title: Neurodevelopmental investigations among methylmercury-exposed children in French Guiana.
abstract: French Guiana, like its neighbors, suffers from environmental pollution with methylmercury from gold mining activities, and Amerindian communities are particularly affected. A neurological and a neurospsychological evaluation were carried out in children of three Amerindian communities with various levels of pollution: 156 children from the Upper Maroni (high exposure), 69 from Camopi on the Oyapock river (median exposure), and 153 from Awala on the Atlantic coast (low exposure). Exposure to methylmercury was measured by determination of total mercury in the hair of the children and their mothers (geometric mean, 12.7 microg/g in Upper Maroni). No major neurologic signs were observed in the children examined. After adjustment for potential confounders, we found a dose-dependent association between maternal hair mercury level and increased deep tendon reflexes, poorer coordination of the legs, and decreased performance in the Stanford-Binet Copying score, which measures visuospatial organization. In this last test, the frequency of rotation errors was high in the 5-6 years age group and increased with mercury exposure. These associations depended on the sex of child and were stronger among boys. The interpretation of these results is limited mainly by the cross-sectional design of the study. It identifies specific neurological and neuropsychological deficits, in some cases modulated by sex, which are consistent with known targets of mercury neurotoxicity.
authors.affiliation: Unit 170-Epidemiological and Statistical Research on Environment and Health, National Institute of Health and Medical Research (INSERM), 94807 Villejuif Cedex, France.
authors.forename: Sylvaine
authors.initials: S
authors.lastname: Cordier
authors.forename: Micheline
authors.initials: M
authors.lastname: Garel
authors.forename: Laurence
authors.initials: L
authors.lastname: Mandereau
authors.forename: Hervé
authors.initials: H
authors.lastname: Morcel
authors.forename: Philippe
authors.initials: P
authors.lastname: Doineau
authors.forename: Sylvie
authors.initials: S
authors.lastname: Gosme-Seguret
authors.forename: Denise
authors.initials: D
authors.lastname: Josse
authors.forename: Roberta
authors.initials: R
authors.lastname: White
authors.forename: Claudine
authors.initials: C
authors.lastname: Amiel-Tison
mesh_terms: D002648:Child; D002675:Child, Preschool; D003072:Cognition Disorders / Q000139:chemically induced; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D005260:Female; D005616:French Guiana; D006801:Humans; D007198:Indians, North American; D007223:Infant; D008297:Male; D008767:Methylmercury Compounds / Q000009:adverse effects*; D019957:Motor Skills Disorders / Q000139:chemically induced; D009420:Nervous System / Q000187:drug effects* / Q000254:growth & development*; D009483:Neuropsychological Tests
chemical_list: D008767:Methylmercury Compounds