Sex-specific difference of the association between ambient air pollution and the prevalence of obesity in Chinese adults from a high pollution range area: 33 Communities Chinese Health Study

Experimental data suggests that exposure to airborne fine particulate matter is associated with obesity. There is little supporting epidemiologic evidence of this, however. To evaluate the effects of ambient air pollution on the prevalence of obesity among adults living in a primarily industrial province of northeast China, 24,845 Chinese adults between the ages of 18 and 74 were randomly recruited from 33 communities in 11 districts of three northeastern Chinese cities during 2009. The participants' weight and height were measured. Three-year (2006-2008) average concentrations of particles with an aerodynamic diameter <= 10 mu m (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O-3) were calculated from monitoring stations in each of the 11 districts. Two-level logistic regressions models were used to examine the effects of pollutants exposure. Overall, 353% (8764) were overweight and 5.8% (1435) were obese. After adjusting for confounding factors, significant associations between concentrations of air pollutants and prevalence of obesity were found. When the analysis was stratified by sex, the associations were significant only in women. Among women, an increased prevalence of obesity was associated with an interquartile range increase in PM10 (19 mu g/m(3); odds ratio [ORs] = 1.18; 95% confidence interval [CI]:1.06-1.32), NO2 (9 mu g/m(3); ORs = 1.24; 95% Cl: 1.09-1.41), and O-3 (22 mu g/m(3); ORs = 1.14; 95% Cl: 1.01-1.30). Associations were stronger among older participants. In conclusion, this study reveals a positive association between the long-term exposure to ambient air pollution and increased prevalence of obesity, and that these associations were more apparent in women than in men. (C) 2015 Elsevier Ltd. All rights reserved.