Residential accessibility to indoor and outdoor physical activity facilities and overweight/obesity among Chinese preschool children in 551 cities.

Childhood overweight and obesity remain major public health concerns worldwide. Accessibility to neighborhood physical activity (PA) facilities has been proposed as a potentially modifiable environmental factor, but existing evidence remains inconsistent. In this cross-sectional analysis of 164,649 Chinese preschool children, we examined the associations between residential accessibility to indoor and outdoor PA facilities and overweight/obesity. Facility accessibility, measured via point-of-interest (POI) data and weighted by road-network distance (RND) within residential buffers of 500m, 1000m, and 1500m. Multilevel regression models accounting for clustering at the city and kindergarten levels were applied to estimate associations between POI-derived facility accessibility and childhood weight status. Results showed that greater accessibility to indoor PA facilities was consistently associated with lower odds of overweight/obesity (OR = 0.89-0.98) and obesity (OR = 0.84-0.98) across nearly all buffers (each P < 0.05), In contrast, protective associations for outdoor facilities were primarily observed within 1500m buffers after covariates adjustment. Stratified analyses showed that the inverse associations for indoor facilities were more pronounced among children living in areas with higher PM2.5 exposure and among children whose mothers had lower educational attainment. These findings, which were robust in sensitivity analyses, suggest that greater residential accessibility to PA facilities, particularly indoor facilities, was associated with lower odds of overweight/obesity among Chinese preschool children. Public health strategies should prioritize context-specific planning, optimizing the distribution of both indoor and outdoor PA infrastructure across neighborhoods, while addressing social inequalities that may limit the effective use of such resources.