for in the multivariable model.\n\nSETTING: A poultry-processing plant in southern Brazil.\n\nSUBJECTS: Nine hundred and five shift workers (63 % female).\n\nRESULTS: Obesity was more prevalent in the participants who were female, aged 40 years and older, who had less schooling and reported excess weight in both parents. Sleep deprivation levels I and II were associated with increased income, number of meals consumed throughout the day and nightshift work. All of the workers who exhibited a degree of sleep deprivation worked the night shift. After controlling for potential confounding factors, the prevalence ratios of obesity were 1u00b74 (95 % CI 0u00b78, 2u00b72) and 4u00b74 (95 % CI 2u00b74, 8u00b70) in the workers with sleep deprivation levels I and II, respectively, compared with the reference group.\n\nCONCLUSIONS: These results show a strong association between sleep deprivation and obesity in shift workers and that sleep deprivation may be a direct consequence of working at night.”, “author” : { “dropping-particle” : “”, “family” : “Canuto”, “given” : “Raquel”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pattussi”, “given” : “Marcos Pascoal”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Macagnan”, “given” : “Jamile Block Araldi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Henn”, “given” : “Ruth Liane”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Olinto”, “given” : “Maria Teresa Anselmo”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Public Health Nutrition”, “id” : “ITEM-1”, “issue” : “11”, “issued” : { “date-parts” : “2013” }, “page” : “2619-2623”, “title” : “Sleep deprivation and obesity in shift workers in southern Brazil”, “type” : “article-journal”, “volume” : “17” }, “uris” : “http://www.mendeley.com/documents/?uuid=25695ff2-3ef2-4c3c-b04a-2ea9b19fe521” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Canuto</b> et al.</b></b>, <b>2013</b>)”, “manualFormatting” : ” Canuto et al., 2013)”, “plainTextFormattedCitation” : “(Canuto et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Canuto</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” } Canuto et al., 2013).
There are appetite-regulating hormones, especially leptin (stimulates anorexigen hormones) and ghrelin (act directly as orexigen). These hormones are essential in controlling appetite and feeding behavior through sending stimulatory and inhibitory signals to the CNS, particularly the hypothalamus. It has been shown that lack of sleep; short sleep duration and changes in sleeping time were all associated with significant reduction in sera leptin and elevation in sera ghrelin levels. This finding suggests that sleep loss can affect the peripheral regulators of hunger and this may clarify the relation between short shift work and obesity ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.physbeh.2014.01.001”, “ISBN” : “1873-507X (Electronic)\r0031-9384 (Linking)”, “ISSN” : “1873507X”, “PMID” : “24467926”, “abstract” : “Recent studies link energy regulation to the circadian clock at the behavioral, physiological and molecular levels, emphasizing that the timing of food intake itself may have a significant role in obesity. In this regards, there is emerging literature in animals demonstrating a relationship between the timing of feeding and weight regulation. Unusual feeding time can produce a disruption of the circadian system which might produce unhealthy consequences in humans. In a longitudinal study, we recently showed that the timing of the main meal was predictive of weight loss during a 20-week dietary intervention and that this effect was independent from total 24-h caloric intake. The importance of caloric distribution across the day on weight loss therapy was supported by a recent 12-week experimental study showing that subjects assigned to high caloric intake during breakfast lost significantly more weight than those assigned to high caloric intake during the dinner. Furthermore, one of the most influential discoveries relevant for this area of research in the last years is the presence of an active circadian clock in different organs related to food intake. This is the case for stomach, intestine, pancreas or liver. New data also suggest that there is a temporal component in the regulation of adipose tissue functions. Thus, a specific temporal order in the daily patterns of adipose tissue genes appears to be crucial for adipose tissue to exclusively either accumulate fat or to mobilize fat at the proper time. Taking into account that feeding is the source of energy for adipose tissue, the time of feeding, particularly for high-energy content meals, may be decisive, and changes in this timing could have metabolic consequences for the development of obesity and for weight loss.”, “author” : { “dropping-particle” : “”, “family” : “Garaulet”, “given” : “Marta”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gu00f3mez-Abellu00e1n”, “given” : “Purificaciu00f3n”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Physiology & behavior”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2014” }, “page” : “44-50”, “title” : “Timing of food intake and obesity: a novel association”, “type” : “article”, “volume” : “134” }, “uris” : “http://www.mendeley.com/documents/?uuid=64d498fd-ad92-47ae-ad61-10913297dfda” } , “mendeley” : { “formattedCitation” : “(<b><b>Garaulet</b> and <b>Gu00f3mez-Abellu00e1n</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Garaulet and Gu00f3mez-Abellu00e1n, 2014)”, “previouslyFormattedCitation” : “(<b><b>Garaulet</b> and <b>Gu00f3mez-Abellu00e1n</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Garaulet and Gómez-Abellán, 2014).

A systematic review performed in 2011 provided strong evidence of the link between shift work and increased body weight. Moreover, behavioral changes that are usually associated with shift work as reduced physical activity, may independently contribute to weight gain ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.3143”, “ISSN” : “0355-3140”, “PMID” : “21243319”, “author” : { “dropping-particle” : “”, “family” : “Drongelen”, “given” : “Alwin”, “non-dropping-particle” : “van”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Boot”, “given” : “Cu00e9cile”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Merkus”, “given” : “Suzanne”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Smid”, “given” : “Tjabe”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Beek”, “given” : “Allard J”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian Journal of Work, Environment & Health”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2011” }, “page” : “263-275”, “title” : “The effects of shift work on body weight change u2212 a systematic review of longitudinal studies”, “type” : “article-journal”, “volume” : “37” }, “uris” : “http://www.mendeley.com/documents/?uuid=f9b0b940-a322-4bfb-bc0b-3ff5ffdbacda” } , “mendeley” : { “formattedCitation” : “(<b><b><b>van Drongelen</b> et al.</b></b>, <b>2011</b>)”, “plainTextFormattedCitation” : “(van Drongelen et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>van Drongelen</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(van Drongelen et al., 2011). Evidence confirms that late night snacking decreases fat oxidation and elevates LDL cholesterol. Short-duration of sleep was found to be associated with increased risk for weight gain, obesity, and higher body fat composition ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1152/ajpregu.00115.2012”, “ISBN” : “0363-6119”, “ISSN” : “0363-6119”, “PMID” : “23174861”, “author” : { “dropping-particle” : “”, “family” : “Hibi”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Masumoto”, “given” : “A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Naito”, “given” : “Y.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kiuchi”, “given” : “K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Yoshimoto”, “given” : “Y.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Matsumoto”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Katashima”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Oka”, “given” : “J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ikemoto”, “given” : “S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “American Journal of Physiology. Regulatory Integrative and Comparative Physiology”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2013” }, “page” : “R94-R101”, “title” : “Nighttime snacking reduces whole body fat oxidation and increases LDL cholesterol in healthy young women”, “type” : “article-journal”, “volume” : “304” }, “uris” : “http://www.mendeley.com/documents/?uuid=66af54b2-8f89-4c55-8a6a-c2b551250af9” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Hibi</b> et al.</b></b>, <b>2013</b>)”, “plainTextFormattedCitation” : “(Hibi et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Hibi</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Hibi et al., 2013). In spite of the stated evidence confirming the great strength in the association between shift work and obesity, the mechanisms involved in this association needs further studies to be fully explicit ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/s13098-015-0041-4”, “ISSN” : “1758-5996”, “author” : { “dropping-particle” : “”, “family” : “Brum”, “given” : “Maria Carlota Borba”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Filho”, “given” : “Fu00e1bio Fernandes Dantas”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schnorr”, “given” : “Claudia Carolina”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bottega”, “given” : “Gustavo Borchardt”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rodrigues”, “given” : “Ticiana C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Diabetology & Metabolic Syndrome”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2015” }, “page” : “1-7”, “publisher” : “???”, “title” : “Shift work and its association with metabolic disorders”, “type” : “article-journal”, “volume” : “7” }, “uris” : “http://www.mendeley.com/documents/?uuid=7b266ff4-ad7c-448d-862d-482f430c258b” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Brum</b> et al.</b></b>, <b>2015</b>)”, “plainTextFormattedCitation” : “(Brum et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Brum</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Brum et al., 2015).

Type 2 diabetes and insulin resistance
Diabetes mellitus (DM) is one of the major public health challenges worldwide. Globally, an estimated 422 million adults were living with diabetes in 2014. Diabetes caused 1.5 million deaths in 2012. Moreover, it caused an additional 2.2 million deaths, by increasing the risks of cardiovascular and other diseases. Diabetes is one of four priority non-communicable diseases (NCDs) directed by world leaders in the 2011 “Political Declaration on the Prevention and Control of NCDs”. The majority of patients with diabetes are affected by type 2 diabetes ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “ISBN 978 92 4 156525 7”, “ISBN” : “978 92 4 156525 7”, “ISSN” : “1098-6596”, “PMID” : “25246403”, “abstract” : “Diabetes is a serious, chronic disease that occurs either when the pancreas does not produce enough insulin (a hormone that regulates blood sugar, or glucose), or when the body cannot effectively use the insulin it produces. Diabetes is an important public health problem, one of four priority noncommunicable diseases (NCDs) targeted for action by world leaders. Both the number of cases and the prevalence of diabetes have been steadily increasing over the past few decades.”, “author” : { “dropping-particle” : “”, “family” : “WHO”, “given” : “World Health Organization”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “world health organization”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “number-of-pages” : “6”, “title” : “Global Report on Diabetes”, “type” : “report” }, “uris” : “http://www.mendeley.com/documents/?uuid=323cfc9a-7c83-4657-a45b-58daca4e5a24” } , “mendeley” : { “formattedCitation” : “(<b><b>WHO</b></b>, <b>2016</b>)”, “manualFormatting” : “(WHO, 2016)”, “plainTextFormattedCitation” : “(WHO, 2016)”, “previouslyFormattedCitation” : “(<b><b>WHO</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(WHO, 2016).
The significant mortality and morbidity of DM impose great burden on economic, health and societal aspects. Thus, the identification of modifiable risk factors for the primary prevention of DM is of great public health importance. During the past decades, epidemiological studies have assessed the relation between shift work and the risk of DM, but the results were inconsistent ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1136/oemed-2014-102150”, “ISBN” : “1470-7926 (Electronic) 1351-0711 (Linking)”, “ISSN” : “1470-7926”, “PMID” : “25030030”, “abstract” : “BACKGROUND: Observational studies suggest that shift work may be associated with diabetes mellitus (DM). However, the results are inconsistent. No systematic reviews have applied quantitative techniques to compute summary risk estimates.\n\nOBJECTIVES: To conduct a meta-analysis of observational studies assessing the association between shift work and the risk of DM.\n\nMETHODS: Relevant studies were identified by a search of PubMed, Embase, Web of Science and ProQuest Dissertation and Theses databases to April 2014. We also reviewed reference lists from retrieved articles. We included observational studies that reported OR with 95% CIs for the association between shift work and the risk of DM. Two authors independently extracted data and assessed the study quality.\n\nRESULTS: Twelve studies with 28 independent reports involving 226 652 participants and 14 595 patients with DM were included. A pooled adjusted OR for the association between ever exposure to shift work and DM risk was 1.09 (95% CI 1.05 to 1.12; p=0.014; I(2)=40.9%). Subgroup analyses suggested a stronger association between shift work and DM for men (OR=1.37, 95% CI 1.20 to 1.56) than for women (OR=1.09, 95% CI 1.04 to 1.14) (p for interaction=0.01). All shift work schedules with the exception of mixed shifts and evening shifts were associated with a statistically higher risk of DM than normal daytime schedules, and the difference among those shift work schedules was significant (p for interaction=0.04).\n\nCONCLUSIONS: Shift work is associated with an increased risk of DM. The increase was significantly higher among men and the rotating shift group, which warrants further studies.”, “author” : { “dropping-particle” : “”, “family” : “Gan”, “given” : “Yong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Yang”, “given” : “Chen”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tong”, “given” : “Xinyue”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sun”, “given” : “Huilian”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Cong”, “given” : “Yingjie”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Yin”, “given” : “Xiaoxu”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Li”, “given” : “Liqing”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Cao”, “given” : “Shiyi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dong”, “given” : “Xiaoxin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gong”, “given” : “Yanhong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Shi”, “given” : “Oumin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Deng”, “given” : “Jian”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bi”, “given” : “Huashan”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lu”, “given” : “Zuxun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2014” }, “page” : “1-8”, “title” : “Shift work and diabetes mellitus: a meta-analysis of observational studies.”, “type” : “article-journal”, “volume” : “1” }, “uris” : “http://www.mendeley.com/documents/?uuid=b8a86d2b-effe-45f3-9e49-bdfd6df5f6de” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Gan</b> et al.</b></b>, <b>2014</b>)”, “manualFormatting” : “(Gan et al., 2015)”, “plainTextFormattedCitation” : “(Gan et al., 2014)”, “previouslyFormattedCitation” : “(<b><b><b>Gan</b> et al.</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Gan et al., 2015).
Diabetes mellitus can affect shift workers due to two main factors which are abnormal glucose metabolism and insulin resistance. Regarding glucose metabolism, it has been stated in many studies that shift schedules affect glucose metabolism and cause significant increases in the risk of developing type 2 diabetes mellitus ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “doi: 10.1097/01.jom.0000214355.69182.fa”, “author” : { “dropping-particle” : “”, “family” : “Suwazono Yasushi ; Sakata Kouichi ; Okubo Yasushi; Harada Hideto; Oishi Mitsuhiro; Kobayashi Etsuko; Uetani Mirei; Kido Teruhiko; Nogawa Koji”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Occupational & Environmental Medicine”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2006” }, “page” : “455 – 461”, “title” : “Long-Term Longitudinal Study on the Relationship Between Alternating Shift Work and the Onset of Diabetes Mellitus in Male Japanese Workers”, “type” : “article-journal”, “volume” : “48” }, “uris” : “http://www.mendeley.com/documents/?uuid=bedc23bb-3cd8-4d43-b02a-bc4aad169cf6” } , “mendeley” : { “formattedCitation” : “(<b><b>Suwazono Yasushiu202f; Sakata Kouichiu202f; Okubo Yasushi; Harada Hideto; Oishi Mitsuhiro; Kobayashi Etsuko; Uetani Mirei; Kido Teruhiko; Nogawa Koji</b></b>, <b>2006</b>)”, “manualFormatting” : “(Suwazono et al., 2006; Kivimu00e4ki et al., 2011; Gan et al., 2014; “, “plainTextFormattedCitation” : “(Suwazono Yasushiu202f; Sakata Kouichiu202f; Okubo Yasushi; Harada Hideto; Oishi Mitsuhiro; Kobayashi Etsuko; Uetani Mirei; Kido Teruhiko; Nogawa Koji, 2006)”, “previouslyFormattedCitation” : “(<b><b>Suwazono Yasushiu202f; Sakata Kouichiu202f; Okubo Yasushi; Harada Hideto; Oishi Mitsuhiro; Kobayashi Etsuko; Uetani Mirei; Kido Teruhiko; Nogawa Koji</b></b>, <b>2006</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Suwazono et al., 2006; Kivimäki et al., 2011; Gan et al., 2014; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1136/oemed-2015-103342”, “ISBN” : “1470-7926”, “ISSN” : “14707926”, “PMID” : “26889020”, “abstract” : “OBJECTIVES Night shift work has been associated with poor sleep, weight gain, metabolic syndrome, which are recognised risk factor for diabetes. However, only a few studies have examined the effect of shift work on diabetes risk. Here, we study the association between shift work and incidence of diabetes in Danish nurses. METHODS We used the Danish Nurse Cohort with 28,731 participating female nurses recruited in 1993 (19,898) or 1999 (8833), when self-reported baseline information on diabetes prevalence, lifestyle and working time were collected, and followed them in the Danish Diabetes Register for incidence of diabetes until 2013. Nurses reported whether they worked night, evening, rotating or day shifts. We analysed the association between working time and diabetes incidence using a Cox proportional hazards model adjusted for diabetes risk factors, separately with and without adjustment for body mass index (BMI) which might be an intermediate variable. RESULTS Of 19,873 nurses who worked and were diabetes-free at recruitment, 837 (4.4%) developed diabetes during 15 years of follow-up. The majority of nurses (62.4%) worked day shifts, 21.8% rotating shift, 10.1% evening and 5.5% night shifts. Compared with nurses who worked day shifts, we found statistically significantly increased risk of diabetes in nurses who worked night (1.58; 1.25 to 1.99) or evening shifts (1.29; 1.04 to 1.59) in the fully adjusted models including BMI. CONCLUSIONS Danish nurses working night and evening shifts have increased risk for diabetes, with the highest risk associated with current night shift work.”, “author” : { “dropping-particle” : “”, “family” : “Hansen”, “given” : “Anne B.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Stayner”, “given” : “Leslie”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hansen”, “given” : “Johnni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Andersen”, “given” : “Zorana J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational and Environmental Medicine”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2016” }, “page” : “262-268”, “title” : “Night shift work and incidence of diabetes in the Danish Nurse Cohort”, “type” : “article”, “volume” : “73” }, “uris” : “http://www.mendeley.com/documents/?uuid=669677c1-0376-4fe8-808b-d2b1e0313325” } , “mendeley” : { “formattedCitation” : “(<b><b><b>A. B. Hansen</b> et al.</b></b>, <b>2016</b>)”, “manualFormatting” : “Hansen et al., 2016)”, “plainTextFormattedCitation” : “(A. B. Hansen et al., 2016)”, “previouslyFormattedCitation” : “(<b><b><b>A. B. Hansen</b> et al.</b></b>, <b>2016</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Hansen et al., 2016). Some studies reported that shift workers had a twofold increased risk of developing T2DM ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “doi: 10.1097/01.jom.0000214355.69182.fa”, “author” : { “dropping-particle” : “”, “family” : “Suwazono Yasushi ; Sakata Kouichi ; Okubo Yasushi; Harada Hideto; Oishi Mitsuhiro; Kobayashi Etsuko; Uetani Mirei; Kido Teruhiko; Nogawa Koji”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Occupational & Environmental Medicine”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2006” }, “page” : “455 – 461”, “title” : “Long-Term Longitudinal Study on the Relationship Between Alternating Shift Work and the Onset of Diabetes Mellitus in Male Japanese Workers”, “type” : “article-journal”, “volume” : “48” }, “uris” : “http://www.mendeley.com/documents/?uuid=bedc23bb-3cd8-4d43-b02a-bc4aad169cf6” } , “mendeley” : { “formattedCitation” : “(<b><b>Suwazono Yasushiu202f; Sakata Kouichiu202f; Okubo Yasushi; Harada Hideto; Oishi Mitsuhiro; Kobayashi Etsuko; Uetani Mirei; Kido Teruhiko; Nogawa Koji</b></b>, <b>2006</b>)”, “manualFormatting” : “(Suwazono et al., 2006”, “plainTextFormattedCitation” : “(Suwazono Yasushiu202f; Sakata Kouichiu202f; Okubo Yasushi; Harada Hideto; Oishi Mitsuhiro; Kobayashi Etsuko; Uetani Mirei; Kido Teruhiko; Nogawa Koji, 2006)”, “previouslyFormattedCitation” : “(<b><b>Suwazono Yasushiu202f; Sakata Kouichiu202f; Okubo Yasushi; Harada Hideto; Oishi Mitsuhiro; Kobayashi Etsuko; Uetani Mirei; Kido Teruhiko; Nogawa Koji</b></b>, <b>2006</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Suwazono et al., 2006; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “0386-300X”, “ISSN” : “0386-300X”, “PMID” : “23439506”, “abstract” : “The purpose of this study was to examine the association between shift work and diabetes mellitus by separating shift workers according to the intensity of their shift work (seasonal shift work and continuous shift work). Between May and October 2009, we collected data from annual health checkups and questionnaires at a manufacturing company in Shizuoka, Japan. Questionnaires were returned by 1,601 workers (response rate:96.2%, men/womenuff1d1,314/287). Diabetes mellitus was defined as hemoglobin A1c>6.5% and fasting blood sugar>126mg/dl. After exclusions, which included all the women and clerical workers because they did not work in shifts, we analyzed 475 skilled male workers. After adjusting for age, smoking status, frequency of alcohol consumption, and cohabitation status, odds ratios for diabetes mellitus were 0.98 (95% confidence interval CI:0.28-4.81) and 2.10 (95% CI:0.77-5.71) among seasonal shift workers and continuous shift workers, respectively, compared with non-shift workers. In an age-stratified analysis (uff1c45 years vs.>45 years), the association between continuous shift work and diabetes mellitus was more pronounced among older participants. Compared with non-shift workers, the risk of diabetes mellitus was increased among continuous shift workers, whereas its effect is limited among seasonal shift workers.”, “author” : { “dropping-particle” : “”, “family” : “Ika”, “given” : “Katsuhiko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Suzuki”, “given” : “Etsuji”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mitsuhashi”, “given” : “Toshiharu”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Takao”, “given” : “Soshi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Doi”, “given” : “Hiroyuki”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Acta medica Okayama”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “page” : “25-33”, “title” : “Shift Work and Diabetes Mellitus among Male Workers in Japan:Does the Intensity of Shift Work Matter?”, “type” : “article-journal”, “volume” : “67” }, “uris” : “http://www.mendeley.com/documents/?uuid=3a42f16b-d9f4-4620-9ae9-a1ecaf31857f” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Ika</b> et al.</b></b>, <b>2013</b>)”, “manualFormatting” : “Ika et al., 2013)”, “plainTextFormattedCitation” : “(Ika et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Ika</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Ika et al., 2013) and poor glycemic control ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1093/occmed/kqs176”, “ISSN” : “09627480”, “PMID” : “23024256”, “abstract” : “BACKGROUND: People with type 1 diabetes may find diabetic control more difficult when working shifts. AIMS: To investigate the proportion of people with type 1 diabetes in employment undertaking shift work and diabetic control as assessed by glycosylated haemoglobin (HbA1c) among individuals undertaking shift work compared to those not doing so. METHODS: A postal questionnaire sent to all those aged 16-65 attending two city hospitals for type 1 diabetes care. HbA1c results were used to assess diabetic control. RESULTS: Twenty-two per cent (296 of 1370 eligible patients) responded. Sixty-seven (23%) respondents were involved in shift work. Shift workers had higher mean HbA1c values than non-shift workers (9.02 versus 8.35; P < 0.01). CONCLUSIONS: Poorer control of diabetes was associated with working shifts in this study. Occupational health practitioners should be aware of this association and be able to advise on management strategies to improve diabetic control while working shifts.”, “author” : { “dropping-particle” : “”, “family” : “Young”, “given” : “J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Waclawski”, “given” : “E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Young”, “given” : “J. A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Spencer”, “given” : “J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational Medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “page” : “70-72”, “title” : “Control of type 1 diabetes mellitus and shift work”, “type” : “article-journal”, “volume” : “63” }, “uris” : “http://www.mendeley.com/documents/?uuid=02c0bb80-3e46-4aef-93a9-eb8e21cfd842” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Young</b> et al.</b></b>, <b>2013</b>)”, “plainTextFormattedCitation” : “(Young et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Young</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Young et al., 2013). A meta-analysis carried out in 2014s concluded that shift work is associated with a substantially increased risk of DM, especially in men and groups engaged in rotating shifts ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1136/oemed-2014-102150”, “ISBN” : “1470-7926 (Electronic) 1351-0711 (Linking)”, “ISSN” : “1470-7926”, “PMID” : “25030030”, “abstract” : “BACKGROUND: Observational studies suggest that shift work may be associated with diabetes mellitus (DM). However, the results are inconsistent. No systematic reviews have applied quantitative techniques to compute summary risk estimates.\n\nOBJECTIVES: To conduct a meta-analysis of observational studies assessing the association between shift work and the risk of DM.\n\nMETHODS: Relevant studies were identified by a search of PubMed, Embase, Web of Science and ProQuest Dissertation and Theses databases to April 2014. We also reviewed reference lists from retrieved articles. We included observational studies that reported OR with 95% CIs for the association between shift work and the risk of DM. Two authors independently extracted data and assessed the study quality.\n\nRESULTS: Twelve studies with 28 independent reports involving 226 652 participants and 14 595 patients with DM were included. A pooled adjusted OR for the association between ever exposure to shift work and DM risk was 1.09 (95% CI 1.05 to 1.12; p=0.014; I(2)=40.9%). Subgroup analyses suggested a stronger association between shift work and DM for men (OR=1.37, 95% CI 1.20 to 1.56) than for women (OR=1.09, 95% CI 1.04 to 1.14) (p for interaction=0.01). All shift work schedules with the exception of mixed shifts and evening shifts were associated with a statistically higher risk of DM than normal daytime schedules, and the difference among those shift work schedules was significant (p for interaction=0.04).\n\nCONCLUSIONS: Shift work is associated with an increased risk of DM. The increase was significantly higher among men and the rotating shift group, which warrants further studies.”, “author” : { “dropping-particle” : “”, “family” : “Gan”, “given” : “Yong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Yang”, “given” : “Chen”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Tong”, “given” : “Xinyue”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sun”, “given” : “Huilian”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Cong”, “given” : “Yingjie”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Yin”, “given” : “Xiaoxu”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Li”, “given” : “Liqing”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Cao”, “given” : “Shiyi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dong”, “given” : “Xiaoxin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gong”, “given” : “Yanhong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Shi”, “given” : “Oumin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Deng”, “given” : “Jian”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bi”, “given” : “Huashan”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lu”, “given” : “Zuxun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2014” }, “page” : “1-8”, “title” : “Shift work and diabetes mellitus: a meta-analysis of observational studies.”, “type” : “article-journal”, “volume” : “1” }, “uris” : “http://www.mendeley.com/documents/?uuid=b8a86d2b-effe-45f3-9e49-bdfd6df5f6de” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Gan</b> et al.</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Gan et al., 2014)”, “previouslyFormattedCitation” : “(<b><b><b>Gan</b> et al.</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Gan et al., 2014).
The nurses’ health study is large-scale study that revealed a progressive association between the duration the nurses had been working in shifts and risk of developing T2DM. Compared with women who had never worked in shifts, participants with 1–2 years of shift work had a 5% greater risk of T2DM, rising to 20% after 3–9 years, 40% after 10–19 years, and almost 60% for > 20 years. This conclusion means that years of working in shift strengthens the association with development of T2DM ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1371/journal.pmed.1001141”, “ISBN” : “1549-1676 (Electronic)\r1549-1277 (Linking)”, “ISSN” : “15491277”, “PMID” : “22162955”, “abstract” : “BACKGROUND: Rotating night shift work disrupts circadian rhythms and has been associated with obesity, metabolic syndrome, and glucose dysregulation. However, its association with type 2 diabetes remains unclear. Therefore, we aimed to evaluate this association in two cohorts of US women.\n\nMETHODS AND FINDINGS: We followed 69,269 women aged 42-67 in Nurses’ Health Study I (NHS I, 1988-2008), and 107,915 women aged 25-42 in NHS II (1989-2007) without diabetes, cardiovascular disease, and cancer at baseline. Participants were asked how long they had worked rotating night shifts (defined as at least three nights/month in addition to days and evenings in that month) at baseline. This information was updated every 2-4 years in NHS II. Self-reported type 2 diabetes was confirmed by a validated supplementary questionnaire. We documented 6,165 (NHS I) and 3,961 (NHS II) incident type 2 diabetes cases during the 18-20 years of follow-up. In the Cox proportional models adjusted for diabetes risk factors, duration of shift work was monotonically associated with an increased risk of type 2 diabetes in both cohorts. Compared with women who reported no shift work, the pooled hazard ratios (95% confidence intervals) for participants with 1-2, 3-9, 10-19, and u226520 years of shift work were 1.05 (1.00-1.11), 1.20 (1.14-1.26), 1.40 (1.30-1.51), and 1.58 (1.43-1.74, p-value for trend ;0.001), respectively. Further adjustment for updated body mass index attenuated the association, and the pooled hazard ratios were 1.03 (0.98-1.08), 1.06 (1.01-1.11), 1.10 (1.02-1.18), and 1.24 (1.13-1.37, p-value for trend ;0.001).\n\nCONCLUSIONS: Our results suggest that an extended period of rotating night shift work is associated with a modestly increased risk of type 2 diabetes in women, which appears to be partly mediated through body weight. Proper screening and intervention strategies in rotating night shift workers are needed for prevention of diabetes.”, “author” : { “dropping-particle” : “”, “family” : “Pan”, “given” : “An”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schernhammer”, “given” : “Eva S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sun”, “given” : “Qi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hu”, “given” : “Frank B.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “PLoS Medicine”, “id” : “ITEM-1”, “issue” : “12”, “issued” : { “date-parts” : “2011” }, “title” : “Rotating night shift work and risk of type 2 diabetes: Two prospective cohort studies in women”, “type” : “article-journal”, “volume” : “8” }, “uris” : “http://www.mendeley.com/documents/?uuid=057a8b1c-2ab1-466c-be3f-1ed9c4bfebc4” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Pan;/b; et al.;/b;;/b;, ;b;2011;/b;)”, “plainTextFormattedCitation” : “(Pan et al., 2011)”, “previouslyFormattedCitation” : “(;b;;b;;b;Pan;/b; et al.;/b;;/b;, ;b;2011;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Pan et al., 2011). The association between permanent shift work and T2DM was more evident among older subjects (aged > 45 years). On the contrary, no clear association was observed between seasonal shift work and DM. which confirms that the relation between shift work and DM is cumulative ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “ISBN” : “0386-300X”, “ISSN” : “0386-300X”, “PMID” : “23439506”, “abstract” : “The purpose of this study was to examine the association between shift work and diabetes mellitus by separating shift workers according to the intensity of their shift work (seasonal shift work and continuous shift work). Between May and October 2009, we collected data from annual health checkups and questionnaires at a manufacturing company in Shizuoka, Japan. Questionnaires were returned by 1,601 workers (response rate:96.2%, men/womenuff1d1,314/287). Diabetes mellitus was defined as hemoglobin A1c;6.5% and fasting blood sugar;126mg/dl. After exclusions, which included all the women and clerical workers because they did not work in shifts, we analyzed 475 skilled male workers. After adjusting for age, smoking status, frequency of alcohol consumption, and cohabitation status, odds ratios for diabetes mellitus were 0.98 (95% confidence interval CI:0.28-4.81) and 2.10 (95% CI:0.77-5.71) among seasonal shift workers and continuous shift workers, respectively, compared with non-shift workers. In an age-stratified analysis (uff1c45 years vs.;45 years), the association between continuous shift work and diabetes mellitus was more pronounced among older participants. Compared with non-shift workers, the risk of diabetes mellitus was increased among continuous shift workers, whereas its effect is limited among seasonal shift workers.”, “author” : { “dropping-particle” : “”, “family” : “Ika”, “given” : “Katsuhiko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Suzuki”, “given” : “Etsuji”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mitsuhashi”, “given” : “Toshiharu”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Takao”, “given” : “Soshi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Doi”, “given” : “Hiroyuki”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Acta medica Okayama”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “page” : “25-33”, “title” : “Shift Work and Diabetes Mellitus among Male Workers in Japan:Does the Intensity of Shift Work Matter?”, “type” : “article-journal”, “volume” : “67” }, “uris” : “http://www.mendeley.com/documents/?uuid=3a42f16b-d9f4-4620-9ae9-a1ecaf31857f” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Ika;/b; et al.;/b;;/b;, ;b;2013;/b;)”, “plainTextFormattedCitation” : “(Ika et al., 2013)”, “previouslyFormattedCitation” : “(;b;;b;;b;Ika;/b; et al.;/b;;/b;, ;b;2013;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ika et al., 2013).

