Suicide among regular-duty military personnel: a retrospective case-control study of occupation-specific risk factors for workplace suicide.

OBJECTIVE The purpose of this study was to examine the epidemiology, phenomenology, and occupation-specific risk factors for suicide among regular-duty military personnel as a model for other professions at risk for workplace suicide. METHOD Suicide incidence and methods were determined in a retrospective military cohort comprising all deaths (N=732) of regular-duty military personnel in the Irish Defence Forces between 1970 and 2002. A retrospective, case-control study using pair-matched military comparison subjects was conducted to determine occupation-specific risk factors for suicide, particularly by firearm, among military personnel. Risk factors were subjected to chi-square analysis or independent t tests and entered into a binary logistic regression analysis model. RESULTS The period-averaged suicide rate for the cohort was 15.3/100,000. Firearm suicides accounted for 53% of the cases. Suicides that took place on duty occurred predominantly when personnel were alone shortly after duty commencement in the morning. Bivariate and logistic regression analyses identified psychiatric illness and a past history of deliberate self-harm, morning duty (shortly after duty assumption and consequent access to firearms), and a recent medical downgrading as independent risk factors predicting firearm suicide among military personnel. CONCLUSIONS Occupation influences suicide method. Access to and opportunity to use lethal means in the workplace are distinct but related occupation-specific suicide risk factors in the military and in other at-risk professions. In professions where access to lethal means is inevitable, moderating opportunity for suicide is crucially important. In regular-duty military personnel, a medical downgrading, combined with risk factors established in civilians such as younger age, male gender, psychiatric illness, and past self-harm, increases the risk of suicide. The findings may be used to guide military harm-reduction strategies and have applicability in strategies for other professions at risk for workplace suicide.