Incidence and risk factors for lumbar degenerative disc disease in the United States military 1999-2008.

The epidemiology of lumbar degenerative disc disease (DDD) is poorly understood, and the incidence of this disorder has not previously been characterized for a young, physically active population. This study sought to evaluate the incidence of lumbar DDD, and identify risk factors for its development, among individuals serving in the U.S. military over a 10-year period. The Defense Medical Epidemiology Database was queried for the years 1999-2008 using the International Classification of Diseases, Ninth Revision, Clinical Modification code for lumbar disc degeneration (722.52). Overall incidence was determined and multivariate Poisson regression analysis was performed to identify risk factors among demographic characteristics such as age, sex, race, military rank, and branch of service. White race, female sex, Army, Air Force, or Marine service, enlisted positions within the ranks, and age were found to be significant risk factors for the development of lumbar disc degeneration. Increased age appeared to be one of the most important risk factors, with adjusted incidence rates successively increasing for each age group under study. The incidence of lumbar DDD in this young, racially diverse, and physically active population is higher than most other degenerative conditions.