There is a clear association between disruption of circadian rhythms and insulin resistance. The mechanism underlying this resistance is not fully understood, but a combination of factors related to shift work has been suggested. Factors include alterations in hormonal levels and eating at times unfavorable for digestion. A reduction in melatonin level can be associated with an increase in insulin resistance; this is because melatonin has been considered a key factor in the synthesis, secretion, and proper action of insulin. Melatonin also regulates the expression of transporter glucose type 4 (GLUT 4) or triggers phosphorylation of the insulin receptor. This may explain recommendations of some researchers for melatonin supplementation for shift workers. Low level of nocturnal melatonin was not only associated with insulin resistance but also have been related to an increased risk of T2DM ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2015/826249”, “ISBN” : “1687-8337 (Print)\r1687-8337 (Linking)”, “ISSN” : “1687-8337”, “PMID” : “25892993”, “abstract” : “;p;The objective of this review was to investigate the impact of shift and night work on metabolic processes and the role of alterations in the sleep-wake cycle and feeding times and environmental changes in the occurrence of metabolic disorders. The literature review was performed by searching three electronic databases for relevant studies published in the last 10 years. The methodological quality of each study was assessed, and best-evidence synthesis was applied to draw conclusions. The literature has shown changes in concentrations of melatonin, cortisol, ghrelin, and leptin among shift workers. Melatonin has been implicated for its role in the synthesis and action of insulin. The action of this hormone also regulates the expression of transporter glucose type 4 or triggers phosphorylation of the insulin receptor. Therefore, a reduction in melatonin can be associated with an increase in insulin resistance and a propensity for the development of diabetes. Moreover, shift work can negatively affect sleep and contribute to sedentarism, unhealthy eating habits, and stress. Recent studies on metabolic processes have increasingly revealed their complexity. Physiological changes induced in workers who invert their activity-rest cycle to fulfill work hours include disruptions in metabolic processes.;/p;”, “author” : { “dropping-particle” : “”, “family” : “Ulhu00f4a”, “given” : “M. A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Marqueze”, “given” : “E. C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Burgos”, “given” : “L. G. A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Moreno”, “given” : “C. R. C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International Journal of Endocrinology”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2015” }, “page” : “1-11”, “title” : “Shift Work and Endocrine Disorders”, “type” : “article-journal”, “volume” : “2015” }, “uris” : “http://www.mendeley.com/documents/?uuid=3bc3c285-793f-45be-98b2-7bb45b6a4d6e” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Ulhu00f4a;/b; et al.;/b;;/b;, ;b;2015;/b;)”, “plainTextFormattedCitation” : “(Ulhu00f4a et al., 2015)”, “previouslyFormattedCitation” : “(;b;;b;;b;Ulhu00f4a;/b; et al.;/b;;/b;, ;b;2015;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ulhôa et al., 2015).
Laboratory-based experiments found that individuals who sleep outside natural sleep times have decreased sensitivity to insulin, without a corresponding increase in insulin secretion. The same study concluded that circadian misalignment that affects shift workers may increase risk of insulin resistance, inflammation and DM, independently of sleep deprivation. melatonin is also involved in reducing insulin sensitivity ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.2337/db13-1546”, “ISBN” : “1939-327X (Electronic)\r0012-1797 (Linking)”, “ISSN” : “1939327X”, “PMID” : “24458353”, “abstract” : “Shift workers, who are exposed to irregular sleep schedules resulting in sleep deprivation and misalignment of circadian rhythms, have an increased risk of diabetes relative to day workers. In healthy adults, sleep restriction without circadian misalignment promotes insulin resistance. To determine whether the misalignment of circadian rhythms that typically occurs in shift work involves intrinsic adverse metabolic effects independently of sleep loss, a parallel group design was used to study 26 healthy adults. Both interventions involved 3 inpatient days with 10-h bedtimes, followed by 8 inpatient days of sleep restriction to 5 h with fixed nocturnal bedtimes (circadian alignment) or with bedtimes delayed by 8.5 h on 4 of the 8 days (circadian misalignment). Daily total sleep time (SD) during the intervention was nearly identical in the aligned and misaligned conditions (4 h 48 min 5 min vs. 4 h 45 min 6 min). In both groups, insulin sensitivity (SI) significantly decreased after sleep restriction, without a compensatory increase in insulin secretion, and inflammation increased. In male participants exposed to circadian misalignment, the reduction in SI and the increase in inflammation both doubled compared with those who maintained regular nocturnal bedtimes. Circadian misalignment that occurs in shift work may increase diabetes risk and inflammation, independently of sleep loss.”, “author” : { “dropping-particle” : “”, “family” : “Leproult”, “given” : “Rachel”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Holmbu00e4ck”, “given” : “Ulf”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Cauter”, “given” : “Eve”, “non-dropping-particle” : “Van”, “parse-names” : false, “suffix” : “” } , “container-title” : “Diabetes”, “id” : “ITEM-1”, “issue” : “6”, “issued” : { “date-parts” : “2014” }, “page” : “1860-1869”, “title” : “Circadian misalignment augments markers of insulin resistance and inflammation, independently of sleep loss”, “type” : “article-journal”, “volume” : “63” }, “uris” : “http://www.mendeley.com/documents/?uuid=891a1d36-fa28-46fa-99bb-d4b35c9d1d34” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Leproult;/b; et al.;/b;;/b;, ;b;2014;/b;)”, “plainTextFormattedCitation” : “(Leproult et al., 2014)”, “previouslyFormattedCitation” : “(;b;;b;;b;Leproult;/b; et al.;/b;;/b;, ;b;2014;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Leproult et al., 2014). Moreover, the risk of a high ?-cell activity was increased almost three fold in shift workers who work at night and very early shift ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.3109/07420528.2012.719959”, “ISBN” : “1525-6073(Electronic);0742-0528(Print)”, “ISSN” : “07420528”, “PMID” : “23005602”, “abstract” : “Previous studies have suggested that shiftwork can affect the prevalence of metabolic syndrome. This is thought to be related to disturbance of lipid parameters rather than their effects on glucose metabolism. Several complex mechanisms are suspected to be involved and notably insulin resistance, though the available data are limited. The objective of the present study was to provide further evidence for the effects of shiftwork on glucose and lipid metabolism with a specific focus on insulin resistance. A cross-sectional study has recruited 97 shiftworkers (SWs) (three shifts, 8 h) and 95 strictly day workers (DWs) from the same plant for 2001-2002. Several indices of insulin sensitivity or resistance were calculated, based on formulas of the homeostasis model assessment for insulin resistance (HOMA-IR), the Revised-Quicki, McAuley and Disse indices. The HOMA-u03b2-cell index was used as a reflection of pancreatic secretion. Characteristics of the occupation, habitual diet and lifestyles were recorded. Logistic regression analysis in which pancreatic function or insulin sensitivity was the dependent variable was used to compare alternative models. Results: SWs were characterized as having significantly higher triglycerides and free fatty acids and normal but lower blood glucose. The risk of a high u03b2-cell activity was increased almost three-fold in SWs. By adjusting for many confounding factors, SWs had significantly lower insulin sensitivity according to several indices, whereas HOMA-IR was not meaningfully different between shift and DWs. Lower insulin sensitivity and a compensatory pancreas response to maintain a normal glucose tolerance may suggest an intermediate state before development of frank insulin resistance in SWs. Early detection of these moderate alterations of the insulin/glucose balance could be important in the prevention of diabetes.”, “author” : { “dropping-particle” : “”, “family” : “Esquirol”, “given” : “Yolande”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bongard”, “given” : “Vanina”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ferrieres”, “given” : “Jean”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Verdier”, “given” : “Helu00e8ne”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Perret”, “given” : “Bertrand”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Chronobiology International”, “id” : “ITEM-1”, “issue” : “9”, “issued” : { “date-parts” : “2012” }, “page” : “1258-1266”, “title” : “Shiftwork and higher pancreatic secretion: Early detection of an intermediate state of insulin resistance?”, “type” : “article”, “volume” : “29” }, “uris” : “http://www.mendeley.com/documents/?uuid=cb794232-1fe8-4193-ab93-57c15336f6ac” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Esquirol;/b; et al.;/b;;/b;, ;b;2012;/b;)”, “plainTextFormattedCitation” : “(Esquirol et al., 2012)”, “previouslyFormattedCitation” : “(;b;;b;;b;Esquirol;/b; et al.;/b;;/b;, ;b;2012;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Esquirol et al., 2012).

