Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and neuropsychological status among older adults in New York

Polybrominated diphenyl ethers (PBDEs) are emerging environmental contaminants, but little is known about their possible human health effects. The objective of this study is to evaluate the association between exposure to PBDEs and neuropsychological function among older adults and the possibility of effect modification with polychlorinated biphenyls (PCBs). Serum samples were analyzed for concentrations of 9 PBDE and 30 PCB congeners and 34 tests of cognitive and motor function, affective state, and olfactory function were assessed among 144 men and women of 55-74 years of age. After adjustment for relevant confounders, no overall associations were observed between the sum of the PBDE congener concentrations in serum (Sigma PBDE) and scores on the neuropsychological tests. However, statistically significant interactions were found between PBDEs and PCBs for some measures of verbal learning and memory. Among persons with Sigma PCB concentrations at or above the median of 467 ppb (lipid basis), an increase in Sigma PBDE concentrations from the 25th to 75th percentile was associated with decreases between 7% and 12% on scores for certain subscales of the California Verbal Learning Test. In contrast, no statistically significant associations were observed for PBDEs among persons with Sigma PCB levels below the median. The results suggest that PBDEs and PCBs may interact to affect verbal memory and learning among persons 55-74 years old. This is the first study to evaluate the neuropsychological effects of PBDEs in adults and the possibility of synergy with PCBs in humans. (C) 2011 Elsevier Inc. All rights reserved.