[Association between residential greenness exposure and obesity risk based on remote sensing]

Objective: To evaluate the associations between greenness exposure level and obesity risk based on remote sensing, and analyze the mediating roles of physical activity and air pollutants. Methods: Data were derived from a population-based cohort in Fujian, Hubei, and Yunnan provinces during 2018-2021. Circular buffers with radii of 250, 500, 1 000 m around the participants' residences were constructed, and the averages of normalized difference vegetation index, enhanced vegetation index (EVI), soil-adjusted vegetation index, atmosphere-resistant vegetation index, fractional vegetation coverage, and area ratio of greenness within 3 years before survey were calculated to evaluate the greenness exposure level. Multilevel logistic regression model was used to investigate the association between greenness exposure and risk for obesity, and the heterogeneities among subgroups. Structural equation model was used to examine the mediating roles of physical activity and air pollutants. Results: A total of 104 699 adults were included, with an obesity prevalence of 12.0%. Within the 500 m of the buffer zone, each 0.1-unit increase in EVI was associated with about 5% (OR=0.95, 95%CI: 0.91-0.98) lower risk for obesity. The association was stronger in the adults aged ≥60 years, of Han ethnicity, married/cohabiting, those with educational level below senior high school, the unemployed, smokers, and those with sedentary time <6 h/d. The association between EVI and obesity riak was mediated by physical activity, but the association strength was attenuated by air pollutants. Conclusion: Residential greenness exposure was negatively associated with obesity risk in study participants, indicating that optimizing community greenness patterns might reduce the obesity risk.