PBDE exposure and the association with testosterone, estrone and estradiol around the time of thelarche

Abstract

Background: Polybrominated diphenyl ethers (PBDEs) are flame retardants, exposing humans primarily though diet, dust and inhalation. Higher levels of PBDEs have been associated with adverse health outcomes including lower thyroid hormone levels and later ages of pubertal transition. We hypothesize that higher levels of PBDE are associated with lower levels of reproductive sex hormones by acting as endocrine disrupters.Methods: We analyzed data of 299 girls from Cincinnati, within a longitudinal cohort study of puberty (2005-2015). Semiannual exams included anthropometric measurements and pubertal maturation staging. PBDEs were measured in serum collected at the initial visit, ages 6-8. Four measured hormones, DHEA-S, estrone, estradiol, and testosterone, were associated with five time periods (-18 months, -12 months, -6 months, thelarche, +6 months) relative to each individual girl’s onset of puberty, thelarche (median=8.83 years). Results: Linear regression analysis revealed a statistically significant inverse relationship between PBDE 153 and testosterone at -6 months (β=-0.1245, p=0.0271). PBDE 100 had an inverse relationship with testosterone at thelarche (β=-0.0939, p=0.0902). The ΣPBDEs (β=-0.1176, p=.0608), PBDEs 99 (β=-.09085, p=0.0948) and 100 (β=-0.1102, p=0.0626) had inverse relationships with estrone at thelarche. The ΣPBDEs (β=-0.1940, p=0.0556) and PBDEs 99 (β=-0.1522, p=0.0786) and 153 (β=-0.1843, p=0.0681) had inverse relationships with estradiol at 6 months after thelarche. There were no statistically significant relationships at -18 or -12 months or with DHEA-S. When stratified by BMI (lowest BMI 50% vs highest BMI 50%), the inverse relationships between the PBDEs and the hormones were strengthened for the girls with higher BMI% while the girls with a lower BMI% had no statistically significant relationships between the PBDEs and the hormones.Conclusions: We found evidence that suggests exposure to PBDEs in early childhood affects testosterone and estrone levels at thelarche and estradiol at 6 months after thelarche thus disrupting the endocrine system during puberty.