Summary: A large new study finds a strong association between long-term exposure to trichloroethylene (TCE) and an elevated risk of Parkinson’s disease—about a 70% higher risk among veterans exposed to contaminated water at Marine Corps Base Camp Lejeune.
Researchers compared medical records for roughly 160,000 Navy and Marine veterans who served at two large bases during 1975–1985. More than half of the veterans studied had been stationed at Camp Lejeune in North Carolina, where water supplies were contaminated with TCE and other volatile organic compounds (VOCs). The remainder served at Camp Pendleton in California, whose water was not contaminated.
Key Facts:
- TCE (trichloroethylene) is a widely used industrial solvent, historically employed as an anesthetic and more recently as a degreasing agent for metal parts. It can volatilize during use and persist in soil and groundwater for decades once released into the environment.
- In this population-based cohort study, veterans who lived at Camp Lejeune had a 70% higher risk of being diagnosed with Parkinson’s disease compared with veterans who lived at Camp Pendleton.
- Environmental monitoring has detected TCE in many U.S. water supplies; estimates cited by the study authors indicate measurable levels in a substantial fraction of systems, meaning civilian populations can also be at risk of exposure.
Study overview and methods
Investigators from the University of California, San Francisco (UCSF) and the San Francisco VA Medical Center conducted a cohort study that followed veterans who spent at least three months at either Camp Lejeune or Camp Pendleton between 1975 and 1985. Health records were available in Veterans Health Administration and Medicare databases for follow-up between January 1, 1997, and February 17, 2021. Diagnoses of Parkinson’s disease and related parkinsonism were identified through diagnostic codes and medication records and were confirmed by medical record review.
Exposure details
Camp Lejeune’s water supplies were contaminated with several volatile organic compounds, with TCE concentrations reaching monthly median values more than 70 times higher than permissible limits during the period examined. Service members typically spent about two years stationed at these bases, beginning at an average age of roughly 20. Parkinson’s diagnoses in affected veterans occurred decades later, at an average age in the early 50s.
Results
Of the 158,122 veterans with available health data, 430 received a confirmed diagnosis of Parkinson’s disease. Of these, 279 were veterans who had lived at Camp Lejeune (prevalence 0.33%) and 151 were veterans from Camp Pendleton (prevalence 0.21%). After adjusting for relevant factors, the analysis indicated that Camp Lejeune veterans had a 70% higher odds of Parkinson’s disease (odds ratio 1.70; 95% CI, 1.39–2.07; P < .001) compared with Camp Pendleton veterans. The study did not find an excess risk for other forms of neurodegenerative parkinsonism.
Prodromal symptoms and risk scores
Beyond diagnosed Parkinson’s disease, the Camp Lejeune group showed a higher prevalence of prodromal features—early symptoms that can precede a formal Parkinson’s diagnosis. These included tremor, sleep disturbances, anxiety, constipation, loss of smell, and other nonmotor signs. When combined into cumulative risk scores used to estimate future Parkinson’s risk, Lejeune veterans scored higher than those from Pendleton, suggesting an elevated likelihood of developing the disease in the future.
Implications
The findings support the conclusion that environmental exposure to TCE and related VOCs can increase the long-term risk of Parkinson’s disease. Because TCE has been widely used and can persist in the environment, these results have potential public health implications for both veterans and civilian communities with contaminated air, soil, or water supplies. The authors note that TCE production and availability remain significant, and routine biomedical testing detects only recent exposures, limiting its usefulness for assessing past contact with the chemical.
Funding
This research was supported by a clinical science research and development merit award (I01 CX002040-01) from the U.S. Department of Veterans Affairs, with additional support for data access from VA and Centers for Medicare & Medicaid Services resources and project numbers from the VA Information Resource Center.
About this Parkinson’s disease research news
Author: Suzanne Leigh
Source: UCSF
Contact: Suzanne Leigh – UCSF
Image credit: Neuroscience News
Original research: Open access. Study title: “Risk of Parkinson Disease Among Service Members at Marine Corps Base Camp Lejeune” by Samuel M. Goldman et al., published in JAMA Neurology.
Abstract (summary)
Importance: Trichloroethylene (TCE) exposure has been implicated in Parkinson’s disease risk, but large population-based data have been limited. Millions worldwide have experienced environmental exposure to TCE through air, food, and water.
Objective: To determine whether veterans who lived at Camp Lejeune, where water was contaminated with TCE and other VOCs, had a higher risk of Parkinson’s disease than veterans who lived at Camp Pendleton, whose water was not contaminated.
Design, setting, and participants: This cohort study included Marines and Navy personnel who resided at Camp Lejeune (n = 172,128) or Camp Pendleton (n = 168,361) for at least three months between 1975 and 1985, with follow-up from 1997 to 2021. PD diagnoses and prodromal features were identified in VA and Medicare records and confirmed through chart review.
Exposures: Water at Camp Lejeune contained multiple VOCs with particularly high levels of TCE during the years studied, often far above permissible concentrations.
Main outcome and measures: The main outcome was diagnosis of Parkinson’s disease. Researchers also assessed diagnoses associated with prodromal PD and combined these into cumulative risk scores.
Results and conclusions: Among veterans with available health data, Camp Lejeune residence was associated with a significantly higher risk of Parkinson’s disease and greater prevalence of prodromal signs. The results suggest that historical exposure to TCE and related VOCs is linked to an increased risk of Parkinson’s disease decades later, underscoring ongoing public health concerns about this common environmental contaminant.