OBJECTIVE: Neighborhood walkability may influence mental health through physical activity, but the behavioral pathway and underlying mechanisms remain unclear. We examined whether walkability affects psychological distress through physical activity, and whether benefits operate via metabolic improvements or direct pathways independent of body mass index (BMI). METHODS: We analyzed data from 5858 United States All of Us Research Program participants (mean age 58.5 ± 15.6 years, 69% female, data collected 2018-2023) with device-measured physical activity and validated psychological distress assessments. Structural equation modeling (SEM) tested pathways from perceived neighborhood walkability to psychological distress through moderate-to-vigorous physical activity (MVPA) and BMI, controlling for age and neighborhood socioeconomic disadvantage. RESULTS: Walkability significantly predicted greater MVPA (β = 0.11, p < .001), which predicted lower psychological distress (β = -0.11, p < .001). This effect was intensity-specific: only MVPA demonstrated associations with both walkability and all distress indicators. Pathway decomposition showed 85% of MVPA's protective effect operated through direct pathways rather than BMI reduction (15%). CONCLUSIONS: Neighborhood walkability is associated with lower psychological distress primarily through MVPA-mediated pathways that operate independently of BMI changes. These findings support walkable infrastructure investments as upstream, population-level mental health interventions aligned with health-at-every-size frameworks, with infrastructure designed to facilitate MVPA.
Lee et al. (Tue,) studied this question.