Hypertension and dyslipidemia
There is an association between each of sleep deficiency and sleep loss and endothelial dysfunction that may be related to altered nitrous oxide level and sympathetic over-activity. Endothelial dysfunction is an established independent risk factor for CVDs ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2015/615681”, “ISBN” : “2090-0384”, “ISSN” : “20900392”, “PMID” : “26495139”, “abstract” : “Sleep plays a vital role in an individual’s mental, emotional, and physiological well-being. Not only does sleep deficiency lead to neurological and psychological disorders, but also the literature has explored the adverse effects of sleep deficiency on the cardiovascular system. Decreased quantity and quality of sleep have been linked to cardiovascular disease (CVD) risk factors, such as hypertension, obesity, diabetes, and dyslipidemia. We explore the literature correlating primary sleep deficiency and deprivation as a cause for cardiovascular disease and cite endothelial dysfunction as a common underlying mechanism.”, “author” : { “dropping-particle” : “”, “family” : “Kohansieh”, “given” : “Michelle”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Makaryus”, “given” : “Amgad N.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International Journal of Hypertension”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2015” }, “title” : “Sleep Deficiency and Deprivation Leading to Cardiovascular Disease”, “type” : “article-journal”, “volume” : “2015” }, “uris” : “http://www.mendeley.com/documents/?uuid=ae31c4de-ab97-4c67-aa32-246e51a4ec12” } , “mendeley” : { “formattedCitation” : “(<b><b>Kohansieh</b> and <b>Makaryus</b></b>, <b>2015</b>)”, “plainTextFormattedCitation” : “(Kohansieh and Makaryus, 2015)”, “previouslyFormattedCitation” : “(<b><b>Kohansieh</b> and <b>Makaryus</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Kohansieh and Makaryus, 2015). Shift and night work have also been associated with a higher risk of developing dyslipidemias. Studies found a relationship between shift work and lipids showing a greater proportion of shift workers with elevated triglyceride levels and low high density lipoprotein (HDL) concentrations compared to day workers. After adjusting for confounders as age, socioeconomic factors, physical exercise, smoking, social support, and job stress, shift workers exhibited double the risk of low HDL concentrations (OR 2.02). High triglyceride levels were also significantly associated with both shift and night work ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/s00420-003-0440-y”, “ISBN” : “0340-0131 (Print)\r0340-0131 (Linking)”, “ISSN” : “03400131”, “PMID” : “12783235”, “abstract” : “OBJECTIVES: The aim of the present study was to investigate the relationship between important metabolic risk factors for coronary heart disease (CHD) and type 2 diabetes in shift workers and day workers. METHODS: Cross-sectional data from a sub-population in the WOLF study consisting of 665 day workers and 659 three-shift workers in two plants were analysed. RESULTS: A higher proportion of shift workers than day workers had high triglyceride levels (> or =1.7 mmol/l), low levels of HDL-cholesterol (<0.9 mmol/l) and abdominal obesity (waist/hip ratio>0.9). The risk of low HDL-cholesterol was doubled in shift workers, (odds ratio (OR): 2.02, 95% confidence interval (95% CI): 1.24-3.28) after being adjusted for age, socio-economic factors, physical activity, current smoking, social support and job strain. High levels of triglycerides were also significantly associated with shift work (OR: 1.40, 95% CI: 1.08-1.83). The OR for abdominal obesity was 1.19, (95% CI: 0.92-1.56). The prevalence of hyperglycaemia (serum glucose > or =7.0 mmol/l) was similar in day and shift workers. No significant interaction was seen between shift work and abdominal obesity with regard to the associations with triglycerides and HDL-cholesterol. CONCLUSIONS: We found a significant association between shift work and lipid disturbances (i.e. low HDL-cholesterol and high triglyceride levels). We did not find any association with hyperglycaemia.”, “author” : { “dropping-particle” : “”, “family” : “Karlsson”, “given” : “Berndt H.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Knutsson”, “given” : “Anders K.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lindahl”, “given” : “Bernt O.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Alfredsson”, “given” : “Lars S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International Archives of Occupational and Environmental Health”, “id” : “ITEM-1”, “issue” : “6”, “issued” : { “date-parts” : “2003” }, “page” : “424-430”, “title” : “Metabolic disturbances in male workers with rotating three-shift work. Result of the WOLF study”, “type” : “article-journal”, “volume” : “76” }, “uris” : “http://www.mendeley.com/documents/?uuid=0e1f7091-b1ef-4e63-ba74-3ec15cf0e43a” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Karlsson</b> et al.</b></b>, <b>2003</b>)”, “manualFormatting” : “(Karlsson et al., 2003”, “plainTextFormattedCitation” : “(Karlsson et al., 2003)”, “previouslyFormattedCitation” : “(<b><b><b>Karlsson</b> et al.</b></b>, <b>2003</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Karlsson et al., 2003; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1111/j.1365-2796.2007.01766.x”, “ISBN” : “0954-6820 (Print)\r0954-6820 (Linking)”, “ISSN” : “09546820”, “PMID” : “17305651”, “abstract” : “OBJECTIVE: The major function of the circadian system is the internal cycling of physiological and metabolic events. The present study sought to explore the effect of rotating shift work schedule on leucocyte count and its relationship with risk factors of metabolic syndrome (MS). DESIGN AND PARTICIPANTS: From a population-based design, 1351 men of self-reported European ancestry were included in a cross-sectional study: 877 day workers were compared with 474 rotating shift workers. Medical history, health examination including anthropometric and arterial blood pressure measurements, a questionnaire on health-related behaviours and biochemical determinations was given to all participants. RESULTS: In comparison with day workers, rotating shift workers had elevated (mean +/- SE) body mass index (27.1 +/- 0.3 vs. 26.3 +/- 0.2, P < 0.0154), waist-hip ratio (0.95 +/- 0.01 vs. 0.93 +/- 0.01, P < 0.00024), diastolic arterial blood pressure (78 +/- 1 vs. 76 +/- 1, P < 0.033), fasting insulin (65.5 +/- 2.9 vs. 55.9 +/- 1.9 pmol L(-1), P < 0.017), Homeostasis Model Assessment index (2.12 +/- 0.11 vs. 1.77 +/- 0.07, P < 0.0027), triglycerides (1.71 +/- 0.1 vs. 1.5 +/- 0.1 mmol L(-1), P < 0.002), uric acid (292.7 +/- 2.8 vs. 282 +/- 3.4 micromol L(-1), P < 0.01) and leucocyte count (7030 +/- 84 vs. 6730 +/- 58, P < 0.0094). In multiple regression analysis, leucocyte count was correlated with rotating shift work independently of age, smoking, education and components of MS. CONCLUSION: The odds ratio for MS in rotating shift workers compared with day workers was 1.51 (95% CI 1.01-2.25), independently of age and physical activity. Increased leucocyte count, a biological marker of systemic inflammation, was associated with rotating shift work.”, “author” : { “dropping-particle” : “”, “family” : “Sookoian”, “given” : “S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gemma”, “given” : “C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Fernu00e1ndez Gianotti”, “given” : “T.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Burgueu00f1o”, “given” : “a.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Alvarez”, “given” : “a.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gonzu00e1lez”, “given” : “C. D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pirola”, “given” : “C. J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Internal Medicine”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2007” }, “page” : “285-292”, “title” : “Effects of rotating shift work on biomarkers of metabolic syndrome and inflammation”, “type” : “article-journal”, “volume” : “261” }, “uris” : “http://www.mendeley.com/documents/?uuid=f8736c8c-30ad-4f2b-b6e7-742736e85e1d” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Sookoian</b> et al.</b></b>, <b>2007</b>)”, “manualFormatting” : “Sookoian et al., 2007”, “plainTextFormattedCitation” : “(Sookoian et al., 2007)”, “previouslyFormattedCitation” : “(<b><b><b>Sookoian</b> et al.</b></b>, <b>2007</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Sookoian et al., 2007; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1155/2015/826249”, “ISBN” : “1687-8337 (Print)\r1687-8337 (Linking)”, “ISSN” : “1687-8337”, “PMID” : “25892993”, “abstract” : “<p>The objective of this review was to investigate the impact of shift and night work on metabolic processes and the role of alterations in the sleep-wake cycle and feeding times and environmental changes in the occurrence of metabolic disorders. The literature review was performed by searching three electronic databases for relevant studies published in the last 10 years. The methodological quality of each study was assessed, and best-evidence synthesis was applied to draw conclusions. The literature has shown changes in concentrations of melatonin, cortisol, ghrelin, and leptin among shift workers. Melatonin has been implicated for its role in the synthesis and action of insulin. The action of this hormone also regulates the expression of transporter glucose type 4 or triggers phosphorylation of the insulin receptor. Therefore, a reduction in melatonin can be associated with an increase in insulin resistance and a propensity for the development of diabetes. Moreover, shift work can negatively affect sleep and contribute to sedentarism, unhealthy eating habits, and stress. Recent studies on metabolic processes have increasingly revealed their complexity. Physiological changes induced in workers who invert their activity-rest cycle to fulfill work hours include disruptions in metabolic processes.</p>”, “author” : { “dropping-particle” : “”, “family” : “Ulhu00f4a”, “given” : “M. A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Marqueze”, “given” : “E. C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Burgos”, “given” : “L. G. A.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Moreno”, “given” : “C. R. C.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International Journal of Endocrinology”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2015” }, “page” : “1-11”, “title” : “Shift Work and Endocrine Disorders”, “type” : “article-journal”, “volume” : “2015” }, “uris” : “http://www.mendeley.com/documents/?uuid=3bc3c285-793f-45be-98b2-7bb45b6a4d6e” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Ulhu00f4a</b> et al.</b></b>, <b>2015</b>)”, “manualFormatting” : “Ulhu00f4a et al., 2015)”, “plainTextFormattedCitation” : “(Ulhu00f4a et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Ulhu00f4a</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Ulhôa et al., 2015).

A relation between shift work and other CVDs has been hypothesized and highlighted increasingly in recent years, but cannot be definitely confirmed. A systematic review published in 2009 focused on ischemic heart disease and based on 16 studies (1972—2008) failed to conclude certainly that shift work has an impact on CVDs ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Objective The objective of this review was to evaluate the epidemiologic evidence for a causal relation Methods We conducted a systematic search until the end of March 2008 for studies providing information on the relative risk of ischemic heart disease in relation to shift work. The quality of included papers was evaluated with respect to design, exposure and outcome information, bias, and exposure response assessment. Results Of the 16 studies examined, relevant information was retrieved from 14. Seven of these analyzed fatal events, six combined fatal and non-fatal events, while one study reported separately on both types of events. Relative risks ranged from 0.6-1 .4 in 12 papers while two papers reported relative risks around 2.0. Most studies based on fatal events showed no or weak associations while studies that combined fatal and non-fatal events showed modest positive associations. In a majority of studies, we could not reasonably rule out negative or positive bias due to the quality of outcome or exposure information, or confounder control. Five studies used years in shift work for exposure response analysis and no consistent pattern were seen. Conclusion There is limited epidemiologic evidence for a causal relation between shift work and ischemic h”, “author” : { “dropping-particle” : “”, “family” : “Frost”, “given” : “Poul”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kolstad”, “given” : “Henrik A”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Bonde”, “given” : “Jens Peter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Scandinavian”, “given” : “Source”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “May”, “given” : “No”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scand J Work Environ Health”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2009” }, “page” : “163-179”, “title” : “Shift work and the risk of ischemic heart disease – a systematic review of the”, “type” : “article-journal”, “volume” : “35” }, “uris” : “http://www.mendeley.com/documents/?uuid=544a2453-ee5b-4dd2-9322-b7bd0be1095f” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Frost</b> et al.</b></b>, <b>2009</b>)”, “plainTextFormattedCitation” : “(Frost et al., 2009)”, “previouslyFormattedCitation” : “(<b><b><b>Frost</b> et al.</b></b>, <b>2009</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Frost et al., 2009). Generally, similar results were seen recently from a 22-year follow-up of a Finnish cohort which analyzed mortality due to coronary heart disease in both genders and didn’t support the association between shift work and cardiovascular morbidity ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/s10654-010-9439-3”, “ISBN” : “1065401094”, “ISSN” : “03932990”, “PMID” : “20229313”, “abstract” : “Studies on the association between shift-work and cardiovascular disease (CVD), in particular coronary heart disease (CHD), have given conflicting results. In this prospective population-based study we assessed the association of shift-work with three endpoints: CHD mortality, disability retirement due to CVD, and incident hypertension. A cohort of 20,142 adults (the Finnish Twin Cohort) was followed from 1982 to 2003. Type of working time (daytime/nighttime/shift-work) was assessed by questionnaires in 1975 (response rate 89%) and in 1981 (84%). Causes of death, information on disability retirement and hypertension medication were obtained from nationwide official registers. Cox proportional hazard models were used to obtain hazard ratios (HR) for each endpoint by type of working time. Adjustments were made for 14 socio-demographic and lifestyle covariates. 76.9% were daytime workers and 9.5% shift-workers both in 1975 and in 1981. During the follow-up, 857 deaths due to CHD, 721 disability retirements due to CVD, and 2,642 new cases of medicated hypertension were observed. However, HRs for shift-work were not significant (mortality HR men 1.09 and women 1.22; retirement 1.15 and 0.96; hypertension 1.15 and 0.98, respectively). The results were essentially similar after full adjustments for all covariates. Within twin pairs, no association between shift work and outcome was observed. Our results do not support an association between shift-work and cardiovascular morbidity.”, “author” : { “dropping-particle” : “”, “family” : “Hublin”, “given” : “Christer”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Partinen”, “given” : “Markku”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Koskenvuo”, “given” : “Karoliina”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Silventoinen”, “given” : “Karri”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Koskenvuo”, “given” : “Markku”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kaprio”, “given” : “Jaakko”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “European Journal of Epidemiology”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2010” }, “page” : “315-323”, “title” : “Shift-work and cardiovascular disease: A population-based 22-year follow-up study”, “type” : “article-journal”, “volume” : “25” }, “uris” : “http://www.mendeley.com/documents/?uuid=19be3a4c-8869-4910-81b3-a209b4255a5c” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Hublin</b> et al.</b></b>, <b>2010</b>)”, “plainTextFormattedCitation” : “(Hublin et al., 2010)”, “previouslyFormattedCitation” : “(<b><b><b>Hublin</b> et al.</b></b>, <b>2010</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Hublin et al., 2010).
On the contrary, more recent studies confirm the association between shift work and CVD. A systematic review and meta-analysis in 2012 found moderate evidence for the association between shift work and each of myocardial infarction and cerebrovasular accidents; and a low evidence for shift work association with coronary events ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1136/bmj.e4800”, “ISBN” : “1756-1833 (Electronic)\r0959-535X (Linking)”, “ISSN” : “1756-1833”, “PMID” : “22835925”, “abstract” : “OBJECTIVE: To synthesise the association of shift work with major vascular events as reported in the literature. DATA SOURCES: Systematic searches of major bibliographic databases, contact with experts in the field, and review of reference lists of primary articles, review papers, and guidelines. STUDY SELECTION: Observational studies that reported risk ratios for vascular morbidity, vascular mortality, or all cause mortality in relation to shift work were included; control groups could be non-shift (“day”) workers or the general population. DATA EXTRACTION: Study quality was assessed with the Downs and Black scale for observational studies. The three primary outcomes were myocardial infarction, ischaemic stroke, and any coronary event. Heterogeneity was measured with the I(2) statistic and computed random effects models. RESULTS: 34 studies in 2,011,935 people were identified. Shift work was associated with myocardial infarction (risk ratio 1.23, 95% confidence interval 1.15 to 1.31; I(2)=0) and ischaemic stroke (1.05, 1.01 to 1.09; I(2)=0). Coronary events were also increased (risk ratio 1.24, 1.10 to 1.39), albeit with significant heterogeneity across studies (I(2)=85%). Pooled risk ratios were significant for both unadjusted analyses and analyses adjusted for risk factors. All shift work schedules with the exception of evening shifts were associated with a statistically higher risk of coronary events. Shift work was not associated with increased rates of mortality (whether vascular cause specific or overall). Presence or absence of adjustment for smoking and socioeconomic status was not a source of heterogeneity in the primary studies. 6598 myocardial infarctions, 17,359 coronary events, and 1854 ischaemic strokes occurred. On the basis of the Canadian prevalence of shift work of 32.8%, the population attributable risks related to shift work were 7.0% for myocardial infarction, 7.3% for all coronary events, and 1.6% for ischaemic stroke. CONCLUSIONS: Shift work is associated with vascular events, which may have implications for public policy and occupational medicine.”, “author” : { “dropping-particle” : “V.”, “family” : “Vyas”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Garg”, “given” : “a. X.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “V.”, “family” : “Iansavichus”, “given” : “a.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Costella”, “given” : “J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Donner”, “given” : “a.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Laugsand”, “given” : “L. E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Janszky”, “given” : “I.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mrkobrada”, “given” : “M.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Parraga”, “given” : “G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Hackam”, “given” : “D. G.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Bmj”, “id” : “ITEM-1”, “issue” : “jul26 1”, “issued” : { “date-parts” : “2012” }, “page” : “e4800-e4800”, “title” : “Shift work and vascular events: systematic review and meta-analysis”, “type” : “article-journal”, “volume” : “345” }, “uris” : “http://www.mendeley.com/documents/?uuid=2afdba4a-2fb9-44fe-a67c-079640d93da9” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Vyas</b> et al.</b></b>, <b>2012</b>)”, “plainTextFormattedCitation” : “(Vyas et al., 2012)”, “previouslyFormattedCitation” : “(<b><b><b>Vyas</b> et al.</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Vyas et al., 2012). Another meta-analysis performed in 2015 concluded that night shift work was associated with a 2.7% increase in cardiovascular mortality ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.sleep.2015.02.543”, “ISBN” : “1389-9457(Print)”, “ISSN” : “18785506”, “PMID” : “26498240”, “abstract” : “Night-shift work (NSW) has previously been related to incidents of breast cancer and all-cause mortality, but many published studies have reported inconclusive results. The aim of the present study was to quantify a potential dose-effect relationship between NSW and morbidity of breast cancer, and to evaluate the association between NSW and risk of all-cause mortality. The outcomes included NSW, morbidity of breast cancer, cardiovascular mortality, cancer-related mortality, and all-cause mortality.Sixteen investigations were included, involving 2,020,641 participants, 10,004 incident breast cancer cases, 7185 cancer-related deaths, 4820 cardiovascular end points, and 2480 all-cause mortalities. The summary risk ratio (RR) of incident breast cancer for an increase of NSW was 1.057 95% confidence interval (CI) 1.014-1.102; test for heterogeneity p = 0.358, I2= 9.2%. The combined RR (95% CI) of breast cancer risk for NSW vs daytime work was: 1.029 (0.969-1.093) in the <5-year subgroup, 1.019 (1.001-1.038) for 5-year incremental risk, 1.025 (1.006-1.044) for 5- to 10-year exposure times, 1.074 (1.010-1.142) in the 10- to 20-year subgroup, and 1.088 (1.012-1.169) for >20-year exposure lengths. The overall RR was 1.089 (95% CI 1.016-1.166) in a fixed-effects model (test for heterogeneity p = 0.838, I2= 0%) comparing rotating NSW and day work. Night-shift work was associated with an increased risk of cardiovascular death (RR 1.027, 95% CI 1.001-1.053), and all-cause death 1.253 (95% CI 0.786-1.997). In summary, NSW increased the risk of breast cancer morbidity by: 1.9% for 5 years, 2.5% for 5-10 years, 7.4% for 10-20 years, and 8.8% for >20-years of NSW. Additionally, rotating NSW enhanced the morbidity of breast cancer by 8.9%. Moreover, NSW was associated with a 2.7% increase in cardiovascular death.”, “author” : { “dropping-particle” : “”, “family” : “Lin”, “given” : “Xiaoti”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Chen”, “given” : “Weiyu”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Wei”, “given” : “Fengqin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ying”, “given” : “Mingang”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Wei”, “given” : “Weidong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Xie”, “given” : “Xiaoming”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Sleep Medicine”, “id” : “ITEM-1”, “issue” : “11”, “issued” : { “date-parts” : “2015” }, “page” : “1381-1387”, “title” : “Night-shift work increases morbidity of breast cancer and all-cause mortality: A meta-analysis of 16 prospective cohort studies”, “type” : “article”, “volume” : “16” }, “uris” : “http://www.mendeley.com/documents/?uuid=03c10ab0-3723-4edc-b139-f7e10689041f” } , “mendeley” : { “formattedCitation” : “(<b><b><b>X. Lin</b> et al.</b></b>, <b>2015</b>)”, “manualFormatting” : “(Lin et al., 2015)”, “plainTextFormattedCitation” : “(X. Lin et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>X. Lin</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Lin et al., 2015).
A large prospective cohort study of 189,158 healthy nurse followed up over 24 years in the Nurses’ Health Studies concluded that longer duration of rotating night shift work was associated with a statistically significant but small absolute increase in CVDs risk ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1001/jama.2016.4454”, “ISSN” : “15383598”, “abstract” : “IMPORTANCE: Prospective studies linking shift work to coronary heart disease (CHD) have been inconsistent and limited by short follow-up. OBJECTIVE To determine whether rotating night shift work is associated with CHD risk. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study of 189 158 initially healthy women followed up over 24 years in the Nurses’ Health Studies (NHS 1988-2012: N = 73 623 and NHS2 1989-2013: N = 115 535). EXPOSURES Lifetime history of rotating night shift work (u22653 night shifts per month in addition to day and evening shifts) at baseline (updated every 2 to 4 years in the NHS2). MAIN OUTCOMES AND MEASURES: Incident CHD; ie, nonfatalmyocardial infarction, CHD death, angiogram-confirmed angina pectoris, coronary artery bypass graft surgery, stents, and angioplasty. RESULTS: During follow-up, 7303 incident CHD cases occurred in the NHS (mean age at baseline, 54.5 years) and 3519 in the NHS2 (mean age, 34.8 years). In multivariable-adjusted Cox proportional hazards models, increasing years of baseline rotating night shift work was associated with significantly higher CHD risk in both cohorts. In the NHS, the association between duration of shift work and CHD was stronger in the first half of follow-up than in the second half (P=.02 for interaction), suggesting waning risk after cessation of shift work. Longer time since quitting shift work was associated with decreased CHD risk among ever shift workers in the NHS2 (P;.001 for trend). CONCLUSIONS AND RELEVANCE: Among women who worked as registered nurses, longer duration of rotating night shift work was associated with a statistically significant but small absolute increase in CHD risk. Further research is needed to explore whether the association is related to specific work hours and individual characteristics. u00a9 2016 American Medical Association. All rights reserved.”, “author” : { “dropping-particle” : “”, “family” : “Vetter”, “given” : “Cu00e9line”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Devore”, “given” : “Elizabeth E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Wegrzyn”, “given” : “Lani R.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Massa”, “given” : “Jennifer”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Speizer”, “given” : “Frank E.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kawachi”, “given” : “Ichiro”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Rosner”, “given” : “Bernard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Stampfer”, “given” : “Meir J.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Schernhammer”, “given” : “Eva S.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “JAMA – Journal of the American Medical Association”, “id” : “ITEM-1”, “issue” : “16”, “issued” : { “date-parts” : “2016” }, “page” : “1726-1734”, “title” : “Association between rotating night shiftwork and risk of coronary heart disease among women”, “type” : “article-journal”, “volume” : “315” }, “uris” : “http://www.mendeley.com/documents/?uuid=08412a17-ab85-460b-ace4-e36a7d6ee210” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Vetter;/b; et al.;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Vetter et al., 2016)”, “previouslyFormattedCitation” : “(;b;;b;;b;Vetter;/b; et al.;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Vetter et al., 2016). The difficulties in analyzing the consequences of shift work on cardiovascular risks are related to several reasons as; diverse definitions of shift work; variability in the confounding factors included in studies; and the pathological and physiological mechanisms considered ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.acvd.2011.09.004”, “ISBN” : “1875-2136”, “ISSN” : “18752136”, “PMID” : “22152516”, “abstract” : “Cardiovascular diseases remain a major public health problem. The involvement of several occupational factors has recently been discussed, notably the organization of work schedules, e.g. shift work. To analyse the progress of knowledge on the relationship between cardiovascular risk factors and shift work. A review of English-language literature dealing with the link between cardiovascular factors and shift workers (published during 2000-2010) was conducted. Studies published in the past 10 years tend to document an impact of shift work on blood pressure, lipid profile (triglyceride levels), metabolic syndrome and, possibly, body mass index. However, the consequences on glucose metabolism are unclear. These results are not yet firmly established, but are supported by strong hypotheses. Some advice could reasonably be proposed to guide the clinical practitioner. ?? 2011 Elsevier Masson SAS. All rights reserved.”, “author” : { “dropping-particle” : “”, “family” : “Esquirol”, “given” : “Yolande”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Perret”, “given” : “Bertrand”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ruidavets”, “given” : “Jean Bernard”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Marquie”, “given” : “Jean Claude”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Dienne”, “given” : “Eloi”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Niezborala”, “given” : “Michel”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ferrieres”, “given” : “Jean”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Archives of Cardiovascular Diseases”, “id” : “ITEM-1”, “issue” : “12”, “issued” : { “date-parts” : “2011” }, “page” : “636-668”, “publisher” : “Elsevier Masson SAS”, “title” : “Shift work and cardiovascular risk factors: New knowledge from the past decade”, “type” : “article-journal”, “volume” : “104” }, “uris” : “http://www.mendeley.com/documents/?uuid=4bc56eba-58ba-4875-9f45-09f98976d807” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Esquirol;/b; et al.;/b;;/b;, ;b;2011;/b;)”, “plainTextFormattedCitation” : “(Esquirol et al., 2011)”, “previouslyFormattedCitation” : “(;b;;b;;b;Esquirol;/b; et al.;/b;;/b;, ;b;2011;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Esquirol et al., 2011).
HEALTH PROMOTION and wellbeing of shift workers
Despite the health hazards associated with shift work, elimination of shift work isn’t a realistic goal so instead preventive measures and health promotion programs should be followed. Preventive measures should start from the choice of shift workers. Pre-placement examination should assess shift work tolerance (SWT) among workers before assigning them to shift schedules. Factors related to SWT can be divided into five categories: demographic, individual, psychosocial, lifestyle, and working condition factors. Demographic factors shown to be associated with SWT include age and gender. Most studies found that individuals of a higher age had a lower tolerance for shift work. With regards to gender, the reduced SWT of women is contributed to family burden (i.e., number of children) ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.apnr.2014.09.007”, “ISSN” : “0897-1897”, “author” : { “dropping-particle” : “”, “family” : “Jung”, “given” : “Hye-sun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lee”, “given” : “Bokim”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Applied Nursing Research”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2015” }, “page” : “150-155”, “publisher” : “Elsevier Inc.”, “title” : “Contributors to shift work tolerance in South Korean nurses working rotating shift”, “type” : “article-journal”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=95f15ac6-9c42-4ba1-af93-f4ec5f40a1da” } , “mendeley” : { “formattedCitation” : “(;b;;b;Jung;/b; and ;b;Lee;/b;;/b;, ;b;2015;/b;)”, “plainTextFormattedCitation” : “(Jung and Lee, 2015)”, “previouslyFormattedCitation” : “(;b;;b;Jung;/b; and ;b;Lee;/b;;/b;, ;b;2015;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Jung and Lee, 2015).
Individual factors such as morningness, flexibility and self-esteem have also been linked with SWT. Most studies have found that flexibility and self-esteem are positively related to SWT; low scores on morningness are related to high SWT. Regarding psychosocial factors such as job stress and social support, research indicates that sleepiness during the night shift was positively associated with job stress, but inversely associated with support from colleagues. Lifestyle factors, especially smoking, and physical activity have also been studied. Smoking among shift workers is associated with adverse health outcomes. Physical activity can reduce sleep problems related to shift work ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.apnr.2014.09.007”, “ISSN” : “0897-1897”, “author” : { “dropping-particle” : “”, “family” : “Jung”, “given” : “Hye-sun”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Lee”, “given” : “Bokim”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Applied Nursing Research”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2015” }, “page” : “150-155”, “publisher” : “Elsevier Inc.”, “title” : “Contributors to shift work tolerance in South Korean nurses working rotating shift”, “type” : “article-journal”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=95f15ac6-9c42-4ba1-af93-f4ec5f40a1da” } , “mendeley” : { “formattedCitation” : “(;b;;b;Jung;/b; and ;b;Lee;/b;;/b;, ;b;2015;/b;)”, “plainTextFormattedCitation” : “(Jung and Lee, 2015)”, “previouslyFormattedCitation” : “(;b;;b;Jung;/b; and ;b;Lee;/b;;/b;, ;b;2015;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Jung and Lee, 2015).

