External-cause mortality after psychologic trauma: the effects of stress exposure and predisposition

Abstract

Research suggests that exposure to psychologic trauma is associated with mortality from external causes, including homicide, suicide, drug overdoses, and unintended injury. However, the etiology of this association is unclear. We examined the survival time and cause of death among a national sample of 15 288 US Army veterans by posttraumatic stress disorder (PTSD) status 30 years after military service. In these analyses, we included demographic (age, race, marital status, service entry age, and birthplace), predisposing (army volunteer status, discharge status, history of drug abuse, early-age alcohol use, and intelligence), and combat exposure variables. After adjusting for demographic and predisposing factors, all-cause mortality was associated with PTSD for all veterans combined (hazards ratio [HR] = 2.1, P < .001), as well as for era veterans without Vietnam service (HR = 2.0, P = .001) and theater veterans with Vietnam service (HR = 2.1, P < .001). For theater veterans, PTSD remained significant for all-cause mortality, even after controlling for demographic, predisposition, and combat exposure measures (HR = 2.1, P < .001). For external mortality, the adjusted results indicated that PTSD was associated with death for all veterans combined (HR = 2.3, P < .001) and for theater veterans separately (HR = 2.2, P = .002). For era veterans, the adjusted external mortality results also approached statistical significance (HR = 2.2, P = .068). Among theater veterans, PTSD remained significant for external mortality, even after controlling for all variables and combat exposure (HR = 2.2, P = .002). Combat exposure was not associated with external mortality once all variables were controlled. In addition, theater veterans who volunteered for Vietnam and those with dishonorable discharges were at increased risk for external-cause mortality.