The incidence and worsening of newly diagnosed low back pain in a population of young male military recruits

Background: Low back pain (LBP) is a leading cause of referral to occupational health clinics and of consequent work absenteeism. There is lack of data concerning ages 18-21. The objective of our study was to evaluate the occurrence of newly diagnosed LBP and the recurrence and worsening of preexisting LBP in young male military recruits. Methods: In this retrospective cohort study, we examined the medical history of army recruits during the 30-month period after their induction into the Israel Defense Forces (IDF). The duty status of soldiers in combat units (CU), maintenance units (MU) and administrative units (AU) was evaluated according to their morbidity. The study's end point was defined as significant findings on clinical examination with presence of neurological deficits which correlate to radiological findings on CT or MRI showing herniated disks, spinal stenosis or pressure on neurological roots. Results: The annual incidence rate of LBP in a total of 159,295 recruits was 0.05 %. The relative risk (RR) for developing LBP was significantly higher among subjects who were assigned to AU as compared to CU and MU in all LBP categories. The RR for LBP recurrence in soldiers with a positive history of LBP (categories 3 and 4) was 4.1 and 10.7 compare to category 1 respectively. Conclusions: The lower than expected overall incidence rate of 0.05 % reflects the fact that severe LBP occurrences are not common at this age group. This finding is a more truthful reflection of LBP occurrence rates relative to other studies since the end point is based on precise clinical definitions in medical records and not on questionnaires, as in most studies. The RR for developing LBP was significantly higher among subjects who were assigned to AU as compared to CU and MU in all LBP categories. Childhood history of LBP was found as a significant risk factor for LBP exacerbations at adulthood. Positive history of LBP was found as a risk factor for the recurrence of LBP in all occupation types and particularly in sedentary ones.