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Home » News » Prenatal Exposure to Insecticide Chlorpyrifos Linked to Alterations in Brain Structure and Cognition 04/29/2012

Prenatal Exposure to Insecticide Chlorpyrifos Linked to Alterations in Brain Structure and Cognition

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Main Effects of CPF Exposure on Brain Surface Measures

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While No Longer Registered for Household Use in the U.S., the Insecticide Is Widely Used Around the World and in U.S. Agriculture

 

Even low to moderate levels of exposure to the insecticide chlorpyrifos during pregnancy may lead to long-term, potentially irreversible changes in the brain structure of the child, according to a new brain imaging study by researchers from the Columbia Center for Children's Environmental Health at the Mailman School of Public Health, Duke University Medical Center, Emory University, and the New York State Psychiatric Institute. The changes in brain structure are consistent with cognitive deficits found in children exposed to this chemical.

Results of the study appear online in the April 30 PNAS.

The new study is the first to use MRI to identify the structural evidence for these cognitive deficits in humans,confirming earlier findings in animals. Changes were visible across the surface of the brain, with abnormal enlargement of some areas and thinning in others. The disturbances in brain structure are consistent with the IQ deficits previously reported in the children with high exposure levels of chlorpyrifos, or CPF, suggesting a link between prenatal exposure to CPF and deficits in IQ and working memory at age 7.

The study also reports evidence that CPF may eliminate or reverse the male-female differences that are ordinarily present in the brain. Further study is needed to determine the consequences of these changes before and after puberty, the researchers say.

Notably, the brain abnormalities appeared to occur at exposure levels below the current EPA threshold for toxicity, which is based on exposures high enough to inhibit the action of the key neurological enzyme cholinesterase. The present findings suggest that the mechanism underlying structural changes in the brain may involve other pathways.

According to the lead author, Virginia Rauh, ScD, Professor at the Mailman School of Public Health and Deputy Director of the Columbia Center for Children's Environmental Health, "By measuring a biomarker of CPF exposure during pregnancy, and following the children prospectively from birth into middle childhood, the present study provides evidence that the prenatal period is a vulnerable time for the developing child, and that toxic exposure during this critical period can have far-reaching effects on brain development and behavioral functioning."

"By combining brain imaging and community-based research, we now have much stronger evidence linking exposure to chlorpyrifos with neurodevelopmental problems," adds senior author Bradley S. Peterson, MD, Chief of Child & Adolescent Psychiatry, New York State Psychiatric Institute, an