Study Design. Epidemiological study. Objective. To investigate the incidence and risk factors for developing low back pain in active duty military population to include age, sex, race, and rank, and military service. Summary of Background Data. Low back pain is among the most common musculoskeletal conditions worldwide and is estimated to affect nearly two-thirds of the US population at some point in their lives. Low back pain is a multifactorial disease and many risk factors have been implicated including age, race, sex, and marital status. Methods. A query was performed using the US Defense Medical Epidemiology Database (DMED) for the International Classifi cation of Diseases, Ninth Revision, Clinical Modifi cation code for low back pain (724.20). 13,754,261 person-years of data were investigated. Multivariate Poisson regression analysis was used to estimate the rate of low back pain per 1000 person-years, whereas controlling for sex, race, rank, service, age, and marital status. Results. The overall unadjusted incidence rate of low back pain was 40.5 per 1000 person-years. Women, compared with men, had a signifi cantly increased incidence rate ratio for low back pain of 1.45. The incidence rate ratio for the 40 + age group compared with the 20 to 29 years of age group was 1.28. With junior offi cers as the referent category, junior-and senior-enlisted rank groups had increased incidence rate ratio for low back pain, 1.95 and 1.35, respectively. Each service, when compared with the Marines as the referent category, had a signifi cantly increased incidence rate L ow back pain is among the most common musculoskeletal conditions worldwide and is estimated to affect up to 85% of the US population at some point in their lives. It is a signifi cant cause of disability in the working population and carries a substantial economic impact with an estimated annual cost of $28 billion in the United States alone.2 , 3 Because of the impact it has on a signifi cant portion of the general population, it has been the subject of numerous studies to identify populations at greater risk as well as factors that contribute to the development of this condition.Although low back pain is such a common condition, it remains poorly understood. It is a complex and multifactorial condition with many contributing variables to include psychosocial factors 4 -6 The US Armed Forces represents a physically active population of male and female service members with generally high occupational demands. These patients are also screened at the initial military entry examination for preexisting spinal conditions. Findings of any preexisting spinal abnormalities exclude patients from entry to active duty military service. Once in military service, these patients must meet the standards of a semiannual physical fi tness test and height/weight requirements and must also participate in organized physical fi tness training programs. The purpose of our study is to evaluate the incidence and demographic risk factors associated with new onset low back pa...
