Occupational exposure to pesticides and Parkinson's disease: a systematic review and meta-analysis of cohort studies.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational cohort studies.
PubMed 22698719 · doi:10.1016/j.envint.2012.05.004
What was done
MEDLINE and reference lists were searched through November 30, 2011, to identify cohort studies examining occupational exposure to pesticides and Parkinson's disease (PD). Relative risk estimates from 12 studies published between 1985 and 2011 were combined into meta-rate ratio (mRR) estimates using fixed- and random-effects models. Stratified analyses were performed by gender, exposure characterisation, case identification method, geographic location, risk estimator, and cohort design.
What was found
Combining all 12 studies showed a statistically significant increased risk of PD with pesticide exposure (mRR=1.28; 95% CI: 1.03-1.59), with high heterogeneity across studies. Stronger associations were observed in studies with neurologist-confirmed PD diagnosis (mRR=2.56; 95% CI: 1.46-4.48; n=4), cohort studies reporting PD incidence (mRR=1.95; 95% CI: 1.29-2.97; n=3), prospective cohorts (mRR=1.39; 95% CI: 1.09-1.78; n=6), and plantation workers in banana, sugarcane, and pineapple agriculture (mRR=2.05; 95% CI: 1.23-3.42; n=2).
Why it matters
This meta-analysis synthesizes longitudinal cohort evidence linking occupational pesticide exposure to Parkinson's disease, showing more pronounced risk estimates in studies with confirmed neurological diagnoses.
Limits
High heterogeneity and inconsistency were present across the included studies. Subgroup analyses were based on very small numbers of studies (2 to 6 per stratum). Individual chemical agents, exposure doses, and participant-level confounders are not detailed in the abstract.
Cited by
- supports Pesticide exposure from agricultural crop spraying is associated with Parkinson's disease.