Sickle cell trait prevalence among U.S. military service members: 1992–2012

Background: Population-based estimates of sickle cell trait (SCT) prevalence in the U.S. military across services and over time are lacking. Methods: SCT prevalence by service, race/ethnicity, and gender in 5-year time intervals was estimated using demographic, ambulatory, and hospital SCT encounter (International Classification of Diseases, 9th Revision, Clinical Modification 282.5) data for active duty, enlisted between 1992 and 2012 and limited SCT laboratory results. Results: Our study identified 15,081 SCT subjects. SCT prevalence varied significantly by race, year, gender, and service branch. SCT prevalence was highest for non-Hispanic blacks (5.02%; prevalence ratio = 56.33, confidence interval [CI] = 52.14–60.85; compared to non-Hispanic white) in 2005–2009 (0.40%; prevalence ratio = 10.04, CI = 9.21–10.94; compared to 1992–1994), for women (2.97%; prevalence ratio = 3.14, CI = 3.04–3.25; compared to men), and in the Navy (2.26%; prevalence ratio = 2.96, CI = 2.84–3.02; compared to Army). Among foreign born, Africans were more likely to be SCT+ (prevalence ratio = 1.68, CI = 1.39–2.04; compared to non-U.S. North American). Conclusion: This study estimated the prevalence of SCT within U.S. military enlisted force and describes variability across services for race, time intervals, gender, and foreign-born region and will support investigation into the health effects of SCT in young adult populations.