Relation of prenatal methylmercury exposure from environmental sources to childhood IQ
Jacobson, JL; Muckle, G; Ayotte, P; Dewailly, É; Jacobson, SW
HERO ID
3103322
Reference Type
Journal Article
Year
2015
Language
English
PMID
| HERO ID | 3103322 |
|---|---|
| In Press | No |
| Year | 2015 |
| Title | Relation of prenatal methylmercury exposure from environmental sources to childhood IQ |
| Authors | Jacobson, JL; Muckle, G; Ayotte, P; Dewailly, É; Jacobson, SW |
| Journal | Environmental Health Perspectives |
| Volume | 123 |
| Issue | 8 |
| Page Numbers | 827-833 |
| Abstract | <strong>BACKGROUND: </strong>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.<br /><br /><strong>OBJECTIVES: </strong>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.<br /><br /><strong>METHODS: </strong>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.<br /><br /><strong>RESULTS: </strong>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.<br /><br /><strong>CONCLUSIONS: </strong>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. |
| Doi | 10.1289/ehp.1408554 |
| Pmid | 25757069 |
| Wosid | WOS:000360693100026 |
| Url | https://www.scopus.com/inward/record.uri?eid=2-s2.0-84929449315&doi=10.1289%2fehp.1408554&partnerID=40&md5=8e0ec6031d9d685ead5d5d7adfe792cc |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Scopus URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84929449315&doi=10.1289%2fehp.1408554&partnerID=40&md5=8e0ec6031d9d685ead5d5d7adfe792cc |
| Is Public | Yes |
| Language Text | English |
| Keyword | 2,2',4,4',5,5' hexachlorobiphenyl; docosahexaenoic acid; lead; mercury; methylmercury; selenium; docosahexaenoic acid; methylmercury derivative; pollutant; polychlorinated biphenyl; adolescent; Article; behavioral science; blood sampling; child; cognition; controlled study; dietary intake; environmental exposure; female; functional assessment; hair analysis; human; intellectual impairment; intelligence quotient; limit of detection; male; mass fragmentography; neuropsychological test; Perceptual Reasoning Index; priority journal; Processing Speed Index; Verbal Comprehension Index; Wechsler Intelligence Scale; Working Memory Index; Arctic; chemically induced; cohort analysis; drug effects; epidemiology; intelligence; pollutant; pregnancy; prenatal exposure; Quebec; toxicity; Adolescent; Arctic Regions; Child; Cohort Studies; Docosahexaenoic Acids; Environmental Exposure; Environmental Pollutants; Female; Humans; Intelligence; Male; Methylmercury Compounds; Polychlorinated Biphenyls; Pregnancy; Prenatal Exposure Delayed Effects; Quebec |
| Relationship(s) |
|