Other preventive measures include some generally acknowledged coping strategies against acute effects of shift work as: napping, nutrition, light, lifestyle training, and cognitive and behavioral interventions. Short naps which minimize sleep inertia can generally be helpful. Caffeine consumption and a wholefood diet consisting of vegetables, fruit, wholegrain, and low-carb food with the avoidance of sugar-rich products with a high glycemic load were all recommended to increase vigilance and improve performance of shift workers. The exposure to bright artificial light can counteract melatonin suppression and may lead to the circadian adaptation to night or shift work. Furthermore; it was concluded that, bright light reduces sleepiness, improves alertness, and leads to better physical fitness, a more balanced sleep pattern, and higher efficiency of shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/s13167-016-0064-4”, “ISSN” : “1878-5077”, “author” : { “dropping-particle” : “”, “family” : “Richter”, “given” : “Kneginja”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Acker”, “given” : “Jens”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Adam”, “given” : “Sophia”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Niklewski”, “given” : “Guenter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “EPMA Journal”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “7 – 16”, “publisher” : “EPMA Journal”, “title” : “Prevention of fatigue and insomnia in shift workers u2014 a review of non-pharmacological measures”, “type” : “article-journal” }, “uris” : “http://www.mendeley.com/documents/?uuid=ef621279-4956-4f21-afdc-93f89b031ce5” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Richter;/b; et al.;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Richter et al., 2016)”, “previouslyFormattedCitation” : “(;b;;b;;b;Richter;/b; et al.;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Richter et al., 2016).

Lifestyle training is a measure that provides shift workers with information on healthy diet, managing fatigue and alertness levels, advice on how to sleep better, recommendations for using naps effectively and on balancing work and social life. Involving the families of shift workers in the training can be very effective to give families a better understanding of how to adjust to a shift worker’s schedule with emphasis on his needs for sleep, healthy nutrition, and the organization of family activities. Cognitive and behavioral interventions was also studied and proved to improve sleep hygiene, enhance sleep quality and combat insomnia and excessive sleepiness and these improvements were found to be long lasting ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/s13167-016-0064-4”, “ISSN” : “1878-5077”, “author” : { “dropping-particle” : “”, “family” : “Richter”, “given” : “Kneginja”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Acker”, “given” : “Jens”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Adam”, “given” : “Sophia”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Niklewski”, “given” : “Guenter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “EPMA Journal”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “7 – 16”, “publisher” : “EPMA Journal”, “title” : “Prevention of fatigue and insomnia in shift workers u2014 a review of non-pharmacological measures”, “type” : “article-journal” }, “uris” : “http://www.mendeley.com/documents/?uuid=ef621279-4956-4f21-afdc-93f89b031ce5” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Richter;/b; et al.;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Richter et al., 2016)”, “previouslyFormattedCitation” : “(;b;;b;;b;Richter;/b; et al.;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Richter et al., 2016).
In addition to the mentioned coping strategies a comprehensive periodic medical examination that is tailored according to long term effects of shift work should be designed and applied to all workers involved in shift work. Adequate supervision and availability of safety measures in night shifts as well as day shifts to reduce accidents frequency and improve performance of shift workers.

Workplace health promotion is a strategy to improve the health and well-being of workers at their workplaces. In spite of the high impact of shift work on workers’ health; the implementation of strategies for health promotion for shift workers and the prevention of shift work disorders is still low ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/s13167-010-0057-7”, “ISBN” : “1316701000577”, “ISSN” : “18785077”, “PMID” : “23199115”, “abstract” : “Workplace health promotion is a strategy to improve the health and well-being of people at work. The measures aim at the personal, organisational and work environment. Shift work is one of many reasons provoking increased job stress. According to worldwide epidemiological data, up to 30% of the working population are employed in shifts. Taking into consideration that shift work causes a large number of somatic and psychiatric diseases which bear considerable negative consequences for the health status and the quality of life, it seems to be important to initiate health promotion strategies for shift workers in the companies. The results of recent studies indicate that well-scheduled und targeted health programmes can change the lifestyle of shift working employees and have an impact on the risk factors involved. One problem, though, is a considerable time lag till effects become apparent; therefore, the long-term economic effects of workplace health promotion have not been evaluated sufficiently to date. These definitely positive effects highlight the demand for trainings and workshops for people in shift work. We urgently suggest a speedy implementation of the recommended strategies by companies with shift work systems. In our view, this poses a challenge to the u201cinfantu201d interdisciplinary field of sleep medicine that should be solved.”, “author” : { “dropping-particle” : “”, “family” : “Richter”, “given” : “Kneginja D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Acker”, “given” : “Jens”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Scholz”, “given” : “Friederike”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Niklewski”, “given” : “Gu00fcnter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “EPMA Journal”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2010” }, “page” : “611-618”, “title” : “Health promotion and work: Prevention of shift work disorders in companies”, “type” : “article-journal”, “volume” : “1” }, “uris” : “http://www.mendeley.com/documents/?uuid=2fa53361-c68a-4236-af95-d304fc33022d” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Richter;/b; et al.;/b;;/b;, ;b;2010;/b;)”, “plainTextFormattedCitation” : “(Richter et al., 2010)”, “previouslyFormattedCitation” : “(;b;;b;;b;Richter;/b; et al.;/b;;/b;, ;b;2010;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Richter et al., 2010). Unfortunately general workplace health promotion activities do not reach shift workers to the same extent as day workers. This may be related to that workplace health promotion takes place during day hours, thus they would be less available for shift workers. Furthermore, participation in workplace health promotion is also lower by shift workers. Therefore, both in terms of availability and participation, there are likely more barriers for interventions to reach shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5271/sjweh.3469”, “ISBN” : “0355-3140”, “ISSN” : “1795990X”, “PMID” : “25417210”, “abstract” : “OBJECTIVES: One reason for health disparities between shift and day workers may be that workplace health promotion does not reach shift workers to the same extent as it reaches day workers. This study aimed to investigate the association between shift work and the availability of and participation in workplace health promotion.\n\nMETHODS: We used cross-sectional questionnaire data from a large representative sample of all employed people in Denmark. We obtained information on the availability of and participation in six types of workplace health promotion. We also obtained information on working hours, ie, fixed day work (reference) and shift work (four categories), psychosocial work factors, and health behaviors. We conducted binary logistic regression analyses both in the total sample (N=7555) and in a sub-sample consisting of job groups with representatives in all shift work categories (N=2064).\n\nRESULTS: In the general working population, fixed evening and fixed night workers, and employees working variable shifts including night work reported a higher availability of health promotion, while employees working variable shifts without night work reported a lower availability of health promotion. Within job groups undertaking shift work, we found few differences between day and shift workers, and these few differences appear to favor shift workers. Day workers and shift workers did not differ significantly with respect to their participation in health promotion.\n\nCONCLUSIONS: The present study could not confirm that shift workers in general report a lower availability of and participation in workplace health promotion.”, “author” : { “dropping-particle” : “”, “family” : “Nabe-Nielsen”, “given” : “Kirsten”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Garde”, “given” : “Anne H elene”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Clausen”, “given” : “Thomas”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ju00f8rgensen”, “given” : “Marie B irk”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandinavian journal of work, environment ; health”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2015” }, “page” : “84-93”, “title” : “Does workplace health promotion reach shift workers?”, “type” : “article-journal”, “volume” : “41” }, “uris” : “http://www.mendeley.com/documents/?uuid=90f428f5-e6db-4ddb-9565-4012d0f96a00” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Nabe-Nielsen;/b; et al.;/b;;/b;, ;b;2015;/b;)”, “plainTextFormattedCitation” : “(Nabe-Nielsen et al., 2015)”, “previouslyFormattedCitation” : “(;b;;b;;b;Nabe-Nielsen;/b; et al.;/b;;/b;, ;b;2015;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Nabe-Nielsen et al., 2015).

Specific health promotion program for shift workers is urgently required. Papers that offer recommended programs for optimizing the environments of shift work do exist, but there is still a need for scientific evaluation of these programs. An effective health promotion program should include strategies that work on personal, organizational, and work environment levels. Working on the organizational level by optimizing the shift work system through the management of the duration of shifts, shift rotation systems and rest periods. This should be complemented by working on the personal level through regular educational programs. The contents of the educational programs should include sleep hygiene, behavioral strategies to avoid fatigue, prevention of somatic and psychiatric manifestations associated with shift work, individual strategies to improve sleep quality and daily vigilance; these educational programs can prevent fatigue and sleep disorders and contribute strongly to the preservation of the physical health of shift workers. Finally the optimization of workplace conditions (e.g. by adjusting the intensity of illumination and rest-rooms) should follow the previous two levels to complete the health promotion program ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/s13167-010-0057-7”, “ISBN” : “1316701000577”, “ISSN” : “18785077”, “PMID” : “23199115”, “abstract” : “Workplace health promotion is a strategy to improve the health and well-being of people at work. The measures aim at the personal, organisational and work environment. Shift work is one of many reasons provoking increased job stress. According to worldwide epidemiological data, up to 30% of the working population are employed in shifts. Taking into consideration that shift work causes a large number of somatic and psychiatric diseases which bear considerable negative consequences for the health status and the quality of life, it seems to be important to initiate health promotion strategies for shift workers in the companies. The results of recent studies indicate that well-scheduled und targeted health programmes can change the lifestyle of shift working employees and have an impact on the risk factors involved. One problem, though, is a considerable time lag till effects become apparent; therefore, the long-term economic effects of workplace health promotion have not been evaluated sufficiently to date. These definitely positive effects highlight the demand for trainings and workshops for people in shift work. We urgently suggest a speedy implementation of the recommended strategies by companies with shift work systems. In our view, this poses a challenge to the u201cinfantu201d interdisciplinary field of sleep medicine that should be solved.”, “author” : { “dropping-particle” : “”, “family” : “Richter”, “given” : “Kneginja D.”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Acker”, “given” : “Jens”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Scholz”, “given” : “Friederike”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Niklewski”, “given” : “Gu00fcnter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “EPMA Journal”, “id” : “ITEM-1”, “issue” : “4”, “issued” : { “date-parts” : “2010” }, “page” : “611-618”, “title” : “Health promotion and work: Prevention of shift work disorders in companies”, “type” : “article-journal”, “volume” : “1” }, “uris” : “http://www.mendeley.com/documents/?uuid=2fa53361-c68a-4236-af95-d304fc33022d” } , “mendeley” : { “formattedCitation” : “(;b;;b;;b;Richter;/b; et al.;/b;;/b;, ;b;2010;/b;)”, “plainTextFormattedCitation” : “(Richter et al., 2010)”, “previouslyFormattedCitation” : “(;b;;b;;b;Richter;/b; et al.;/b;;/b;, ;b;2010;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Richter et al., 2010).
Regarding shift systems and rest periods up to date, it is worth mentioning that there is no “best” shift system to be recommended in general, but each shift work schedule should be scheduled and adapted according to the different job activities and demands, as well as to the particular characteristics, social life, cultural background and personal preference of the worker involved. This entails a careful strategy for the planning of shift schedules, that involves workers’ participation in the design, implementation and assessment of the shift system chosen ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1007/978-3-319-42286-2”, “ISBN” : “9783319422862”, “abstract” : “This chapter gives an overview of the health problems associated with shift work, and the main organizational guidelines on how to protect workersu2019 health and well-being. Working time organization is becoming a key factor on account of new technologies, market globalization, economic competition, and extension of social services to general population, involving more and more people in continuous assistance and control of the work processes over the 24 h. The strong increase of epidemiological studies on this issue demonstrates the seriousness of this risk factor for human health and well-being, at both social and psychophysical levels, starting from disruption of biological circadian rhythms and the sleep/wake cycle, ending in several psychosomatic troubles and disorders, probably including cancer, and passing through impairment of performance efficiency and family and social life. Appropriate interventions on the organization of shift schedules according to ergonomic criteria, on the one hand, and a careful health surveillance and social support to shift workers, on the other hand, are important preventive and corrective measures able to allow people to keep working without significant health and social impairment.”, “author” : { “dropping-particle” : “”, “family” : “Costa”, “given” : “Giovanni”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Social and Family Issues in Shift Work and Non Standard Working Hours”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2016” }, “page” : “19 – 35”, “title” : “introduction to problems of shift work”, “type” : “chapter” }, “uris” : “http://www.mendeley.com/documents/?uuid=874a938e-65eb-4202-a8b5-6f6ab71f6b21” } , “mendeley” : { “formattedCitation” : “(;b;;b;Costa;/b;;/b;, ;b;2016;/b;)”, “plainTextFormattedCitation” : “(Costa, 2016)”, “previouslyFormattedCitation” : “(;b;;b;Costa;/b;;/b;, ;b;2016;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Costa, 2016).

Some international directives have stressed on the necessity of a careful organization of shift and night schedules to protect the workers’ health, mainly the ILO Convention no. 171 and Recommendation concerning Night Work (1990) and the European Parliament Directives 2003/88/EC concerning “certain aspects of the organization of working time”. The main guidelines are shown in table IV.

Table IV. Guidelines for arranging shift schedule
Quickly rotating shift systems are preferred to slowly rotating ones, since they interfere less with circadian rhythms and minimize the degree of cumulative sleep deficit.

Clockwise rotation (morning/afternoon/night) is better than counter-clockwise (afternoon/morning/night) since it matches the endogenous circadian rhythms (which display a periodicity slightly longer than 24 h), avoids quick returns or changeovers (e.g. morning and night shift on the same day) and allows longer rest periods that allow rapid recovery from fatigue and sleep deficit.

Early starts of morning shifts should be avoided in order to decrease the truncation of sleep (REM phase in particular) and subsequent fatigue and risk of errors.

Extended work shifts (9–12 h) should only be planned when the workload is suitable, there are adequate breaks, and the shift system is designed to minimize the accumulation of fatigue and the exposure to toxic materials.

