The Association Between Sickle Cell Trait in U.S. Service Members with Deployment, Length of Service, and Mortality, 1992-2012

• Published in: Military medicine 2018-03, Vol.183 (3-4), p.e213-e218
• Main Authors: Singer, Darrell E, Chen, Ligong, Shao, Stephanie, Goldsmith, Jonathan, Byrne, Celia, Niebuhr, David W
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Armed forces; Cohort Studies; Continental Population Groups - statistics & numerical data; Defense; Female; Gender; Hispanic people; Humans; Laboratories; Male; Military deployment; Military occupations; Military personnel; Military Personnel - statistics & numerical data; Military recruitment; Mortality; Public health; Retention; Retrospective Studies; Risk Factors; Sickle cell disease; Sickle Cell Trait - complications; Sickle Cell Trait - epidemiology; Sickle Cell Trait - mortality; Time Factors; United States - epidemiology; Warfare - statistics & numerical data
• ISSN: 0026-4075; 1930-613X
• DOI: 10.1093/milmed/usx037

Sickle cell trait (SCT) affects an estimated 5.02% of non-Hispanic blacks, 1.08% of Hispanics, and 0.1% of Whites in the U.S. military. Policies for SCT screening and occupational restrictions vary by service. Population-based studies of SCT with quantification of military-relevant outcomes are lacking. The study design was a retrospective cohort of 15,081 SCT-positive versus 60,320 SCT-negative U.S. active duty personnel enlisted from 1992 to 2012 and followed through 2013. Military-relevant outcome included number and days of deployment, length of service, and cause of death. SCT-positive versus SCT-negative service members experienced more deployments (p < 0.01) and longer number of days deployed for all services, especially the Army (p < 0.001). The median length of service was longer for SCT-positive service members stratified by service and by gender (p < 0.05). The adjusted risk of length of service greater than 5 yr by SCT status was 1.37 (95% confidence interval 1.31-1.43) with greater than a three-fold higher risk in the Navy and Air Force compared with the Army. Crude mortality rate was not significantly different by SCT status, although deaths due to suicide, self-directed violence, and other non-specific causes were more common in SCT-positive service members. We found that SCT-positive service members deployed more frequently, for greater lengths of time, and remained in service longer. No significant difference in crude mortality ratio was discovered. Additional research on military-relevant outcomes and a cost-effectiveness analysis of SCT screening practices are needed to inform evidence-based SCT enlistment policies.