Associations of total daily working hours encompassing unpaid care and domestic work with nonrestorative sleep and mental health in middle-aged Japanese men and women: A cross-sectional study.

Women reported significantly longer total daily working hours than men despite spending less time on paid employment.

• Cross-sectional study of 3959 healthy middle-aged Japanese adults engaged in paid employment, using a postal survey.
• Women's greater total working hours were primarily attributable to their greater involvement in unpaid housework.
• Participants self-reported average daily hours spent on income-generating work, housework, childcare, and caregiving.

Total daily working hours had higher predictive value for nonrestorative sleep than income-generating work hours alone, particularly in women.

• ROC curve analysis was used to compare the predictive value of total daily working hours versus income-generating work hours alone.
• The higher predictive value of total working hours was especially notable in women.
• Nonrestorative sleep was assessed using a widely used single-item measure.

Total daily working hours had higher predictive value for poor mental health than income-generating work hours alone, particularly in women.

• Mental health was evaluated using a five-point Likert scale, dichotomized into 'very good/good/average' and 'poor/very poor.'
• ROC curve analysis revealed this higher predictive value especially in women.
• The association was more notable in women than in men.

Longer total working hours were significantly associated with higher adjusted odds ratios for nonrestorative sleep in both men and women.

• Analyses were adjusted for confounders.
• The association with nonrestorative sleep was observed in both genders.
• Total working hours included income-generating work, housework, childcare, and caregiving hours combined.

Longer total working hours were significantly associated with higher adjusted odds ratios for poor mental health in women.

• The association with poor mental health after adjusting for confounders was statistically significant for women.
• This association was not reported as significant for men, representing a gender difference in the mental health outcome.
• Mental health was dichotomized into 'very good/good/average' versus 'poor/very poor' for analysis.

The study concludes that unpaid care and domestic work should be incorporated into time burden assessments for health and social policies.

• Total daily working hours encompassing unpaid care and domestic work represent an important factor influencing sleep and mental health outcomes.
• The authors underscore the importance of gender-equitable strategies that account for total working hours.
• Notable associations were observed particularly in women, highlighting gendered disparities in unpaid work burden.