Background: Childhood obesity is a global health issue, and limited evidence suggests that air pollution may be a contributing factor. This study aims to examine whether exposure to fine particulate matter (PM2.5) is associated with obesity status in a nationally representative sample of schoolchildren in China.
Methods: The study population consisted of 41,439 schoolchildren of 6-17 years old, recruited from 30 provinces in China using a multi-stage stratified sampling method. Weights and heights were measured for all the participants, and sociodemographic information was collected using a questionnaire. The obesity status was classified following the Chinese national standards. The PM2.5 exposure was estimated as the 5-year average concentration at the school location for each participant. The association between obesity status and PM2.5 exposure was examined using weighted logistic regressions adjusted for potential confounders.
Results: The prevalence of normal weight, overweight, and obesity were 78.5%, 12.4%, and 9.0%, respectively. PM2.5 exposure averaged 59.8 ± 17.6 μg/m3 with a range of 30.5-115.2 μg/m3 among all the participants. The risk of obesity increased by 10.0% (95% confidence interval: 3.0-16.0%) per 10 μg/m3 increase in PM2.5 exposure. The PM2.5-associated risk was significantly elevated in older age groups and children living in urban areas (interaction p-values < 0.05).
Conclusions: This national survey revealed that approximately 1 in 5 Chinese schoolchildren were overweight or obese. Exposure to PM2.5 in the ambient air was significantly associated with childhood obesity. The findings suggest the need for further research to uncover the roles of PM2.5 exposure in childhood obesity development.
Keywords: Adolescents; Children; China; Cross-sectional; Obesity; Particulate matter.
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