Ursano RJ, et al. - Researchers aimed to ascertain the associations of time-related deployment variables with subsequent suicide attempt (SA) among soldiers who had deployed twice. They recognized time in service before first deployment and dwell time (DT) (ie, length of time between deployments) as modifiable risk factors for SA risk among soldiers.

Methods

• From January 1, 2004, through December 31, 2009, researchers performed a longitudinal, retrospective cohort study identifying person-month records of active-duty Regular Army enlisted soldiers who had served continuously in the US Army for at least 2 years and deployed exactly twice using administrative data.
• From March 1 to December 1, 2017, analysis was performed .
• They recognized 593 soldiers with a medically documented SA during or after their second deployment.
• They selected an equal-probability sample of control person-months from other soldiers with exactly 2 deployments (n = 19,034).
• Using logistic regression analyses, they examined the associations of time in service before first deployment, duration of first deployment, and DT with subsequent SA.
• Using US Department of Defense Suicide Event Report records and International Classification of Diseases, Ninth Revision, Clinical Modification E950 to E958 diagnostic codes, suicide attempts during or after second deployment were identified.
• Independent variables were constructed from US Army personnel records.

Results

• Researchers identified 593 SA cases; most of these were male (513 [86.5%]), white non-Hispanic (392 [66.1%]), at least high school educated (477 [80.4%]), currently married (398 [67.1%]), and younger than 21 years when they entered the US Army (384 [64.8%]).
• In multivariable models adjusting for sociodemographics, service-related characteristics, and previous mental health diagnosis, soldiers whose first deployment occurred within the first 12 months of service vs after 12 months showed higher odds of SA during or after second deployment (odds ratio, 2.0; 95% CI, 1.6-2.4); this was also evident in those with a DT of 6 months or less vs longer than 6 months (odds ratio, 1.6; 95% CI, 1.2-2.0).
• No association of duration of first deployment with subsequent SA was noted.
• Analysis of 2-way interactions indicated that other characteristics did not modify the associations of early deployment and DT with SA risk.
• In this study, multivariable population-attributable risk proportions were 14.2% for deployment within the first 12 months of service and 4.0% for DT of 6 months or less.