Parkinson's disease risk greater in those exposed to trichloroethylene

November 14, 2011

A novel study in twins found that exposure to trichloroethylene (TCE) -- a hazardous organic contaminant found in soil, groundwater, and air -- is significantly associated with increased risk of Parkinson's disease (PD). Possibility of developing this neurodegenerative disease is also linked to perchloroethylene (PERC) and carbon tetrachloride (CCI4) exposure according to the study appearing today in Annals of Neurology, a journal published by Wiley-Blackwell on behalf of the American Neurological Association and Child Neurology Society.

The National Institute of Neurological Disorders and Stroke (NINDS) estimates that as many as 500,000 Americans have PD and more than 50,000 new cases are diagnosed annually. While there is much debate regarding cause of PD, studies suggest that genetic and environmental factors likely trigger the disease which is characterized by symptoms such as limb tremors, slowed movement, muscle stiffness, and speech impairment. Several studies have reported that exposure to solvents may increase risk of PD, but research assessing specific agents is limited.

The current epidemiological study, led by Drs. Samuel Goldman and Caroline Tanner with The Parkinson's Institute in Sunnyvale, California, investigated exposure to TCE, PERC and CCI4 and risk of developing PD. The team interviewed 99 twin pairs from the National Academy of Sciences/National Research Council World War II Veteran Twins Cohort in which one twin had PD and one didn't, inquiring about lifetime occupations and hobbies. Lifetime exposures to six specific solvents previously linked to PD in medical literature -- n-hexane, xylene, toluene, CCl4, TCE and PERC -- were inferred for each job or hobby.

The findings are the first to report a significant association between TCE exposure and PD -- a more than 6-fold increased risk. Researchers also found that exposure to PERC and CCI4 tended toward significant risk of developing the disease. "Our study confirms that common environmental contaminants may increase the risk of developing PD, which has considerable public health implications," commented Dr. Goldman.

TCE, PERC and CCI4 have been used extensively worldwide, with TCE noted as a common agent in dry-cleaning solutions, adhesives, paints, and carpet cleaners. Despite the Food and Drug Administration (FDA) banning the use of TCE as a general anesthetic, skin disinfectant, and coffee decaffeinating agent in 1977, it is still widely used today as a degreasing agent. In the U.S., millions of pounds of TCE are still released into the environment each year and it is the most common organic contaminant found in ground water, detected in up to 30% of drinking water supplies in the country.

While this study focused on occupational exposures, the solvents investigated are pervasive in the environment. The authors suggest that replication of well-characterized exposures in other populations is necessary. Dr. Goldman concluded, "Our findings, as well as prior case reports, suggest a lag time of up to 40 years between TCE exposure and onset of PD, providing a critical window of opportunity to potentially slow the disease process before clinical symptoms appear."

In a release issued on September 28, 2011 the Environmental Protection Agency (EPA) announced that TCE is carcinogenic to humans.
-end-
This study is published in Annals of Neurology. Media wishing to receive a PDF of this article may contact healthnews@wiley.com.

Full citation: "Solvent Exposures and Parkinson's Disease Risk in Twins"; Samuel M Goldman, Patricia J Quinlan, G Webster Ross, Connie Marras, Cheryl Meng, Grace S Bhudhikanok, Kathleen Comyns, Monica Korell, Anabel R Chade, Meike Kasten, Benjamin Priestley, Kelvin L Chou, Hubert H Fernandez, Franca Cambi, J William Langston and Caroline M Tanner. Annals of Neurology; Published Online: November 14, 2011 (DOI:10.1002/ana.22629). http://doi.wiley.com/10.1002/ana.22629

Author Contact: To arrange an interview with Dr. Sam Goldman or Dr. Caroline Tanner, please contact Hallie Baron at hallie@halliebaron.com, 415-928-2317 (office) or 415-793-7435 (cell).

