Exposure to Outdoor Trichloroethylene May Increase Parkinson's Disease Risk

Recent research indicates that long-term exposure to the industrial solvent trichloroethylene (TCE) in outdoor air may be associated with a higher risk of developing Parkinson's disease. Published in the journal Neurology, this large-scale nationwide study analyzed data from Medicare beneficiaries over age 67, identifying a significant link between environmental TCE levels and Parkinson's incidence.

TCE, a chemical commonly used in metal degreasing, dry cleaning, and various industrial processes, continues to be prevalent in the environment despite bans on certain applications. Its persistence in air, water, and soil across the U.S. raises concerns about ongoing exposure, especially in areas with high industrial activity.

Researchers used EPA data to estimate TCE exposure based on residential ZIP+4 codes and mapped concentrations in small geographic areas. Participants living in regions with the highest TCE levels exhibited a 10% increased risk of Parkinson's compared to those in the lowest exposure zones. The study controlled for factors like age, smoking history, and air pollution, strengthening the association.

The investigation also identified geographic 'hot spots' with elevated TCE levels, notably in the U.S. Rust Belt and other regions. Further analysis revealed that proximity to major TCE-emitting facilities correlated with higher Parkinson's risk, particularly within 10 miles.

While the findings do not prove causation, they highlight the potential public health impact of environmental pollutants. The researchers emphasize the need for stricter regulations and better monitoring of industrial chemicals like TCE to mitigate health risks.

It's important to note that the study focused on an older population; therefore, implications for younger individuals remain uncertain. The TCE exposure estimates were based on outdoor air levels from 2002 and may not reflect lifetime or indoor exposures. Nonetheless, this study adds to the growing evidence that environmental factors could play a role in Parkinson's disease development.

Source: https://medicalxpress.com/news/2025-10-outdoor-air-exposure-industrial-solvent.html