Thyroid and growth hormone concentrations in 8-year-old children exposed in utero to dioxins and polychlorinated biphenyls.

The objective of this study was to examine the effects of in utero exposure to polychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/F) on thyroid and growth hormone concentrations and growth in 8-year-old children. A total of 56 children (23 boys, 33 girls) were included in the study. All were stratified into high and low PCDD/F + PCB exposure groups based on maternal median indicator PCB and PCDD/F + PCB concentrations during pregnancy. Height, weight, body mass index, and thyroid and growth hormone concentrations were assessed and compared among the different exposure groups. There were no significant effects of indicator PCB or PCDD/F + PCB exposure levels on growth (height, weight, and bone age) among 8-year-old boys or girls. Boys exposed to high PCDD/F + PCB levels had significantly higher thyroxine-binding globulin (TBG) concentrations than boys exposed to low levels (P = 0.027). Girls exposed to high PCB levels had significantly lower IGF-binding protein-3 (IGFBP-3) concentrations than girls exposed to low levels (P = 0.038). Low levels of in utero exposure to PCDD/F+PCB and high indicator PCB levels were significantly associated with reduced serum concentrations of IGFBP-3. High levels of in utero exposure to PCDD/F+PCB plus either high or low indicator PCB levels were significantly associated with increased serum concentrations of growth hormone, T3, T4, and TBG. These findings suggest that the level of in utero exposure to PCBs and dioxins may affect serum concentrations of growth hormone, thyroid hormones, TBG, and IGFBP-3 in 8-year-old children.