Persons who are occupationally or otherwise regularly exposed to pesticides are at a 70% higher risk for Parkinson disease (PD) than is the general population. The findings were drawn from a subpopulation of 7864 persons who reported pesticide exposure in 1982. They were part of a larger study population of 143,325 persons participating in the Cancer Prevention Study II (CPS-II) Nutrition Cohort, a longitudinal, survey-based research project begun in 1992.
Participants in the CPS-II Nutrition Cohort were questioned about lifestyle habits and issues related to chemical exposure 4 times between 1992 and 2001. The last survey took a look at the incidence of PD; 840 persons reported a recent (poststudy entry) PD diagnosis. For 648 of these persons, diagnosis was confirmed through medical records. After excluding those persons in whom disease developed before 1992, the research team analyzed 413 cases of PD in relation to frequent pesticide exposure in 1989.
After adjusting for age (mean age of onset was 70 years regardless of pesticide exposure), sex, and smoking habits, the risk of PD was 70% higher among persons exposed to pesticides 20-odd years ago compared with those not exposed.
Although these issues need to be fleshed out to further clarify the matter, the researchers commented that their findings corroborate the results of a number of other studies suggesting that pesticide exposure strongly influences PD development.The citation for this study is Ascherio A, Chen H, Weisskopf MG, et al. Pesticide exposure and risk for Parkinson's disease. Ann Neurol. 2006;60:197-203.