Associations of Mercury Exposure with Serum Sex Steroid Hormones in Children 6-18 Years from NHANES 2013-2016.

Introduction: To examine the relationship between mercury exposure and serum sex steroid hormones among children aged 6-18 years.

Methods: Data were collected from the NHANES 2013-2016. A cohort of 2,637 Children with available information on mercury exposure, serum sex steroid hormones, and covariates was enrolled. Generalized linear models were applied to explore the association of mercury exposure with sex steroid hormones. Finally, we adopted the Bayesian kernel machine regression (BKMR) model to investigate the effect of mixture exposure to mercury on hormone levels.

Results: Methyl mercury (MeHg) and total mercury (Hg) were associated with all sex steroid hormones except E2 (P <0.05). After adjusting for covariates, MeHg and Hg were related to sex hormone- binding globulin (SHBG) and free androgen index (FAI) (P <0.05). Stratified analysis by sex-puberty revealed a negative relationship between Hg and SHBG, while a positive association of MeHg with FAI in prepubertal girls (P <0.05). Their associations were confirmed by the BKMR model analysis, in which the mixture exposure was positively linked to FAI but inversely related to SHBG, particularly among prepubertal girls.

Discussion: These findings suggest that mercury may disrupt sex hormone homeostasis during critical developmental windows. Appropriate measures should be implemented to mitigate the adverse effects of mercury on sex hormones in the young population. However, future longitudinal large-scale studies are required for validation.

Conclusion: Exposure to MeHg and Hg is associated with increased FAI levels, but decreased levels of SHBG, which are more pronounced in girls. The heightened susceptibility of prepubertal girls underscores the need for targeted public health interventions, including dietary guidance on seafood consumption and early biomonitoring of mercury levels in high-risk populations, to mitigate potential health impacts.