Use of pesticides linked with Parkinson’s

U.S. researchers said Monday they had made more links between the use of pesticides and Parkinson’s disease but said they only found a higher risk for people who use the chemicals as part of their job.

Three compounds, including an ingredient in the Vietnam-era herbicide Agent Orange, the herbicide paraquat and the insecticide permethrin were associated with a more than three-fold increased risk of Parkinson’s disease, they found.

Their study, published in the Archives of Neurology, backs a growing body of research linking the incurable and often deadly brain disease with pesticide and herbicide use.

"Because few investigations have identified specific pesticides, we studied eight pesticides with high neurotoxic plausibility based on laboratory findings,” Dr. Caroline Tanner of the Parkinson’s Institute in Sunnyvale, California and colleagues wrote.

They studied 519 people with Parkinson’s disease and 511 similar people who did not have Parkinson’s.

"We examined risk of parkinsonism in occupations (agriculture, education, health care, welding, and mining) and toxicant exposures (solvents and pesticides) putatively associated with parkinsonism,” they wrote.

"Work in agriculture, education, health care, or welding was not associated with increased risk of parkinsonism,” they added.

"Occupational use of pesticides was associated with an almost 80 percent greater risk of parkinsonism. Growing evidence suggests a causal association between pesticide use and parkinsonism.”

In July, an Institute of Medicine panel found links between Agent Orange exposure and both Parkinson’s and heart disease, but the report by Tanner’s team is the first to make a link with permethrin, a commonly used synthetic bug killer and repellent.