Parkinson's risk increases with exposure to common chemical, study suggests

A UCLA study published in the journal Springer Nature Link suggests that exposure to chlorpyrifos could increase the risk of the neurological disease.

The study compared 829 people with Parkinson's to 824 people without the disease over a 45-year period, focusing on their proximity to chlorpyrifos.

In humans, the study revealed that long-term exposure to chlorpyrifos led to more than a 2.5 times higher risk of Parkinson's.

In mice, exposure to the pesticide caused movement problems similar to Parkinson's symptoms, loss of dopamine-producing neurons, increased brain inflammation and build-up of harmful proteins.

Dr. Jeff Bronstein, director of the Movement Disorders Program at UCLA and professor of neurology and molecular toxicology, noted that previous human studies also suggested an association between chlorpyrifos exposure and Parkinson's.

"[We were] surprised that the mechanism of toxicity was apparent in both mice and zebrafish," he said. "We rarely find such consistent results in different animal models."

The researcher emphasized that the association between pesticide exposure and Parkinson's was "very strong," and the longer someone was exposed, the higher the risk became.

"People should avoid exposure to CPF and similar pesticides (organophosphates) by not using them in their home, eating organics, and washing fruits and vegetables before eating them," Bronstein advised.

The study did have some limitations, the researchers acknowledged, primarily that it was observational, meaning it shows an association but cannot prove causation.

There was also the possibility that chlorpyrifos was used along with other chemicals, which means it could be difficult to measure its specific impact, the study noted.

Chlorpyrifos is used to control different kinds of pests, like termites, mosquitoes and roundworms, among crops, according to the National Pesticide Information Center (NPIC) at Oregon State University.

In 2021, the EPA banned the use of chlorpyrifos on food crops, but a federal appeals court overturned that decision in 2023, allowing its use to resume on some crops while regulators revisit the rule.

In January 2026, the EPA issued an update outlining plans to move forward with a rule that would ban most uses of chlorpyrifos.

Fox News Digital reached out to several manufacturers of the chemical for comment.

Corteva, an Indiana agrichemical company formed in 2019 through the merger of Dow Chemical and DuPont, announced in 2020 that it would end production of chlorpyrifos within the year, citing declining sales.

In April 2022, the German chemical company BASF requested the cancellation of its pesticide registrations for products containing chlorpyrifos. 

No products from Corteva or BASF were included in the study linking chlorpyrifos to Parkinson's disease.