Association of polybrominated diphenylethers (PBDEs) and hydroxylated metabolites (OH-PBDEs) serum levels with thyroid function in thyroid cancer patients
Polybrominated diphenylethers (PBDE) have been demonstrated to be associated with significant alterations in hormone levels in humans. However, yet few epidemiological human evidence has associated thyroid function with hydroxylated polybrominated diphenylethers (OH-PBDEs), which may be more potent in disrupting thyroid hormone homeostasis. In the present study, the body burdens of 7 PBDEs and 11 OH-PBDEs as well as the serum thyroid status were examined in a cohort of 33 thyroid cancer patients. The levels of ∑PBDEs and ∑OH-PBDEs ranged from 1.07 to 39 ng/g lipid, and 0.01–0.46 ng/g lipid, respectively. BDE-47, 6-OH-BDE-47 and 3-OH-BDE-47 were the predominant congeners. The associations between these PBDE congeners and thyroid function were not significant after controlling for sociodemographic characteristics, as well as the associations between OH-PBDEs and free T3. There were an inverse association between lg3-OH-BDE-47 and lgFT4 (free T4) but a positive association between lg4'-OH-BDE-49 and TSH. Both lgΣ5OH-PBDEs (the sum of HO-tetra-BDEs) and lgΣOH-PBDEs were significantly and positively associated with lgTSH. Our results are consistent with most human studies, suggesting that OH-PBDEs can alter thyroid function by enhancing the elimination of serum FT4 with elevated TSH levels. To our knowledge, this is the first study to examine and report associations between OH-PBDEs and thyroid function in a cancer population.