There is strong evidence that exposure to trichloroethylene (TCE), often found in US groundwater, increases the risk of developing Parkinson disease (PD), according to study findings published in JAMA Neurology.
Marine and Navy personnel at Camp Lejeune, North Carolina, from 1953 until 1987, drank well water heavily contaminated with volatile organic compounds. This included concentrations of TCE over 70 times the Environmental Protection Agency’s recommended concentration limit.
Such large-scale exposure to TCE had not been studied previously. However, animal studies, and small studies in humans, had indicated a link between TCE exposure and PD. Therefore, for the study, researchers reviewed medical records of a cohort of 84,824 personnel at Camp Lejeune who subsequently accessed Veterans Administration or Medicare health benefits. They had been stationed there between 1975 and 1985, the period of maximal water TCE contamination. For comparison, the team recruited records for 73,298 personnel at Camp Pendleton, California, which was not affected by significant water contamination.
In the review, the researchers identified patients with subsequent diagnoses of PD and other neurodegenerative parkinsonian diseases, as well as prodromal manifestations. The researchers conducted logistic regression analyses and predictive models to examine the links between each diagnosis and camp location, controlling for age, sex, ethnicity, military rank, and smoking status.
The analysis revealed that veterans of Camp Lejeune were 70% more likely to be diagnosed with probable or possible PD than those who had lived at Camp Pendleton (odds ratio [OR], 1.70; 95% CI, 1.39-2.07; P <.001); and, 81% were more likely to be diagnosed with probable PD (OR, 1.81; 95% CI, 1.46-2.24; P <.001). Camp Lejeune exposure was not associated with other neurodegenerative conditions, including Lewy-body dementia, progressive supranuclear palsy, and multiple system atrophy.
Among prodromal features, anxiety (OR, 1.08; 95% CI, 1.05-1.10), tremor (OR, 1.19; 95% CI, 1.09-1.29), and erectile dysfunction (OR, 1.12; 95% CI, 1.09-1.14) were more common among veterans of Camp Lejeune. Those veterans were also between 14% and 18% more likely to score at or above the 99th percentile for cumulative risk for prodromal diagnosis; therefore, at the time of evaluation, it was most probable that members of that cohort may have been in the early evolution of PD.
Sensitivity analysis indicated that veterans’ awareness of the 2017 federal notification regarding their exposure, and the associated Veterans Administration (VA) health benefit, would have had only a modest effect on diagnosis risk; analyzing data for patients only before that date yielded smaller, but still significantly higher odds for a PD diagnosis.
The researchers acknowledged that their methods may not have accounted for other unknown environmental exposures, including those not sustained at the camp; or the effect of other known water contaminants at Camp Lejeune during the same period, which included tetrachloroethylene, vinyl chloride, and benzene.
However, they noted, “in addition to the exposed service members studied here, hundreds of thousands of family members and civilian workers exposed to contaminated water at Camp Lejeune may also be at increased risk of PD, cancers, and other health consequences. Continued prospective follow-up of this population is essential.”
Disclosures: Several study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures.
This article originally appeared on Neurology Advisor
Goldman SM, Weaver FM, Stroupe KT, et al. Risk of Parkinson disease among service members at Marine Corps Base Camp Lejeune. JAMA Neurol. Published online May 15, 2023. doi:10.1001/jamaneurol.2023.1168