Relationships Between Brominated Flame Retardant Concentrations in House Dust and Serum Hormone Levels in Men

Abstract

ISEE-0454 Background and Objective: Human exposure to brominated flame retardants (BFRs) is widespread, occurring primarily through diet or contact with indoor dust. There is laboratory evidence of endocrine disruption in animals following exposure to BFRs, but human studies are limited. In this preliminary investigation, we examined the association between BFR levels in house dust and hormone levels in men. Methods: We measured serum hormone levels and BFR concentrations in participant vacuum bag dust from 38 men recruited through a Massachusetts infertility clinic as part of an ongoing study of environmental exposures and male reproductive health. Statistical methods included the calculation of Spearman correlations among BFRs and between BFRs and serum hormone levels, and multivariable linear regression. Results: There were strong correlations (r ≥ 0.80, P < 0.05) among dust concentrations of brominated diphenyl ether (BDE) congener groups with a similar degree of bromination. Positive correlations were found (P ≤ 0.05) between several BDE congeners and serum levels of prolactin and total T3, and between bistribromophenoxyethane and total T3. Hexabromocyclododecane was positively correlated with free androgen index (FAI) (r = 0.46, P = 0.004). Most of these relationships remained statistically significant or suggestive in multivariate linear regression models adjusted for age and BMI. There was a suggestive inverse association between BDE209 and testosterone when adjusting for age, BMI, and serum sex hormone binding globulin (SHBG) (P = 0.09). When dust concentrations of BDE99 were combined with results from a previous analysis of 24 men from the same cohort (n = 62), regression models adjusted for age, BMI, and dust analytical method showed positive relationships between BDE99 and serum estradiol, free T4, and SHBG (P < 0.05). Inverse associations between BDE99 and follicle stimulating hormone (P < 0.05) and FAI (P = 0.11) were also found. Conclusion: This study provides evidence of altered hormone levels in relation to BFR exposure and that house dust may be an important source of human BFR exposure.