Food Contaminants
pesticide exposure increases Parkinson's disease risk
In plain terms: Do pesticides cause Parkinson's disease?
Part of: 🔍 pesticides in food
For farm workers and people living near sprayed fields, this is one of the more credible pesticide risks, particularly for paraquat. But no study has ever linked it to the residue levels on supermarket food.
📅 Last reviewed: 2026-07-29 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: All trials, pooled (Meta-analysis)
How the studies fall
What the evidence shows
One of the better-supported claims in this hub, and it is not about food. The signal is occupational and residential: farmworkers, applicators, and people living near sprayed fields. Paraquat and rotenone carry the strongest case, both being dopaminergic neurotoxicants that damage mitochondrial Complex I, with pooled analyses reporting meaningfully elevated odds.
The evidence (12)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Vaccari C, El Dib R, Gomaa H, Lopes LC, de Camargo JL 2019 · Journal of toxicology and environmental health. Part B, Critical reviews | meta-analysis | mixed | moderate | 2019 systematic review/meta-analysis of 9 case-control studies (OCCUPATIONAL paraquat exposure, farmworkers/applicators): PD occurrence 25% higher in exposed vs unexposed (pooled estimate; abstract gives no numeric CI). The single cohort st |
| Kamel F, Goldman SM, Umbach DM, Chen H, Richardson G, Barber MR, Meng C, Marras C, Korell M, Kasten M, Hoppin JA, Comyns K, Chade A, Blair A, Bhudhikanok GS, Webster Ross G, William Langston J, Sandler DP, Tanner CM 2014 · Parkinsonism & related disorders | observational | supports | moderate | Nested case-control in the Agricultural Health Study (OCCUPATIONAL cohort of pesticide applicators/spouses; NIH-funded; 89 PD cases, 336 controls): paraquat OR 4.2 (95% CI 1.5-12) in low-PUFA-diet individuals vs 1.2 (0.4-3.4) in high-PUFA i |
| Tsalenchuk M, Farmer K, Castro S, Scheirer A, Ye Y, Timothy Greenamyre J, Rocha EM, Marzi SJ 2025 · NPJ Parkinson's disease | animal | mixed | low | EXPERIMENTAL ANIMAL rotenone rat model (dose not specified in abstract): H3K27ac ChIP-seq and RNA-seq showed region-specific epigenomic changes despite uniform mitochondrial complex-I inhibition - a rotenone-induced immune/complement (C1q) TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Al Saeedy DY, Hawkins E, Dozmorov MG, Tripathi O, Mahdiani S, Jahr FM, AlAzzeh O, Deshpande LS, McClay JL 2026 · Journal of molecular neuroscience : MN | animal | mixed | low | EXPERIMENTAL ANIMAL dosing (far above human dietary exposure): male Lewis rats given rotenone 3 mg/kg i.p. daily for 9 days developed cataleptic motor deficits plus striatal transcriptional dysregulation (Ddc, Angpt2, circadian genes Per3/A TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| da Silva PHP et al 2025 · preprint | meta-analysis | supports | moderate | 2025 systematic review/meta-analysis of 124 human studies (PubMed/EMBASE/Web of Science to Jul 2024): PD positively associated with any pesticide class and with herbicides overall. OCCUPATIONAL exposure was associated with PD for all pestic |
| Wood G. 2026 · MetaArXiv | observational | mixed | low | 2026 narrative comparison of six regulators reviewing the SAME paraquat-PD evidence base (2003-2026) reaching opposite conclusions: California DPR (2024) acknowledged 'moderate to strong' associations in the newest meta-analyses yet still d |
| Joshi P et al 2025 · bioRxiv | animal | mixed | low | EXPERIMENTAL ANIMAL dosing (far above dietary exposure): mice given rotenone 2.5 mg/kg/day i.p. for 21 days lost ~40% of substantia nigra dopaminergic neurons and developed motor/anxiety deficits by 4 weeks, but ALL deficits and neuronal de |
| Meerman JJ, Sinnige TL, Klerx W, Tuominen A, Legler J, Piersma AH, Heusinkveld HJ, Westerink RHS 2026 · Toxicology | in-vitro | mixed | low | In-vitro human SH-SY5Y neuroblastoma cells exposed to rotenone (plus dinoseb, endosulfan, mancozeb) at 0.1-100 uM across varied durations/frequencies: neurotoxic potency rose with exposure duration and, for rotenone/mancozeb, with time elap |
| Bergemann CM, Mello DF, Chitrakar R, Fisher K, Bijwadia SR, Huayta J, Ryde IT, Presman R, Huang Z, Herring AH, Murphy SK, Baugh LR, Meyer JN 2026 · Toxicological sciences : an official journal of the Society of Toxicology | animal | mixed | low | EXPERIMENTAL ANIMAL dosing in C. elegans: a HIGH rotenone concentration that itself impaired parental (P0) health caused altered mitochondrial respiration and greater dopaminergic-neurodegeneration susceptibility in offspring (F1); a LOW co |
| Yang H, Yang Y, Yang L, Li Z, Lyu L, Zhang X 2026 · Ecotoxicology and environmental safety | animal | mixed | low | EXPERIMENTAL ANIMAL/in-vitro paraquat model: paraquat exposure induced neuroinflammation and dopaminergic neurodegeneration via microglia-driven conversion of astrocytes to a pro-inflammatory phenotype (PI3K/AKT-dependent); effects were rev TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Nakao S, Kogoh Y, Funahashi H, Yanoma Y, Azuma M, Ishida Y, Hirano Y 2026 · PCN reports : psychiatry and clinical neurosciences | observational | supports | low | Single case report: acute high-dose organophosphate poisoning (RESIDENTIAL/accidental exposure, pesticide found in the patient's home shed - not chronic low-level exposure) produced toxic parkinsonism confirmed serially by DAT-SPECT (progre |
| Gómez-Chavarín M, Morales-Gómez R, Padilla-Mendoza JR, Padilla P, Torres-Saldaña I, Vergara-Aragón P, Silva-Lucero MD, Galindo-Solano N 2026 · Toxics | animal | mixed | low | EXPERIMENTAL ANIMAL dosing, PRENATAL/early-life route: Wistar rats given rotenone 1 mg/kg/day during gestation/lactation vs. adult-onset (postnatal day 60-102) exposure - developmental exposure caused earlier, more severe, and more persiste TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
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Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.