Risk and Protective Factors for Cancer Mortality among United States Service Members and Veterans (2001-2018).

BACKGROUND: Prior research linking military factors with cancer-specific mortality has shown inconsistent findings, with few studies examining these associations among U.S. service members and veterans who served in Operation Iraqi Freedom/Operation Enduring Freedom conflicts. METHODS: Cancer mortality between 2001 and 2018 was ascertained from the Department of Defense Medical Mortality Registry and National Death Index for 194,689 Millennium Cohort Study participants. Cause-specific Cox proportional hazard models were used to examine links between military characteristics and cancer mortality [overall, early (<45 years), and lung]. RESULTS: Compared with individuals who deployed with no combat experiences, non-deployers had a greater risk of overall [HR = 1.34; 95% confidence interval (CI) = 1.01-1.77] and early cancer mortality (HR = 1.80; 95% CI = 1.06-3.04). Enlisted individuals had a greater risk of lung cancer mortality compared with officers (HR = 2.65; 95% CI = 1.27-5.53). No associations by service component, branch, or military occupation and cancer mortality were observed. Higher education was associated with reduced overall, early and lung cancer mortality risk and smoking and life stressors were associated with elevated overall and lung cancer mortality risk. CONCLUSIONS: These findings are consistent with the healthy deployer effect in which military personnel who were deployed tend to be healthier than those who did not deploy. Further, these findings highlight the importance of considering socioeconomic factors, such as military rank, that may have long-term implications for health. IMPACT: These findings highlight military occupational factors that may predict long-term health outcomes. Additional work is necessary to investigate more nuanced environmental and occupational military exposures and cancer mortality.