Long working hours and depressive symptoms: moderating effects of gender, socioeconomic status, and job resources
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Systematic reviews and meta-analyses have found inconsistent associations between working hours and depressive symptoms. The purpose of this study was to investigate the possible moderators of this association, using data from a large-scale cross-sectional survey.
A total of 16,136 Japanese employees (men 83.5%; women 16.5%) responded to a self-administered questionnaire inquiring about overtime working hours during the previous month and depressive symptoms (Center for Epidemiologic Studies Depression scale), as well as moderating factors including gender, age, marital status, socioeconomic status, commuting time, sleeping hours per day, job control and worksite social support (Job Content Questionnaire), neuroticism (Eysenck’s Personality Questionnaire Revised), and social desirability (Social Desirability Scale) (response rate, 85%). We conducted sequential regression analyses to investigate the main effects and interaction effects of all moderating variables.
The association between overtime working hours and depressive symptoms was significantly moderated by gender (interaction effect: β = 0.03), age (β = − 0.02), manager (β = 0.03), sleeping hours (β = − 0.02), job control (β = − 0.03), and neuroticism (β = 0.02). Among workers engaged in 80 + hours of overtime, higher depressive symptoms were reported by women, younger employees, non-managers, employees with low job control, low worksite social support, and high neuroticism. A significant main effect of long overtime working hours on depressive symptoms was also observed even after controlling for all independent variables (β = 0.02).
Long overtime working hours is associated with depressive symptoms. We also found significant heterogeneity in the association according to employee characteristics, which may explain the inconsistent findings in previous literature.
KeywordsDepression Japan Overwork Mental Health Workplace
The following are members of JSTRESS (the Japan Work Stress and Health Cohort Study) group: Takashi Haratani (National Institute of Occupational Safety and Health, Japan), Fumio Kobayashi (Aichi Medical University, Japan), Masao Ishizaki (Kanazawa Medical University, Japan), Takeshi Hayashi (Hitachi Health Care Center, Japan), Osamu Fujita (Kariya Toyota General Hospital, Japan), Yoshiharu Aizawa (Kitasato University, Japan), Shogo Miyazaki (Kanda Christian Clinic, Japan), Hisanori Hiro (University of Occupational and Environmental Health, Japan),Takeshi Masumoto (Kimitsu Health Service Center, Japan), Shuji Hashimoto (Fujita Health University School of Medicine, Japan), and Shunichi Araki (Saitama Occupational Health Promotion Center, Japan).
This study was supported by a special research grant for the prevention of work-related diseases in 1995–1999 from the Ministry of Health, Labour and Welfare, Japan.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
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