Plantation work and risk of Parkinson disease in a population-based longitudinal study

Arch Neurol. 2002 Nov;59(11):1787-92. doi: 10.1001/archneur.59.11.1787.


Context: Parkinson disease (PD) has an unknown cause; however, convincing evidence is emerging that indicates pesticides can selectively injure the dopaminergic system in laboratory animals. Retrospective studies in humans demonstrate a link between exposure to agricultural lifestyle factors and PD.

Objective: To determine whether working on a plantation in Hawaii and exposure to pesticides are associated with an increased risk of PD decades later.

Design and setting: Prospective cohort study based on the island of Oahu, Hawaii, with 30 years of follow-up. Years of work on a plantation were assessed by questionnaire at study enrollment in 1965. Self-reported information on pesticide exposure was collected at a separate examination 6 years later.

Participants: Participants were 7986 Japanese American men born between 1900 and 1919 who were enrolled in the longitudinal Honolulu Heart Program.

Main outcome measures: Incident PD was determined by medical record review or by an examination conducted by a study neurologist at a later date.

Results: During follow-up, 116 men developed PD. Age-adjusted incidence increased significantly among men who worked more than 10 years on a plantation. The relative risk of PD was 1.0 (95% confidence interval, 0.6-1.6), 1.7 (95% confidence interval, 0.8-3.7), and 1.9 (95% confidence interval, 1.0-3.5) for men who worked on a plantation 1 to 10 years, 11 to 20 years, and more than 20 years compared with men who never did plantation work (P =.006, test for trend). Age-adjusted incidence of PD was higher in men exposed to pesticides than in men not exposed to pesticides although this was not statistically significant (P =.10, test for trend).

Conclusion: These longitudinal observations regarding plantation work in Hawaii support case-control studies suggesting that exposure to pesticides increases the risk of PD.

Publication types

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

MeSH terms

  • Aged
  • Agricultural Workers' Diseases / epidemiology*
  • Analysis of Variance
  • Asian / statistics & numerical data
  • Confidence Intervals
  • Follow-Up Studies
  • Hawaii / epidemiology
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Occupational Exposure / statistics & numerical data*
  • Parkinson Disease / epidemiology*
  • Pesticides / adverse effects
  • Proportional Hazards Models
  • Prospective Studies
  • Risk Assessment
  • Surveys and Questionnaires


  • Pesticides