The association between living alone and depressive symptoms and the role of pet ownership among Japanese workers

Background Living alone has been positively associated with the prevalence of depressive symptoms. We examined how a combination of living alone and pet ownership relates to depressive symptoms. Methods As part of the Japan Epidemiology Collaboration on Occupational Health Study, we conducted a survey on health-related lifestyles, including living arrangements and pet ownership, among 12,763 employees of five companies in 2018-2021. Depressive symptoms were assessed using the 11-item Center for Epidemiological Studies-Depression Scale (cutoff score [greater than or equal to] 9). A Poisson regression model with a robust variance estimator was used to calculate prevalence ratio and 95% confidence interval (CI) while adjusting for covariates. Results Among the participants, 30.9% were depressed, 17.7% had pets, and 29.1% lived alone. Compared to individuals living with others but not with a pet, those living alone and not with a pet had a 1.17 times higher prevalence ratio of depressive symptoms (95% CI: 1.08-1.26). The corresponding figures were 1.03 (95% CI: 0.95-1.11) for those living with others and pet(s) and 1.42 (95% CI: 1.18-1.69) for those living alone but with pet(s). Conclusion Living alone was significantly associated with a higher prevalence of depressive symptoms. The association was rather stronger among individuals with vs. without pets. Pet ownership may not be associated with decreased depressive symptoms. Keywords: Pet ownership, Living alone, Depression, Depressive symptoms, CES-D, Japan