Shift schedules should be as regular as possible and assure as many free weekends as possible, to allow people to enjoy their leisure and social time more conveniently.

Permanent night work can be acceptable only for special working situations, which require a complete adaptation to night work in order to ensure the highest levels of safety.

Flexible working hours arrangements should be supported in order to meet workers’ needs and preferences.

(ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Knauth”, “given” : “Peter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Scandanavian journal for work and environmental health”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “1998” }, “page” : “13-17”, “title” : “lnnovative worktime arrangements”, “type” : “article-journal”, “volume” : “24” }, “uris” : “http://www.mendeley.com/documents/?uuid=dba57541-95c6-44eb-9a1d-82d577dbc1be” } , “mendeley” : { “formattedCitation” : “(;b;;b;Knauth;/b;;/b;, ;b;1998;/b;)”, “manualFormatting” : “Knauth, 1998”, “plainTextFormattedCitation” : “(Knauth, 1998)”, “previouslyFormattedCitation” : “(;b;;b;Knauth;/b;;/b;, ;b;1998;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Knauth, 1998; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.2486/indhealth.45.125”, “ISBN” : “0019-8366 (Print)\r0019-8366 (Linking)”, “ISSN” : “0019-8366”, “PMID” : “17284884”, “abstract” : “A literature review of 105 studies on the effects of extended daily working hours was conducted. Potential negative effects of extended working hours are discussed: More accidents on the job; more accidents off the job; reduced duration and quality of sleep due to moonlighting; sleepiness; reduced alertness; fatigue; adverse effects on performance; prolonged toxic exposure; adverse effects on health; increased absenteeism; problems communicating with managers; and problems while driving home. Potential positive effects of extended working hours are discussed: Less travel time and costs; more time for the family, social life, and domestic duties; increased satisfaction with working hours; fewer handovers; and less overtime. No firm conclusions can be drawn because of the partly contradictory results and the methodological problems of many studies. However, caution is advised when considering the introduction of extended work shifts, particularly where public safety is at stake. A checklist is provided (concerning work load, breaks, staffing level, systematic assessments of health and safety factors) to support decisions for or against the use of extended work shifts.”, “author” : { “dropping-particle” : “”, “family” : “Knauth”, “given” : “Peter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Industrialial Health”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2007” }, “page” : “125-136”, “title” : “Extended Work Periods”, “type” : “article-journal”, “volume” : “45” }, “uris” : “http://www.mendeley.com/documents/?uuid=20b5a7ea-01ab-4229-9c30-4adb42971c05” } , “mendeley” : { “formattedCitation” : “(;b;;b;Knauth;/b;;/b;, ;b;2007;/b;)”, “manualFormatting” : “Knauth, 2007)”, “plainTextFormattedCitation” : “(Knauth, 2007)”, “previouslyFormattedCitation” : “(;b;;b;Knauth;/b;;/b;, ;b;2007;/b;)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Knauth, 2007).

SUBJECTS AND METHODS
Study design
The study is a comparative study (ex post facto) to assess the effect of rotating shift work pattern on metabolic syndrome components as follows:
Exposure variable: Rotating shift work pattern.
Outcome variables: Components of metabolic syndrome which are (waist circumference, blood pressure, fasting blood sugar, triglycerides and reduced HDL).

Two groups of workers were defined according to exposure status (i.e. rotating shift workers and day workers).

Study setting and population
The study was conducted at the Canal Company for Electricity Distribution (CCED) in Ismailia city.
The Ccompany for Electricity Distribution is one of the major companies affiliated to the Egyptian Electricity Holding Company (EEHC) – Ministry of Electricity and Energy – Egypt. The geographical area of CCED include (Port said, Ismailia, Suez, Sharkia , Sinai, Red Sea , and New Cites) and covers around 30% of Egypt area.

Main activities of the company are:
Supplying medium and low voltage electric energy for different purposes.

Management, operation and maintenance on medium and low voltage of both electrical networks generation plants and isolated form untied network.

Studying, researching, designing and implementing of electrical current connectivity projects for different purposes (CCED, 2010).

Ismailia city includes the general bureau encompassing control center, the training center and Ismailia networking sector. The study was carried out in Ismailia networking sector which includes 3 engineering sectors according to Ismailia districts (1st, 2nd and 3rd districts) and the general bureau.
The company has two patterns of rotating shift work; the pattern followed in the whole company except Ismailia engineering sectors is classified into 3 work shifts 8 hours each and the shift rotates weekly for 3 weeks followed by one week rest; while in the 3 engineering sector of Ismailia, the shift work is classified into 2 work shifts 12 hours each and workers rotate weekly for 2 weeks followed by one week rest.

Table V. Description of shift schedule among studied shift workers in Ismailia engineering sectors.

Week Day shift Night shift Rest
1st week Group 1 Group 2 Group 3
2nd week Group 3 Group 1 Group 2
3rd week Group 2 Group 3 Group 1
Shift is 12 hours duration
Table VI. Description of shift schedule among studied shift workers in the general bureau.

Week Day shift Afternoon shift Night shift Rest
1st week Group 1 Group 2 Group 3 Group 4
2nd week Group 4 Group 1 Group 2 Group 3
3rd week Group 3 Group 4 Group 1 Group 2
4th week Group 2 Group 3 Group 4 Group 1
Shift is 8 hours duration

Study included both blue collar and white collar workers.
The blue collars included in the study were electrical panel technicians and electrical network technicians (both included operating technicians and maintaining technicians), electric panel monitors and electric network monitors and security personnel.

The white collars included in the study were engineers, accountants and clerks.

Then according to work schedule 2 groups were selected from study population
Group 1 (study): rotating shift workers in the 3 engineering sectors of Ismailia city which are (Awal, Thany and Al-sheikh zayed engineering sectors) and the general bureau. They included about 316 shift workers encompassing, 199 blue collars and 127 white collars all were males.

Group 2 (control): regular day workers in the same 3 engineering sectors and the general bureau matched with shift workers for age and occupation.

The following inclusion criteria were applied to all participants
Inclusion criteria:
Workers with at least 2 years experience in the current work schedule (Korompeli et al., 2014).

Ascertainment of working for at least 6 successive uninterrupted months in the same work schedule.

Sampling
Sample Size
Sample size was calculated based on the difference between the 2 study groups regarding one of the outcome variables which is systolic blood pressure as follows:
1080770173355
ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Dawson”, “given” : “B”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Trapp”, “given” : “RG”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “edition” : “4th”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2004” }, “publisher” : “McGraw-Hill”, “publisher-place” : “USA”, “title” : “Basic and clinical biostatistics”, “type” : “book” }, “uris” : “http://www.mendeley.com/documents/?uuid=7d13d3a8-93e5-4226-adf5-bcd3edc453a2” } , “mendeley” : { “formattedCitation” : “(Dawson ; Trapp, 2004)”, “manualFormatting” : “(Dawson and Trapp, 2004)”, “plainTextFormattedCitation” : “(Dawson ; Trapp, 2004)”, “previouslyFormattedCitation” : “(Dawson ; Trapp, 2004)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Dawson and Trapp, 2004)
n = required sample size,
Z?/2 = 1.96 (The critical value that divides the central 95% of the Z distribution from the 5% in the tail)
Z? = 1.28 (The critical value that separates the lower 10% of the Z distribution from the upper 90%)
? = the estimate of the standard deviation of systolic blood pressure among studied subjects = 17 mmHg ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/2052-4374-25-33”, “ISBN” : “10.1186/2052-4374-25-33”, “ISSN” : “2052-4374”, “PMID” : “24472469”, “abstract” : “OBJECTIVE: This study aimed to determine identify any association between shift work and the metabolic syndrome by comparing the prevalence rates of the metabolic syndrome in shift work groups and daytime work groups for female workers.\n\nMETHODS: Based on data from health examinations carried out from April to December of 2012, we selected as our subjects 254 female workers from the Daegu area Dyeing Industrial Complex. We diagnosed the metabolic syndrome using the examination results, and information about age, whether or not they did shift work, job type, smoking habits, drinking habits, exercise habits, and past medical history was collected through self-administered questionnaire surveys and face-to-face interviews. The variables found in a univariate analysis to be significant in the occurrence of the metabolic syndrome – age, drinking habits, exercise habits, and shift work – were included in a logistic regression analysis of the risk of the metabolic syndrome for female workers.\n\nRESULTS: The prevalence rates of the metabolic syndrome for the total group of study subjects was 11.8%, for daytime workers was 2.8%, and for shift workers was 15.3%. A logistic regression analysis of the odds of the metabolic syndrome for female workers was conducted that included factors associated with the occurrence of the metabolic syndrome: age, drinking habits, exercise habits, and shift work. The results revealed that the odds ratio of the metabolic syndrome in the shift work group, 6.30 (95% CI 1.24-32.15), was significantly higher when compared with the daytime work group.\n\nCONCLUSION: Shift work appears to have an association with the metabolic syndrome in female workers. Accordingly, we believe that the attention of government agencies and business owners is needed together with the individual practice of health behaviors to manage the metabolic syndrome for the prevention of cardiovascular disease in female shift workers.”, “author” : { “dropping-particle” : “”, “family” : “Ye”, “given” : “Han Hui”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeong”, “given” : “Jae Uk”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeon”, “given” : “Man Joong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sakong”, “given” : “Joon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annals of occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “page” : “33”, “title” : “The Association between Shift Work and the Metabolic Syndrome in Female Workers.”, “type” : “article-journal”, “volume” : “25” }, “uris” : “http://www.mendeley.com/documents/?uuid=1c6e46ae-d8d1-4cc0-af02-e995027a42ca” } , “mendeley” : { “formattedCitation” : “(Ye et al., 2013)”, “plainTextFormattedCitation” : “(Ye et al., 2013)”, “previouslyFormattedCitation” : “(Ye et al., 2013)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ye et al., 2013).µ1 = mean systolic blood pressure among rotating shift workers = 125.1 mmHg ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/2052-4374-25-33”, “ISBN” : “10.1186/2052-4374-25-33”, “ISSN” : “2052-4374”, “PMID” : “24472469”, “abstract” : “OBJECTIVE: This study aimed to determine identify any association between shift work and the metabolic syndrome by comparing the prevalence rates of the metabolic syndrome in shift work groups and daytime work groups for female workers.\n\nMETHODS: Based on data from health examinations carried out from April to December of 2012, we selected as our subjects 254 female workers from the Daegu area Dyeing Industrial Complex. We diagnosed the metabolic syndrome using the examination results, and information about age, whether or not they did shift work, job type, smoking habits, drinking habits, exercise habits, and past medical history was collected through self-administered questionnaire surveys and face-to-face interviews. The variables found in a univariate analysis to be significant in the occurrence of the metabolic syndrome – age, drinking habits, exercise habits, and shift work – were included in a logistic regression analysis of the risk of the metabolic syndrome for female workers.\n\nRESULTS: The prevalence rates of the metabolic syndrome for the total group of study subjects was 11.8%, for daytime workers was 2.8%, and for shift workers was 15.3%. A logistic regression analysis of the odds of the metabolic syndrome for female workers was conducted that included factors associated with the occurrence of the metabolic syndrome: age, drinking habits, exercise habits, and shift work. The results revealed that the odds ratio of the metabolic syndrome in the shift work group, 6.30 (95% CI 1.24-32.15), was significantly higher when compared with the daytime work group.\n\nCONCLUSION: Shift work appears to have an association with the metabolic syndrome in female workers. Accordingly, we believe that the attention of government agencies and business owners is needed together with the individual practice of health behaviors to manage the metabolic syndrome for the prevention of cardiovascular disease in female shift workers.”, “author” : { “dropping-particle” : “”, “family” : “Ye”, “given” : “Han Hui”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeong”, “given” : “Jae Uk”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeon”, “given” : “Man Joong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sakong”, “given” : “Joon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annals of occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “page” : “33”, “title” : “The Association between Shift Work and the Metabolic Syndrome in Female Workers.”, “type” : “article-journal”, “volume” : “25” }, “uris” : “http://www.mendeley.com/documents/?uuid=1c6e46ae-d8d1-4cc0-af02-e995027a42ca” } , “mendeley” : { “formattedCitation” : “(Ye et al., 2013)”, “plainTextFormattedCitation” : “(Ye et al., 2013)”, “previouslyFormattedCitation” : “(Ye et al., 2013)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ye et al., 2013). µ2 = mean systolic blood pressure in the control group = 117.3 mmHg ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/2052-4374-25-33”, “ISBN” : “10.1186/2052-4374-25-33”, “ISSN” : “2052-4374”, “PMID” : “24472469”, “abstract” : “OBJECTIVE: This study aimed to determine identify any association between shift work and the metabolic syndrome by comparing the prevalence rates of the metabolic syndrome in shift work groups and daytime work groups for female workers.\n\nMETHODS: Based on data from health examinations carried out from April to December of 2012, we selected as our subjects 254 female workers from the Daegu area Dyeing Industrial Complex. We diagnosed the metabolic syndrome using the examination results, and information about age, whether or not they did shift work, job type, smoking habits, drinking habits, exercise habits, and past medical history was collected through self-administered questionnaire surveys and face-to-face interviews. The variables found in a univariate analysis to be significant in the occurrence of the metabolic syndrome – age, drinking habits, exercise habits, and shift work – were included in a logistic regression analysis of the risk of the metabolic syndrome for female workers.\n\nRESULTS: The prevalence rates of the metabolic syndrome for the total group of study subjects was 11.8%, for daytime workers was 2.8%, and for shift workers was 15.3%. A logistic regression analysis of the odds of the metabolic syndrome for female workers was conducted that included factors associated with the occurrence of the metabolic syndrome: age, drinking habits, exercise habits, and shift work. The results revealed that the odds ratio of the metabolic syndrome in the shift work group, 6.30 (95% CI 1.24-32.15), was significantly higher when compared with the daytime work group.\n\nCONCLUSION: Shift work appears to have an association with the metabolic syndrome in female workers. Accordingly, we believe that the attention of government agencies and business owners is needed together with the individual practice of health behaviors to manage the metabolic syndrome for the prevention of cardiovascular disease in female shift workers.”, “author” : { “dropping-particle” : “”, “family” : “Ye”, “given” : “Han Hui”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeong”, “given” : “Jae Uk”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeon”, “given” : “Man Joong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sakong”, “given” : “Joon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annals of occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “page” : “33”, “title” : “The Association between Shift Work and the Metabolic Syndrome in Female Workers.”, “type” : “article-journal”, “volume” : “25” }, “uris” : “http://www.mendeley.com/documents/?uuid=1c6e46ae-d8d1-4cc0-af02-e995027a42ca” } , “mendeley” : { “formattedCitation” : “(Ye et al., 2013)”, “plainTextFormattedCitation” : “(Ye et al., 2013)”, “previouslyFormattedCitation” : “(Ye et al., 2013)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ye et al., 2013).

n = 99.73; so 100 workers were studied in each group.

Sampling Technique
A complete list of all workers who fulfilled the inclusion criteria constituted our sampling frame in each group. Sampling frame of shift workers (326 worker) was stratified according to occupational groups blue collars and white collars (199 blue collars and 127 white collars) then proportionate sample was taken from each stratum by systematic random method (61 blue collars and 39 white collars). Matched numbers were selected from day workers.

Study methods
To achieve study objectives all participants were subjected to
Structured Interview Questionnaire inquired about (appendix I):
Personal history (e.g. age, gender, residency, marital status);
Occupational history (e.g. current occupation, duration of employment in current occupation, duration of work shift, pattern of shift work, rest days);
Medical history (history of diabetes, hypertension, dyslipidemia, chronic illness);
Other risk factors (confounders) for metabolic syndrome (based on cardiovascular risk assessment questionnaire) ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “author” : { “dropping-particle” : “”, “family” : “Clinic”, “given” : “Sydney Natural Health and Life Style”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “id” : “ITEM-1”, “issue” : “page 11”, “issued” : { “date-parts” : “2015” }, “page” : “1-12”, “title” : “Cardiovascular Risk”, “type” : “article-journal” }, “uris” : “http://www.mendeley.com/documents/?uuid=76bc3752-93f3-4b85-8860-4da0c538a582” } , “mendeley” : { “formattedCitation” : “(Clinic, 2015)”, “manualFormatting” : “(Sydney Natural Health and Life Style Clinic, 2015)”, “plainTextFormattedCitation” : “(Clinic, 2015)”, “previouslyFormattedCitation” : “(Clinic, 2015)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Sydney Natural Health and Life Style Clinic, 2015) including:
Special habits (e.g. smoking habits, alcohol consumption, physical activity and environment);
Dietary assessment
Family history of cardiovascular diseases or type 2 diabetes.

Stress history
Sleep history
Clinical Measurements
Measurement of body weight and height to calculate body mass index (BMI):
BMI is a person’s weight in kilograms divided by the square of height in meters. Its formula is weight (kg) / height (m)2.
For adults 20 years old and older, BMI is interpreted using standard weight status categories. These categories are the same for men and women of all body types and ages. Below 18.5 is considered underweight. Between 18.5– 24.9 is considered normal or healthy weight. Between 25.0– 29.9 is considered overweight. 30.0 or above is considered obese (CDC, 2015).

Waist circumference measurement.

Waist circumference is actually a perimeter, which provides an estimate of body girth at the level of the abdomen.
Measurements should be made around a patient’s bare midriff, after the patient exhales while standing without shoes, both feet touching, and arms hanging freely. The tape should be placed perpendicular to the long axis of the body, and applied with sufficient tension to conform to the measurement surface. The anatomical landmark that will be used is the umbilicus ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.2337/dc07-9921”, “ISBN” : “1935-5548 (Electronic)\r0149-5992 (Linking)”, “ISSN” : “01495992”, “PMID” : “17495180”, “author” : { “dropping-particle” : “”, “family” : “Klein”, “given” : “S”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Allison”, “given” : “Db”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Heymsfield”, “given” : “Sb”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kelley”, “given” : “De”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Leibel”, “given” : “Rl”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nonas”, “given” : “C”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kahn”, “given” : “R”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Obesity”, “id” : “ITEM-1”, “issue” : “5”, “issued” : { “date-parts” : “2007” }, “page” : “1061-1067”, “title” : “Waist circumference and cardiometabolic risk: a consensus statement from Shaping Americau2019s Health: Association for Weight Management and Obesity Prevention”, “type” : “article-journal”, “volume” : “15” }, “uris” : “http://www.mendeley.com/documents/?uuid=4ea56c35-58b3-4124-9258-9ffe569ec921” } , “mendeley” : { “formattedCitation” : “(Klein et al., 2007)”, “plainTextFormattedCitation” : “(Klein et al., 2007)”, “previouslyFormattedCitation” : “(Klein et al., 2007)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Klein et al., 2007).

Blood pressure measurement by auscultation method as follows:
The subject was asked to relax for 10–15 min (in order to minimize anxiety and any white-coat effect)
Blood pressure was measured in the left upper arm by a standard mercury sphygmomanometer and a quality stethoscope, the components of which have been carefully checked before testing. Measurement was performed with the arm supported at heart level; the level of the manometer does not affect the accuracy of measurement, but it should be at eye level and within 1 m of the observer ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1097/01.hjh.0000059016.82022.ca”, “ISBN” : “0263-6352 (Print)\n0263-6352 (Linking)”, “ISSN” : “0263-6352”, “PMID” : “12714851”, “abstract” : “BACKGROUND: Long-term weight control after conventional diet is disappointing but may be improved when diet is assisted by gastric restrictive surgery (GRS). OBJECTIVE: To determine the effects of GRS on ambulatory blood pressure (ABP) and neuroendocrine BP control in 28 morbidly obese subjects. METHODS: A BP and heart rate were recorded every 10 min for 25 h before and 4 months after GRS. Effects of marked reductions in body weight on the renin-angiotensinaldosterone system, on plasma insulin and on sympathetic activity were also determined. RESULTS: Body mass index decreased from 43 1 to 34 1 kg/m2 and systolic (S) BP decreased by 7 2 mmHg during daytime (P=0.01) and by 8 3 mmHg during the night (P=0.02). Pulse pressure, a marker of reduced arterial compliance, decreased by 5 1 mmHg throughout the 24 h period (P ; 0.001). Diastolic BP remained unchanged. Heart rate decreased more during the night (-13 2 bpm, P;0.0001) than during daytime (-5 2 bpm, P=0.03). Reductions in SBP were largest in subjects with highest initial BP values (r = -0.63, P;0.001) but were unrelated to weight loss. GRS decreased fasting glycaemia, plasma insulin, plasma C peptide and 24 h urine sodium (n=20) and noradrenaline (n=19) excretion (P;0.01). CONCLUSIONS: Diet-assisted GRS favourably affects neuroendocrine BP control in obese patients. Reductions in sodium intake, insulin levels and sympathetic tone combined with possible improvements in arterial compliance induce persistent 24 h reductions in SBP and pulse BP. Reductions in BP are largest in subjects with highest initial BP values and are unrelated to the amount of weight loss, thereby emphasizing the importance of even moderate reductions in weight on BP control.”, “author” : { “dropping-particle” : “”, “family” : “O’Brien”, “given” : “Eoin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Asmar”, “given” : “Roland”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Beilin”, “given” : “Lawrie”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Imai”, “given” : “Yutaka”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mallion”, “given” : “Jean-Michel”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mancia”, “given” : “Giuseppe”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Mengden”, “given” : “Thomas”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Myers”, “given” : “Martin”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Padfield”, “given” : “Paul”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Palatini”, “given” : “Paolo”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Parati”, “given” : “Gianfranco”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Pickering”, “given” : “Thomas”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Redon”, “given” : “Josep”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Staessen”, “given” : “Jan”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Stergiou”, “given” : “George”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Verdecchia”, “given” : “Paolo”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Hypertension”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2003” }, “page” : “301-306”, “title” : “European Society of Hypertension recommendations for conventional, ambulatory and home blood pressure measurement.”, “type” : “article-journal”, “volume” : “21” }, “uris” : “http://www.mendeley.com/documents/?uuid=3939d7b1-4ee1-4e77-8451-bbaf5d792245” } , “mendeley” : { “formattedCitation” : “(Ou2019Brien et al., 2003)”, “plainTextFormattedCitation” : “(Ou2019Brien et al., 2003)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(O’Brien et al., 2003).

