Overtime work and stress response in a group of Japanese workers.
BACKGROUND
Working long overtime hours is considered a cause of mental health problems among workers but such a relationship has yet to be empirically confirmed.


OBJECTIVE
To clarify the influence of overtime work on response to stress and to assess the role of other stress-related factors on this relationship.


METHODS
The study was conducted among 24 685 employees of a company in Japan. Stress response, job stressors and social supports were assessed by the Brief Job Stress Questionnaire. Participants were divided into five categories of overtime (0-19, 20-39, 40-59, >or=60 h of overtime per month and exempted employees).


RESULTS
The nonadjusted odds ratios for stress response for 40-59 and >or=60 overtime hours per month in reference to 0-19 overtime hours were 1.11 [95% confidence interval (CI) 1.03-1.19] and 1.62 (95% CI 1.50-1.76), respectively. After adjustment for self-assessed amount of work, mental workload and sleeping time, the association between overtime work and stress response disappeared.


CONCLUSIONS
This large cross-sectional study shows that overtime work appears to influence stress response indirectly through other stress factors such as self-assessed amount of work, mental workload and sleeping time.
Sato
Yuji
Y
Department of Occupational Health, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
Miyake
Hitoshi
H
Thériault
Gilles
G
D000328:Adult; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology / Q000209:etiology*; D010561:Personnel Staffing and Scheduling; D013315:Stress, Psychological / Q000453:epidemiology / Q000209:etiology*; D014940:Work Schedule Tolerance / Q000502:physiology*; D016526:Workload / Q000706:statistics & numerical data*