The Effects of Ambient Air Pollution and Residential Greenness on Metabolic Disease Biomarkers in China

Abstract

BACKGROUND AND AIM: We aim to study the association between air pollution, greenness, and metabolic syndrome (MetS) biomarkers, as mechanisms for cardiovascular diseases (CVD) and the mortality among the elderly in China. METHODS: We used the 2012 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) Biomarker Cohort. The cohort sampled participants from urban and rural areas of eight longevity counties. We matched the annual average fine particulate matter (PM2.5) concentrations in a 1 km × 1 km grid and calculated Normalized Difference Vegetation Index (NDVI) with a 500-meter radius. The medical technicians measured blood cholesterol, fasting glucose, blood pressure, height, weight, and waist circumference. We defined metabolic syndrome using modified Adult Treatment Panel III criteria. RESULTS:We had 1801 participants. Three-year average NDVI was slightly higher in the rural area than urban area (mean: 0.495 vs. 0.443) while the rural area had a similar three-year average PM2.5 level with the urban area (mean: 49.0 vs. 49.1). We found higher PM2.5 was associated with higher odds of abdominal obesity (AO) [OR (95%CI): 1.254 (1.159, 1.361)] and MetS [OR (95%CI): 1.165 (1.067, 1.278)]. Higher NDVI was associated with lower risk of AO [0.811 (0.711, 0.925)] and elevated fasting glucose [OR (95%CI): 0.84 (0.721, 0.982)], but was not significantly associated with MetS [OR (95% CI): 0.95 (0.821, 1.104)]. PM2.5 and NDVI had significant interaction on the risk of AO but not on the risk of MetS [p value of interaction term: 0.005 and 0.630 respectively]. CONCLUSIONS:We saw convergence of air pollution and greenness levels between urban and rural area among the eight counties studied in our cohort, with higher harmful effect of air pollution in rural areas and higher beneficial effect of greenness in urban areas. KEYWORDS: metabolic disease, greenness, air pollution, PM2.5, aging, China