Karshi-Khanabad Surveillance Program (K2SP)

OBJECTIVE: The aim of this study was to evaluate associations between deployment to Karshi-Khanabad (K2) and adverse health outcomes. METHODS: This is a retrospective cohort study comparing K2 veterans (2001 to 2005) with two matched groups: veterans deployed to Southwest Asia (Operation Enduring Freedom [OEF]-deployed) and non-deployed veterans (OEF-era). Morbidity (through 2022) was identified via Veterans Affairs (VA)/Department of Defense health care databases, and prevalence ratios were estimated using generalized linear models. Mortality (through 2021) was assessed via VA/DoD Mortality Data Repository using standardized mortality ratios and Cox proportional hazards models. RESULTS: Only 2 of the 60 outcomes had elevated prevalence but did not show a pattern suggesting association with K2 deployment. Mortality (hazard ratio: 1.03; 95% confidence interval: 0.88 to 1.22) was not elevated among K2 veterans. CONCLUSIONS: Deployment to K2 does not appear to be associated with increased morbidity or mortality at this time. Continued surveillance of this cohort is planned over the next decade.