A recent study identified a worrying link between prenatal exposure to the common insecticide chlorpyrifos (CPF) and persistent changes in brain structure and decreased motor function in children and adolescents. These findings published in the journal JAMA Neurologyprovides the first evidence of widespread and lasting effects on molecular, cellular, and metabolic processes in the brain due to early exposure to chemicals.
Researchers from Columbia University Mailman School of Public Health, Children’s Hospital Los Angeles, and the Keck School of Medicine of the University of Southern California collaborated on the study. They monitored 270 children and adolescents participating in a birth cohort at the Columbia Children’s Environmental Health Center. 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 assessments and brain imaging.
Effects of exposure on brain development
The results showed a clear dose-dependent relationship. Higher levels of prenatal pesticide exposure were directly associated with more profound changes in brain structure, function, and metabolic health. Additionally, those with higher levels of exposure showed poorer performance on tests measuring motor speed and motor programming. The researchers concluded that prenatal exposure to CPF appears to cause lasting impairments in brain development proportional to the amount of exposure a child receives before birth.
Sources of exposure and ongoing risks
Although the U.S. Environmental Protection Agency (EPA) banned CPF from indoor residential use in 2001, the chemical continues to be used on a variety of non-organic fruits, grains, and vegetables for agricultural purposes. As a result, people living near agricultural areas can still encounter toxins through dust and outside air.
“Current widespread exposures comparable to the levels experienced in this sample continue to put farmworkers, pregnant women, and fetuses at risk. As infants continue to be at risk, it is critical that we continue to monitor exposure levels in potentially vulnerable populations, especially pregnant women in rural areas,” explained the study’s lead author, Dr. Virginia Lau, the Jane and Alan Batkin Professor at the Columbia Mailman School.
protect early brain development
The researchers highlighted that the effects of this single pesticide were seen across a wide range of brain regions. Because other organophosphate pesticides may carry similar risks, the researchers suggest that precautions should be taken to reduce exposure during pregnancy and early childhood, when the brain is rapidly developing and is highly sensitive to toxic substances.
“The brain tissue and metabolic disturbances observed with prenatal exposure to this particular pesticide were significantly widespread throughout the brain. Other organophosphate pesticides are likely to have similar effects, and care must be taken to minimize exposure during pregnancy, infancy, and early childhood, when the brain is rapidly developing and is especially vulnerable to these toxic chemicals,” said the study’s lead author, Bradley Peterson, M.D., vice chair of research and director of the Division of Child and Adolescent Psychiatry. at the Keck School of Medicine of the University of Southern California.
Research contributors and funders
An extensive team of experts participated in this investigation, including Columbia Mailman’s Howard Andrews, Wanda Garcia, and Frederica Perera. Sahar Deravalli, Ravi Bansal, Siddhant Sawardekar, and Chaitanya Gupte from the Institute of Mental Development at Children’s Hospital Los Angeles; and Lori A. Hepner of the State University of New York Downstate School of Public Health.
Financial support for this project was provided by the National Institute of Environmental Health Sciences, the U.S. Environmental Protection Agency’s STAR program, the National Institute of Mental Health, and the John and Wendy Neu Family Foundation. Additional funding was provided by anonymous donors the Robert Cooley Family, the InSpirit Foundation, and Patrice Harmon and Mike Harmon.
Regarding conflicts of interest, Dr. Peterson is president of Evolve Psychiatry Professional Corporation and a consultant to Evolve Adolescent Behavioral Health, where he receives stock options and provides expert testimony. Dr. Peterson and Dr. Bansal hold a US patent (number 61/424,172), and Dr. Peterson holds two additional US patents (61/601,772 and 8,143,890B2). All other authors report no competing or potential conflicts of interest.
