Backgrounds: Perfluoroalkyl compounds (PFCs) have been suggested as potential thyroid disrupting chemicals. However, previous studies about the associations between PFCs and childhood thyroid function are scarce, and inconclusive. We evaluated the PFC exposure in Korean preschool children, and investigated the temporal relationship with thyroid hormone concentration.
Methods: From a prospective the Environment and Development of Children (EDC) cohort study, we used data on 14 kinds of PFCs concentrations at ages 2, 4, and 6 years and thyroid function test (Serum thyroid stimulating hormone [TSH] concentrations at ages 2, 4, and 6 years, and free thyroxine [FT4] and triiodothyronine [T3] and TSH concentrations at 6 years of age).
Results: When young children were serially followed-up from ages 2, 4, to 6 years, perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were detected in >90% of the serum samples. After adjusting for age, body mass index and iodine intake, the association between serum PFC concentrations and thyroid function were significant among boys, but not among girls. For TSH levels, both PFDA and PFOS concentrations at 2 years of age were inversely associated with TSH levels at 2 years of age (P<0.05 for both), and serum PFNA concentrations at 6 years of age was negatively related to TSH levels at 6 years of age (P=0.044). Serum FT4 levels at 6 years of age was positively associated with PFNA concentrations at 2 years of age (P=0.009) and PFOA concentrations at 6 years of age (P=0.018). In addition, serum T3 levels at 6 years of age were positively associated with PFNA concentrations at ages 2 and 4 years, and PFOS concentrations at 6 years of age (P<0.05 for all).
Conclusion: PFOS, PFOA, PFHxS, PFDA, and PFNA were consistently detected >90% in Korean children from ages 2, 4, to 6 years. Significant effect of PFCs on increased FT4 and T3 and decreased TSH levels was found among boys.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology