Prenatal Insecticide Exposure Alters Developing Brain

(HealthDay News) – Prenatal exposure to chlorpyrifos (CPF), an organophosphate insecticide, correlates with structural changes in the developing brain.

Virginia A Rauh, ScD, from the Heilbrunn Center for Population and Family Health in New York City, and colleagues used magnetic resonance imaging from 40 children, aged 5.9–11.2 years, to investigate the association between CPF exposure and brain morphology. Cortical surface features were compared for 20 high-exposure (upper tertile of CPF concentrations in umbilical cord blood) and 20 low-exposure children.

The researchers found that high CPF exposure correlated with enlargement of the following brain regions: superior temporal, posterior middle temporal, and inferior postcentral gyri bilaterally; supramarginal gyrus and inferior parietal lobule of the right hemisphere; and superior frontal gyrus, gyrus rectus, cuneus, and precuneus along the mesial wall of the right hemisphere. The group differences were due to the effects of exposure on the underlying white matter. In low-exposure children, CPF disruption of normal IQ associations with surface measures resulted in a significant exposure × IQ interaction. Expected sex differences were not seen in high-exposure children in the right inferior parietal lobule and superior marginal gyrus, and reversal of sex differences were seen in the right mesial superior frontal gyrus. Frontal and parietal cortical thinning were seen in high-exposure children, with an inverse dose-response relationship between CPF and cortical thickness.

“This study reports significant associations of prenatal exposure to a widely used environmental neurotoxicant, at standard use levels, with structural changes in the developing human brain,” the authors write.

One author has provided expert testimony on the health effects of chlorpyrifos.

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