Association of maternal serum concentration of hydroxylated polychlorinated biphenyls with maternal and neonatal thyroid hormones: The Hokkaido birth cohort study

摘要: Abstract Background Evidence on the toxicity of hydroxylated metabolites polychlorinated biphenyls (OH-PCBs) for thyroid hormones (TH) is limited, and underlying mechanism remains unknown. Objectives We aimed to investigate effects environmental prenatal exposure OH-PCBs maternal neonatal TH levels, taking maternal-fetal transfer into account. Methods In this prospective birth cohort (the “Hokkaido study”) we included 222 mother-neonate pairs. measured five OH-PCB isomers in serum samples either during pregnancy or within 5 days delivery. Thyroid stimulating hormone (TSH) free thyroxine (FT4) levels were obtained from blood at an early gestational stage (median; 11.1 weeks) heel prick neonates between 4 7 after birth. Multiple linear regression analysis structural equation modeling (SEM) performed associations levels. Results Median concentration ∑OH-PCBs was 25.37 pg/g wet weight. The predominant isomer 4-OH-CB187, followed by 4-OH-CB146+3-OH-CB153. fully adjusted analysis, positively associated with FT4, 4-OH-CB187 both FT4 Maternal showed no significant association TSH among mothers neonates. Path indicated indirect pathway increased via THs TSH. Conclusions These findings suggest that may increase Neonatal presumed be indirectly, process mediated