People with long-term, low-level exposure to pesticides have a 70 percent higher incidence of Parkinson's disease than people who have not been exposed much to bug sprays, US researchers reported on June 26.
Such workers include mostly farmers, ranchers and fishermen, the researchers report in the July issue of Annals of Neurology.
Their study supports previous research that suggests pesticides can be linked with Parkinson's, which is caused by the destruction of key brain cells, the team at the Harvard School of Public Health said.
"The findings support the hypothesis that exposure to pesticides is a risk factor for Parkinson's disease," they wrote.
The researchers contacted those people who reported they had been diagnosed with Parkinson's.
More men than women said they had been exposed to pesticides and those reporting exposure were more likely to report their occupation as farmer, rancher or fisherman, the researchers said.
People who had other jobs and who reported pesticide exposure most likely were using the chemicals at home or while gardening, the researchers speculated.
Exposure to asbestos, chemicals, acids, solvents, or coal or stone dust was not associated with a higher risk, the researchers said.