Occupational driving as a risk factor for low back pain in active-duty military service members

Background contextAlthough occupational driving has been associated with low back pain, little has been reported on the incidence rates for this disorder.PurposeTo determine the incidence rate and demographic risk factors of low back pain in an ethnically diverse and physically active population of US military vehicle operators.Study design/settingRetrospective database analysis.Patient sampleAll active-duty military service members between 1998 and 2006.Outcome measuresLow back pain requiring visit to a health-care provider.MethodsA query was performed using the US Defense Medical Epidemiology Database for the International Classification of Diseases, Ninth Revision, Clinical Modification code for low back pain (724.20). Multivariate Poisson regression analysis was used to estimate the rate of low back pain among military vehicle operators and control subjects per 1,000 person-years, while controlling for sex, race, rank, service, age, and marital status.ResultsA total of 8,447,167 person-years of data were investigated. The overall unadjusted low back pain incidence rate for military members whose occupation is vehicle operator was 54.2 per 1,000 person-years. Compared with service members with other occupations, motor vehicle operators had a significantly increased adjusted incidence rate ratio (IRR) for low back pain of 1.15 (95% confidence interval [CI] 1.13–1.17). Female motor vehicle operators, compared with males, had a significantly increased adjusted IRR for low back pain of 1.45 (95% CI 1.39–1.52). With senior enlisted as the referent category, the junior enlisted rank group of motor vehicle operators had a significantly increased adjusted IRR for low back pain: 1.60 (95% CI 1.52–1.70). Compared with Marine service members, those motor vehicle operators in both the Army, 2.74 (95% CI 2.60–2.89), and the Air Force, 1.98 (95% CI 1.84–2.14), had a significantly increased adjusted IRR for low back pain. The adjusted IRRs for the less than 20-year and more than 40-year age groups, compared with the 30- to 39-year age group, were 1.24 (1.15–1.36) and 1.23 (1.10–1.38), respectively.ConclusionsMotor vehicle operators have a small but statistically significantly increased rate of low back pain compared with matched control population.