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Background: Although prenatal methylmercury exposure has been linked to poorer intellectual function in several studies, data from two major prospective, longitudinal studies yielded contradictory results. Associations with cognitive deficits were reported in a Faroe Islands cohort, but few were found in a study in the Seychelles Islands. It has been suggested that co-exposure to another contaminant, polychlorinated biphenyls (PCBs), may be responsible for the positive findings in the former study and that co-exposure to nutrients in methylmercury-contaminated fish may have obscured and/or protected against adverse effects in the latter. Objectives: We aimed to determine the degree to which co-exposure to PCBs may account for the adverse effects of methylmercury and the degree to which co-exposure to docosahexaenoic acid (DHA) may obscure these effects in a sample of Inuit children in Arctic Québec. Methods: IQ was estimated in 282 school-age children from whom umbilical cord blood samples had been obtained and analyzed for mercury and other environmental exposures. Results: Prenatal mercury exposure was related to poorer estimated IQ after adjustment for potential confounding variables. The entry of DHA into the model significantly strengthened the association with mercury, supporting the hypothesis that beneficial effects from DHA intake can obscure adverse effects of mercury exposure. Children with cord mercury ≥ 7.5 μg/L were four times as likely to have an IQ score < 80, the clinical cut-off for borderline intellectual disability. Co-exposure to PCBs did not alter the association of mercury with IQ. Conclusions: To our knowledge, this is the first study to document an association of prenatal mercury exposure with poorer performance on a school-age assessment of IQ, a measure whose relevance for occupational success in adulthood is well established. This association was seen at levels in the range within which many U.S. children of Asian-American background are exposed. [ABSTRACT FROM AUTHOR]

Alcohol consumption during pregnancy, a known teratogen often associated with drug use and smoking is a well-known public health concern. This study provides prevalence data for alcohol, smoking, and illicit drug use before, during, and after pregnancy among Inuit. Factors associated with alcohol use are also identified. Two hundred and eight Inuit women from Arctic Quebec were interviewed at mid-pregnancy, and at 1 and 11 months postpartum to provide descriptive data on smoking, alcohol, and drug use during pregnancy, and the year before and after pregnancy. Sociodemographic and family characteristics potentially associated with alcohol use were documented. Ninety-two percent of the women reported smoking and 61% reported drinking during pregnancy. Episodes of binging during pregnancy were reported by 62% of the alcohol users, which correspond to 38% of pregnant women. Thirty-six percent of the participants reported using marijuana during pregnancy. Alcohol use and binge drinking during pregnancy were more likely to be reported by women who lived in less crowded houses, had a better knowledge of a second language, drank alcohol more often and in larger amounts prior to pregnancy, and used illicit drugs. Binge drinkers were more likely to be single women and to have had fewer previous pregnancies. Postpartum distress and violence were more likely to be experienced by women who used alcohol during pregnancy. Binge drinking during pregnancy was best predicted by drinking habits before pregnancy, maternal symptoms of depression, the use of illicit drugs during pregnancy, and the number of young children living with the mother. These results confirm that alcohol is a major risk factor to maternal and child health in this population, underscoring the need for culturally relevant and effective prevention programs. [ABSTRACT FROM AUTHOR]