Deployment to Karshi-Khanabad Air Base, Uzbekistan between 2001 and 2005 and subsequent risk of specific cancers among US service members.

Abstract

Adverse health events have been reported among US service members who served at Karshi-Khanabad (K2) Air Base, Uzbekistan, but prior studies of cancer risk had key limitations. We conducted a nested case-control study to assess the association between K2 deployment and cancer outcomes among military personnel deployed between 2001-2005. Eight malignant outcomes (brain, colorectal, liver, urinary tract, pancreatic, prostate, leukemia, non-Hodgkin's lymphoma [NHL]) were identified via health records from the Department of Defense and Veterans Administration through 2022. Cases were matched to controls (1:100) on age, sex, and health system usage. Covariate-adjusted conditional logistic regression models estimated outcome likelihood by exposure surrogates without and with lagging. Among 619,403 service members, 15,031 (2.3%) were deployed at least once to K2 (median duration 130 days). We identified cancer cases (count; cumulative incidence per 10,000) for brain (450; 7.3), colorectal (1,542; 25.0), liver (113; 1.8), urinary tract (1,831; 29.7), pancreatic (417; 6.8), prostate (5,165; 83.6), leukemia (707; 11.5), NHL (1,700; 27.5). Across seven of eight outcomes, there were no associations between deployment and case status. In contrast, each additional month of deployment increased the odds of NHL by 13% (95% CI, 4%-23%) and deployment >180 days was associated with higher odds (OR 1.78; 95% CI, 1.08-2.94). When lagging exposure by 12-15 years, these associations strengthened (range: 2.38 [1.17-4.82] to 3.09 [1.73-5.52]). Long-term K2 deployment was associated with increased likelihood of non-Hodgkin's lymphoma. Careful clinical monitoring and continued follow-up of this cohort for cancer and other outcomes are warranted.