1. Domain-Specific Effects of Prenatal Exposure to PCBs, Mercury, and Lead on Infant Cognition: Results from the Environmental Contaminants and Child Development Study in Nunavik.
- Author
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Boucher, Olivier, Muckle, Gina, Jacobson, Joseph L., Carter, R. Colin, Kaplan-Estrin, Melissa, Ayotte, Pierre, Dewailly, Éric, and Jacobson, Sandra W.
- Subjects
BREAST milk ,COGNITION ,CONFIDENCE intervals ,CORD blood ,INTELLIGENCE tests ,LEAD ,MERCURY ,POLYCHLORINATED biphenyls ,RESEARCH funding ,MULTIPLE regression analysis ,DATA analysis software ,DESCRIPTIVE statistics ,CHILDREN ,FETUS - Abstract
Background: Polychlorinated biphenyls (PCBs), methylmercury (MeHg), and lead (Pb) are environmental contaminants known for their adverse effects on cognitive development. Objectives: In this study we examined the effects of prenatal exposure to PCBs, MeHg, and Pb on cognitive development in a sample of Inuit infants from Arctic Québec. Methods: Mothers were recruited at local prenatal clinics. PCBs, mercury (Hg), Pb, and two seafood nutrients-docosahexaenoic acid (DHA) and selenium (Se)--were measured in umbilical cord blood. Infants (n = 94) were assessed at 6.5 and 11 months of age on the Fagan Test of Infant Intelligence (FTII), A-not-B test, and Bayley Scales of Infant Development-2nd Edition (BSID-II). Results: Multiple regression analyses revealed that higher prenatal PCB exposure was associated with decreased FTII novelty preference, indicating impaired visual recognition memory. Prenatal Hg was associated with poorer performance on A-not-B, which depends on working memory and is believed to be a precursor of executive function. Prenatal Pb was related to longer FTII fixation durations, indicating slower speed of information processing. Conclusions: PCBs, MeHg, and Pb each showed specific and distinct patterns of adverse associations with the outcomes measured during infancy. By contrast, none of these exposures was associated with performance on the BSID-II, a global developmental measure. The more focused, narrow band measures of cognitive function that appeared to be sensitive to these exposures also provide early indications of long-term impairment in specific domains that would otherwise not likely be evident until school age. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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