Are chronotype, social jetlag and sleep duration associated with health measured by Work Ability Index?
The present study investigates the impact of chronotype, social jetlag and sleep duration on self-perceived health, measured by Work Ability Index (WAI), within an industrial setting. Between 2011 and 2013, 2474 day and shift workers participated in a health check offered by an occupational health promotion program and filled out the Munich ChronoType Questionnaire (adapted to the rotational 12-h schedule for shift workers) and the WAI. We computed sleep duration on work and free days, chronotype, and social jetlag. We used linear regression models to examine chronotype, sleep duration and social jetlag for association with the WAI sum score, and proportional odds models to estimate the combined effect of social jetlag and sleep duration. Participants reported an average daily sleep duration of 7.35 h (SD: 1.2 h), had an average chronotype of 3:08 a.m. (SD: 1 h), and the average social jetlag corresponded to 1.96 h (SD: 2.05 h). Increasing social jetlag and shorter sleep duration were independently associated with a decreasing WAI, while chronotype per se was not associated with WAI. Short sleep duration combined with high social jetlag significantly increased the risk of poor WAI (OR = 1.36; 95% CI: 1.09-1.72), while long sleep duration and high social jetlag were not associated with poor WAI (OR = 1.09; 95% CI: 0.88-1.35). Our results add to a growing body of literature, suggesting that circadian misalignment, but not chronotype per se, may be critical for health. Our results indicate that longer sleep may override the adverse effects of social jetlag on WAI.
a Occupational Medicine and Health Protection Department , BASF Societas Europaea , Ludwigshafen , Germany.
Mei
M
Yong
b Institute of Medical Psychology , Ludwig-Maximilians-University , Munich , Germany.
Dorothee
D
Fischer
a Occupational Medicine and Health Protection Department , BASF Societas Europaea , Ludwigshafen , Germany.
Christina
C
Germann
a Occupational Medicine and Health Protection Department , BASF Societas Europaea , Ludwigshafen , Germany.
Stefan
S
Lang
c Channing Division of Network Medicine , Brigham and Women's Hospital and Harvard Medical School , Boston , MA , USA.
Céline
C
Vetter
a Occupational Medicine and Health Protection Department , BASF Societas Europaea , Ludwigshafen , Germany.
Christoph
C
Oberlinner
D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D020179:Jet Lag Syndrome / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016272:Occupational Health; D012890:Sleep / Q000502:physiology*; D012919:Social Behavior; D011795:Surveys and Questionnaires; D013997:Time Factors; D014940:Work Schedule Tolerance
Chronotype; Work Ability Index; circadian disruption; occupational epidemiology; sleep; social jetlag