title: The Relationship Between Shift Work and Metabolic Risk Factors: A Systematic Review of Longitudinal Studies.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
authors.affiliation: National Institute for Public Health and the Environment, Bilthoven, the Netherlands; Department of Public and Occupational Health, EMGO+ Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands;. Electronic address: karin.proper@rivm.nl.
authors.forename: Karin I
authors.initials: KI
authors.lastname: Proper
authors.affiliation: Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands.
authors.forename: Daniëlla
authors.initials: D
authors.lastname: van de Langenberg
authors.affiliation: National Institute for Public Health and the Environment, Bilthoven, the Netherlands.
authors.forename: Wendy
authors.initials: W
authors.lastname: Rodenburg
authors.affiliation: Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands.
authors.forename: Roel C H
authors.initials: RCH
authors.lastname: Vermeulen
authors.affiliation: Department of Public and Occupational Health, EMGO+ Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Allard J
authors.initials: AJ
authors.lastname: van der Beek
authors.affiliation: National Institute for Public Health and the Environment, Bilthoven, the Netherlands.
authors.forename: Harry
authors.initials: H
authors.lastname: van Steeg
authors.affiliation: National Institute for Public Health and the Environment, Bilthoven, the Netherlands.
authors.forename: Linda W M
authors.initials: LWM
authors.lastname: van Kerkhof
mesh_terms: D018149:Glucose Intolerance / Q000453:epidemiology*; D006801:Humans; D008019:Life Style; D008055:Lipids / Q000097:blood; D008137:Longitudinal Studies; D050177:Overweight / Q000453:epidemiology*; D012307:Risk Factors; D015430:Weight Gain / Q000502:physiology; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: D008055:Lipids