Studies have shown that ambient air pollution is associated with obesity in adults, but epidemiological evidence is scarce for children and adolescents. This study sought to examine the association between long-term exposure to ambient air pollution and obesity in a large population of children and adolescents in China. A cross-sectional analysis was performed from a school-based health lifestyles intervention project between September 1, 2019 and November 31, 2019, including 36,456 participants aged 9-17 years in Jiangsu province of China. Exposure to air pollutants (nitrogen dioxide (NO), ozone (O), particulate matter with aerodynamic diameters ≤10 μm (PM), and ≤2.5 μm (PM)) were measured based on the nearest air monitoring station for each selected school. Data on each participant's weight and height was also recorded. Demographic and obesity-related behavioral information was collected using a self-reported questionnaire. We used the multivariate regression model to estimate the effects of three-year (2016-2018) average concentrations and the exceedance concentration days (ECD) of air pollutants on obesity after adjusting potential confounders. The ECD was defined as daily concentration exceeding the Chinese National Ambient Air Quality Standard and World Health Organization Ambient Air Quality Guidelines. We observed that higher concentrations of PM, NO, and Owere associated with elevated likelihood of obesity. For each 10 μg/mincrement in concentration, odds ratio of obesity was 1.185 (95% confidence interval (CI): 1.054, 1.333) for PM, 1.127 (95%CI: 1.042, 1.219) for NO, and 1.041 (95%CI: 1.001, 1.082) for O, respectively. A significant association between the ECD and obesity was also found for PMand O. Effects of air pollutants on obesity were stronger in males, low economic level regions, and age subgroups of 9-11 and 15-17 years. Our findings suggest that long-term exposures to PM, NO, and Owere associated with higher prevalence of obesity in children and adolescents. Continuous efforts to reduce air pollution level could help ease the increasing prevalence of obesity within a region. 2 3 10 2.5 2.5 2 3 2.5 2 3 2.5 3 2.5 2 3 3
