Proximity to public transportation and incidence of depression risk among older adults: A three-year longitudinal analysis from the Japan Gerontological evaluation study

Objective: Depression in older adults has been associated with environmental factors, such as green spaces and walkable neighborhoods; however, evidence on the relationship between proximity to public transportation and mental health is scarce. This multi-municipality longitudinal study examined the association between proximity to public transportation and risk of depression among older adults and considered car usage. Methods: We analyzed data from 4947 functionally independent adults, aged 65 years and older who resided in 25 municipalities across Japan. Data were obtained via the Japan Gerontological Evaluation Study in 2016 and 2019. We assessed depression over three years in older adults without depression at baseline via the Geriatric Depression Scale-15. We subjectively and objectively measured their proximity to public transportation. Logistic regression analyses were performed, adjusted for covariates, with analyses stratified by car usage. Results: Of the participants, 9.76 % developed depression over a three-year period. Those without car usage and with reported lack of proximal public transport exhibited a higher incidence of depression (OR = 1.60, 95 %CI: 1.05-2.42) compared with those who had better access. No significant association was observed in the car user group. Furthermore, no significant association was observed in the analysis that used objective measures with Geographic Information System (GIS) data. Conclusion: Subjective limited access to public transport was significantly associated with the risk of depression among older adults without car usage. Hence, improving and maintaining transportation infrastructure may mitigate the risk of depression.