From air to adipose: Investigating PM2.5-bound chlorinated paraffins and overweight/obesity in Chinese children and adolescents.

Previous studies have reported associations between exposure to persistent organic pollutants (POPs) and childhood obesity. However, the role of chlorinated paraffins (CPs), an emerging class of POPs, in childhood obesity remains underexplored. To assess the associations, a total of 131,370 school-aged children and adolescents from 105 primary and middle schools in the Pearl River Delta region of southern China were included in this study. PM2.5 samples were collected and the PM2.5-bound CPs were detected. Age- and sex-specific BMI z-scores were calculated based on the World Health Organization growth standards. Overweight and obesity were defined according to Chinese screening criteria for children and adolescents. Generalized linear mixed-effects models (GLMMs) were used to evaluate the associations between PM2.5-bound CPs and BMI z-scores as well as weight status. The Quantile G-Computation model was employed to assess the combined effects of CPs mixture. Interaction analyses were conducted to assess potential effect modifications by covariates. We found each interquartile range (IQR) increase in ∑CPs was associated with higher BMI z-scores (β: 0.03; 95% CI: 0.02, 0.04) and increased risks of overweight (OR: 1.44; 95% CI: 1.41, 1.47) and obesity (OR: 1.50; 95% CI: 1.46, 1.53). Similarly, positive associations were also observed in SCCPs, MCCPs and LCCPs. QG-Comp analysis indicated SCCPs accounted for the highest contribution to the overall mixture effect, followed by MCCPs and LCCPs. No significant sex- or age-specific differences in the associations between CPs exposure and overweight/obesity risk were found in the interaction analyses. Our findings provide epidemiological evidence linking CPs to obesity and contribute to their health risk assessment.