title: Non-occupational physical activity levels of shift workers compared with non-shift workers.
abstract: Lack of physical activity (PA) has been hypothesised as an underlying mechanism in the adverse health effects of shift work. Therefore, our aim was to compare non-occupational PA levels between shift workers and non-shift workers. Furthermore, exposure-response relationships for frequency of night shifts and years of shift work regarding non-occupational PA levels were studied.
  
  
  
  Data of 5980 non-shift workers and 532 shift workers from the European Prospective Investigation into Cancer and Nutrition-Netherlands (EPIC-NL) were used in these cross-sectional analyses. Time spent (hours/week) in different PA types (walking/cycling/exercise/chores) and intensities (moderate/vigorous) were calculated based on self-reported PA. Furthermore, sports were operationalised as: playing sports (no/yes), individual versus non-individual sports, and non-vigorous-intensity versus vigorous-intensity sports. PA levels were compared between shift workers and non-shift workers using Generalized Estimating Equations and logistic regression.
  
  
  
  Shift workers reported spending more time walking than non-shift workers (B=2.3 (95% CI 1.2 to 3.4)), but shift work was not associated with other PA types and any of the sports activities. Shift workers who worked 1-4 night shifts/month (B=2.4 (95% CI 0.6 to 4.3)) and ≥5 night shifts/month (B=3.7 (95% CI 1.8 to 5.6)) spent more time walking than non-shift workers. No exposure-response relationships were found between years of shift work and PA levels.
  
  
  
  Shift workers spent more time walking than non-shift workers, but we observed no differences in other non-occupational PA levels. To better understand if and how PA plays a role in the negative health consequences of shift work, our findings need to be confirmed in future studies.
authors.affiliation: Center for Nutrition, Prevention and Health Services, 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, Amsterdam, The Netherlands.
authors.forename: Bette
authors.initials: B
authors.lastname: Loef
authors.affiliation: Center for Nutrition, Prevention and Health Services, 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, Amsterdam, The Netherlands.
authors.forename: Gerben
authors.initials: G
authors.lastname: Hulsegge
authors.affiliation: Center for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
authors.forename: G C Wanda
authors.initials: GC
authors.lastname: Wendel-Vos
authors.affiliation: Center for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.|Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: W M Monique
authors.initials: WM
authors.lastname: Verschuren
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.|Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Roel C H
authors.identifier: 0000-0003-4082-8163
authors.initials: RC
authors.lastname: Vermeulen
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Marije F
authors.initials: MF
authors.lastname: Bakker
authors.affiliation: Department of Public and Occupational Health, EMGO Institute for Health and Care Research, VU University Medical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: Allard J
authors.initials: AJ
authors.lastname: van der Beek
authors.affiliation: Center for Nutrition, Prevention and Health Services, 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, Amsterdam, The Netherlands.
authors.forename: Karin I
authors.initials: KI
authors.lastname: Proper
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D009790:Occupations / Q000145:classification; D005082:Physical Exertion; D013177:Sports; D011795:Surveys and Questionnaires; D016138:Walking / Q000706:statistics & numerical data; D014940:Work Schedule Tolerance; D055815:Young Adult
keywords: Physical activity