Dorsey · Journal of Parkinson's disease 2023 · narrative review and illustrative case series · n=7

Trichloroethylene: An Invisible Cause of Parkinson's Disease?

Cited 77 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

Narrative review and hypothesis paper presenting seven illustrative cases without systematic search or quantitative synthesis.

PubMed 36938742 · doi:10.3233/JPD-225047 · record verified 2026-08-27

What was done

The authors conducted a narrative literature review and compiled seven illustrative clinical cases to evaluate evidence linking exposure to the industrial solvent trichloroethylene (TCE)—via occupational use, outdoor air, groundwater, and indoor vapor intrusion—with the development of Parkinson's disease (PD).

What was found

The review cites historical evidence dating to 1969, including four prior case studies (totaling eight individuals), animal models demonstrating that TCE reproduces pathological features of PD, and one small epidemiological study reporting a 500% increased risk of PD associated with occupational or hobby TCE exposure. The authors present seven illustrative cases to support the hypothesis that ubiquitous TCE exposure contributes to global PD prevalence.

Why it matters

TCE is widely used in industrial degreasing and dry cleaning and persists as a common groundwater and indoor air pollutant; recognizing environmental neurotoxicants could inform environmental regulation and PD prevention strategies.

Limits

This is a narrative review and hypothesis paper, not a systematic review or prospective epidemiological study. The underlying human evidence cited is limited to small observational studies, anecdotal case reports, and non-systematic illustrative cases. Abstract provides no primary quantitative risk estimates, exposure thresholds, or control comparisons.

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