Association between greenspace morphology and disability prevalence mediated by physical activity and mental health in Los Angeles city

Neighborhood greenspace has been linked to various disability risk factors, including immunoregulation, mental health issues, and neurological and degenerative diseases. However, the precise nature of the relationship between greenspace and disability remains poorly defined, particularly concerning the spatial characteristics of greenspace beyond its mere quantity. This study aims to elucidate the relationship between greenspace quantity, spatial morphology, and disability prevalence in urban neighborhoods of Los Angeles city. It further explores the mediating effects of physical activity and mental health on these relationships. High-resolution (1-meter) satellite imagery was utilized to assess and quantify greenspace morphology metrics, including percentage, aggregation, fragmentation, average size, shape complexity, and connectedness, across 865 census tracts. Conditional spatial autoregressive models were employed to investigate the associations between these greenspace morphology metrics and disability prevalence while controlling for sociodemographic and geographic variables. Mediation analysis was conducted to identify potential mediators. Larger, less fragmented, and more connected and clustered greenspace spatial distributions were associated with lower disability rates. Specifically, the standardized coefficients for the greenspace morphology metrics were as follows: greenspace percentage (−0.350; 95% CI: −0.658 to −0.042), mean size (−0.444; 95% CI: −0.718 to −0.170), fragmentation (0.383; 95% CI: 0.103 to 0.663), connectedness (−0.345; 95% CI: −0.641 to −0.049), and aggregation (−0.301; 95% CI: −0.601 to −0.001). Mediation analysis revealed that lack of leisure time physical activity, and frequent mental distress significantly mediated the relationship between greenspace morphology and disability prevalence. The study highlights that both the quantity and spatial morphology of greenspace are crucial factors in understanding their impact on disability prevalence. These findings underscore the importance of incorporating greenspace morphology into public health research and urban planning to optimize disability prevention strategies.