Laboratory Investigations
Fasting blood sugar
Serum triglycerides
Serum high density lipoproteins (HDL).

Laboratory tests were performed in the clinical pathology laboratory for Suez Canal University hospital by fully automated auto analyzer Cobus C501 (Roche diagnostics, Germany).

Applying updated IDF criteria for diagnosis of metabolic syndrome among study participants which states that:
Central obesity: defined as waist circumference ? 94 cm. If BMI is ; 30kg/m², central obesity can be assumed and waist circumference does not need to be measured.

plus any two of the following four factors:
Raised triglycerides: ? 150 mg/dl, or specific treatment for this lipid abnormality.

Reduced HDL: ; 40 mg/dl, or specific treatment for this lipid abnormality.

Raised blood pressure: systolic BP ? 130 mmHg or diastolic BP ? 85 mmHg, or treatment of previously diagnosed hypertension.

Raised fasting plasma glucose: ? 100 mg/dl, or previously diagnosed with type 2 diabetes ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1159/000282084”, “ISBN” : “0003-9926 (Print) 0003-9926 (Linking)”, “ISSN” : “14219875”, “PMID” : “20460909”, “abstract” : “Over the last few years, the paradigm in hepatology has changed from focusing on a single liver disease to considering concurrent diseases, in particular obesity and related metabolic factors. Obesity has reached epidemic proportions globally and is associated with insulin resistance, steatosis and a low-grade systemic inflammatory state. These metabolic factors have a synergistic role in the natural history and treatment outcomes related to chronic liver disease. This is characterized best in chronic hepatitis C where steatosis and insulin resistance are caused by viral and metabolic effects. Non-alcoholic fatty liver disease and related metabolic abnormalities also exacerbate other diseases, such as alcoholic liver disease and haemochromatosis. In addition, there is growing evidence linking obesity and type 2 diabetes with hepatocellular carcinoma in subjects with chronic viral hepatitis. The pathogenesis of co-morbid disease may be related to increased oxidative stress, inflammatory injury and cell death, along with altered hepatocyte regeneration and repair. Hyperinsulinaemia and other metabolic factors may also have a direct role in the progression of liver injury. Data indicate that weight reduction improves steatosis and inflammation in patients with chronic hepatitis C. This has important clinical and therapeutic implications and suggests that obesity should be actively addressed in the management of patients with other chronic liver diseases.”, “author” : { “dropping-particle” : “”, “family” : “International Diabetes Federation”, “given” : “”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “The IDF consensus worldwide definition of the metabolic syndrome”, “id” : “ITEM-1”, “issued” : { “date-parts” : “2006” }, “page” : “1-7”, “title” : “The IDF consensus worldwide definition of the metabolic syndrome”, “type” : “article-journal”, “volume” : “28” }, “uris” : “http://www.mendeley.com/documents/?uuid=967b5632-9ea7-41c5-8a79-5b435c026da5” } , “mendeley” : { “formattedCitation” : “(International Diabetes Federation, 2006)”, “manualFormatting” : “(IDF, 2006)”, “plainTextFormattedCitation” : “(International Diabetes Federation, 2006)”, “previouslyFormattedCitation” : “(International Diabetes Federation, 2006)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(IDF, 2006).

Data management
Data were coded and entered into the computer statistical program. All statistical analyses were performed using the Statistical Package for Social Science (SPSS) version 20.

Qualitative data as gender and prevalence of metabolic syndrome were presented as number and percentage while quantitative data as laboratory investigation results (s. fasting blood sugar and s. triglycerides) were presented as mean ± Standard deviation.

Student’s t test and Mann Whitney U test were used for quantitative variables while chi square and Fisher’s exact tests were used for qualitative variables. Spearman’s correlation coefficient was used to assess the strength of association between number of metabolic syndrome components and its different risk factors. Logistic regression analysis was used to find out the best predictor of metabolic syndrome.

P value of <0.05 was considered as statistically significant.

ETHICAL CONSIDERATIONS
All ethical considerations were considered.

The study were approved by community medicine department and administration of Faculty of Medicine, Suez Canal University.

The study was approved by ethical committee of Faculty of Medicine, Suez Canal University number (2772) on 11th of April 2016.

The study procedures were in accordance with the guidelines of Helsiniki declarations on human experimentation (World Medical association, 2004).

Permission of the work place was taken.

An informed consent was obtained from all participants before getting them involved in the study (appendix II).

The participants were informed that responding is voluntary and that they can refuse responding without stating any reason.

Procedures performed in the present study had no harmful effects or threatening to patients’ lives.

Blood samples were collected in coded tubes and were discarded after finishing the test. Precautions were taken during samples collections and infection control measures were applied.

Participants were informed about all results of procedures and tests performed normal and abnormal.

Information confidentiality was kept.

Samples were not used for other purposes.

After finishing the study, a feedback on the study results was given to the workplace administration.

RESULTS
DESCRIPTION OF STUDY PARTICIPANTS
Two hundred workers were enrolled in the study, 100 shift workers and 100 day workers to study the relation between rotating shift work and metabolic syndrome components.
The shift work group included a proportionate sample of 61 blue collars (technicians and craftsmen) and 39 white collars (engineers and office workers); day work group included matched sample of the same work categories.
As shown in table 1 the age distribution of workers in the 2 groups (either aging ? 45 years or ; 45 years) didn’t differ significantly with mean age of shift worker 43.9±10 and mean age of day workers 44.3±10.5. Most of study participants were married (97% among shift workers and 91% among day workers); the remaining workers were either single or divorced.
All included participants had at least 2 years of experience in the current work schedule and with at least 6 successive uninterrupted months in the same work schedule. Distribution of work duration among the 2 groups is shown in table 2. The mean duration of shift workers 17.6 ± 9.6 years and among day worker 19.8 ± 9.3
Eight three participating shift workers were enrolled from the 3 engineering sectors and were working on the 12 hour shift system while the remaining 17% were enrolled from the general bureau who worked on the 8 hour shift system.

Table 1. Distribution of age and marital status of shift workers and day workers.

Characteristic Shift workers
No. (%) Day workers
No. (%) p-value
Age < 45 51 (5 %) 46 (46 %) 0.4791
? 45 49 (49 %) 54 (54 %) Marital status Married 97 (97 %) 91 (91 %) 0.0741
Single/Divorced 3 (3 %) 9 (9 %) Residence Urban 57 (57 %) 69 (69 %) 0.0791
Rural 43 (43 %) 31 (31 %) 1. Chi square test.

36563305397544.3 ± 10.5
0044.3 ± 10.5
11220455397543.9 ± 10
0043.9 ± 10
4609465479425P = 0.649
00P = 0.649

Figure 1. Age of shift workers and day workers (mean ± SD).

Table 2: Work duration among shift workers and day workers
Work duration Shift workers
No. (%) Day workers
No. (%) p-value
? 15 45 (45%) 34 (34 %) 0.1121
> 15 55 (55%) 66 (66 %) 1. Chi square test.
366839530797519.8 ± 9.3
0019.8 ± 9.3

Figure 2. Mean work duration among shift workers and day workers (mean ± SD).

History of non-communicable diseases (NCDs) or other medical problems among studied workers are shown in figure 3. The difference in NCDs and other medical problem between the 2 groups wasn’t statistically significant. Eleven percent in each group had cardiovascular diseases other than hypertension and dyslipidemia (e.g. ischemic heart diseases or dysrhythmias). Twenty four percent in each group had other medical problems as chronic liver disease, chronic kidney disease, GIT troubles or cancers
4637405148590P = 1
00P = 1
35960051085215P = 1
00P = 1
2439670148590P = 0.298
00P = 0.298
1465580840105P = 0.535
00P = 0.535
529590300990P = 0.599
00P = 0.599

Figure 3. Distribution of NCDs and other medical problems among shift workers and day workers
ASSESSMENT OF RISK FACTORS FOR METABOLIC SYNDROME
Certain risk factors for metabolic syndrome were assessed by questions adopted from cardiovascular risk assessment questionnaire and results were compared between the 2 groups.
Non-Modifiable Risk Factors
Family history
Family history of any of hypertension, diabetes or ischemic heart diseases was assessed as a non-modifiable risk factor and results are shown in table 3. Almost two thirds of each group (70% of shift workers and 65% of day workers) had positive family history for hypertension, diabetes or ischemic heart diseases among one or both parents.

Table 3. Frequency of family history among shift workers and day workers.

Family history Shift workers
No. (%) Day workers
No. (%) p-value
No family history 30 (30 %) 35 (35 %) 0.7741
1. Mother with hypertension, ischemic heart or stroke ; 65 years 14 (14 %) 15 (15 %) 2. Father with hypertension, ischemic heart or stroke ; 55 years 10 (10 %) 7 (7 %) 3. One or both parents with type 2 diabetes mellitus 14 (14 %) 12 (12 %) 1 and 2 4 (4 %) 2 (2 %) 1 and 3 9 (9 %) 11 (1 %) 2 and 3 12 (12 %) 7 (7 %) 1, 2 and 3 7 (7 %) 11 (11 %) 1. Fisher’s exact test.

4598670765810P = 0.724
00P = 0.724
10687055651516.4 ± 13.7
0016.4 ± 13.7
36449005651516.1 ± 14.9
0016.1 ± 14.9

Figure 4. Family history score among shift workers and day workers (mean ± SD).

Background stress
Exposure to any background stressful situation in the last 6 month was considered a risk factor. Stress scores of shift workers and day workers are shown in figure 5.

3549650425454.6 ± 7.7
004.6 ± 7.7
994410425457.3 ± 9.9
007.3 ± 9.9
4577080723265P = 0.115
00P = 0.115

Figure 5. Background stress score among shift workers and day workers (mean ± SD).

Modifiable Risk Factors
Lifestyle, sleep and dietary habits were assessed among all participants and a score was calculated for each category.
Lifestyle assessment
As shown in table 4; lifestyle assessment includes practicing exercise, smoking status, exposure to passive smoking and surrounding residential environment. No one of the participant in our study reported alcohol use.

Forty seven percent of shift workers were smokers compared to 38% of day workers. Most of participants in the 2 groups reported exposure to passive smoking (86% of shift workers and 74% of day worker) and the difference was statistically significant. Among non-smoker shift workers; 39 (73.6 %) reported exposure to passive smoking at work and among non-smoker day workers 36 (58.1 %) reported exposure to passive smoking at work (figure 6).

Most workers among both shift work and day work groups reported not practicing exercises at all (94% versus 88% respectively). More than half of workers in each group were urban residents (57% of shift work group compared to 69% of day work group).

Table 4. Life style assessment among shift workers and day workers.

Life style assessment parameters Shift workers
No. (%) Day workers
No. (%) OR (95% CI) p-value
Practicing exercise Never 94 (94%) 88 (88%) 2.14 (0.77 –
5.94) 0.1381
At least once/week 6 (6%) 12 (12%) Smoking Current smoker 47 (47%) 38 (38%) 1.45 (0.82 – 2.54) 0.1981
Non smoker 53 (53%) 62 (62%) Passive smoking among non-smokers Exposed 39 (73.6%) 36 (58.1%) 2.01 (0.91 – 4.44) 0.0821
Not exposed 14 (26.4%) 26 (41.9%) Residential environment Urban or industrial area 57 (57%) 69 (69%) 0.6 (0.33 – 1.06) 0.0791
Rural area 43 (43%) 31 (31%) Total score High risk (? 22) 93 (93%) 94 (94%) 0.85 (0.27 – 2.62) 0.7741
Low risk (< 22) 7 (7%) 6 (6%) Chi square test; *Statistically significant at p < 0.05.

4481830653415P = 0.134
00P = 0.134
35814007874055.7 ± 29.6
0055.7 ± 29.6
11855457874061.8 ± 30.2
0061.8 ± 30.2

Figure 6. Lifestyle score among shift workers and day workers (mean ± SD).
Sleep assessment
Sleep was assessed both quantitatively and qualitatively though asking about average hours slept at night and presence of sleep problems as insomnia, snoring or obstructive sleep apnea (table 5). No one of study participants reported sleep apnea.
Average hours slept at night didn’t differ significantly between shift workers and day workers. Regarding sleep problems as snoring, insomnia or both; prevalence is higher among shift workers compared to day workers (table 5). Insomnia specifically affected 35 % of shift workers compared to 22 % of day workers and this was statistically significant (figure 7).

Table 5. Sleep assessment among shift workers and day workers.

Sleep assessment parameters Shift workers
No. (%) Day workers
No. (%) OR (95% CI) p-value
average hours slept at night ? 6 hours 65 (65 %) 52 (52 %) 1.71 (0.97 – 30.3) 0.062
; 6 hours 35 (35 %) 48 (48 %) Sleep problems Present 55 (55%) 39 (39%) 1.9 (1.09 – 3.36) 0.0232*
Absent 45 (45 %) 61 (61 %) Total score High risk (? 6) 47 (47%) 19 (19%) 3.78 (2 – 7.14) ;0.0011*
Low risk (; 6) 53 (53%) 81 (81%) 1. Fisher’s exact test. 2. Chi square test;
*Statistically significant at p < 0.05.

Figure 7. Frequency of insomnia among shift workers and day workers.

3604260590553.1 ± 2.6
003.1 ± 2.6
Figure 8. Sleep score among shift workers and day workers (mean ± SD).

Dietary assessment
Dietary assessment asked about consumption of some food staffs on average. As shown in table 6; many participants in both groups had unhealthy dietary habits but some habits were significantly higher among shift workers as consumption of sweet foods and frequency of teaspoons of white sugar.
Regarding the good dietary habits; 90% of participants in each group drink average amount of water (> 1.25 liters / day); 96% in each group drink 2 or less cups of coffee per day and near half of participants in each group consume one or more pieces of fruit per day. More than 80% of participants in each group eat fish once or more per week.
Vegetables consumption was significantly better among shift workers.

Table 6. Dietary assessment among shift workers and day workers.

Frequency of consumption of food staffs Shift workers
No. (%) Day workers
No. (%) OR (95% CI) p-value
Fried foods
3 times or more/week 63 (63%) 51 (51%) 1.64 (0.93 – 2.88) 0.0861
? 1 – 2 times /week 37 (37%) 49 (49%) Starchy foods as (bread, potatoes, rice, pasta, others)
3 or more serves daily 85 (85%) 80 (80%) 1.42 (0.68 – 2.96 0.3521
? 2 serves daily 15 (15%) 20 (20%) Sweet foods as cakes, biscuits, chocolate, others)
1 – 2 serves daily 32 (32%) 15 (15%) 2.67 (1.34 – 5.32) 0.0461*
Usually none 68 (68%) 85 (85%) Number of teaspoons of sugar consumed daily in hot drinks, added to foods, others
4 or more 69 (69%) 54 (54%) 1.9 (1.06 – 3.38) 0.0291*
0 – 3 31 (31%) 46 (46%) Eating fish
Rarely 16 (16%) 17 (17%) 0.93 (0.44 – 1.96) 0.8481
More than once/week 84 (70%) 83 (80%) Number of fruit pieces usually consumed per day
Usually none 51 (51%) 43 (43%) 1.38 (0.79 – 2.41) 0.2571
1 piece or more/day 49 (49%) 57 (57%) Serves of vegetables usually consumed per day
Usually none 38 (38%) 58 (58%) 0.44 (0.25 – 0.78) 0.0041*
1 or more serves/day 62 (62%) 42 (42%) Amount of soft drinks that are drunk on average per week
< 500 ml / week 76 (76%) 84 (84%) 0.6 (0.3 – 1.22) 0.1571
500 ml or more/week 24 (24%) 16 (16%) Total score
High (? 7) 51 (51%) 36 (36%) 1.85 (1.05 – 3.26) 0.0321*
Low (< 7) 49 (49%) 64 (64%) 1.Chi square test; *Statistically significant at p < 005.

36099751098554.4 ± 5.9
004.4 ± 5.9

Figure 9. Dietary assessment score among shift workers and day workers (mean ± SD).

Metabolic Syndrome Components Assessment
Clinical and laboratory measurements were made to assess the five components of metabolic syndrome among shift workers and day workers and results of each measurement are shown in figures (10 – 16).

Mean systolic and diastolic blood pressures were significantly higher among shift workers compared to day workers (systolic: 127 ± 14.2 mmHg versus 125 ± 20.2 mmHg; p = 0.036, respectively), (diastolic: 83.2 ± 9.9 mmHg versus 79.5 ± 10.4 mmHg; p = 0.005, respectively). Other measurements mean values didn’t differ significantly.

4725670191135P = 0.690
00P = 0.690

Figure 10. BMI among shift workers and day workers
4885055181610P = 0.907
00P = 0.907
Figure 11. Waist circumference among shift workers and day workers.

4758055191135P = 0.036
00P = 0.036

Figure 12. Systolic blood pressure among shift workers and day workers.

4821555165735P = 0.005
00P = 0.005

Figure 13. Diastolic blood pressure among shift workers and day workers
4906645180975P = 0.884
00P = 0.884
Figure 14. Fasting blood sugar among shift workers and day workers.

4758055207645P = 0.590
00P = 0.590

Figure 15. Triglycerides level among shift workers and day workers.

4737100191135P = 0.731
00P = 0.731

Figure 16. HDL level among shift workers and day workers.

When applying cutoff values of updated IDF criteria (2006) for diagnosis of metabolic syndrome; shift workers had significantly higher frequency of central obesity (waist circumference ; 94 cm), elevated systolic blood pressure (? 130), elevated diastolic (? 85 mmHg) and elevated fasting blood sugar (; 100 mg/dl) (table 7).

Table 7. Metabolic syndrome components among shift workers and day workers.

Metabolic syndrome components Shift workers
No. (%) Day workers
No. (%) OR (95% CI) p-value
BMI in kg/m2
; 30 28 (28 %) 26 (26 %) 1.11 (0.59 – 12.07) 0.7501
? 30 72(72 %) 74 (74 %) Waist circumference in cm
? 94 82 (82 %) 70 (70 %) 1.95 (1 – 3.8) 0.0471*
; 94 18 (18 %) 30 (30 %) Systolic blood pressure in mmHg
? 130 48 (48 %) 34 (34 %) 2.1 (1.19 – 3.72) 0.0441*
; 130 52 (52%) 66 (66 %) Diastolic blood pressure in mmHg
? 85 46 (46 %) 26 (26 %) 2.33 (1.29 – 4.21) 0.0031*
; 85 54 (54 %) 74 (74 %) Fasting blood sugar in mg/dl
? 100 33 (33 %) 19 (19 %) 2.1 (1.1 – 4.02) 0.0241*
; 100 67 (67 %) 81 (81 %) Triglycerides
? 150 28 (28 %) 24 (24 %) 1.23 (0.65 – 2.32) 0.5191
; 150 72 (72 %) 76 (76 %) HDL
; 40 51 (51 %) 51 (51 %) 1 (0.57 – 1.74) 11
? 40 49 (49 %) 49 (49 %) 1. Chi square test; 2. Mann Whitney U test; *Statistically significant at p ; 0.05
Updated IDF criteria (2006) were applied for diagnosing metabolic syndrome; frequency of metabolic syndrome was significantly higher among shift workers compared to day workers (54 % versus 40 % respectively; p = 0.047) with odds ratio 1.8 (table 8). The highest odds ratio for each component was for raised blood pressure which had 2.4 greater risk among shift workers compared to day workers.

