POSTNATAL EXPOSURE TO CHLORINATED DIOXINS AND RELATED CHEMICALS ON THYROID-HORMONE STATUS IN JAPANESE BREAST-FED INFANTS

Effects of postnatal exposure to polychlorinated dibenzo-p-dioxins (PC DDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinat ed biphenyls (Co-PCBs) on thyroid hormone status were studied in the p eripheral blood of 36 breast-fed Japanese infants. Estimated total int akes of these chemicals in toxic equivalent quantity (TEQ) converted i nto 2,3,7,8-tetrachlorodibenzo-p-dioxin, (2,3,7,8-TCDD) from the breas t milk significantly and negatively correlated with the levels of trii odothyronine (T-3) and thyroxine (T-4) in the blood of breast-fed babi es. Therefore, exposure to background levels of the highly toxic organ ochlorine chemicals through the breast milk may cause some effects on thyroid hormone status in Japanese infants. (C) 1998 Elsevier Science Ltd. All rights reserved.