Suicide Risk Among US Veterans With Military Service During the Vietnam War

Importance There are persistent questions about suicide deaths among US veterans who served in the Vietnam War. It has been believed that Vietnam War veterans may be at an increased risk for suicide.Objective To determine whether military service in the Vietnam War was associated with an increased risk of suicide, and to enumerate the number of suicides and analyze patterns in suicides among Vietnam War theater veterans compared with the US population.Design, Setting, and Participants This cohort study compiled a roster of all Vietnam War-era veterans and Vietnam War theater veterans who served between February 28, 1961, and May 7, 1975. The 2 cohorts included theater veterans, defined as those who were deployed to the Vietnam War, and nontheater veterans, defined as those who served during the Vietnam War era but were not deployed to the Vietnam War. Mortality in these 2 cohorts was monitored from 1979 (beginning of follow-up) through 2019 (end of follow-up). Data analysis was performed between January 2022 and July 2023.Main Outcomes and Measures The outcome of interest was death by suicide occurring between January 1, 1979, and December 31, 2019. Suicide mortality was ascertained from the National Death Index. Hazard ratios (HRs) that reflected adjusted associations between suicide risk and theater status were estimated with Cox proportional hazards regression models. Standardized mortality rates (SMRs) were calculated to compare the number of suicides among theater and nontheater veterans with the expected number of suicides among the US population.Results This study identified 2 465 343 theater veterans (2 450 025 males [99.4%]; mean [SD] age at year of entry, 33.8 [6.7] years) and 7 122 976 nontheater veterans (6 874 606 males [96.5%]; mean [SD] age at year of entry, 33.3 [8.2] years). There were 22 736 suicides (24.1%) among theater veterans and 71 761 (75.9%) among nontheater veterans. After adjustments for covariates, Vietnam War deployment was not associated with an increased risk of suicide (HR, 0.94; 95% CI, 0.93-0.96). There was no increased risk of suicide among either theater (SMR, 0.97; 95% CI, 0.96-0.99) or nontheater (SMR, 0.97; 95% CI, 0.97-0.98) veterans compared with the US population.Conclusions and Relevance This cohort study found no association between Vietnam War-era military service and increased risk of suicide between 1979 and 2019. Nonetheless, the 94 497 suicides among all Vietnam War-era veterans during this period are noteworthy and merit the ongoing attention of health policymakers and mental health professionals.