Finds Pesticide Exposure Associated With Parkinson’s Disease
(Beyond Pesticides, June 28, 2006) A new study finds that exposure to pesticides can increase the risk of Parkinson’s disease by 70%. The study, conducted by the Harvard School of Public Health (HSPH), finds that exposure to other environmental contaminants such as asbestos, coal or stone dust, chemicals, acids, or solvents did not show any risk of Parkinson’s. The HSPH study looks at data from the Cancer Prevention Study II Nutrition Cohort, a prospective study begun in 1992 by the American Cancer Society. Participants from this study were given a follow up survey in 2001. The HSPS researchers contacted those participants who filled out the follow up survey. In the end, the HSPS study included a total of 413 cases of PD with onset of symptoms and diagnosis after 1992.
The researchers, lead by Dr. Alberto Ascherio, associate professor of nutrition and epidemiology at the Harvard School of Public Health, also looked at the results from the Cancer Prevention Society II mortality study, a 1982 study from which the Nutrition Cohort was drawn. According to an analysis of the study on the ScienceDaily website,
“Exposure to pesticides was reported by 5,203 men (8.2 percent) and 2,661 women (3.3 percent). Among those reporting exposure, after adjusting for age, sex, and other risk factors for Parkinson's disease, there was a 70 percent higher incidence of PD than among people who reported no exposure. Those reporting exposure were more likely to be male than female to report their occupation as farmer, rancher or fisherman and to be blue-collar workers, but none of these factors could account for the increased risk of Parkinson's disease, which was similar in men or women, and in non-farmers as well as farmers. The significant association between pesticide exposure and Parkinson's disease among individuals who are not farmers is most likely explained by use of pesticides at home or in gardening.”
The HSPS study is significant in that it is the first study to so thoroughly highlight the link between pesticide exposure and Parkinson’s disease. Dr. Ascherio explains, “This is the first large human study that shows that exposure to pesticide is associated with a higher incidence of Parkinson's.” More research is needed to determine what exactly it is about pesticides that account for such a dramatic increase of Parkinson’s disease and also which specific pesticides are most likely the key offenders.