Chlorinated solvents are commonly used in a variety of occupations. The solvents trichloroethylene (TCE) and perchloroethylene (PERC) have been associated with an increased risk of Parkinson’s disease in small studies in humans. This study of mechanics with occupational exposure to solvents will collect preliminary information to support a future prospective investigation of the association between chlorinated solvent exposure and risk of PD.
In this pilot study, a subgroup of the mechanics who have enrolled in the Bay Area Solvent Study will be invited to participate in an in-person evaluation, including a neurologic examination, and interviews collecting histories of lifetime health and occupation. Some of those participating in the in-person assessment will be invited to undergo a brain scan using a chemical called DaTSCAN. DaTSCAN binds to the dopamine transporter (a carrier for the brain chemical messenger dopamine). In PD, DaTSCAN binding is reduced in a specific brain area affected in PD, the striatum. Lifelong exposure to the solvents TCE, PERC, and other risk factors will be estimated for each participant, using the information provided in the interview. Analyses will test whether mechanics with exposure to these solvents have changes on their neurological exam or lower striatal dopamine transporter binding.
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
This project will lay the ground work for a future investigation. The future study will determine whether exposure to the chlorinated solvents TCE or PERC increases the risk of developing PD. Better understanding of the role of chlorinated solvents in PD risk may allow for earlier diagnosis and treatment of PD, as well as the possibility of preventing PD in people at risk.
The two key results we anticipate from this study are: 1) a better understanding of causes and risk factors for PD and 2) possible identification of a population “at risk” for PD. These results will likely be relevant not only for mechanics, but for many others. Chlorinated solvent use is common in numerous occupations. These solvents are also frequent environmental contaminants, including drinking water. The population of people who may be exposed to these toxicants and possibly at risk for PD extends beyond the occupational setting and into the home. This work will lay the foundation for a study investigating the role chlorinated solvent exposure may play in causing PD.