Associations of residential greenness and ambient air pollution with overweight and obesity in older adults
Lihong Ye, Jinhui Zhou, Yanlin Tian, Jia Cui, Chen Chen, Jun Wang, Yueqing Wang, Wei Yuan, Jiaming Ye, Chenfeng Li, Xin Chai, Chris Sun, Fangyu Li, Jiaonan Wang, Yanbo Guo, Jouni J. K. Jaakkola, Yuebin Lv, Juan Zhang, Xiaoming Shi
Abstract
Abstract Objective This study aimed to examine the impact of greenness and fine particulate matter <2.5 μm (PM 2.5 ) on overweight/obesity among older adults in China. Methods A total of 21,355 participants aged ≥65 years were included from the Chinese Longitudinal Healthy Longevity Survey between 2000 and 2018. Normalized difference vegetation index (NDVI) with a radius of 250 m and PM 2.5 in a 1 × 1‐km grid resolution were calculated around each participant's residence. Cox proportional hazards models were used to estimate the effects of NDVI and PM 2.5 on overweight/obesity. Interaction and mediation analyses were conducted to explore combined effects. Results The study observed 1895 incident cases of overweight/obesity over 109,566 person‐years. For every 0.1‐unit increase in NDVI the hazard ratio of overweight/obesity was 0.91 (95% CI: 0.88–0.95), and for every 10‐μg/m 3 increase in PM 2.5 the hazard ratio was 1.11 (95% CI: 1.07–1.14). The effect of NDVI on overweight/obesity was partially mediated by PM 2.5 , with a relative mediation proportion of 20.10% (95% CI: 1.63%‐38.57%). Conclusions Greenness exposure appears to lower the risk of overweight/obesity in older adults in China, whereas PM 2.5 , acting as a mediator, partly mediated this protective effect.