Study finds link between Parkinson’s disease and pesticide use in the Great Plains region

May 6, 2024, 5 a.m. ·

Map of the Great Plains Region in the United States
Image of the Great Plains Region in the United States

Dr. Brittany Krzyzanowski, a researcher at the Barrow Neurological Institute in Phoenix, led a study suggesting that use of certain pesticides and herbicides in agriculture may increase the risk of Parkinson's disease.

Parkinson's Disease is a progressive disorder that impacts the nervous system. A part of the brain deteriorates, causing more and more symptoms over time. It is the fastest-growing neurological disorder in the world, according to a release from the American Academy of Neurology.

The goal of the study was to see if there was a link between pesticide and herbicide use and Parkinson's in the Great Plains and Rocky Mountain areas. She said it was inspired by a previous study that found an association between the disease and cropland density.

“It found that association between Parkinson's and cropland density was the strongest in the northern Great Plains area,” Krzyzanowski said. “This initial study is what inspired us to move from cropland, which is a little less specific, to actually studying the pesticides in this area."

The study looked at records of 21.5 million people enrolled in Medicare in 2009 in the Rocky Mountain, Great Plains and western Midwest regions. Out of the 65 different pesticides and herbicides studied, 14 were found to be associated with the disease, with the herbicides atrazine and simazine being seen the most.

Krzyzanowski said while they can’t make definitive claims, their work adds to the research showing a link between pesticide and herbicide usage and the disease.

“We can't really make any causal conclusions from our study at this point, because it was observational research," she said. "You know, there's considerable evidence to suggest that exposure to pesticides, like paraquat, increases your risk of Parkinson's disease.”

The stand-outs atrazine and simazine are both banned in parts of Europe. Areas in the study exposed to the simazine were 36% and atrazine 31% more likely to develop Parkinson’s than non-exposed areas.

Krzyzanowski said they plan to move forward with their research, beginning to work away from the county level toward doing more person level studies to give a better understanding of what is going on with the two chemicals in the area.

She hopes the study will positively impact agricultural practices and public health.

“We're just hoping that more research into this will be what results in the public health policy change and implications that might come," she said.