Shift work and mental health sickness absence: A 10-year observational cohort study among male production workers

Objectives
Epidemiological studies investigating mental-health-related sickness absence (SA) among shift workers are lacking. This 10-year observational study investigated the risk of mental health SA among shift compared with day workers.
Methods
The data of 5826 male production workers were used for analyses: 4288 (74%) shift and 1538 (26%) day workers. The risk of mental health SA was analyzed with Cox regression analysis. Hazard ratios (HR) and 95% confidence intervals (95% CI) were adjusted for age and occupational grade.
Results
During a 10-year follow-up, 351 shift workers and 126 day workers had incident mental health SA. The risk of mental health SA did not differ (HR 1.03, 95% CI 0.84–1.26) between shift and day workers. Among shift workers, the risk of SA due to mood disorders (HR 1.87, 95% CI 0.73–4.76) was non-significantly higher than among day workers. A total of 96 shift workers and 21 day workers had recurrent mental health SA. The risk of recurrent mental health SA did not differ (HR 1.04, 95% CI 0.62–1.74) between shift and day workers.
Conclusion
The risk of incident and recurrent mental health SA did not differ between shift and day workers.
Key terms: absenteeism; cohort study; ICD-10; incidence; irregular work hour; men; mental disorder; mental health; production worker; psychiatric disorder; shift work; sick leave; sickness absence; worker