Mediating Role of Leisure-Time Physical Activity on the Association Between Public Open Spaces and Hypertension in...

Access to green and recreational areas has been linked to cardiovascular health, but evidence from low- and middle-income megacities remains limited. This study investigated the prospective association between public open spaces (POSs) and incident hypertension in adults living in São Paulo, Brazil and whether leisure-time physical activity (LTPA) mediates this relationship.

Data from 1056 participants free of hypertension at baseline were analyzed, collected through the "Health Survey of São Paulo: Physical Activity and Environment" cohort (2014-2021). Exposure to POSs, including parks, squares, outdoor gyms, and bike paths, was assessed using geographic information systems within 500-m buffers around participants' residences. The number of types of POSs was categorized as 0, 1 to 2, or 3 to 4. Hypertension was self-reported, and LTPA was measured via the long-form International Physical Activity Questionnaire. Poisson regression models estimated the relative risks of developing hypertension, and mediation was tested using Sobel and bootstrap methods.

Living near 3 or 4 types of POSs was associated with a lower risk of hypertension (relative risk: 0.93; 95% CI, 0.87-0.99). LTPA significantly mediated this association. Among individuals engaging in ≥150 minutes per week of LTPA, proximity to 3 or 4 POSs types was associated with an even lower risk (relative risk: 0.88; 95% CI, 0.79-0.98), while no effect was observed among inactive participants.

A greater variety of POSs near home is associated with a reduced risk of hypertension, partly explained by increased LTPA. These findings support urban planning strategies that enhance diverse recreational environments to promote cardiovascular health in middle-income urban cities.