0.05). When study subjects were stratified by hospitalization status and number of times wounded and compared with U.S. men, those who received at least one wound that required hospitalization had a higher risk of suicide than those not hospitalized (standardized mortality ratio 1.22, 95% CI 1.00-1.46), and those wounded more than once had a higher risk of suicide than those wounded only once (standardized mortality ratio 1.58, 95% CI 1.06-2.26). Vietnam veterans who were wounded only once and never required hospitalization had the lowest risk of suicide (standardized mortality ratio 0.96, 95% CI 0.72-1.24), and those who were wounded more than once and required hospitalization for at least one wound had the highest risk of suicide (standardized mortality ratio 1.73, 95% CI 1.10-2.60). Strengths of the study included a 95% statistical power to detect a 1.2-fold increase in relative risk of motor-vehicle accidents and a 1.28-fold increase in relative risk of suicide in comparison with the U.S. general population using an alpha level of 0.05 and a two-sided test. Furthermore, although most studies of exposure to combat trauma rely on interview data to ascertain exposure, this study was able to minimize that source of potential bias by using military records (that is, military reports of casualties) to determine exposure. However, this study, like many, was unable to include data on potentially predisposing psychologic and behavioral characteristics that might be important risk factors for suicide after military service.
Kang and Bullman (1996) obtained death certificates of Gulf War veterans, of a control group that was mobilized and deployed elsewhere, and of a control group of veterans who were not deployed at all. Death certificates were provided through VA regional offices, as identified from combined data sources, which included the BIRLS database and the files from Social Security Administration. A qualified nosologist used the ICD-9 to code all causes of death and was blinded to subjects’ deployment status. Of 695,516 Gulf War veterans, 1765 had died, and death certificates were located for 1654 (93.7%). Of 746,291 controls deployed elsewhere or not deployed, 1729 had died, and death certificates were located for 1615 (93.4%). Gulf War veterans had a significantly higher mortality than veterans deployed elsewhere or never deployed during the period (adjusted mortality rate ratio 1.09, 95% CI 1.01-1.16). Accidental death accounted for the largest part of the difference (rate ratio 1.25, 95% CI 1.13-1.39), but the suicide rate in Gulf War veterans was not higher (rate ratio 0.94, 95% CI 0.79-1.12); rate ratios were adjusted for age, race, sex, branch of service, and type of unit. In general, the contrast between mortality for all causes in female veterans who served in the Gulf War and the general U.S. population was greater (standardized mortality ratio 0.56, 95% CI 0.44-0.71); however, the excess risk of suicide in female veterans approached significance in comparison with women in the general U.S. population (standardized mortality ratio 1.81, 95% CI 0.90-3.24).
Kang and Bullman (2001) extended their 1996 study for an additional 4 years and evaluated changing patterns of mortality in U.S. veterans of the Gulf War for almost 7 years of followup. They compared cause-specific mortality in 621,902 Gulf War veterans who arrived in the Persian Gulf before March 1, 1991, with nondeployed veterans. That excluded people who arrived in the Persian Gulf after hostilities had ended and therefore were not likely to have received the exposures of interest, which included the psychologic stresses of combat. A stratified random sample of all military personnel who served during the war but were not deployed to the Persian Gulf made up the control group of 746,248 veterans. Vital status was determined by using multiple databases, including those of the VA BIRLS and Social Security Administration. Death certificates were requested from VA regional offices. For death certificates that could not be located in that manner, the National Death Index was used to capture causes of death. As in their previous study of Vietnam veterans, the investigators used a