Pesticides and risk of Parkinson disease: a population-based case-control study

Arch Neurol. 2005 Jan;62(1):91-5. doi: 10.1001/archneur.62.1.91.


Background: Pesticide exposures are suspected risk factors for Parkinson disease (PD), but epidemiological observations have been inconsistent.

Objective: To investigate associations between pesticide exposures and idiopathic PD.

Design: Population-based case-control study.

Setting: Group Health Cooperative, a health care system in western Washington State, and the University of Washington.

Participants: Two hundred fifty incident PD case patients and 388 healthy control subjects (age- and sex-matched). We assessed self-reported pesticide exposures using a structured interview. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined using logistic regression models, controlling for age, sex, and smoking.

Results: Odds ratios for occupational exposures were not significant but suggested a gradient that paralleled occupational exposures (pesticide worker: OR, 2.07; 95% CI, 0.67-6.38; crop farmer: OR, 1.65; 95% CI, 0.84-3.27; animal and crop farmer: OR, 1.10; 95% CI, 0.60-2.00; and dairy farmer: OR, 0.88; 95% CI, 0.46-1.70). Odds ratios for organophosphates paralleled the World Health Organization hazard classifications, with parathion much higher than diazinon or malathion. We also found elevated ORs from herbicides (OR, 1.41; 95% CI, 0.51-3.88) and paraquat (OR, 1.67; 95% CI, 0.22-12.76). We found no evidence of risk from home-based pesticide exposures. We found significantly increased ORs from lifelong well water consumption (OR, 1.81; 95% CI, 1.02-3.21).

Conclusions: The findings for occupational pesticide exposures are consistent with a growing body of information linking pesticide exposures with PD. However, the lack of significant associations, absence of associations with home-based exposures, and weak associations with rural exposures suggest that pesticides did not play a substantial etiologic role in this population.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Case-Control Studies
  • Community Health Planning / statistics & numerical data*
  • Confidence Intervals
  • Environmental Exposure
  • Female
  • Humans
  • Male
  • Middle Aged
  • Odds Ratio
  • Parkinson Disease / epidemiology
  • Parkinson Disease / etiology*
  • Pesticides / adverse effects*
  • Risk*


  • Pesticides