Occupational Pesticide Use and Parkinson’s Disease in Central California

Abstract

Introduction: The purpose of our study is to examine occupational pesticide use and Parkinson’s Disease (PD) in a population with considerable information on various sources of pesticide exposure. Methods: In a population-based case control study in Central California with 360 PD cases and 827 controls, we used structured interviews to collect occupational history details including pesticide uses in jobs, duration of use, product names, and personal protective equipment use. We linked reported products to California’s pesticide product label database to assess exposure to pesticide active ingredients and identified occupational uses of fungicides, insecticides, herbicides, and pesticide chemical classes. Using unconditional logistic regression, we estimated odds ratios and 95% confidence intervals between PD and occupational pesticide use. Results: Using pesticides for >10 years doubled the risk of PD compared with no occupational pesticide use. PD risk increased 29-89% with ever occupational use of fungicides, herbicides, and insecticides. Ever use of carbamates increased risk by 245%. Surprisingly, we found higher risk among those who reported using personal protective equipment (PPE). Comparing ever occupational pesticide users with never users with low exposures to pesticides from other sources, including ambient exposures at residences and workplaces and household use, we found 60-67% increases in PD risks for all occupational pesticide use categories, and use of organophosphorus (OP) and organochlorine (OC) pesticides doubled risk. Conclusions: Our findings support previous reports for occupational pesticide exposures and increased PD risk, provide evidence suggesting occupational use of carbamates, OPs, and OCs increase risk, and suggest that use of PPEs did not reduce risk in this population.