LOS ANGELES, CA (Catholic Online) - The new study also found that exposure to another man-made chemical similar to TCE, known as perchloroethylene or tetrachloroethylene, also known as PERC, has been associated with a tenfold increased risk of Parkinson's. Both TCE and PERC have been found in metal degreasers, metal cleaners, paint, spot removers, and carpet-cleaning fluids.

"The fact that we were able to find a six-to-tenfold increased risk in exposure I think is very meaningful," Dr. Samuel M. Goldman, an associate professor of clinical research at The Parkinson's Institute and the lead author of the study said.

An epidemiologic study had never before been attempted to link the chemicals with either medical condition. Both PERC and TCE had previously been anecdotally linked to Parkinson's disease.

Goldman along with his colleagues identified six specific solvents previously suspected to be related to the development of Parkinson's, two of which were TCE and PERC.
Researchers then reached out to 99 all-male pairs of twins, each composed of one twin with Parkinson's and one without. The test subjects were all male as they were part of the National Academy of Sciences/National Research Council World War II Veteran Twins Registry that was founded in the 1960s using military records.

The medical team then interviewed the twins using detailed job-specific questionnaires to gauge the likelihood of each person being exposed to the predetermined solvents.

"We designed these extremely detailed interviews so that we didn't have to rely on the memory or the knowledge of the respondent," Goldman explains.

"We know the geographic locations where [each participant] worked, the decade, and what they did so we can say, 'OK - we know that with someone who worked in the 1950s, in a plant with air plane engines, and they were working with the degreasing process, there is a high likelihood that person was exposed to TCE.'"

In working with the twins, Goldman and his team were able to account for genetic and lifestyles factors and focus on the job differences between each brother, one of whom had Parkinson's. They found that exposure to TCE, PERC, and to a lesser extent another chemical known as carbon tetrachloride, were all associated with an increased risk of the neurodegenerative disease.

© 2011, Catholic Online. Distributed by NEWS CONSORTIUM.