CHLORINATED CONTAMINANTS, GROWTH AND THYROID-FUNCTION IN SCHOOLCHILDREN FROM THE ARAL SEA REGION IN KAZAKSTAN

It has been shown by others that offspring of mothers who had been exp osed to dioxins and polychlorinated biphenyls (PCBs) during pregnancy have elevated plasma levels of thyroid-stimulating hormone (TSH) for a t least 3 months after birth and reduced plasma levels of free and tot al thyroxine during the second week after birth. As elevated levels of dioxins and PCBs can thus alter thyroid hormone status, the relation between the levels of some polychlorinated organic compounds in the bl ood lipids and growth and thyroid hormone status was studied in 12 hos pitalized schoolchildren from the Aral Sea region known to have high e xposure to such compounds. Their level of PCBs was two to four times h igher than in healthy Stockholm children. Their height was found to be lower than in healthy Swedish children of the same age mean (SDS -0.5 2) and the body mass index (BMI) was inversely correlated to the total concentrations of PCBs and dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorophenyldichloroethylene (DDE) in the blood lipid s. As the levels of insulin-like growth factor-1 were reduced to the s ame extent as the BMI it seems likely that PCBs and DDT cause malnutri tion as a result of malabsorption. None of the children had any impair ment of thyroid function, as revealed by the plasma levels of TSH and thyroxine. Although the concentrations of beta-hexachlorocyclohexane ( beta-HCH) and DDE were extremely high in some of the children there wa s no relation between thyroid hormone status and the blood lipid level s of PCBs, hexachlorocyclohexane and DDT. However, the concentration o f dioxins was not analysed.