Overtime Work and the Incidence of Long-term Sickness Absence Due to Mental Disorders: A Prospective Cohort Study

• Published in: Journal of Epidemiology Vol. 32; no. 6; pp. 283 - 289
• Main Authors: Inoue, Yosuke, Yamamoto, Shuichiro, Stickley, Andrew, Kuwahara, Keisuke, Miyamoto, Toshiaki, Nakagawa, Tohru, Honda, Toru, Imai, Teppei, Nishihara, Akiko, Kabe, Isamu, Mizoue, Tetsuya, Dohi, Seitaro
• Format: Journal Article
• Language: English
• Published: Japan Japan Epidemiological Association 05-06-2022
• Subjects: Asia; Cohort analysis; Epidemiology; Health problems; healthy workers effect; Humans; Illnesses; Incidence; Mental disorders; Mental Disorders - epidemiology; Mental health; Occupation; Occupational Health; Original; Overtime; Prospective Studies; Risk; Sick Leave; Statistical models; Working hours; workplace; healthy workers effect; Asia; occupational health; workplace; prospective studies
• ISSN: 0917-5040; 1349-9092
• DOI: 10.2188/jea.JE20200382

Background: Although previous research has focused on the association between long working hours and several mental health outcomes, little is known about the association in relation to mental health-related sickness absence, which is a measure of productive loss. We aimed to investigate the association between overtime work and the incidence of long-term sickness absence (LTSA) due to mental disorders.Methods: Data came from the Japan Epidemiology Collaboration on Occupational Health Study (J-ECOH). A total of 47,422 subjects were followed-up in the period between April 2012 and March 2017. Information on LTSA was obtained via a study-specific registry. Baseline information was obtained at an annual health checkup in 2011; overtime working hours were categorized into <45; 45–79; 80–99; and ≥100 hours/month.Results: During a total follow-up period of 211,443 person-years, 536 people took LTSA due to mental disorders. A Cox proportional hazards model showed that compared to those with less than 45 hours/month of overtime work, those with 45–79 hours/month were at a lower risk of LTSA due to mental health problems (hazard ratio [HR] 0.63; 95% confidence interval [CI], 0.56–0.71) while those with overtime work of ≥100 hours/month had a 2.11 (95% CI, 1.12–3.98) times higher risk of LTSA due to mental health problems.Conclusion: Engaging in excessive overtime work was linked with a higher risk of LTSA due to mental health problems while the lower risk observed among individuals working 45–79 hours/month of overtime work might have been due to a healthy worker effect.