Common Insecticide Used In Homes, Landscaping Linked To Autism In New Study

Early exposure to a common class of insecticides called pyrethroids could increase the risk of autism and neurodevelopmental disorders.

Researchers from the University of Toledo found in a recently published study how the brain is affected by the common insecticide deemed safe by federal regulators at certain levels when exposed early.

"If you have someone who comes and sprays in your house, this is likely what they're spraying. It's used in landscaping, it's what they fog in the streets for mosquitos. It's everywhere," corresponding author Dr. James Burkett said in a release.

"Our study, however, adds to the evidence that these chemicals might not be as safe for children and pregnant women as we once believed," the assistant professor of neuroscience at the UToledo College of Medicine and Life Sciences added.

According to the research team, neurodevelopmental disorders (NDD) have become widespread, affecting around 17% of children in the United States. Since pyrethroids are some of the most widely used insecticides in the country, they wanted to see if this was a contributing factor.

Pyrethroids are present in many consumer products and industrial preparations. Federal regulators allowed their use at levels deemed safe for human exposure. But the new study published in PNAS Nexus says otherwise.

Previous epidemiological research documented higher rates of brain development problems in places where the insecticide was frequently used, sparking interest in a possible link between the chemicals and autism.

"Ambient exposure to pyrethroid pesticides during pregnancy has been implicated as a potential risk factor for NDD in the unborn child. Using a mouse model, we demonstrate here that low-dose developmental exposure to the pyrethroid deltamethrin causes an NDD-relevant behavioral phenotype, along with related changes in the dopamine system in the brain," the team wrote.

To find out how low-level exposure to pyrethroids affected developing brains, Burkett and colleagues from Columbia, Emory and the University of Southern California examined the offspring of female mice exposed to small doses of the insecticide before, during and after pregnancy.

The scientists noticed that the young mice developed repetitive behaviors and had increased hyperactivity. They also mostly failed basic learning tests compared to the control group.

"These are all similar to symptoms human patients with neurodevelopmental disorders might have. We are not saying these mice have autism or that they have ADHD. That's not the goal here," Burkett said.

"What we are saying is that something in their brain has been altered by this exposure, and it's resulting in the same kinds of behaviors that we see in children with autism."

Burkett added that while their findings may not be definitive proof that the insecticide directly causes autism in humans, they suggest the importance of revisiting the levels of the pesticide deemed safe for human exposure, especially among pregnant women and kids.