Multi-Academic Study Finds No Link Between Pesticide Exposure and Autism Traits

Prenatal exposure to certain insecticides used in agriculture does not appear to be linked to social communication problems and other traits related to autism, according to a new study, “Prenatal Organophosphate Exposure and Autism-Related Traits in Children,” published in JAMA Pediatrics.

Evidence over time has suggested that organophosphate pesticides, which work by interfering with the nervous system of insects, increase children’s risk for neurodevelopmental issues such as IQ loss, cognitive challenges, and attention deficit hyperactivity disorder (ADHD) and. However, whether the chemicals may also contribute to autism-related traits has remained unclear.

Led by NYU Langone Health researchers, the study of pairs of mothers and children showed that nearly all mothers had detectable levels of organophosphate pesticides in their urine during pregnancy, yet the team found no significant relationship in the children between this exposure and traits related to autism.

Potential role of a healthy diet

“While we know that that organophosphate pesticides can harm the developing brain, they were not a major driver of characteristics seen in autism at the relatively low exposure levels we observed,” said study lead author Haleigh Cavalier, PhD. “These results should not be interpreted to mean that such pesticides are safe, nor do they rule out autism-related risks at higher exposures or among more vulnerable groups.”

Cavalier, who was a doctoral student at NYU Grossman School of Medicine’s departments of population health and pediatrics during the study and is now a postdoctoral research scientist at Columbia University, noted that outside of agricultural or occupational settings, most Americans primarily encounter the insecticides when they eat fresh produce. One explanation for the results could be that the health benefits of a diet high in fruits and vegetables may partially offset the chemicals’ potential impact on brain development.

Scientists have identified several genetic markers linked to autism-related traits, but environmental factors that could play a role have remained hotly debated. Small studies of prenatal organophosphate-pesticide exposure have yielded inconsistent findings, with some investigations uncovering a connection while others did not.

For the study, the research team analyzed data from 3,339 mother-child pairs enrolled at 20 medical centers in the U.S. National Institutes of Health’s Environmental Influences on Child Health Outcomes (ECHO) Program. This large nationwide study made it possible to consider many environmental, social, and biological factors that may shape children’s health that past smaller ones could not.

Then, the researchers looked for associations between these metabolite levels and the children’s scores on the Social Responsiveness Scale, a 65-item questionnaire designed to identify social communication problems and autism-related traits.

By rating such challenges on a spectrum, the tool could capture participants who had not been formally diagnosed with autism but displayed many of its common traits, such as avoidance of eye contact, difficulty understanding other people’s emotions, and needing to follow certain routines. The participants were evaluated when they were five to seven years old on average.

“Our results demonstrate that there is still much more to be learned about autism,” said study senior author Akhgar Ghassabian, MD, PhD. “Careful, long-term research can help clarify which environmental exposures matter most so that communities and policymakers can make more-informed decisions.”

Ghassabian, an associate professor in NYU Grossman’s departments of pediatrics and population health, says the researchers next plan to examine how other types of pesticides, as well as microplastics and other toxins, may contribute to autism. They also plan to assess how genes tied to the condition may interact with these environmental hazards.

The authors caution that the metabolites measured in the study are short-lived in the human body, so they can vary over time. They are also influenced by each participant’s metabolism. As a result, the markers might not provide a full picture of pesticide exposure.

The new assessment is the largest and most diverse of its kind to examine whether the insecticides might contribute to autism, the authors point out. Other study co-investigators included researchers from Johns Hopkins University, Drexel University, the New York State Department of Health, University of Washington, Kaiser Permanente in Pleasanton, CA, University of California, Davis, University of Southern California in Los Angeles, University of Utah, Michigan State University, Emory University, University of Michigan, University of Illinois Urbana-Champaign, University of Rochester in New York, Dartmouth College, and Columbia University.

The post Multi-Academic Study Finds No Link Between Pesticide Exposure and Autism Traits appeared first on GEN - Genetic Engineering and Biotechnology News.