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Effects of environmental contaminant exposure on visual brain development: a prospective electrophysiological study in school-aged children.
- Source :
-
Neurotoxicology [Neurotoxicology] 2012 Oct; Vol. 33 (5), pp. 1075-85. Date of Electronic Publication: 2012 Jun 07. - Publication Year :
- 2012
-
Abstract
- The Inuit from Nunavik (Northern Québec) are one of the most highly exposed populations to environmental contaminants in North America mainly due to the bioaccumulation of contaminants in fish and marine mammals that constitute an important part of their diet. This follow-up study aimed to assess the impact of exposure to contaminants on visual brain development in school-age Inuit children (mean age=10.9 years). Concentrations of polychlorinated biphenyls (PCBs), mercury (Hg), and lead (Pb) were measured in umbilical cord blood and again in blood samples at the time of testing, reflecting pre- and current exposure, respectively. Pattern-reversal visual evoked potentials (VEPs) were scalp-recorded at the occipital cortex. Visual stimulation consisted of achromatic gratings presented at four visual contrast levels: 95%, 30%, 12% and 4%. The relation between environmental contaminant body burdens and VEPs was examined by regression analysis controlling for confounding variables, including fish nutrients and other toxicants. No significant association was found for PCB exposure after statistical adjustments. Cord blood mercury level was associated with a reduction of the N75 amplitude at the highest contrast level and with a delay of the N75 latency at the 12% contrast level. Prenatal exposure to lead was associated with a delay of the N150 latency at most contrast levels. This study suggests that heavy metal exposure, in particular during the gestational period, can impair the development of visual processing.<br /> (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Subjects :
- Analysis of Variance
Brain physiology
Brain Mapping
Canada epidemiology
Canada ethnology
Child
Electroencephalography
Environmental Pollutants blood
Evoked Potentials, Visual physiology
Female
Follow-Up Studies
Humans
Inuit
Lead blood
Lead toxicity
Linear Models
Male
Mercury blood
Mercury toxicity
Nutrition Assessment
Photic Stimulation methods
Polychlorinated Biphenyls blood
Polychlorinated Biphenyls toxicity
Prospective Studies
Reaction Time drug effects
Brain drug effects
Environmental Exposure adverse effects
Environmental Pollutants toxicity
Evoked Potentials, Visual drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 1872-9711
- Volume :
- 33
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Neurotoxicology
- Publication Type :
- Academic Journal
- Accession number :
- 22683800
- Full Text :
- https://doi.org/10.1016/j.neuro.2012.05.010