Association between residential greenspace structures and frailty in a cohort of older Chinese adults

Background: Frailty is a late-life clinical syndrome resulting from the accumulation of aging-induced decline. Greenness measured with normalized difference vegetation index (NDVI) is protective of frailty, but NDVI is less informative than structure indices describing greenspaces’ constitution, shape, and connectivity (largest patch index [LPI], shape index, and cohesion index). We aimed to study the association between greenness structures and frailty in a cohort of older Chinese adults. Methods: Older adults from the 2008–2014 China Longitudinal Healthy Longevity Survey (CLHLS) were included. Greenspace structure indices (area-edge, shape, proximity) at county level were derived from satellite data; frailty index (FI) was calculated as outcome. Cross-sectional analyses used linear and logistic regression; longitudinal analyses used generalized estimating equations (GEE). Results: Among 8,776 baseline participants, mean LPI, shape, cohesion, and FI were 7.93, 8.11, 97.6, and 0.17. Cross-sectional analyses showed negative dose–response relationships between greenspace structures and frailty, especially in females, centenarians, illiterate people, city residents, unmarried people, and individuals with increased frailty. Participants in the highest quartile of LPI, shape, and cohesion had 32% (95% CI: 21–42%), 35% (95% CI: 24–44%), and 37% (95% CI: 26–46%) lower odds of frailty than the lowest quartile. No significant associations were found in longitudinal analyses. Conclusions: Higher levels of greenness structures (area-edge, shape, and proximity) may be related to lower frailty, though a clear longitudinal benefit was not identified.