Marital status, household size, and lifestyle changes during the first COVID-19 pandemic: NIPPON DATA2010.

Stay-at-home strategies taken during the COVID-19 pandemic changed our lifestyle drastically. Although marital status and household size are important social determinants of health that affect lifestyle, their impacts on lifestyle during the pandemic are still unclear. We aimed to evaluate the association between marital status, household size, and lifestyle changes during the first pandemic in Japan. Questionnaire surveys on lifestyle changes from before to during the first COVID-19 pandemic were conducted on October 2020 in Japan. Classified into age groups, multivariable logistic regression analysis was performed to examine the combined association of marital status and household size on lifestyle, adjusted for potential confounders including socioeconomic factors. In our prospective cohort study, 1928 participants were included. Among older participants, the singles living alone were likely to perceive more unhealthy lifestyle changes (45.8%), compared with the married (33.2%), and significantly associated with at least one unhealthy change [adjusted odds ratio (OR): 1.81, 95% confidence interval (CI): 1,18-2.78], mainly due to decreased physical activity and increased alcohol consumption. Meanwhile, the younger participants showed no significant association between marital status, household size, and unhealthy changes, while those living alone had 2.87 times higher odds of weight gain (≥ 3 kg) than the married (adjusted OR: 2.87, 95% CI: 0.96-8.54) during the pandemic. Our findings suggest that older singles living alone are potentially vulnerable subgroups to drastic social changes which warrant special attention to prevent adverse health outcomes and additional burden on health systems in the following future.