Veterans who were stationed at Camp Lejeune in North Carolina have a 70% greater risk of developing Parkinson's disease than those who were stationed at Camp Pendleton in California, according to a new study.
Published Monday in the journal JAMA Neurology, researchers said the difference may be due to the Marines at Camp Lejeune being exposed to a pervasive environmental contaminant known as trichloroethylene (TCE).
The number of people diagnosed with Parkinson's has been increasing worldwide and, though scientists aren't exactly sure what causes the degenerative brain disease, it's believed that age is a factor. Some estimates suggest that nearly 20 million people could develop Parkinson's by 2040.
Some say that exposure to chemicals like TCE is contributing to the uptick in cases.
Dr. Ray Dorsey, the David M. Levy professor of neurology at the University of Rochester, told CNN he believes that TCE exposure may be one of the most important factors in developing Parkinson's disease in the United States.
According to the Agency for Toxic Substances and Disease Registry, between 4.5% and 18% of the drinking water sources that the Environmental Protection Agency tests on a yearly basis have some TCE contamination.
Dorsey was not involved in the new study, but he has conducted similar research. He pointed to the relatively short period of time that the Marines involved in the study were exposed to TCE.
"There could be many more Marines that developed Parkinson's disease," he told CNN. "Almost everyone reading your story likely lives near a site contaminated with TCE, so this is a real concern."
First synthesized in 1864, TCE became one of the most widely used industrial solvents in the 1920s. It was used as a cleaning agent and degreaser, mainly for metal, and it is also used in the manufacturing of some refrigerants. The colorless, volatile organic compound can be found in paints, sealants, coatings, and some automobile products such as brake cleaners.
Having been widely used for the past 100 years, TCE has been found in thousands of water sources around the world and can remain in groundwater for long periods of time, according to the federal Centers for Disease Control and Prevention (CDC).
Although most people are exposed to TCE by drinking contaminated groundwater, exposure can also occur by breathing the chemical in as it is released from the water or from processes that use it.
The U.S. Department of Veterans Affairs told CNN in a statement that it "encourages all Veterans who served for at least 30 days total at Camp Lejeune between August 1, 1953, and December 31, 1987 — and their family members — to apply for the care and benefits they deserve at VA.gov/CampLejeune."
"Parkinson's disease is a presumptive condition for Veterans who were exposed to the contaminated water at Camp Lejeune," the statement continued. "This means that when eligible Veterans apply for benefits, they do not need to prove that their service caused their Parkinson's disease; instead, VA automatically assumes service-connection for these Veterans and provides benefits accordingly."