OBJECTIVES: Physical inactivity and social isolation are key obstacles to achieving healthy and active aging. This study evaluated the association between participation in a citywide economic incentive Yokohama Walking Point (YWP) program with walking time, the risk of being homebound, and social isolation. We also explored the heterogeneities in the association across gender, socioeconomic status (SES), and built environment (BE). METHODS: A prospective cohort study was conducted on 3,171 residents aged ≥65 years from the Japan Gerontological Evaluation Study. YWP participation status was confirmed in 2016, outcomes were measured in 2020, and covariates were obtained in 2013. Built environment variables were measured based on geographic information system. General linear regression and modified Poisson regression models were performed using doubly robust estimation with inverse probability of treatment weighting. RESULTS: Participation in YWP was associated with an increase of 6.83 min per day of walking time, and a 21 % decreased risk of social isolation. The associations showed heterogeneity
participants with low income and those living near parks had lower risks of being homebound. Men, participants with low education levels, and those living in high population density areas exhibited lower risks of social isolation compared with their counterparts. CONCLUSIONS: Participation in YWP was associated with improved physical and social activity. Gender, SES, and BE moderated these associations, highlighting their potential role in reducing social health disparity. These findings emphasized the need for integrated policy interventions incorporating program design and urban planning to create an age-friendly community fostering healthy and inclusive aging.