Neurodevelopmental investigations among methylmercury-exposed children in French Guiana.
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.
Cordier
Sylvaine
S
Unit 170-Epidemiological and Statistical Research on Environment and Health, National Institute of Health and Medical Research (INSERM), 94807 Villejuif Cedex, France.
Garel
Micheline
M
Mandereau
Laurence
L
Morcel
Hervé
H
Doineau
Philippe
P
Gosme-Seguret
Sylvie
S
Josse
Denise
D
White
Roberta
R
Amiel-Tison
Claudine
C
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
D008767:Methylmercury Compounds