Ming Wen

Objectives: Neighborhood physical activity environments (PAEs)—including walkability, recreational facilities, green space, and civic infrastructure—support active living and population health but are often inequitably distributed. This study examines racial/ethnic and socioeconomic disparities in neighborhood PAEs and assesses variation by urbanicity. Methods: We used population-weighted ordinary least squares regression models with county fixed effects using the latest available 2018 data from 69,889 census tracts in the contiguous United States. Models assessed associations between racial/ethnic and poverty composition and four PAE dimensions—built, physical facilities, natural, and social environments. Sensitivity analyses compared models with and without county fixed effects and population weighting. Urbanicity-stratified models examined disparities across urban, suburban, town, rural, and mixed settings. Results: Non-Hispanic White and low-poverty populations had greater access to PAEs across all domains, except that low-poverty populations lived in areas with lower walkability. Disparities were largest in urban and suburban areas. Rural high-poverty populations had more natural resources but less infrastructure and civic support. County-fixed effects reversed the walkability advantages for non-Hispanic Black observed in unadjusted models. Conclusions: PAE disparities disproportionately affect racial/ethnic minority and high-poverty populations, especially in urban areas. Findings support equity-focused, context-specific interventions for environmental justice in health policy.

The influence of grandparenting on the longevity of older adults remains insufficiently studied, especially in non-Western settings. This research examined how different aspects of grandparenting, including grandparenthood and the provision, duration, and intensity of grandchild caregiving, impact all-cause mortality risk among older adults in China. Using data from the 2011–2020 China Health and Retirement Longitudinal Study, including 14,573 respondents aged 45 to 80 (52,940 observations), we examined the associations between grandparenting and mortality, investigated how factors like gender, marital status, rural-urban residence, and smoking behavior may moderate these relationships, and explored the underlying mechanisms driving these effects. To address health-selection bias, we employed entropy balancing reweighting. Discrete-time complementary log-log models were used to link predictors at one wave to mortality in the subsequent wave. Results revealed a notable distinction: grandparenthood alone had no significant effect on mortality, whereas providing grandchild care was associated with a substantial survival benefit. This benefit was most pronounced among grandparents engaged in long-term care (≥ 2 waves) and low-intensity care (1–99 hours/year). The survival advantage was stronger among urban and widowed grandparents but less evident among former smokers and notably reversed for separated or divorced grandparents. Pathway analyses indicated that these benefits were partly mediated by improved cognitive function (explaining 5.69%), functional capacity (8.52%), and social participation (8.16%). This study highlights that grandchild caregiving is a powerful but conditional protective factor for older adults in China, emphasizing the role of family-based strategies rooted in filial piety in promoting healthy aging.