ST. PAUL, Minn. -- Workers exposed to tricholorethylene (TCE), a chemical once widely used to clean metal such as auto parts, may be at a significantly higher risk of developing Parkinson's disease, according to a study released today that will be presented at the American Academy of Neurology's 62nd Annual Meeting in Toronto April 10 to April 17, 2010.

"This is the first time a population-based study has confirmed case reports that exposure to TCE may increase a person's risk of developing Parkinson's disease," said study author Samuel Goldman, MD, with the Parkinson's Institute in Sunnyvale, California, and a member of the American Academy of Neurology. "TCE was once a popular industrial solvent used in dry cleaning and to clean grease off metal parts, but due to other health concerns the chemical is no longer widely used."

For the study, researchers obtained job histories from 99 pairs of twins in which only one of the twins had Parkinson's disease. All of the twins were men and identified from the World War II-Veterans Twins Cohort study. Scientists used twins in the study because they are genetically identical or very similar and provide an ideal population for evaluating environmental risk factors.

The study found workers who were exposed to TCE were five and a half times more likely to have Parkinson's disease than people not exposed to the chemical. Those who were exposed to TCE had job histories including work as dry cleaners, machinists, mechanics or electricians.

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The study was supported by grants from the National Institute of Neurological Disorders and Stroke, The Valley Foundation and the James and Sharron Clark Family Fund.

The American Academy of Neurology, an association of more than 22,000 neurologists and neuroscience professionals, is dedicated to promoting the highest quality patient-centered neurologic care. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Parkinson's disease, ALS (Lou Gehrig's disease), dementia, epilepsy, and migraine. For more information about the American Academy of Neurology and the AAN Annual Meeting, visit http://www.aan.com.

Editor's Notes: Study authors are available for advance interviews. Please contact Rachel Seroka, rseroka@aan.com. Non-late-breaking abstracts to be presented at the AAN Annual Meeting will be posted online in advance of the AAN Annual Meeting at 4 pm, ET, Wednesday, February 17, 2010, at http://www.aan.com/go/science/abstracts.

Late-breaking abstracts will not be posted online in advance of the Annual Meeting and will remain embargoed until the date and time of presentation of the late-breaking abstract at the AAN Annual Meeting in Toronto, April 10-17, 2010. Late-breaking abstracts will be featured in press release and in press conference at the 2010 AAN Annual Meeting in Toronto. To register to attend the AAN Annual Meeting Press Room in Toronto, visit http://www.aan.com/go/press/registration.