Table 8. Applying updated IDF criteria for diagnosing metabolic syndrome among participants.

Criteria Shift workers
% Day workers
% OR (95% CI) p-value
Central obesity
(waist ? 94 or BMI ; 30) 82 % 70 % 1.9 (1.01 – 3.8) 0.0471*
Raised triglycerides. ? 150 mg/dl, or specific treatment for this lipid abnormality 37 % 38 % 0.9 (0.54 – 1.7) 0.8841
Reduced HDL. ; 40 mg/dl, or specific treatment for this lipid abnormality 51 % 51 % 1 (0.57 – 1.74) 11
Raised blood pressure. Systolic BP ? 130 mmHg or diastolic BP ? 85 mmHg, or treatment of previously diagnosed hypertension. 62 % 41 % 2.4 (1.33 – 4.14) 0.0031*
Raised fasting plasma glucose. ? 100 mg/dl, or previously diagnosed with type 2 diabetes. 35 % 21 % 2 (1.08 – 3.81) 0.0271*
Metabolic syndrome
(central obesity + 2 other criteria) 54 % 40 % 1.8 (1.01 – 3.09) 0.0471*
1. Chi square test; *Statistically significant at p ; 0.05

Figure 17. Frequency of metabolic syndrome among shift workers and day workers

Metabolic syndrome component count density (MSCD) is the arithmetic mean of the summation of the number of metabolic syndrome components in a group of workers. As shown in table 9 MSCD is significantly higher among shift workers compared to day workers.
Table 9. Metabolic syndrome component count density (MSCD) among shift workers and day workers
MSCD Shift workers Day workers p-value
Mean ± SD 2.7 ± 1.3 2.2 ± 1.4 0.0151*
Median 3 2 Mann Whitney U test; *Statistically significant at p ; 0.05.

4811395449580P = 0.009
00P = 0.009

Figure 18. Metabolic syndrome component count among shift workers and day workers
Socio-demographic and occupational risk factors were compared between workers with metabolic syndrome and those without among study participants (table 10).
The probability of working more than 15 years was 2.4 times higher among metabolic syndrome participants compared to those without metabolic syndrome. Probability of urban residence was 1.8 times higher among metabolic syndrome patients compared with workers without. The difference regarding work duration and residence was statistically significant.

Table 10. socio-demographic and occupational risk factors distribution among workers with metabolic syndrome and workers without (n = 200).

Risk factor Metabolic syndrome
(n = 94) No metabolic syndrome
(n =108) OR (95% CI) p-value
Age in years ? 45 45 (47.9%) 58 (54.7%) 0.76 (0.44 – 1.33) 0.3341
; 45 49 (52.1%) 48 (45.3%) Residence Urban 66 (70.2 %) 60 (56.6 %) 1.81 (1.01 – 3.25) 0.0471*
Rural 28 (29.8 %) 46 (43.4 %) Work duration in years ; 15 67 (71.3%) 54 (50.9%) 2.39 (1.33 – 4.3) 0.0031*
? 15 27 (28.7%) 52 (49.1%) Occupation Blue collars 55 (58.5 %) 67 (63.2 %) 0.82 (0.46 – 1.45) 0.4971
White collars 39 (41.5 %) 39 (36.8 %) 1. Chi square test; *Statistically significant at ; 0.05.

The same risk factors were compared among metabolic syndrome patients and those without after stratification according to work schedule (tables 11 and 12).
Among shift workers duration of work was significantly associated with metabolic syndrome where metabolic syndrome patients have 3.4 times increased probability of working ; 15 years compared to workers without metabolic syndrome.

Table 11. socio-demographic and occupational risk factors distribution among shift workers with metabolic syndrome and shift workers without (n = 100).

Risk factor Metabolic syndrome
(n = 54) No metabolic syndrome
(n = 46) OR (95% CI) p-value
Age in years ? 45 25 (46.3%) 24 (52.2%) 0.79 (0.36 – 1.74) 0.5581
; 45 29 (53.7%) 22 (47.8%) Residence Urban 35 (64.8%) 22 (47.8%) 2.01 (0.9 – 4.49) 0.0871
Rural 19 (35.2%) 24 (52.2%) Work duration in years ; 15 37 (68.5%) 18 (39.1%) 3.39 (1.48 – 7.72) 0.0031*
? 15 17 (31.5%) 28 (60.9%) Occupation Blue collars 35 (64.8%) 26 (56.5%) 1.42 (0.63 – 3.18) 0.3971
White collars 19 (35.2%) 20 (43.5%) 1. Chi square test; *Statistically significant at ; 0.05.

Among day workers none of the studied factors showed significant difference between those with metabolic syndrome and those without.
Table 12. Socio-demographic and occupational risk factors distribution among day workers with metabolic syndrome and day workers without (n = 100).

Risk factor Metabolic syndrome
(n = 40) No metabolic syndrome
(n =60) OR (95% CI) p-value
Age in years ? 45 20 (50%) 34 (56.7%) 0.76 (0.34 – 1.71) 0.5121
; 45 20 (50%) 26 (43.3%) Residence Urban 31 (77.5%) 38 (63.3%) 1.99 (0.8 – 4.95) 0.1331
Rural 9 (22.5%) 22 (36.7%) Work duration in years ; 15 30 (75%) 36 (60%) 2 (0.83 – 4.83) 0.1211
? 15 10 (25%) 24 (40%) Occupation Blue collars 20 (50%) 41 (68.3%) 0.46 (0.2 – 1.06) 0.0661
White collars 20 (50%) 19 (31.7%) 1. Chi square test; *Statistically significant at ; 0.05.

The relation between sleep score and different components of metabolic syndrome and metabolic syndrome component count (MSCC) was assessed and results are shown in table 13.
Sleep score had weak positive correlation with blood pressure (both systolic and diastolic), serum triglycerides and MSCC; and it was negatively correlated with HDL and all were statistically significant.
Table 13. Spearman’s correlation coefficient (r) of the relation between sleep score and each component of metabolic syndrome and with metabolic syndrome component count (MSCC)
Metabolic syndrome components Sleep score
r p-value
BMI 0.067 0.344
Waist circumference 0.045 0.527
Systolic blood pressure 0.179 0.011*
Diastolic blood pressure 0.181 0.010*
Fasting blood sugar -0.014 0.849
s. triglycerides 0.194 0.006*
s. HDL -0.188 0.008*
MSCC 0.198 0.048*
MSCC: metabolic syndrome component count *Statistically significant at p < 0.05.

Figure 19. The relation between sleep score and systolic blood pressure.

4457700197485r = 0.181
p = 0.010
r = 0.181
p = 0.010

Figure 20. The relation between sleep score and diastolic blood pressure

Figure 21. The relation between sleep score and serum triglycerides level

Figure 22. The relation between sleep score and serum HDL level.

Figure 23. The relation between sleep score and serum MSCC.

To control the effect of work schedule (either shift or day) on the relation between sleep and metabolic syndrome components; partial correlation was then used to assess the relation between sleep score and metabolic syndrome components and MSCC (table 14). Body mass index, waist circumference, HDL and MSCC were significantly correlated with sleep score.

Table 14. Partial correlation coefficient (r) of the relation between sleep score and each component of metabolic syndrome and with metabolic syndrome component count (MSCC) after controlling for work schedule.

Metabolic syndrome components Sleep score
r p-value
BMI 0.205 0.004*
Waist circumference 0.158 0.026*
Systolic blood pressure 0.112 0.115
Diastolic blood pressure 0.096 0.175
Fasting blood sugar 0.027 0.702
s. triglycerides 0.127 0.074
s. HDL -0.251 <0.001*
MSCC 0.229 0.001*
MSCC: metabolic syndrome component count *Statistically significant at p < 0.05.

Figure 24. The partial relation between sleep score and BMI

Figure 25. The partial relation between sleep score and waist circumference.

Figure 26. The partial relation between sleep score and HDL.

Figure 27. The partial relation between sleep score and MSCC.

The relation between metabolic syndrome components and each other was assessed and a correlation matrix was performed (table 15).
All components were significantly correlated with each other except HDL which was not correlated with blood pressure parameters or fasting blood sugar level.

Table 15 Spearman’s correlation coefficient (r) between metabolic syndrome components and each other.

Waist circumference Systolic blood pressure Diastolic blood pressure Fasting blood sugar s. triglycerides s. HDL
BMI 0.840* 0.210* 0.255* 0.221* 0.335* -0.151*
Waist circumference 0.316* 0.336* 0.360* 0.421* -0.218*
Systolic blood pressure 0.871* 0.309* 0.185* -0.005
Diastolic blood pressure 0.295* 0.177* -0.042
Fasting blood sugar 0.260* -0.096
s. triglycerides -0.434*
*Statistically significant at p ; 0.05.

Binary logistic regression analysis was performed to find the best predictor of metabolic syndrome. Independent covariates entered in the model are shift work, residence, and work duration (table 16).
Shift work, urban residency and increased work duration were significant predictors of metabolic syndrome. Both shift work and urban residency had risk of metabolic syndrome more than 2 times compared to day workers and rural residents respectively.

Table 16. Logistic regression analysis of best predictor of metabolic syndrome.

Covariates ? p- value OR (95 % CI)
Shift or day work# 0.824 0.008* 2.280 (1.243 – 4.182)
Residency (urban or rural)@ 0.715 0.024* 2.044 (1.100 – 3.797)
Work duration 0.053 0.001* 1.054 (1.021 -1.089)
Constant -1.984 ; 0.001* 0.137
Model ?2 = 20.292 ; 0.001* # Shift work is the indicator with code 1; @urban residence is the indicator with code 1;
*Statistically significant at p ; 0.05
Discussion
Shift work disrupt the natural sleep-wakefulness cycle, expose the workers to light at atypical biologic hours, lead to irregular eating patterns and alter the normal family and social life routine. These disturbances lead to the recognition of many potential health effects that are related to shift work. These health effects include mainly nutritional and metabolic disorders as obesity, altered metabolism, insulin resistance, diabetes, dyslipidemias, gastrointestinal disorders and metabolic syndrome. The metabolic syndrome (MS) is a syndrome that is accompanied by abdominal obesity, lipoidosis, impaired glucose tolerance, and high blood pressure. Many studies demonstrated an association between shift work and metabolic syndrome but evidence needs to be confirmed.

This study was conducted to clarify the relation between rotating shift work and metabolic syndrome components through assessment of clinical and laboratory components of metabolic syndrome which are (waist circumference, dyslipedimia, elevated fasting blood sugar and elevated blood pressure) among rotating shift workers and day workers, and comparing the frequency and risk of metabolic syndrome and its components among rotating shift workers and day workers.

The study was conducted in the canal company for electricity distribution in Ismailia governorate. One hundred male shift workers and one hundred male day workers were enrolled in the study. Study sample was somewhat representative to the Egyptian males; this was confirmed by the frequency of some variables in the study that was consistent with their prevalence demonstrated in the latest Egyptian DHS (2015). These variables include smoking whose frequency among study participants was 42.6 % and in the DHS its prevalence among Egyptian males was 46.4%. Another variable is BMI; mean BMI among study participants was 27.8 kg/m2 with prevalence of obesity of 27% this was also consistent with the DHS findings (mean BMI among Egyptian men was 27 kg/m2 and the prevalence of obesity among them was 26.4 %).
Regarding socio-demographic data; mean age of participants in shift work group was 43.9 ± 10 years and the mean age of day workers was 48.3 ± 10.1 years and the difference was not statistically significant. Sixty one percent in each group were blue collars and 39% were white collars. Ninety seven percent of shift workers and ninety one percent of day workers were married. More than half of participants in each group (57% of shift workers and 69% of day workers) were urban residents. Duration of work and history of non-communicable diseases didn’t differ significantly between the two groups.

The study groups were compared regarding some cardiovascular risk factors adopted from cardiovascular risk assessment questionnaire including non-modifiable risk factors (as family history assessment and background stress assessment) and modifiable risk factors (as lifestyle assessment, sleep assessment and dietary assessment). Each participant is given a score for each assessment; this score indicates the degree of cardiovascular risk for this participant. Sleep assessment and dietary assessment mean scores were significantly higher among shift workers compared to day workers; which indicate that sleep problems and unhealthy dietary habits were more common among shift workers compared to day workers that increase their risk. Other assessed risk factors didn’t differ significantly between the two groups.

Regarding sleep assessment; the average hours slept at night didn’t differ significantly between the two groups but the presence of problems as insomnia, snoring or both were significantly higher among shift workers (55% versus 39% respectively) specially insomnia which affected 35% of shift workers versus 22 % of day workers (OR 1.9, p = 0042). Also the OR for having “high risk” sleep score among shift workers was 3.8 compared to day workers. These findings confirm what Boivin and Boudreau stated in their review in (2014); shift workers often complain of decreased sleep quality and symptoms of insomnia. The prevalence of insomnia in our study also corroborates the prevalence found by Eldevik and his working group in (2013) where they found 45 % of their participating shift workers suffer from insomnia.

The difference between the two groups regarding BMI and prevalence of obesity (BMI ? 30) didn’t differ significantly (mean BMI 27.8 ± 5.3 among shift workers and 27.8 ± 4 among day workers; p = 0.690) and the prevalence was (28% among shift workers and 26 % among day workers; p = 0.750).
The present finding contradicts the findings of a Brazilian study by Macagnan et al in (2012) and a Korean study by Kim et al in (2013) who found a statistically significant higher prevalence of overweight and obesity among shift workers compared to day workers.
Updated IDF criteria (2006) were used to define metabolic syndrome and its components among study participants. The 1st criterion; abdominal or central obesity was defined as having waist circumference ? 94 cm. In the present study 82 % of shift workers had abdominal obesity with a mean circumference (104.1 ± 12.3) and 70% of day workers had abdominal obesity with a mean circumference (103.5 ± 11.2) and the difference between the two groups was statistically significant (OR = 1.95; p = 0.04). This finding supports the finding of a Chinese study by Chen et al and a Brazilian study by Antunes et al, both were conducted in (2010) and they found higher mean of waist circumference and higher prevalence of abdominal obesity among shift workers compared to day workers.
On the contrary, the results of both Guo and his group in (2013) and Peplonska et al (2015) didn’t show significant difference in abdominal obesity between shift and day workers; but in Peplonska study they found a significant positive association between cumulative night shift work and waist circumference.
The 2nd and 3rd criteria represent dyslipidemia in the form of elevated triglycerides level (? 150 mg/dl) and decreased HDL level (< 40 mg/dl) and both didn’t differ significantly between the shift workers and day workers in this study. This confirms the findings of Ye and his coworkers in (2013) who found insignificant difference between shift and day workers regarding these dyslipidemia parameters.

In contrast to the present findings Kawada et al (2010) and Mohebbi et al (2012) found significant difference between shift and day workers regarding triglycerides and HDL levels with significantly higher frequency of dyslipidemia among shift workers.
The 4th criterion encompassed systolic and diastolic blood pressures where elevated blood pressure was considered (? 130/85 mmHg). Mean systolic and diastolic blood pressures and frequency of having elevated blood pressure were higher among shift workers compared to day workers and this was statistically significant (OR= 2.4; p = 0.003). These results were consistent with two studies conducted by Guo and his group; the 1st in (2013) and the 2nd in (2015) and in both studies they also found significantly higher mean systolic and diastolic blood pressure among shift workers compared to day workers. Kawabe et al in (2014) also found significantly higher frequency of elevated BP (? 130/85) among shift workers compared to day workers. The Japanese study of Ye et al in (2014) showed OR for elevated blood pressure among shift workers (2.6) when compared to day workers which is close to OR demonstrated in this study.

But these findings contradict what was found by the Indonesian Merijanti et al in (2008) and the Brazilian Sfreddo et al in (2010). Both didn’t find significant difference between shift workers and day workers regarding mean systolic and diastolic blood pressures or prevalence of hypertension and prehypertension. This may be explained by not matching of shift and day workers regarding age and work duration in Merijanti study and both are confounders for blood pressure. In addition both studies were conducted among nursing personnel and nursing is considered stressful occupation per se and stress is an independent risk factor for blood pressure disturbances and this may have elevated mean level and frequency of hypertension among day work group in their studies ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1016/j.jash.2011.09.002”, “ISSN” : “1933-1711”, “author” : { “dropping-particle” : “”, “family” : “Rosenthal”, “given” : “Talma”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Alter”, “given” : “Ariela”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of the American Society of Hypertension”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2012” }, “page” : “2-22”, “publisher” : “Elsevier Ltd”, “title” : “Occupational stress and hypertension”, “type” : “article-journal”, “volume” : “6” }, “uris” : “http://www.mendeley.com/documents/?uuid=d513feae-5a94-40b7-8513-0dc46ffd999d” } , “mendeley” : { “formattedCitation” : “(<b><b>Rosenthal</b> and <b>Alter</b></b>, <b>2012</b>)”, “manualFormatting” : “(Rosenthal and Alter, 2012”, “plainTextFormattedCitation” : “(Rosenthal and Alter, 2012)”, “previouslyFormattedCitation” : “(<b><b>Rosenthal</b> and <b>Alter</b></b>, <b>2012</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Rosenthal and Alter, 2012; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5430/cns.v3n2p46”, “author” : { “dropping-particle” : “”, “family” : “Portela”, “given” : “Luciana Fernandes”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Griep”, “given” : “Rosane Harter”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Landsbergis”, “given” : “Paul”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Roenberg”, “given” : “Lucia”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “clinical nursing studies”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2015” }, “page” : “46-52”, “title” : “Self-reported hypertension and job strain in nursing personnel : Assessing two different formulations of the demand-control model”, “type” : “article-journal”, “volume” : “3” }, “uris” : “http://www.mendeley.com/documents/?uuid=d7a9e60f-2ae8-4f8e-9e70-1104a40eb5c4” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Portela</b> et al.</b></b>, <b>2015</b>)”, “manualFormatting” : “Portela et al., 2015)”, “plainTextFormattedCitation” : “(Portela et al., 2015)”, “previouslyFormattedCitation” : “(<b><b><b>Portela</b> et al.</b></b>, <b>2015</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Portela et al., 2015).

Regarding fasting blood sugar (FBS) (the 5th criterion) having level ? 100 mg/dl was considered elevated. The percent of workers having FBS level ? 100 mg/dl was significantly higher among shift workers (OR = 2; p = 0.027). This finding is consistent with Mohebbi et al in (2012) and Ye et al in (2013) as they found significantly higher percentage of shift workers having FBS ? 100 mg/dl compared to day workers with OR (1.9) in Mohebbi study .
On the contrary, in an Egyptian study conducted by Ghazawy et al in El Minia in (2014), they didn’t find significant difference between shift workers and day workers regarding fasting blood sugar level but in the same study they found significantly higher prevalence of diabetes and higher levels of postprandial blood sugar and hemoglobin A1c among shift workers ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “abstract” : “Introduction: Rotating night shift work disrupts circadian rhythms and it has been associated with chronic conditions including cancers, cardiovascular diseases, obesity, metabolic syndrome and glucose dysregulation. Aim of work: the study aimed at determining the prevalence of glucose abnormalities among Abo-Korkas sugar factory workers and exploring the impact of rotating night shifts on glycemic state and control of diabetes. Materials and Methods: In a cross-sectional study a total of 330 male workers at Abo-Korkas sugar factory were randomly selected to fill out an interview questionnaire, have medical examination and be tested for fasting and post-prandial blood glucose level; with assessment of HbA1c (Hemoglobin A1c test) for those who were diagnosed as diabetics. Results: Our findings showed that 61 (18.4%) workers were diabetics, 7 of them were newly diagnosed diabetics. The prevalence of diabetes was significantly higher (p= 0.01) among former (33.3%) and current (15.7%) night shift than day-time workers (14.4%). The crude Odds Ratio (OR) for developing diabetes mellitus among the current and former shift workers were 1.1 (0.56-2.18) and 2.9 (1.39-6.31), respectively. Moreover, shift working significantly affected diabetes control (p= 0.04) with an OR= 3.83 (1.02-14.34). Conclusion: Rotating shift work especially night shifts have negative effects on health. It was found to be associated with developing type 2 diabetes mellitus and it hindered diabetes control among night shift diabetic workers. Preventive programs should be implemented for high risk Night shift working and its impact on development and control of diabetes mellitus in workers of Abo Korkas sugar factory, El Minia, Egypt (PDF Download Available). Available from: http://www.researchgate.net/publication/273441333_Night_shift_working_and_its_impact_on_development_and_control_of_diabetes_mellitus_in_workers_of_Abo_Korkas_sugar_factory_El_Minia_Egypt accessed Oct 10, 2015.”, “author” : { “dropping-particle” : “”, “family” : “Ghazawy”, “given” : “ER”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kamel”, “given” : “SM”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Gamal”, “given” : “HM”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Ewis”, “given” : “AA”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Egyptian journal of Occupational Medicine”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2014” }, “page” : “197”, “title” : “Night shift working and its impact on development and control of diabetes mellitus in workers of Abo Korkas sugar factory , El Minia ,”, “type” : “article-journal”, “volume” : “38” }, “uris” : “http://www.mendeley.com/documents/?uuid=7ad3ec26-3795-43e4-9633-314289200405” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Ghazawy</b> et al.</b></b>, <b>2014</b>)”, “plainTextFormattedCitation” : “(Ghazawy et al., 2014)”, “previouslyFormattedCitation” : “(<b><b><b>Ghazawy</b> et al.</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(Ghazawy et al., 2014).

