Alterations of visual evoked potentials in preschool Inuit children exposed to methylmercury and polychlorinated biphenyls from a marine diet.
The aim of the present study was to assess the impact of chronic exposure to polychlorinated biphenyls (PCBs) and methylmercury on visual brain processing in Inuit children from Nunavik (Northern Québec, Canada). Concentrations of total mercury in blood and PCB 153 in plasma had been measured at birth and they were again measured at the time of testing in 102 preschool aged children. Relationships between contaminants and pattern-reversal visual evoked potentials (VEPs) were assessed by multivariate regression analyses, taking into account several potential confounding variables. The possible protective effects of selenium and omega-3 polyunsaturated fatty acids against methylmercury and PCB toxicity were also investigated. Results indicate that exposure to methylmercury and PCBs resulting from fish and sea mammal consumption were associated with alterations of VEP responses, especially for the latency of the N75 and of the P100 components. In contrast, the concomitant intake of omega-3 polyunsaturated fatty acids was associated with a shorter latency of the P100. However, no significant interactions between nutrients and contaminants were found, contradicting the notion that these nutrients could afford protection against environmental neurotoxicants. Interestingly, significant associations were found with concentrations of neurotoxicants in blood samples collected at the time of testing, i.e. at the preschool age. Our findings suggest that VEP can be used as a valuable tool to assess the developmental neurotoxicity of environmental contaminants in fish-eating populations.
Saint-Amour
Dave
D
Département d'ophtalmologie, CHU Sainte-Justine, 3175, Côte Sainte-Catherine, Montréal, Que., Canada H3T 1C5.
Roy
Marie-Sylvie
MS
Bastien
Célyne
C
Ayotte
Pierre
P
Dewailly
Eric
E
Després
Christine
C
Gingras
Suzanne
S
Muckle
Gina
G
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D004032:Diet; D005074:Evoked Potentials, Visual / Q000187:drug effects*; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology; D005260:Female; D005506:Food Contamination; D006801:Humans; D007231:Infant, Newborn; D004930:Inuit; D008297:Male; D008767:Methylmercury Compounds / Q000633:toxicity*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012044:Regression Analysis; D012643:Selenium / Q000494:pharmacology
D000975:Antioxidants; D015525:Fatty Acids, Omega-3; D008767:Methylmercury Compounds; D011078:Polychlorinated Biphenyls; D012643:Selenium