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
Boucher, O; Muckle, G; Jacobson, JL; Carter, RC; Kaplan-Estrin, M; Ayotte, P; Dewailly, E; Jacobson, SW
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.Citation: Boucher O, Muckle G, Jacobson JL, Carter RC, Kaplan-Estrin M, Ayotte P, Dewailly É, Jacobson SW. 2014. 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. Environ Health Perspect 122:310-316; http://dx.doi.org/10.1289/ehp.1206323.
docosahexaenoic acid; lead; mercury; polychlorinated biphenyl; selenium; A not B test; adult; article; Bayley Scales of Infant Development; blood sampling; child; cognition; executive function; fagan test of infant intelligence; female; food contamination; human; infant; intelligence quotient; male; named inventories, questionnaires and rating scales; prenatal exposure; priority journal; psychologic test; school child; sea food; umbilical cord blood; visual memory; Wechsler Intelligence Scale; working memory; Adolescent; Adult; Child; Child Development; Cognition; Environmental Exposure; Environmental Monitoring; Environmental Pollutants; Female; Humans; Infant; Inuits; Lead; Male; Methylmercury Compounds; Polychlorinated Biphenyls; Pregnancy; Prenatal Exposure Delayed Effects; Quebec; Young Adult
