Impact of overtime working and social interaction on the deterioration of mental well-being among full-time workers during the COVID-19 pandemic in Japan: Focusing on social isolation by household composition

Objectives The coronavirus disease (COVID-19) pandemic has forced many employees to alter both their work style and lifestyle. This study aimed to examine how the combination of changes in overtime working hours and social interaction affects the full-time employees' mental well-being, focusing on the difference in household composition.Methods In November 2020, we conducted a cross-sectional Internet survey that included 4388 Japanese men and women aged 25-64 years, who continued the same full-time job during the pandemic. We performed a logistic regression analysis using a combination of the changes in overtime working hours and social interaction as an independent variable, and the presence/absence of deterioration of mental well-being as the dependent variable.Results Overall, 44% of participants reported the deterioration of mental well-being compared to before the outbreak. The multivariate analysis revealed that the participants coded as "increased overtime/decreased interaction" were significantly associated with the deterioration of mental well-being compared to those with "unchanged overtime/unchanged interaction" (odds ratio [OR] 2.14, 95% confidence interval [CI] 1.59-2.89). Moreover, this association was relatively stronger among single-person households (OR 2.66, 95% CI 1.50-4.69).Conclusions The negative combination of increasing overtime working hours and decreasing social interaction may have an impact on the deterioration of mental well-being during the COVID-19 pandemic, and this association was comparably strong among single-person households. In the pandemic, it is necessary to pay close attention to both overtime working hours and the presence of social interaction to address the mental well-being among employees.