A new study set to be presented at the American Academy of Neurology’s 76th annual meeting in April has found a link between agricultural pesticides and herbicides and an increased risk of Parkinson’s disease in the Rocky Mountain and Great Plains regions of the United States.
Researchers identified 14 pesticides, including simazine, lindane, and atrazine, that were most closely associated with Parkinson’s disease in 13 states: Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Utah, and Wyoming.
The study found that the herbicide atrazine and insecticide lindane were associated with a 31 percent and 25 percent increased risk of developing Parkinson’s disease, respectively. The use of the herbicide simazine was linked to a 36 percent increased risk.
To reach these conclusions, researchers analyzed nationwide data from 21.5 million Medicare beneficiaries aged 67 and older in 2009 and 465 pesticides included in the U.S. Geological Survey. They focused on 65 pesticides and determined their average annual application by county between 1992 and 2008. The results showed that the more pesticides like simazine, lindane, and atrazine were used, the higher the rates of Parkinson’s disease among people living in those areas.
This study adds to a growing body of evidence linking pesticides to Parkinson’s disease. A May 2023 study published in Nature Communications implicated long-term exposure to pesticides in Parkinson’s disease cases among cotton farm workers, identifying 10 pesticides directly toxic to specific neurons in the brain responsible for voluntary movement.
Parkinson’s disease is one of the fastest-growing neurological disorders in the world, with nearly 90,000 people diagnosed each year in the United States alone. The Parkinson’s Foundation estimates that 1.2 million people will be living with the disease by 2030.
Despite the known toxicity and risk to human health, many pesticides are still widely used in the United States. The Environmental Protection Agency (EPA) regulates pesticide use and determines if a pesticide is harmful, publishing the allowed amount in water in its Human Health Benchmarks for Pesticides table online.
