A common and widely used chemical may be fueling the rise of the world’s fastest growing brain condition—Parkinson’s disease.
- For the past 100 years, trichloroethylene (TCE) has been used to decaffeinate coffee, degrease metal, and dry clean clothes.
- TCE causes cancer, is linked to miscarriages and congenital heart disease, and is associated with a 500 percent increased risk of Parkinson’s disease.
- In a recent paper in the Journal of Parkinson’s Disease, an international team of researchers including University of Rochester Medical Center (URMC) neurologists Dr Ray Dorsey, Dr Ruth Schneider, and Dr Karl Kieburtz, say that TCE may be an invisible cause of Parkinson’s.
- They have detailed the widespread use of the chemical, the evidence linking the toxicant to Parkinson’s, and profile seven individuals, ranging from a former NBA basketball player to a Navy captain to a late US Senator, who developed Parkinson’s disease either after likely working with the chemical or being exposed to it in the environment.
The Industrial Pollutant: TCE was a widely used solvent employed in a number of industrial, consumer, military, and medical applications, including to remove paint, correct typewriting mistakes, clean engines, and anesthetise patients.
Its use in the US peaked in the 1970s, when more than 600 million pounds of the chemical—or two pounds per American—were manufactured annually.
- Some 10 million Americans worked with the chemical or other similar industrial solvents. While domestic use has since fallen, TCE is still used for degreasing metal and spot dry cleaning in the US.
- TCE contaminates countless sites across the country. Half of the most toxic Environmental Protection Agency’s (EPA) Superfund sites contain TCE.
The Disease: The connection between TCE and Parkinson’s was first hinted at in case studies more than 50 years ago.
In the intervening years, research in mice and rats has shown that TCE readily enters the brain and body tissue and at high doses damages the energy-producing parts of cells known as mitochondria.
- In animal studies, TCE causes selective loss of dopamine-producing nerve cells, a hallmark of Parkinson’s disease in humans.
- The case studies include the professional basketball player Brian Grant, who played for 12 years in the NBA and was diagnosed with Parkinson’s at age 36.
- Amy Lindberg was similarly exposed to the contaminated drinking water at Camp Lejeune while serving as a young Navy captain and would go on to be diagnosed with Parkinson’s disease 30 years later.
A Threat: The authors have proposed a series of actions to address the public health threat posed by TCE.
- The researchers have called for finally ending the use of these chemicals in the US.
- Two states, Minnesota and New York, have banned TCE, but the federal government has not, despite findings by the EPA as recently as 2022 that the chemicals pose “an unreasonable risk to human health.”