Frequency of Improvised Explosive Devices and Suicide Attempts in the US Army

Background: Improvised explosive devices (IEDs) were a prominent and initially new threat in the Iraq and Afghanistan war which raised concerns and anticipatory fear in and out of theater. This study examined the association of monthly IED rates with risk of soldier suicide attempt among those deployed and nondeployed. Methods: Person-month records for all active duty Regular Army suicide attempters from 2004 through 2009 (n = 9,791) and an equal-probability sample of control person-months (n = 183,826) were identified. Logistic regression analyses examined soldiers' risk of attempting suicide as a function of monthly IED frequency, controlling for sociodemographics, service-related characteristics, rate of deployment/redeployment, and combat deaths and injuries. The association of IED frequency with suicide attempt was examined overall and by time in service and deployment status. Findings: Soldiers' risk of suicide attempt increased with increasing numbers of IEDs. Suicide attempt was 26% more likely for each 1,000 IED increase in monthly frequency (odds ratio [OR] = 1.26, 95% confidence interval [CI] = 1.22-1.30). The association of IED frequency with suicide attempt was greater for soldiers in their first 2 years of service (OR = 1.30, 95% CI = 1.25-1.36) than for those with 3 or more years of service (OR = 1.18, 95% CI = 1.12-1.24). Among soldiers in their first 2 years of service, the association was constant, regardless of deployment status (chi(2)(2) = 3.89, p = 0.14). Among soldiers with 3 or more years of service, the association was higher for those never deployed (OR = 1.12, 95% CI = 1.01-1.24) and currently deployed (OR = 1.14, 95% CI = 1.05-1.23) than for those previously deployed. Discussion: To our knowledge, this is the first study to examine and demonstrate an association between the aggregate frequency of IEDs and risk of suicide attempts among U.S. Army soldiers. This association was observed across deployment status and time in service, and for early-career soldiers in particular. The findings suggest that the threat of new weapons may increase stress burden among soldiers. Targeting risk perception and perceived preparedness, particularly early in a soldier's career, may improve psychological resilience and reduce suicide risk.