Association between urinary polycyclic aromatic hydrocarbons and childhood obesity index: a cross-sectional study in China

Polycyclic aromatic hydrocarbons (PAHs), known as endocrine disruptors, may be linked to obesity. This study examines the associations between four urinary PAH metabolites and the body mass index (BMI), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) in children. Using the generalized linear model (GLM), restricted cubic spline (RCS), weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) analyses, the associations between urinary PAH metabolites and obesity indicators were revealed. A total of 1409 children (675 boys, 734 girls) with means age of 10.19 and 9.25 years, respectively, were enrolled. The study identified a significant association between the fourth quartile of 1-hydroxypyrene and elevated BMI in boys. Additionally, the third and fourth quartiles of 2-hydroxyfluorene, as well as the second quartile of 9-hydroxyphenanthrene were linked to increased BMI in boys. For girls, the upper two quartiles of 9-hydroxyphenanthrene were independently associated with higher BMI and WHtR. Although nonlinear associations were not significant using RCS, 9-hydroxyphenanthrene demonstrated a significant positive correlation with both BMI and WHtR among girls. PAH mixtures were positively correlated with BMI in both genders and with WHtR in girls, with 2-hydroxyfluorene and 9-hydroxyphenanthrene being particularly influential in obesity. Gender differences in PAHs’ obesogenic effects are observed.