A recent study has identified a concerning connection between prenatal exposure to chlorpyrifos (CPF), a common insecticide, and lasting changes in brain structure as well as reduced motor function in children and adolescents. These findings, published in the journal JAMA Neurology, offer the first evidence of widespread, enduring impacts on the brain’s molecular, cellular, and metabolic processes resulting from early exposure to the chemical.
Researchers from the Columbia University Mailman School of Public Health, Children’s Hospital Los Angeles, and the Keck School of Medicine of USC collaborated on this investigation. They monitored 270 children and adolescents participating in the Columbia Center for Children’s Environmental Health birth cohort. All subjects were born to African-American and Latino mothers and had detectable levels of CPF in their umbilical cord blood. Between the ages of 6 and 14, these participants underwent behavioral evaluations and brain imaging.
How Exposure Affects Brain Development
The results showed a clear, dose-dependent relationship. Higher levels of prenatal insecticide exposure were directly associated with more significant alterations in brain structure, function, and metabolic health. Furthermore, those with higher exposure levels demonstrated poorer performance in tests measuring motor speed and motor programming. The researchers concluded that prenatal exposure to CPF appears to cause persistent disturbances in brain development that are proportional to the amount of exposure a child received before birth.
The Source of Exposure and Ongoing Risks
While the U.S. Environmental Protection Agency (EPA) prohibited the indoor residential use of CPF in 2001, the chemical remains in use for agricultural purposes 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. 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,” explained Virginia Rauh, ScD, the study’s senior author and the Jane and Alan Batkin Professor of Population and Family Health at Columbia Mailman School.
Protecting Early Brain Development
The researchers emphasize that the impacts of this single pesticide were noted across broad areas of the brain. Because other organophosphate pesticides may carry similar risks, the team suggests that individuals should take precautions to reduce exposure during pregnancy and early childhood, periods when the brain is developing 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. 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,” said the study’s first author, Bradley Peterson, MD, who serves as the Vice Chair for Research and Chief of Child & Adolescent Psychiatry at the Keck School of Medicine of USC.
Study Contributors and Funding
This research involved a broad team of experts, including Howard Andrews, Wanda Garcia, and Frederica Perera from Columbia Mailman; Sahar Delavari, Ravi Bansal, Siddhant Sawardekar, and Chaitanya Gupte from the Institute for the Developing Mind at Children’s Hospital Los Angeles; and Lori A. Hoepner from the SUNY Downstate School of Public Health.
Financial support for the project was provided by 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. Additional funding was provided by an anonymous donor, the Robert Coury family, the Inspirit Fund, and Patrice and Mike Harmon.
Regarding conflicts of interest, Dr. Peterson is the President of Evolve Psychiatry Professional Corporation and an advisor to Evolve Adolescent Behavioral Health, where he receives stock options and provides expert testimony. Dr. Peterson and Dr. Bansal hold a U.S. Patent (Number 61/424,172), and Dr. Peterson holds two additional U.S. Patents (61/601,772 and 8,143,890B2). All other authors reported no competing or potential conflicts of interest.