Pesticide exposure and risk of Parkinson’s disease: an umbrella review of systematic reviews and meta-analyses

This umbrella review synthesised meta-analytic evidence on pesticide-related exposures and Parkinson’s disease risk. PubMed/MEDLINE, Web of Science, and Scopus were searched from inception to 21 September 2025; Google Scholar was used as a supplementary search source. English-language systematic reviews with meta-analysis were eligible. The three database searches identified 934 records; after removal of 406 duplicates, 528 titles and abstracts were screened and 102 full-text articles were assessed, resulting in five included reviews. Pooled associations were examined in relation to effect estimates, precision, between-study heterogeneity, and the methodological quality of the source reviews assessed using AMSTAR 2. Broad pesticide exposure was associated with increased Parkinson’s disease risk (OR 1.63, 95% CI 1.37–1.93; k = 29; I2 = 74%), as was occupational pesticide exposure (OR 1.66, 95% CI 1.40–1.96; k = 20; I2 = 40%). Paraquat-related analyses also yielded elevated pooled estimates, including any paraquat exposure in case–control studies (OR 1.64, 95% CI 1.27–2.13; k = 13; I2 = 24.8%) and long-duration exposure (OR 1.75, 95% CI 1.28–2.39; k = 2; I2 = 3%). Estimates for many pesticide subclasses and individual active ingredients were imprecise or included the null, indicating considerable uncertainty for these exposures. Improved exposure assessment and more consistent reporting are needed to strengthen future evidence synthesis. Pooled analyses showed increased Parkinson’s disease risk for broad pesticide exposure and occupational pesticide exposure. Household pesticide use showed a smaller positive pooled estimate than occupational pesticide exposure. Paraquat-related analyses generally yielded elevated pooled estimates across several exposure definitions. Estimates for many pesticide subclasses and individual active ingredients were imprecise and often included the null.