A longitudinal study of radiological changes in the lumbar spine in asymptomatic Japanese military young adults

Abstract

High prevalence of vertebral osteophytes has been observed in men associated with heavy physical activity and found to be associated with low back pain (LBP) in recent reports. However, development of vertebral osteophytes and identification of their predictors in longitudinal observational studies are not well known. In 1984, 45 Japanese Self Defense Forces male military parachutists aged 18 or 19 years, without a history of LBP and radiological abnormal findings, were investigated. After 25 years, 40 subjects were contacted and underwent repeated X-ray. At the 25-year follow-up evaluation, we studied developed lumbar degenerative changes. All 40 subjects completed questionnaires on current LBP and lifestyle factors. Univariate analysis was performed to study the risk factors of LBP. Association of vertebral osteophytes development with various factors was studied using univariate and multivariate analyses. The prevalence of vertebral osteophytes, disc space narrowing or facet joint osteoarthrosis was 70 %, 48 %, or 57 % respectively. Current LBP rated as mild pain was demonstrated in 60 %. We did not find a significant association between LBP and various factors, although vertebral osteophytes showed a greater odds ratio. Among various variables in multiple logistic regression analysis, the number of parachuting descents (≧250) and disc space narrowing were significant predictors for the development of vertebral osteophytes. In asymptomatic and radiologically normal young male parachutists, frequent parachuting descents and disc space narrowing were associated with vertebral osteophytes formation.