Research links common insecticide to neurodevelopmental disorders

Newswise —

A fresh research by The University of Toledo proposes that premature exposure to a prevalent group of insecticides known as pyrethroids could amplify the probability of autism and other developmental maladies, despite being at levels presently acknowledged as safe by federal regulators.

The findings, which come from a study of mice, were published today in the peer-reviewed journal PNAS Nexus.

Pyrethroids are among the most extensively employed insecticides across the nation, found in both commercial formulations and consumer goods.

"Someone who comes and sprays in your house is most likely using this. It's employed in landscaping, and for mosquito fogging in streets. It's ubiquitous," stated Dr. James Burkett, the corresponding author of the paper and an assistant professor of neuroscience at the UToledo College of Medicine and Life Sciences. "Nonetheless, our research further substantiates the notion that these substances may not be as harmless for kids and expectant mothers as we formerly assumed."

The interest in a plausible association between autism and pyrethroids has intensified following several epidemiological investigations that have reported increased occurrences of neurodevelopmental ailments in regions where these pesticides were utilized.

The recent research, led by UToledo, endeavored to advance those population-based investigations by scrutinizing the precise alterations in behavior that can be attributed to minimal exposure to pyrethroids.

Burkett collaborated with a team comprising researchers from Columbia, Emory, and the University of Southern California. They examined the progeny of female mice that were exposed to minute quantities of the pyrethroid insecticide deltamethrin before, during, and immediately after pregnancy.

The researchers discovered that those mice demonstrated elevated levels of hyperactivity and repetitive behaviors, reduced vocalization, and were more prone to failure in fundamental learning assessments as compared to the control group.

The young mice also experienced disruptions in their dopamine system.

"These outcomes are akin to the symptoms exhibited by humans who suffer from neurodevelopmental disorders," Burkett stated. "We're not implying that these mice have autism or ADHD. That's not the aim of our research. What we're suggesting is that exposure to this insecticide has altered something in their brain, resulting in the same patterns of behavior that we witness in children with autism."

Dr. Gary Miller, a co-author of the study and the vice dean for research strategy and innovation at the Columbia University Mailman School of Public Health, affirmed that the research builds upon earlier attempts to recognize other pest control chemicals that may pose a threat to health.

"Over the past few decades, we have reduced our exposure to various hazardous pesticides by imposing restrictions and regulations," Miller commented. "This research contributes to the increasing literature that suggests widely used pyrethroids are not without harmful consequences and should be subjected to further scrutiny regarding their safety."

According to the Centers for Disease Control and Prevention, the frequency of autism in the United States has substantially increased over the last twenty years, climbing from one in 150 children in 2000 to one in 44 children in 2018.

While part of this rise can be attributed to greater awareness of autism spectrum disorder and enhanced diagnostic processes, the majority of autism cases remain without a known cause, leaving scientists uncertain about the exact reasons behind this trend.

Burkett remarked, "Genetics has conventionally been the main focus of research, but it has been recognized that the environment also plays a significant role. However, we still have a very limited understanding of these factors. This is why this research is crucial. While genetics cannot be changed, environmental factors can be addressed."

Although pyrethroids have been connected to autism, they are not the only type of pesticide that has been linked to the disorder. Scientists widely acknowledge that autism is not caused by a single trigger and that multiple factors are involved in its development.

Burkett stated, "This study provides a part of the puzzle. It does not offer conclusive evidence that the pesticide is dangerous or directly linked to autism in humans. Nevertheless, it might indicate that the safe level of the pesticide should be reconsidered for pregnant women and children."