Pesticide Exposure Raises Risk of Parkinson’s Disease

Beate Ritz, M.D., Ph.D.
University of California Los Angeles
NIEHS Grants P30ES007048, R01ES010544, and U54ES012078

NIEHS funded epidemiologists at the University of California Los Angeles found that exposure to the combination of the fungicide maneb and the herbicide paraquat increased the risk of later development of Parkinson’s disease. For people diagnosed with the degenerative disease prior to age 60, the risk was increased four- to six-fold.

The study reports that living within 500 meters of agricultural operations where the pesticides were sprayed increased residents risk by 75 percent. The exposures occurred between 1975 and 1999 and the timing of the exposure proved to be a critical factor in the study. For people who were diagnosed at early ages, the exposure occurred when they were children, teens or young adults. The study participants included 368 long-term Central Valley residents with Parkinson’s.

The research team developed a geographic information system approach for estimating exposure based on California pesticide-use records. All addresses for the study participants were used to give an accurate estimate of their total exposure from 1974 through 1999 coinciding with the dates of the pesticide-use records.

According the study’s senior author, Beate Ritz, the new study confirms previous observations in animal studies that exposure to multiple chemicals may increase the effects of each chemical and that the timing of the exposure is an important risk factor.

Citation: Costello S, Cockburn M, Bronstein J, Zhang X, Ritz B. Parkinson’s disease and residential exposure to maneb and paraquat from agricultural applications in the central valley of California. Am J Epidemiol. 2009 Apr 15;169(8):919-26. Epub 2009 Mar 6.