title: Shiftwork Is Not Associated with Increased Risk of NAFLD: Findings from the National Health and Nutrition Examination Survey.
abstract: There is increased focus on the metabolic impact of shiftwork, especially given the significant number of employees who work nighttime or rotating shifts. Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. We conducted a cross-sectional study to examine the association between shiftwork and the risk of NAFLD.
  
  
  
  We used aggregated data from the 2005-2006, 2007-2008, and 2009-2010 cycles of the National Health and Nutrition Examination Survey (NHANES). We defined NAFLD by elevated serum alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels (males: AST > 40 or ALT > 37; females: AST > 31 or ALT > 31) in the absence of excessive alcohol use and viral hepatitis. We defined shiftworkers as participants who self-reported currently working regular night shifts or rotating shifts. We calculated adjusted odds ratios (OR) and 95% confidence intervals (CI) using multivariable logistic regression.
  
  
  
  Overall, 8159 participants aged 20-79 years reported working at a job or business using the NHANES Occupation Questionnaire and were included in the analysis. Of these, 11.1% were classified as shiftworkers. Compared to non-shiftworkers, shiftworkers were younger, were less likely to be non-Hispanic White, and have health insurance or health care. The overall prevalence of NAFLD was 15.7%. NAFLD occurred more frequently in shiftworkers (17.0%) than non-shiftworkers (15.5%). However, in the overall multivariable analysis, shiftwork was not associated with the risk of NAFLD (OR 1.11, 95% CI 0.87-1.43).
  
  
  
  The findings from this NHANES-based cross-sectional study do not support an association between shiftwork and increased risk of NAFLD.
authors.affiliation: Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA. maya.balakrishnan@bcm.edu.
authors.forename: Maya
authors.identifier: 0000-0002-5196-7284
authors.initials: M
authors.lastname: Balakrishnan
authors.affiliation: Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.|Department of Medicine, Houston VA HSR&D Center for Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, USA.
authors.forename: Hashem B
authors.initials: HB
authors.lastname: El-Serag
authors.affiliation: Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.|Department of Medicine, Houston VA HSR&D Center for Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, USA.
authors.forename: Fasiha
authors.initials: F
authors.lastname: Kanwal
authors.affiliation: Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.|Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Aaron P
authors.initials: AP
authors.lastname: Thrift
mesh_terms: D000328:Adult; D000367:Age Factors; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D003430:Cross-Sectional Studies; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D065626:Non-alcoholic Fatty Liver Disease / Q000097:blood / Q000453:epidemiology*; D009749:Nutrition Surveys; D016017:Odds Ratio; D010561:Personnel Staffing and Scheduling / Q000706:statistics & numerical data*; D015995:Prevalence; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology; D014940:Work Schedule Tolerance; D055815:Young Adult
chemical_list: D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase
keywords: Circadian misalignment; Epidemiology; Metabolic disease; Shiftworkers; Sleep disruption