A new epidemiological study finds that Parkinson’s disease patients who have been exposed to pesticides through their work show elevated rates of the disease. The researchers find that French farmworkers have nearly double the risk for the disease if exposed to pesticides, with a dose-effect for the number of years of exposure. When they looked at the three major classes of pesticides (insecticides, fungicides and herbicides), they find that the farmworkers who used insecticides had over a two-fold increase in the risk of Parkinson’s disease. A slightly higher risk is found for exposure to organochlorine insecticides. According to the study, these associations are stronger in men with older onset Parkinson’s disease than in those with younger onset Parkinson’s.