Associations of Co-Exposure to Polycyclic Aromatic Hydrocarbons and Heavy Metals with Sex Steroid Hormones among Children Aged 6-19 Years.

Introduction: Polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are endocrine-disrupting chemicals (EDCs) that may have a combined effect on sex hormone levels in children. This study investigated the correlations between co-exposure to PAHs and HMs and levels of sex steroid hormones in children.

Methods: We employed the data from the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016, including 1,167 participants aged 6-19 years. Sex hormone indicators include testosterone (TT), estradiol (E2), sex hormone-binding globulin (SHBG), free androgen index (FAI), and the TT/E2 ratio. Weighted multivariate linear regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were used to analyze the associations between co-exposure to PAHs and HMs and sex steroid hormone levels.

Results: Co-exposure to PAHs and HMs was associated with a 16.2% reduction (95% CI [-0.321, -0.004]) in SHBG level among prepubertal males and a 16% reduction (95% CI [-0.30, -0.03]) in E2 level among pubertal males by the WQS regression, and cadmium (Cd) and mercury (Hg) contributed the highest weight, respectively. In the Bayesian kernel machine regression (BKMR) model, co-exposure to PAHs and HMs was positively associated with TT/E2 in pubertal males and negatively correlated with FAI in pubertal females, and 1-hydroxypyrene (1-PYR) and Cd were the most important components, respectively.

Conclusions: Co-exposure to PAHs and HMs was associated with sex hormone levels in children. These findings highlight the necessity for preventing the effects of these chemicals on sex hormones.