Hormone disruption by PBDEs in adult male sport fish consumers

Background: Persistent pollutants, such as polychlorinated biphenyls (PCBs), affect endocrine function. Human exposure to polybrominated diphenyl ethers (PBDEs), which are similar in structure to PCBs, has increased recently, but health effects have not been well studied. Objectives: Our goal in this study was to determine whether PBDE body burdens are related to thyroid and steroid hormone levels, thyroid antibodies, and thyroid disease in a cohort of frequent and infrequent adult male sport fish consumers. Methods: We tested serum from 405 adult males for PBDE congeners, PCB congeners, testosterone, sex-hormone-binding globulin (SHBG), SHBG-bound testosterone, thyroglobulin antibodies, and the thyroid hormones thyroxine (T₄), triiodothyronine (T₃), thyroid-stimulating hormone (TSH), and T₄-binding globulin (TBG). We collected data on demographics, fish consumption, medical diseases, and medication use. Results: The median sum of PBDEs was 38 ng/g lipid. In 308 men without thyroid disease or diabetes, PBDEs were positively related to measures of T₄ and reverse T₃ and inversely related to total T₃ and TSH. PBDEs were positively related to the percentage of T₄ bound to albumin, and inversely related to the percentage of T₄ bound to TBG. Associations of BDE congeners with hormones varied. BDE-47 was positively associated with testosterone levels. Participants with PBDEs over the 95th percentile were more likely to have thyroglobulin antibodies, although high PBDE exposure was not associated with thyroid disease. PBDE effects were independent of PCB exposure and sport fish consumption. Conclusions: PBDE exposure, at levels comparable with those of the general U.S. population, was associated with increased thyroglobulin antibodies and increased T₄ in adult males.