The criteria where then applied to diagnose metabolic syndrome among participants (abdominal obesity with two other components is considered metabolic syndrome positive). The current study showed that the frequency of metabolic syndrome was significantly higher among shift workers compared to day workers (54% versus 40% respectively (OR = 1.8; p = 0.04). This was consistent with each of De Bacquer et al. (2009) (OR = 1.65); Li et al. (2011) (OR = 1.87); Mohebbi et al. (2012) (OR= 1.49); Puttonen et al (2012) (OR = 1.64) and Guo et al (2015) (OR = 1.17). Pietroiusti and his coworkers performed a 4 year follow up study among nurses and found relative risk (RR) of MS among night shift workers compared to day workers (5). In the same year a meta-analysis carried out by Wang and his group in (2014) to assess the relation between night shift work and metabolic syndrome also confirmed our finding where they concluded that the pooled RR for the association between ‘ever exposed to night shift work’ and MS risk was 1.57.

On the contrary Lajoie and his colleagues in (2015) didn’t find significant risk of metabolic syndrome among shift workers although in their study metabolic syndrome affected as twice shift workers than day workers but p = 0.05. This may be related to the significantly older age of day workers compared to shift workers in Lajoie study; another important issue is that 74.6 % of day workers participated in their study were former shift workers; of which 46% worked for more than 7 years in shift and this point out to the postulated cumulative irreversible effect of shift work on metabolic parameters. Another systematic review performed by Canuto et al in (2013) concluded that there was insufficient evidence regarding the association between shift work and prevalent MS when the confounders are taken into account.

Some socio-demographic and occupational risk factors were compared between workers with MS and those without among each group and among all participants. Among shift workers duration of work was significantly associated with probability of metabolic syndrome among those working > 15 years 2 times higher compared to those working ? 15 years. This was consistent with Guo et al. in (2015) who concluded also that duration of shift affect the risk of MS. A meta-analysis in (2014) by Wang et al concluded that presence of a dose response relation between duration of night shifts and MS.

Binary logistic regression analysis was performed in the present study to find out the best predictor of metabolic syndrome. Independent covariates in the model were (work schedule, residency and work duration). All entered variables were found to be significant predictors of metabolic syndrome with OR (2.28, 2.04 and 1.05 respectively). This confirms what was found in different regression models using different covariates in different studies but all of them reported that shift work was a significant predictor of metabolic syndrome ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1093/ije/dyn360”, “ISBN” : “1464-3685 (Electronic)”, “ISSN” : “1464-3685”, “PMID” : “19129266”, “abstract” : “BACKGROUND: Several studies have documented on the elevated cardiovascular risk among shift workers. In order to further explore this relation, we aimed at assessing the association between rotating shift work and the incidence of the metabolic syndrome (MetS). METHODS: In this population-based prospective study, 1529 employees from several large Belgian companies were followed for a median observation period of 6.6 years with respect to the onset of the MetS and its separate components. RESULTS: At baseline, 309 men (20.2%) were rotating shift workers. The MetS incidence rate in these shift workers (60.6 per 1000 person-years) was increased in comparison with day workers (37.2 per 1000 person-years) with an odds ratio (95% CI) of 1.77 (1.34-2.32). Multivariate adjustment for potential lifestyle and work-related confounders did only marginally affect the strength of the association. The risk for the development of MetS gradually increased independently with accumulated years of shift work. Rotating shift work not only had an impact on MetS as a cluster of conditions but on each of its individual components as well. CONCLUSIONS: Hence, prospective evidence was found that rotating shift work increases the risk for developing the MetS over a period of 6 years.”, “author” : { “dropping-particle” : “”, “family” : “Bacquer”, “given” : “D”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Risseghem”, “given” : “M”, “non-dropping-particle” : “Van”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Clays”, “given” : “E”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Kittel”, “given” : “F”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Backer”, “given” : “G”, “non-dropping-particle” : “De”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Braeckman”, “given” : “L”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International journal of epidemiology”, “id” : “ITEM-1”, “issue” : “3”, “issued” : { “date-parts” : “2009” }, “page” : “848-854”, “title” : “Rotating shift work and the metabolic syndrome: a prospective study.”, “type” : “article-journal”, “volume” : “38” }, “uris” : “http://www.mendeley.com/documents/?uuid=0174b47f-e4a6-47d0-b7b8-2df6a00a4cb0” } , “mendeley” : { “formattedCitation” : “(<b><b><b>De Bacquer</b> et al.</b></b>, <b>2009</b>)”, “manualFormatting” : “(De Bacquer et al., 2009”, “plainTextFormattedCitation” : “(De Bacquer et al., 2009)”, “previouslyFormattedCitation” : “(<b><b><b>De Bacquer</b> et al.</b></b>, <b>2009</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }(De Bacquer et al., 2009; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1179/107735211799030960”, “ISBN” : “1077-3525 (Print)\r1077-3525 (Linking)”, “ISSN” : “1077-3525”, “PMID” : “21618947”, “abstract” : “The aim of the present study was to examine the association between shift work and the metabolic syndrome (MetS) using a large-scale longitudinal study design. Data were collected from a historical cohort of health checkups in the Japanese population. The baseline survey, which involved 16,952 inhabitants of the Minami Saku area of the Nagano Prefecture, was started in 1978. A nested case-control study was conducted between 1987 and 1990. This analysis was restricted to 6,712 men and women (age range 25-59 years). A conditional logistic regression model was used to estimate the risk of MetS associated with shift work. Compared with the day workers, shift workers had a significantly higher risk of MetS (odds ratio 1.87; 95% CI, 1.13-3.08). Our results demonstrate that shift work was strongly associated with MetS. The study suggests appropriate dietary habits as a basis for managing the MetS risk of shift workers.”, “author” : { “dropping-particle” : “”, “family” : “Li”, “given” : “Y”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sato”, “given” : “Y”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Yamaguchi”, “given” : “N”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “International journal of occupational and environmental health”, “id” : “ITEM-1”, “issue” : “2”, “issued” : { “date-parts” : “2011” }, “page” : “154-160”, “title” : “Shift work and the risk of metabolic syndrome: a nested case-control study”, “type” : “article-journal”, “volume” : “17” }, “uris” : “http://www.mendeley.com/documents/?uuid=081a1d31-4a6c-4309-8878-df520d397531” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Li</b> et al.</b></b>, <b>2011</b>)”, “manualFormatting” : “Li et al., 2011”, “plainTextFormattedCitation” : “(Li et al., 2011)”, “previouslyFormattedCitation” : “(<b><b><b>Li</b> et al.</b></b>, <b>2011</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Li et al., 2011; ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1186/2052-4374-25-33”, “ISBN” : “10.1186/2052-4374-25-33”, “ISSN” : “2052-4374”, “PMID” : “24472469”, “abstract” : “OBJECTIVE: This study aimed to determine identify any association between shift work and the metabolic syndrome by comparing the prevalence rates of the metabolic syndrome in shift work groups and daytime work groups for female workers.\n\nMETHODS: Based on data from health examinations carried out from April to December of 2012, we selected as our subjects 254 female workers from the Daegu area Dyeing Industrial Complex. We diagnosed the metabolic syndrome using the examination results, and information about age, whether or not they did shift work, job type, smoking habits, drinking habits, exercise habits, and past medical history was collected through self-administered questionnaire surveys and face-to-face interviews. The variables found in a univariate analysis to be significant in the occurrence of the metabolic syndrome – age, drinking habits, exercise habits, and shift work – were included in a logistic regression analysis of the risk of the metabolic syndrome for female workers.\n\nRESULTS: The prevalence rates of the metabolic syndrome for the total group of study subjects was 11.8%, for daytime workers was 2.8%, and for shift workers was 15.3%. A logistic regression analysis of the odds of the metabolic syndrome for female workers was conducted that included factors associated with the occurrence of the metabolic syndrome: age, drinking habits, exercise habits, and shift work. The results revealed that the odds ratio of the metabolic syndrome in the shift work group, 6.30 (95% CI 1.24-32.15), was significantly higher when compared with the daytime work group.\n\nCONCLUSION: Shift work appears to have an association with the metabolic syndrome in female workers. Accordingly, we believe that the attention of government agencies and business owners is needed together with the individual practice of health behaviors to manage the metabolic syndrome for the prevention of cardiovascular disease in female shift workers.”, “author” : { “dropping-particle” : “”, “family” : “Ye”, “given” : “Han Hui”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeong”, “given” : “Jae Uk”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Jeon”, “given” : “Man Joong”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Sakong”, “given” : “Joon”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Annals of occupational and environmental medicine”, “id” : “ITEM-1”, “issue” : “1”, “issued” : { “date-parts” : “2013” }, “page” : “33”, “title” : “The Association between Shift Work and the Metabolic Syndrome in Female Workers.”, “type” : “article-journal”, “volume” : “25” }, “uris” : “http://www.mendeley.com/documents/?uuid=1c6e46ae-d8d1-4cc0-af02-e995027a42ca” } , “mendeley” : { “formattedCitation” : “(<b><b><b>Ye</b> et al.</b></b>, <b>2013</b>)”, “manualFormatting” : “Ye et al., 2013 and Kawabe and Nakamura, 2014)”, “plainTextFormattedCitation” : “(Ye et al., 2013)”, “previouslyFormattedCitation” : “(<b><b><b>Ye</b> et al.</b></b>, <b>2013</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Ye et al., 2013 and ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.5551/jat.19380”, “ISBN” : “1880-3873”, “ISSN” : “1880-3873”, “PMID” : “24599169”, “abstract” : “AIM: To examine the relationship between the type of work and the number of metabolic syndrome diagnostic components(MetS-DC), as well as the risk of MetS, with adjustment for lifestyle habits in Japanese workers.\n\nMETHODS: We examined the baseline data from 4,427 participants(81.4% male) aged 19 to 69 years old. The physical activity of each participant was classified according to the International Physical Activity Questionnaire(IPAQ). We defined the four MetS-DC in this study as follows: 1) high blood pressure(BP): systolic BP u2265130 mmHg, or diastolic BP u226585 mmHg, or the use of antihypertensive drugs; 2) dyslipidemia: high-density lipoprotein-cholesterol concentration uff1c40 mg/dl or triglyceride concentration u2265150 mg/dl, or on medication for dyslipidemia; 3) dysglycemia: fasting blood sugar level u2265110 mg/dl, or if less than eight hours after meals u2265140mg/dl, or on medication for diabetes mellitus; 4) overweight: a body mass index u226525kg/m(2). We defined MetS as overweight plus two or more of the MetS-DC.\n\nRESULTS: There were 3,094 subjects in the daytime work group, 73 in the fixed nighttime work group, 1,017 in the shift work group and 243 in the day-to-night work group. The Poisson regression analysis revealed that fixed nighttime (regression coefficient b=-0.233, P=0.028) and shift work (b=0.098, P=0.034) independently contributed to the number of MetS-DC, compared to daytime work. The multivariate logistic analysis not including sleep hours in the model showed that shift work was positively related to MetS (odd ratio=1.47, Puff1c0.01).\n\nCONCLUSION: Shift work were significantly associated with the number of MetS-DC, and was related to risk of MetS compared to daytime work.”, “author” : { “dropping-particle” : “”, “family” : “Kawabe”, “given” : “Yuri”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” }, { “dropping-particle” : “”, “family” : “Nakamura”, “given” : “Yasuyuki”, “non-dropping-particle” : “”, “parse-names” : false, “suffix” : “” } , “container-title” : “Journal of Atherosclerosis and Thrombosis”, “id” : “ITEM-1”, “issue” : “7”, “issued” : { “date-parts” : “2014” }, “page” : “703-711”, “title” : “Relationship between shift work and clustering of the metabolic syndrome diagnostic components.”, “type” : “article-journal”, “volume” : “21” }, “uris” : “http://www.mendeley.com/documents/?uuid=3652879e-3763-42a3-bd99-8982c66f60ff” } , “mendeley” : { “formattedCitation” : “(<b><b>Kawabe</b> and <b>Nakamura</b></b>, <b>2014</b>)”, “manualFormatting” : “Kawabe and Nakamura, 2014”, “plainTextFormattedCitation” : “(Kawabe and Nakamura, 2014)”, “previouslyFormattedCitation” : “(<b><b>Kawabe</b> and <b>Nakamura</b></b>, <b>2014</b>)” }, “properties” : { “noteIndex” : 0 }, “schema” : “https://github.com/citation-style-language/schema/raw/master/csl-citation.json” }Kawabe and Nakamura, 2014). Also work duration was a significant predictor of metabolic syndrome in some studies ADDIN CSL_CITATION { “citationItems” : { “id” : “ITEM-1”, “itemData” : { “DOI” : “10.1371/journal.pone.0133761”, “ISBN” : “1932-6203”, “ISSN” : “19326203”, “PMID” : “26196859”, “abstract” : “BACKGROUND: Mounting epidemiological evidence suggests that night shift work may contribute to the etiology of increased body weight. The present study aimed to examine association between rotating night shift work and body mass index (BMI), and abdominal adiposity respectively among nurses and midwives.\n\nMETHODS: A cross-sectional study was conducted among 724 female nurses and midwives, aged 40-60 years (354 rotating night shift and 370 daytime workers) in u0141u00f3du017a, Poland, between 2008 and 2011. Information about occupational history and potential confounders was collected during personal interviews. Anthropometric measurements of body weight, height, waist (WC) and hip (HC) circumference were made, and body mass index (BMI), waist to hip ratio (WHR) and waist to height ratio (WHtR) were calculated. GLM regression models and multinomial logit regression models were fitted to explore the association between night shift work and anthropometric parameters, with adjustment for age, body silhouette at age 20, current smoking status, packyears, marital status, and menopausal hormone therapy use.\n\nRESULTS: Cumulative night shift work showed significant associations with BMI, WC, HC and WHtR, with BMI increasing by 0.477 kg/m2 per 1000 night duties and by 0.432 kg/m2 per 10000 night shift hours, WC increasing respectively by 1.089 cm and 0.99 cm, and HC by 0.72 cm and WHtR by 0.007 cm for both metrics. 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CONCLUSION AND RECOMMENDATIONS
The current study concluded that; shift workers have higher frequency of metabolic syndrome compared to day workers. Also some components of metabolic syndrome as central obesity, elevated blood pressure and elevated blood sugar affect shift workers more than day workers. This finding may be related to physiological disturbances associated with shift work as sleep problems which were also higher among shift workers compared to day workers.

The study concluded also that unhealthy lifestyle and unhealthy dietary habits affected both shift workers and day workers. In addition, the study found that the most frequent component of metabolic syndrome was central obesity affecting 76 % of participants.

Based on the study findings the following points are recommended
Recommendations for all companies or corporations that encompass abnormal work schedule
Adopting guidelines for organizing shift schedules that prevent or reduce ill effects of shift work.

Performing pre-employment examination to assess workers tolerance to shift work and their preferences should be considered.

Educating and training workers about coping with shift schedules and how to adapt to sleep disturbances.

Providing shift workers with a balanced healthy meal or snack during shift and making workplace a nonsmoking area to decrease exposure to other risk factors.

Regular monitoring of components of metabolic syndrome by clinical and laboratory examinations to early detect them and to intervene if they appeared.

Use of metabolic syndrome component count (MSCC) as a rapid tool to monitor workers for metabolic disturbances and their progress.

Recommendations to be directed to all workers or population as a whole
Increasing knowledge about concepts, components and importance of healthy diet through mass media or other wide scale education sources
Application of robust smoking cessation program for the population in general and for workers in different occupations.

Encouraging and facilitating regular practice of exercises either at workplace or in specialized areas in leisure time.

Educating the public about the hazards of obesity and the concept of ideal body weight.

Recommendations for researchers
Performing longitudinal studies to confirm the relation between shift work and components of metabolic syndrome.

Performing more studies to better understand the pathophysiological disturbances that affect shift workers to find early predictors that can be used for prevention of metabolic syndrome
SUMMARY
Modern world is moving toward a pattern of working 24 hours a day. To meet the demands of this working pattern; the use of shift schedules have increased dramatically. Shift work is a work schedule involving irregular working hours, compared to those of a normal daytime work schedule. Generally shift work is classified into two main categories, rotating shift work where the employee’s hours of work change; and permanent shift work where the work schedule may be constant but occupy unusual hours of the day. Shift work disrupt the natural sleep-wakefulness cycle, expose the workers to light at atypical biologic hours, lead to irregular eating patterns and alter the normal family and social life routine.

Potential health effects were recognized in relation to shift work. These health effects include obesity, insulin resistance, diabetes, dyslipidemias, gastrointestinal disorders, reproductive disorders, metabolic syndrome and some cancers. The metabolic syndrome (MS) is a syndrome encountering a cluster of cardiovascular disease risk factors. Metabolic syndrome was defined by many parties but all encompass abdominal obesity, lipid disturbances, impaired glucose tolerance, and high blood pressure. Many studies demonstrated an association between shift work and metabolic syndrome but evidence needs to be confirmed.
The current study was carried out to assess the relation between rotating shift work and metabolic syndrome components among workers in an electricity distribution company in Ismailia. Two groups were enrolled in the study; shift work group including 100 shift workers, 61 of them were blue collars and 39 were white collars; and day work group including 100 day workers from the same occupational categories distribution (i.e. 61 blue collars and 39 white collars). Updated IDF criteria was used for diagnosis of metabolic syndrome so to fulfill these criteria all participants were subjected to structure interview questionnaire, clinical measurements of (weight, height, waist circumference, blood pressure) and laboratory investigations (fasting blood sugar, serum triglycerides level and serum HDL level). The results of clinical and laboratory data were compared between the 2 groups.

The study showed that the mean age of shift worker was 43.9±10 and mean age of day workers was 44.3±10.5. Most of study participants were married (97% among shift workers and 91% among day workers). More than half of participants in each group were urban residents (57% of shift workers compared to 69% of day workers). The mean duration of work of shift workers and day workers were (17.6± 9.6 versus 19.8 ± 9.3 respectively). The socio-demographic characteristics and occupational history didn’t differ significantly between the 2 groups.

Some risk factors for metabolic syndrome other than shift work were assessed using some items adopted from the cardiovascular risk assessment questionnaire. Results of risk factors assessment showed that sleep assessment score and dietary assessment score were significantly higher among shift workers compared to day workers. Non modifiable risk factors as family history and background stress scores didn’t differ significantly between the 2 groups. Lifestyle risk factors were high among the 2 groups were (93% of shift workers and 94% of day workers) were among the high risk score category.

Clinical and laboratory measurements were performed then cutoff values of updated IDF criteria (2006) were used. It was found that central obesity (waist circumference ? 94 cm), elevated blood pressure (? 130/85) and elevated fasting blood sugar (? 100 mg/dl) were significantly higher among shift workers compared to day workers. When applying IDF diagnostic criteria for diagnosis of metabolic syndrome; the frequency of metabolic syndrome was significantly higher among shift workers compared to da workers (54 % versus 40 % respectively). Working in shift ; 15 years was a significant risk factor for MS with OR 3.4. The relation between sleep score and metabolic syndrome components was assessed and there was weak positive correlation with blood pressure parameters, s. triglycerides and MSCC and there was a weak negative correlation with s. HDL. When we used partial correlation coefficient to control the effect of shift work sleep score showed weak correlation with BMI and waist circumference. Binary logistic regression analysis for predictors of metabolic syndrome showed that shift work, urban residence and work duration were significant predictors of metabolic syndrome.

The study concluded that shift workers have higher frequency of metabolic syndrome compared to day workers. Also some components of metabolic syndrome as central obesity, elevated blood pressure and elevated blood sugar affect shift workers more than day workers. The study concluded also that unhealthy lifestyle and unhealthy dietary habits affected both shift workers and day workers. In addition, the study found that the most frequent component of metabolic syndrome was central obesity affecting 76 % of participants.