Evaluation of mortality among Marines, Navy personnel, and civilian workers exposed to contaminated drinking water at USMC Base Camp Lejeune: a cohort study

Abstract

Background Drinking water at U.S. Marine Corps Base Camp Lejeune, North Carolina was contaminated with trichloroethylene and other industrial solvents from 1953 to 1985. Methods A cohort mortality study was conducted of Marines/Navy personnel who, between 1975 and 1985, began service and were stationed at Camp Lejeune (N = 159,128) or Camp Pendleton, California (N = 168,406), and civilian workers employed at Camp Lejeune (N = 7,332) or Camp Pendleton (N = 6,677) between October 1972 and December 1985. Camp Pendleton’s drinking water was not known to be contaminated between 1972 and December 1985. Mortality follow-up was between 1979 and 2018. Survival analyses were used to calculate hazard ratios (HRs) comparing mortality rates between Camp Lejeune and Camp Pendleton cohorts and assess the effects of duration at Camp Lejeune. The ratio of upper and lower 95% confidence interval (CI) limits, or CIR, was used to evaluate the precision of effect estimates. The study focused on underlying causes of death with HRs ≥ 1.20 and CIRs ≤ 3. Results from contributing causes were also presented. Results Deaths among Camp Lejeune and Camp Pendleton Marines/Navy personnel totaled 19,250 and 21,134, respectively. Deaths among Camp Lejeune and Camp Pendleton civilian workers totaled 3,055 and 3,280, respectively. Compared to Camp Pendleton Marines/Navy personnel, Camp Lejeune had adjusted HRs ≥ 1.20 with CIRs ≤ 3 for cancers of the kidney (HR = 1.21, 95% CI: 0.95, 1.54), esophagus (HR = 1.24, 95% CI: 1.00, 1.54) and female breast (HR = 1.20, 95% CI: 0.73, 1.98). Causes of death with HRs ≥ 1.20 and CIR > 3, included Parkinson disease, myelodysplastic syndrome and cancers of the testes, cervix and ovary. Compared to Camp Pendleton workers, Camp Lejeune had adjusted HRs ≥ 1.20 with CIRs ≤ 3 for chronic kidney disease (HR = 1.88, 95% CI: 1.13, 3.11) and Parkinson disease (HR = 1.21, 95% CI: 0.72, 2.04). Female breast cancer had an adjusted HR of 1.19 (95% CI: 0.76, 1.88). Sensitivity analyses indicated that confounding bias due to unmeasured risk factors (e.g., smoking) is unlikely to significantly impact the findings. Conclusion Marines/Navy personnel and civilian workers likely exposed to contaminated drinking water at Camp Lejeune had increased hazard ratios for several causes of death compared to Camp Pendleton.