Dioxins, Furans, Polychlorinated Biphenyls and Male Puberty

Abstract

Background. Dioxins, furans and polychlorinated biphenyls (PCBs) are persistent organic compounds released into the environment as a result of industrial activity. They disrupt endocrine function, and may have contributed to recent documented worldwide declines in sperm count and fertility (Diamanti-Kandarakis et al., 2009; Bursian, Newsted and Zwiernik, 2011; Zawatski and Lee, 2013; Gore et al., 2015). However, few studies have examined the longitudinal effects of childhood exposure to these chemicals. This work investigates how boys’ exposure to dioxins, furans and PCBs during the critical peripubertal developmental window might affect 1) serum sex hormones throughout adolescence 2) and the pace of pubertal progression. Methods. The Russian Children’s Study measured serum toxic equivalents (TEQs) of dioxins (PCDDs), furans (PCDFs), coplanar PCBs (c-PCBs) and mono-ortho-PCBs (m-PCBs), and serum concentrations of non-dioxin-like PCBs (NDL-PCBs), in 516 boys aged 8-9. We then followed the boys for 11 years, measuring serum sex hormones and testicular volume (TV) biennially through ages 18-19. We used longitudinal mixed methods to model the association of peripubertal serum organochlorines with serum testosterone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) throughout adolescence. We then created population trajectories of pubertal progression by applying Latent Class Growth Modeling (GBTM) to longitudinal measurements of TV. Finally, using ordinal and multinomial logistic models, we examined associations between organochlorines and trajectories of pubertal progression. Results. Peripubertal serum TEQs were associated with 1) mid-pubertal decreases in serum testosterone (PCDD TEQs and c-PCB TEQs); 2) mid-pubertal decreases in serum FSH (PCDD TEQs); and 3) slower pubertal progression (all TEQs), consistent with prior findings linking TEQs to pubertal delays (Burns et al., 2016). On the other hand, peripubertal exposure to NDL-PCBs was associated with early- to mid-pubertal decreases in serum testosterone and FSH, in conjunction with accelerated pubertal progression. The association with accelerated pubertal progression is consistent with prior observations (Burns et al., 2016), though it is unclear how the accompanying declines in sex hormone concentrations fit in. Conclusion. In boys, increased peripubertal exposure to dioxins, furans and PCBs is associated with disruptions in serum testosterone, FSH and LH throughout adolescence, as well as shifts in tempo of pubertal progression.