PCBs and neurodevelopmental effects in Michigan children: An evaluation ofexposure and dose characterization

Despite the fact that PCB levels in the general environment have continued to decline over the past decade, concern for potential neurodevelopmental d eficits from in utero exposure to these compounds remains unabated. In fact , some regulatory and scientific bodies have concluded that the evidence su ggesting that prenatal exposure to PCBs may lead to neurodevelopmental defi cits is one of the greatest public health concerns surrounding PCBs. The pr imary basis for the concern that low-level in utero exposure to PCBs causes neurodevelopmental deficits in children is a series of reports on a cohort of Michigan children presumably exposed to PCBs as a result of their mothe r's consumption of Great Lakes fish. These children, known collectively as the Jacobson cohort, have been followed from birth to 11 years of age. The investigators following these children concluded that they have demonstrate d persistent neurodevelopmental effects in this cohort attributable solely to PCBs. However, a detailed analysis of the cohort's exposure characteriza tion, particularly in the initial reports, reveals considerable uncertainty as to the actual exposure status of mothers characterized as "fish eaters" and their offspring. Failure to adequately characterize the PCB exposure o f these mothers, or their children, precludes any causal association betwee n in utero exposure to PCBs and neurodevelopmental deficits. (C) 2001 Acade mic Press.