INTELLECTUAL IMPAIRMENT IN CHILDREN EXPOSED TO POLYCHLORINATED-BIPHENYLS IN-UTERO

Background In utero exposure to polychlorinated biphenyls, a ubiquitou s environmental contaminant, has been linked to adverse effects on neu rologic and intellectual function in infants and young children. We as sessed whether these effects persist through school age and examined t heir importance in the acquisition of reading and arithmetic skills. M ethods We tested 212 children, recruited as newborns to overrepresent infants born to women who had eaten Lake Michigan fish contaminated wi th polychlorinated biphenyls, A battery of IQ and achievement tests wa s administered when the children were 11 years of age, Concentrations of polychlorinated biphenyls in maternal serum and milk at delivery we re slightly higher than in the general population. A composite measure of prenatal exposure was derived from concentrations in umbilical-cor d serum and maternal serum and milk. Results Prenatal exposure to poly chlorinated biphenyls was associated with tower full-scale and verbal IQ scores after control for potential confounding variables such as so cioeconomic status (P = 0.02). The strongest effects related to memory and attention. The most highly exposed children were three times as l ikely to have low average IQ scores (P < 0.001) and twice as likely to be at least two years behind in reading comprehension (P = 0.03). Alt hough larger quantities of polychlorinated biphenyls are transferred b y breast-feeding than in utero, there were deficits only in associatio n with transplacental exposure, suggesting that the developing fetal b rain is particularly sensitive to these compounds. Conclusions In uter o exposure to polychlorinated biphenyls in concentrations slightly hig her than those in the general population can have a long-term impact o n intellectual function. (C) 1996, Massachusetts Medical Society.