Chemical Exposure Linked to Parkinson's Disease

Trichloroethylene or TCE, a liquid chemical that persists in the air, water, and soil, may increase the risk of Parkinson's disease by 70% after two years of heavy exposure. Previous research has connected TCE to some cancers. The new study published in JAMA Neurology is thought to be the first large-scale study to show its link to Parkinson's disease (1^✔ ✔Trusted Source
Risk of Parkinson Disease Among Service Members at Marine Corps Base Camp Lejeune

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TCE Exposure at Camp Lejeune and the Lingering Shadow of Parkinson's Disease

TCE has been used for about 100 years in industrial and commercial applications, and it was used as a surgical anesthetic until it was outlawed in 1977. It was most recently employed as a degreasing solvent. It is now mostly used to degrease industrial metal parts. It involves heating TCE in degreasing tanks to produce a vapor that dissolves the grease while also releasing the chemical into the atmosphere. TCE can stay in the soil or groundwater for decades after it enters it. Between 1975 and 1985, service members spent at least three months in the camps, during which time TCE levels in the water at Camp Lejeune surpassed maximum safety norms by a factor of 70. The researchers had access to follow-up health data on the military members from 1997 to 2021 when Parkinson's disease could be expected to occur.

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Uncovering the TCE-Parkinson's Disease Link

Researchers from UC San Francisco and the San Francisco VA Medical Center led the study, which compared Parkinson's diagnoses in about 160,000 Navy and Marine veterans. A little more than half of the samples came from Camp Lejeune in North Carolina, where TCE was used to degrease military equipment and the water was contaminated; the rest came from Camp Pendleton in California, where the water was not contaminated.

Researchers discovered that 430 soldiers had been diagnosed with Parkinson's disease and that the risk for Lejeune veterans was 70% higher than for Pendleton veterans. From 1975 through 1985, servicemen from both camps were stationed there for an average of two years. Parkinson's disease was diagnosed at an average age of 54 at Lejeune and 53 at Pendleton, indicating that the condition took decades to develop following TCE exposure.

The civilian population is also in danger of TCE exposure, according to first author Samuel M. Goldman, M.D., MPH, of the UCSF Division of Occupational, Environmental, and Climate Medicine and the SFVA, who noted that the chemical is present in between 9% and 34% of U.S. water sources.

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Hidden Dangers of TCE Exposure: Potential Indicators of Parkinson's Disease

“TCE is still a very commonly used chemical in the United States and throughout the world. Its production has been increasing over the past several years and it is widely available online,” he said. “Unfortunately, there’s no easy way to know if you’ve been exposed, unless you’ve worked with it directly. Many of us have detectable levels of TCE in our bodies, but it gets metabolized and excreted very quickly, so blood and urine tests only reflect very recent exposure.”

Furthermore, the researchers discovered that the Lejeune veterans had a greater prevalence of prodromal Parkinson's disease, which is defined as symptoms that are indicative of Parkinson's but do not yet meet diagnostic criteria for the condition.

“Loss of sense of smell, a sleep disorder known as RBD, anxiety, depression and constipation can be early signs of Parkinson’s, but only a very small fraction of people with them will develop it,” said senior author Caroline M. Tanner, M.D., Ph.D., of the UCSF Department of Neurology, the Weill Institute for Neurosciences and the SFVA. “The risk of developing Parkinson’s in the future can be estimated using a risk score based on these symptoms. The Lejeune veterans had higher risk scores than the Pendleton veterans, suggesting that they are more likely to develop Parkinson’s in the future.”

Reference:

1. Risk of Parkinson Disease Among Service Members at Marine Corps Base Camp Lejeune - (https://pubmed.ncbi.nlm.nih.gov/37184848/)

Source-Medindia