Long-term exposure to fine particulate matter components with obesity in children and adolescents in China: The age-sex disparities and key effect modifiers.

Long-term fine particulate matter (PM) exposure was associated with childhood obesity. However, the key PM components and whether PM effect may vary by obesity type, growth stage, sex, and individual/family characteristics have yet been examined. In this study, we investigated 213,907 Chinese children and adolescents aged 3-18 years in 2017-2019. Three-year average concentrations of PM and five major components were assigned to each participant's address. Multivariable mixed-effects model and weighted quantile sum regression were used to estimate the effect sizes of each component. Stratified analyses were performed by age and sex groups, with the interactive effects of a series of individual/family features evaluated. The odds ratio of childhood obesity was 1.28 (95 %CI: 1.15-1.43) for per interquartile range increase in PM, with organic matter identified as the key contributor. General central obesity and mixed obesity were more sensitive to PM exposure than peripheral obesity. As children aged, the effect size of PM attenuated for general central obesity, remained unchanged for mixed obesity and increased for peripheral obesity. Females, children with obese parents, and those with lower levels of physical activity were more vulnerable than others. Other adverse effect modifiers for certain children included family with one child, low family income, and less sleep duration. Our findings emphasize that the influence of exposure to PM and its components on risk of obesity in children and adolescents should be considered comprehensively in developing adequate obesity prevention strategies.