Ambient Air Pollution and the Prevalence of Obesity in Chinese Children: The Seven Northeastern Cities Study

Objective: The association between air pollution and the prevalence of overweight and obesity is evaluated. Methods: The population consisted of 30,056 children (aged 2-14 years), randomly selected from 25 districts in Northeast China. Child weight and height were measured, and exposures to particulate matter with an aerodynamic diameter <= 10 mu m (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), and Ozone (O-3) were estimated from the data collected at monitoring stations in the 25 districts. Using two-level logistic models, we examined the association between the exposure and the prevalence of overweight and obesity. Results: Among the study children, 12.3% (3,704) were overweight and 14.1% (4,233) were obese. After adjusting for confounding factors, an increased prevalence of obesity was associated with an interquartile range increase in PM10 (31 mu g/m(3); odds ratio [ORs] 1.19; 95% confidence interval [CI]: 1.11-1.26), SO2 (7.4 ppb; ORs 1.11; 95% CI: 1.03-1.20), NO2 (5.3 ppb; ORs 1.13; 95% CI: 1.04-1.22), and O-3 (11.5 ppb; ORs 1.14; 95% CI: 1.04-1.24). Prevalence of overweight increased with an interquartile range increase in O-3 (11.5 ppb; ORs 1.09; 95% CI: 1.03-1.15). Conclusions: This study suggests that air pollution is positively associated with an increased likelihood of obesity or overweight in children.