People who are exposed to pesticides as part of their occupation have a higher risk of contracting amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder, according to a new study.
In the systematic review, published on Aug. 4 in the Occupational & Environmental Medicine journal, researchers analyzed eight studies conducted between 1990 and 2025 that estimated the risk of ALS following occupational pesticide exposure.
Any occupational exposure to pesticides was found to be associated with a 60 percent higher odds of ALS compared to unexposed individuals, the review said.
ALS risk for people exposed to herbicides was identified as “slightly greater” than when exposed to insecticides or fungicides, according to the study.
Men had two times the risk of developing ALS after exposure compared to their male counterparts without exposure. However, no such increased risk was found between women exposed to pesticides and unexposed females.
According to a November 2024 report from the Centers for Disease Control and Prevention, ALS is a disease that affects nerve cells in the body, causing these cells to stop working and die.
Once a person contracts the disease, the nerves lose their ability to trigger specific muscles. This weakens the muscles, leading to paralysis.
ALS tends to be age-related, with most people finding out they have the disease when they’re between 55 and 75 years old, the CDC said. Affected people typically live for two to five years after symptoms develop. Those who contract the illness at a young age tend to live slightly longer.
The study said the findings add to the evidence that occupational pesticide exposure contributes to the risk of ALS and suggested implementing interventions to reduce occupational pesticide exposure.
The review was funded by the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) in Montreal, Canada. Authors declared no competing interests.
According to a June 25 update from the CDC, between 2014 and 2016, a total of 16,601 new ALS cases popped up in the United States among people aged 18 and above. Most of these new cases were among men. Race-wise, white people accounted for the majority of new cases.
In a comment submitted to the Science Media Center, a charity that seeks to provide accurate and evidence-based information about science and engineering, Martin Scholze, a research fellow at Brunel University of London, said the study’s main finding about a 60 percent higher risk of ALS was based on a relatively small number of studies.
As such, the evidence should be taken as “suggestive rather than definitive,” Scholze said.
Another issue raised by Scholze was that most studies analyzed relied on self-reported occupational exposure and lacked quantitative information on factors such as exposure intensity.
However, “overall, the authors’ conclusions are appropriately cautious and are supported by the available data, provided they are interpreted as evidence of an association rather than proof of causation,” Scholze said.
Meanwhile, in June, Rep. Mike Bost (R-Ill.) introduced the Take Care of America’s Veterans Act. Section 103 of the bill relates to the Dependency and Indemnity Compensation (DIC) given to surviving spouses of veterans who die from ALS.
Section 103 clarifies that a veteran who has been determined to have died from ALS shall be treated as a veteran under DIC regulations without regard for how long the person had such a disease prior to death.
In a June 17 statement, the ALS Association expressed support for Section 103, highlighting that it provides financial security for veterans and surviving spouses.
“Veterans are nearly twice as likely to develop ALS as the general population,” the association said.
“Yet under current law, many surviving spouses are denied enhanced [DIC] benefits because veterans with ALS often do not live long enough to meet an eight-year disability requirement.”
“Section 103 corrects this inequity by ensuring surviving spouses are not penalized simply because ALS progresses rapidly and remains a terminal disease,” according to the association.
