Occupational exposure to specific solvents is linked to increased odds of Parkinson’s disease (PD), with the risk increasing as the number of solvent types rise.
In a cross-sectional analysis of more than 31,000 participants, several solvents used in industrial cleaning and manufacturing were associated with higher odds of PD. The strongest associations involved trichloroethylene (TCE), kerosene, and carbon tetrachloride, with significant links also found for mineral spirits, methyl ethyl ketone (butanone), toluene, and jet fuel.
Each additional solvent type reported was associated with 17% higher odds of PD.
TCE, a solvent used to degrease metal parts, has already been linked to PD, but other solvents remain understudied, co-investigator Francisco Luna-Rangel, MD, a research fellow at School of Medicine and Health Sciences, Tecnológico de Monterrey in Monterrey, Mexico, told Medscape Medical News.
He emphasized that the findings are hypothesis-generating and do not establish causation, adding that he did not want to cause undue alarm among workers exposed to these solvents. He encouraged workers to use personal protective equipment and clinicians to ask about lifetime occupational exposures and monitor for potential neurologic symptoms.The findings were presented on October 5 at the International Congress of Parkinson’s Disease and Movement Disorders (MDS) 2026.
Underrecognized Risk Factors
As previously reported by Medscape Medical News, groundwater, air pollution, and TCE exposure, including from living near dry cleaners, have all been linked to increased risk for PD.
Toxic environmental exposures have drawn increasing attention as potential risk factors for PD, the investigators noted. Although pesticide exposure has been widely studied, occupational solvents have received comparatively little attention, the investigators noted.
To better understand the potential role of occupational solvents in PD, the researchers examined associations with individual solvent types and whether the odds increased with the number of solvent types reported.
In the current cross-sectional observational analysis, the investigators assessed participants from the Parkinson’s Progression Markers Initiative (PPMI) Online study, including 9484 with PD (57% men) and 24,321 healthy control participants (32.6% men).
The mean age at PD diagnosis was 63.6 years; the mean age of control participants was unavailable. In both groups, 90% of participants were White.
Self-reported questionnaires captured at least 100 days of lifetime exposure to 13 commercial solvents. Multivariable adjusted logistic regression models were used to calculate links between solvent exposure and PD, and the Benjamini-Hochberg false discovery rate correction was used to address multiple comparisons.
Seven solvents were associated with higher adjusted odds of PD, with the strongest associations observed for kerosene (adjusted odds ratio [aOR], 1.74), TCE (aOR, 1.71), and carbon tetrachloride (aOR, 1.69; P < .001 for all three).
Mineral spirits (aOR, 1.42; P < .001), methyl ethyl ketone (aOR, 1.35; P < .001), jet fuel (aOR, 1.31; P = .002), and toluene (aOR, 1.29; P < .001) were also significantly associated with PD.
All seven associations remained statistically significant after correction for multiple comparisons. There was also a significant exposure response trend, with an OR of 1.16 per additional solvent (P < .001). The OR was 1.14 per additional life period exposed in those initially exposed to a solvent before the age of 50 (P < .001).
The findings suggest that industrial solvent exposure may be an underrecognized risk factor for PD, the investigators noted. They called for longitudinal studies to clarify whether the associations are causal and help guide prevention efforts.
Study limitations include reliance on self-reported exposure histories and PD diagnoses, the potential for recall bias, and no data on the age of control participants.
Next Up: ‘Toxic Cocktails’
The study was notable for its focus on individual solvent types, whereas several previous studies had assessed solvents collectively, session moderator Sirwan Darweesh, MD, PhD, told Medscape Medical News.
Darweesh, who was not involved in the study, also co-chairs a newly established MDS task force developing a polyexposure score for PD.
“On a high level, I think solvents are among the most understudied yet important classes of environmental toxicants in the etiology of Parkinson’s,” said Darweesh, associate professor and movement disorders neurologist at Radboud University Medical Center in Nijmegen, Netherlands.
He added that solvents are just as important as air pollution and pesticides as potential risk factors but have not been as extensively studied.
This research lays the groundwork for examining how combined solvent exposures may influence the risk for PD, Darweesh said.
“That’s where the field needs to go and I think future studies can build on these results. It will be important to determine what ‘cocktails,’ or multiple exposures to more than one solvent, are most toxic and contribute to Parkinson’s,” he concluded.
The PPMI database, which was used to obtain data in the preparation of the study, is funded by the Michael J. Fox Foundation for Parkinson’s Research and funding partners. However, the current investigators did not receive specific funding for this analysis. Luna-Rangel and Darweesh reported having no relevant financial disclosures.
https://www.medscape.com/viewarticle/seven-workplace-solvents-linked-parkinsons-disease-2026a10011p1
