Prenatal exposure to chlorpyrifos (CPF), a widely used insecticide, causes lasting changes in brain structure and reduced motor function in children and adolescents, according to a new study published inJAMA Neurology. The findings mark the first evidence of widespread, enduring impacts on the brain's molecular, cellular, and metabolic processes from early exposure to the chemical.
Researchers from Columbia University Mailman School of Public Health, Children's Hospital Los Angeles, and the Keck School of Medicine of USC collaborated on the investigation. They monitored 270 children and adolescents from the Columbia Center for Children's Environmental Health birth cohort. All subjects, born to African-American and Latino mothers, had detectable levels of chlorpyrifos in their umbilical cord blood. Between the ages of 6 and 14, these participants underwent behavioral evaluations and brain imaging.
The study found a clear, dose-dependent relationship.
Higher levels of prenatal insecticide exposure correlated directly with more significant alterations in brain structure, function, and metabolic health. At the same time, those with higher exposure levels performed worse on tests measuring motor speed and motor programming. The researchers concluded that prenatal exposure to chlorpyrifos appears to cause persistent disturbances in brain development proportional to the amount of exposure a child received before birth.
Continued Exposure Risks
While the U.S. Environmental Protection Agency (EPA) prohibited the indoor residential use of CPF in 2001, the chemical remains in agricultural use on various non-organic fruits, grains, and vegetables. As a result, individuals living near agricultural zones may still encounter the toxin through dust and outdoor air.
“Current widespread exposures, at levels comparable to those experienced in this sample, continue to place farm workers, pregnant women, and unborn children in harm’s way,” said Virginia Rauh, ScD, the study’s senior author and the Jane and Alan Batkin Professor of Population and Family Health at Columbia Mailman School. “It is vitally important that we continue to monitor the levels of exposure in potentially vulnerable populations, especially in pregnant women in agricultural communities, as their infants continue to be at risk.”
Widespread Brain Impact
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The researchers emphasized that the impacts of this single pesticide were noted across broad areas of the brain. Other organophosphate pesticides may carry similar risks. The team suggests individuals take precautions to reduce exposure during pregnancy and early childhood, periods when the brain develops rapidly and remains highly sensitive to toxic substances.
“The disturbances in brain tissue and metabolism that we observed with prenatal exposure to this one pesticide were remarkably widespread throughout the brain,” said Bradley Peterson, MD, the study’s first author and Vice Chair for Research and Chief of Child & Adolescent Psychiatry at the Keck School of Medicine of USC. “Other organophosphate pesticides likely produce similar effects, warranting caution to minimize exposures in pregnancy, infancy, and early childhood, when brain development is rapid and especially vulnerable to these toxic chemicals.”
The National Institute of Environmental Health Sciences, the U.S. Environmental Protection Agency STAR program, the National Institute of Mental Health, and the John and Wendy Neu Family Foundation provided financial support for the project.
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