Prepubertal exposure to polycyclic aromatic hydrocarbons are associated with early pubertal development onset in boys: A longitudinal study

To investigate the effects of polycyclic aromatic hydrocarbons(PAHs) on puberty in boys. 695 subjects were selected from four primary schools in Chongqing, China. 675 urine samples from these boys were collected four PAH metabolites: 1-hydroxypyrene, 2-hydroxynaphthoic, 2-hydroxyfluorene, and 9-hydroxyphenanthrene. Pubertal development of 695 boys was assessed at follow-up visits starting in December 2015 and occurring every six months thereafter until now, data used in this article ending in June 2021. A total of 12 follow-up visits were performed. Cox proportional hazards regression models were used to analyze the relationship between PAH metabolite concentrations and indicators of pubertal timing. The mean age at puberty onset of testicular volume, facial hair, pubic hair, first ejaculation, and axillary hair in boys was 11.66, 12.43, 12.51, 12.72 and 13.70 years, respectively. Cox proportional hazards regression models showed that boys with moderate level of 1-OHPyr exposure was associated with earlier testicular development (HR: 1.276, 95%CI: 1.006-1.619), with moderate level of 2-OHNap were at higher risk of early testicular development (HR: 1.273, 95%CI: 1.002-1.617) and early axillary hair development (HR: 1.355, 95%CI: 1.040-1.764), with moderate level of 2-OHFlu was associated with earlier pubic hair development (HR: 1.256, 95%CI: 1.001-1.577), with high level of 9-OHPhe were at higher risk of early fisrt ejaculation (HR: 1.333, 95%CI: 1.005-1.767) and early facial hair development (HR: 1.393, 95%CI: 1.059-1.831). Prepubertal exposure to PAHs may be associated with earlier pubertal development in boys. Polycyclic aromatic hydrocarbons(PAHs) are a widespread group of persistent organic pollutants that are ubiquitous in the air, have potential carcinogenicity and teratogenicity. As environmental endocrine disruptors (EEDs), PAHs may enter children's bodies before and after birth in various ways, potentially causing functional disorders of the reproductive system and abnormal development. That's why we considered PAHs as "hazardous material". By exploring the association between PAH metabolites and pubertal development onset(testicular volume, pubic hair, axillary hair, facial hair and first ejaculation) in boys, we expected to provide scientific evidence for reducing exposure to PAHs in various pathways.