Effects of environmental exposure to polychlorinated biphenyls and dioxinson cognitive abilities in Dutch children at 42 months of age

Objective: To study possible adverse effects of environmental exposure to p olychlorinated biphenyls (PCB) and dioxins on cognitive functioning in youn g children. Methods: In a follow-up of the Dutch PCB/Dioxin study, cognitive abilities were assessed with the Kaufman Assessment Battery for Children in 42-month- old children (n = 395). In a subgroup (n = 193) verbal comprehension was as sessed with the Reynell Language Developmental Scales. Prenatal PCB exposur e was estimated from the sum of PCBs 118, 138, 153, and 180 (Sigma PCB) in maternal plasma. Lactational exposure was assessed from breast milk PCB and dioxin concentrations, multiplied by the number of weeks of breast-feeding . Current PCB body burden was estimated from Sigma PCB in 42-month-old plas ma samples. Results: After adjustment was done for covariables, maternal Sigma PCB was associated with lower scores on the overall cognitive and sequential and si multaneous processing scales of the Kaufman Assessment Battery for Children (all P <.05). The highest exposed group (Sigma CPCB greater than or equal to 3 mu g/L) scored 4 points lower on all 3 scales of the K-ABC when compar ed with the lowest exposed group (Sigma PCB < 1.5 mu g/L). Both lactational exposure and current exposure to PCBs and dioxins were not related to 42-m onth cognitive performance. Conclusions: Ln utero exposure to "background" PCB concentrations associate d with poorer cognitive functioning in preschool children. Children Of moth ers at the upper end of exposure are especially at risk. Therefore maternal PCB body burden should be reduced, and breast-feeding should not be discou raged.