Depressive symptoms and other risk factors predicting suicide in middle-aged men: a prospective cohort study among Korean Vietnam War veterans

Background. Few studies have prospectively examined whether depressive symptoms and other risk factors are associated with a higher risk of suicide death in individuals other than high-risk populations such as psychiatric patients and individuals with self-harm histories. The purpose of the study is to prospectively examine whether depressive symptoms assessed by the Beck Depression Inventory (BDI) are associated with greater risk of suicide death and whether depressive symptoms and other risk factors are independent predictors of suicide in general-risk populations. Another aim is to evaluate the sensitivity of the BDI for predicting suicide death. Methods. 10,238 Korean Vietnam War veterans (mean age: 56.3 years) who participated in two surveys in 2001 were followed up for suicide mortality over 7.5 years. Results. 41 men died by suicide. Severely depressed participants had a higher adjusted hazard ratio (aHR = 3.4; 95% CI [1.5-7.7]) of suicide than non-to-moderately depressed ones. Higher suicide risk was associated with more severe depressive symptoms (p for trend = 0.009). After adjustment for depressive symptoms and other factors, very poor health, low education, and past drinking were associated with higher suicide risk, while good health, body mass index, and marital status were not associated with suicide. The sensitivity at the cut-off score of 31 for detecting suicide was higher during the earlier 3.5 years of the follow-up (75%; 95% CI [50-90]) than during the latter 4 years (60%; 95% CI [41-76]). Conclusions. Depressive symptoms are a strong independent predictor and very poor health, low education, and drinking status may be independent predictors of future suicide. The BDI may have acceptable diagnostic properties as a risk assessment tool for identifying people with depression and suicidal potential among middle-aged men.