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


METHODS
Population-based case-control study.


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


METHODS
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.
Firestone
Jordan A
JA
Department of Neurology, University of Washington, PO Box 359739, Seattle, WA 98104, USA. jfire@u.washington.edu
Smith-Weller
Terri
T
Franklin
Gary
G
Swanson
Phillip
P
Longstreth
W T
WT
Checkoway
Harvey
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D018672:Community Health Planning / Q000706:statistics & numerical data*; D016001:Confidence Intervals; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010300:Parkinson Disease / Q000453:epidemiology / Q000209:etiology*; D010575:Pesticides / Q000009:adverse effects*; D012306:Risk
D010575:Pesticides