Identified demographic factors related to causes of disability discharge from the U.S. Army, 1980 to 2005

Objective: Disability is a growing problem in U.S. military and civilian populations. We evaluated demographic risk factors for the most prevalent causes of disability discharge from the U.S. Army. Methods: Time-series and logistic regression analyses were used to study 108,617 active-duty Army soldiers discharged with permanent disability between 1980 and 2005. Results: The most prevalent disability causes were musculoskeletal (70%), cardiovascular (4%), respiratory (4%), neurological (6%), and mental disorders (5%). Musculoskeletal discharge rates increased 2% annually, while rates for cardiovascular (-6%), neurological (-1%), and mental health (-8%) decreased, and respiratory rates remained constant. Preliminary demographic analyses revealed that males were less likely than females to be discharged with musculoskeletal or respiratory conditions but more likely to be discharged with neurological and mental health disorders (OR=0.87, 0.83. 1.23, 1.29, respectively; all p<0.05). Compared to soldiers under age 21, soldiers had higher risks of musculoskeletal (OR range 1.10-1.25, p<0.05) with increasing age until age 40, and then the risk decreased (OR=0.76, p<0.05). The risk of mental health problems increased with age (OR range 1.11-2.38, all p<0.05). Compared to Caucasians, African-Americans were at higher risk of respiratory and cardiovascular discharge but at lower risk of musculoskeletal and neurological discharge (OR=1.66, 1.09, 0.78, 0.87, respectively, all p<0.05), whereas Hispanics had higher risk of respiratory but lower risk of cardiovascular and neurological discharge (OR=1.23, 0.61, 0.89, respectively, all p<0.05). Conclusions: Variations in disability causes across demographic subpopulations should be taken into account when enumerating changes in disability discharge trends and when devising intervention strategies.