About the Authors: Sam Goldman, MD, MPH, is an Associate Professor and Caroline M. Tanner, MD, PhD, is Director of Clinical Research with The Parkinson's Institute and Clinical Center (PI), America's only independent, non-profit organization, providing comprehensive care to individuals with Parkinson's disease (PD). PI is a leader in researching causes and potential cures for PD. Since its founding in 1988, it has helped more than 50,000 PD patients better manage their disease, developed new treatments for this disease, and published ground-breaking research focused on closing the gap between science and practical care. To learn more about The Parkinson's Institute, go to http://www.thepi.org or call 408-734-2800.

About the Journal

Annals of Neurology, the official journal of the American Neurological Association and the Child Neurology Society, publishes articles of broad interest with potential for high impact in understanding the mechanisms and treatment of diseases of the human nervous system. All areas of clinical and basic neuroscience, including new technologies, cellular and molecular neurobiology, population sciences, and studies of behavior, addiction, and psychiatric diseases are of interest to the journal.

About Wiley-Blackwell

Wiley-Blackwell is the international scientific, technical, medical, and scholarly publishing business of John Wiley & Sons, with strengths in every major academic and professional field and partnerships with many of the world's leading societies. Wiley-Blackwell publishes nearly 1,500 peer-reviewed journals and 1,500+ new books annually in print and online, as well as databases, major reference works and laboratory protocols. For more information, please visit http://www.wileyblackwell.com or our new online platform, Wiley Online Library (http://www.wileyonlinelibrary.com), one of the world's most extensive multidisciplinary collections of online resources, covering life, health, social and physical sciences, and humanities.

Wiley

Related Neurodegenerative Disease Articles from Brightsurf:

CLCN6 identified as disease gene for a severe form of lysosomal neurodegenerative disease
A mutation in the CLCN6 gene is associated with a novel, particularly severe neurodegenerative disorder.

Cellular pathway of genetic heart disease similar to neurodegenerative disease
Research on a genetic heart disease has uncovered a new and unexpected mechanism for heart failure.

New ALS guideline establishes national standard for managing neurodegenerative disease
The first Canadian guideline for the care and management of patients with amyotrophic lateral sclerosis (ALS) -- Lou Gehrig's disease -- recommends a patient-focused approach, with attention to holistic and emotional aspects of well-being.

New study reveals undetected rare neurodegenerative disorder that looks like Parkinson's disease
New Singapore study suggests that patients who are carriers of NIID gene mutation may also present with symptoms and signs of Parkinson's disease (PD), and respond to PD drugs.

Designed a new model to predict the life expectancy of a severe neurodegenerative disease
Researchers from IDIBELL, the University of Göttingen and the University of Münster, designed six tables, using data available at the time of diagnosis, where easily extrapolate patient's life expectancy.

AI-analyzed blood test can predict the progression of neurodegenerative disease
A new study shows artificial intelligence (AI) analysis of blood samples can predict and explain disease progression, which could one day help doctors choose more appropriate and effective treatments for patients.

New study sheds light into origins of neurodegenerative disease
New research has shed light on the origins of spinocerebellar ataxia type 7 (SCA7) and demonstrates effective new therapeutic pathways for SCA7 and the more than 40 other types of spinocerebellar ataxia.

Protein aggregation: Protein assemblies relevant not only for neurodegenerative disease
Amyloid fibrils play a crucial role in neurodegenerative illnesses. Scientists from Heinrich Heine University Düsseldorf (HHU) and Forschungszentrum Jülich have now been able to use cryo-electron microscopy (cryo-EM) to decode the spatial structure of the fibrils that are formed from PI3K SH3 domains - an important model system for research.

Temple researchers: Sorting protein in neurons defends against neurodegenerative disease
Like a sorting machine in an assembly line, a molecule known as VPS35 detects and removes defective proteins from neurons.

How mutations lead to neurodegenerative disease
Scientists have discovered how mutations in DNA can cause neurodegenerative disease.

Read More: Neurodegenerative Disease News and Neurodegenerative Disease Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.