title: A longitudinal study for incidence of low back pain and radiological changes of lumbar spine in asymptomatic Japanese military young adults.
abstract: BACKGROUND
  The relation between radiological abnormalities on lumbar spine and low back pain (LBP) has been debated, presumably because of potential biases related to heterogeneity in selection of the subjects, radiological abnormalities at entry, or its cross-sectional observation in nature. Therefore, the aim of this study of a selected population of asymptomatic Japanese Self Defense Forces (JSDF) young adults male with normal lumbar radiographs was to investigate the incidence of newly developed lumbar degenerative changes at middle age and to study their association to LBP.
  
  
  METHODS
  In 1990, 84 JSDF male military servicemen aged 18 years, without a history of LBP and radiological abnormal findings, were enrolled. After 20 years, 84 subjects were underwent repeated X-ray and completed questionnaires on current LBP and lifestyle factors.
  
  
  RESULTS
  The prevalence of LBP was demonstrated 59 %, with 85 % of them showing mild pain. Analysis of lumbar radiographs revealed that 48 % had normal findings and 52 % had degenerative changes. The association between LBP and life style factors was not demonstrated. Lumbar spine in subjects with LBP was more degenerated than in those without. Although disc space narrowing and LBP did not achieve a statistical significance, a significant correlation existed between vertebral osteophyte and LBP in univariate and multivariate analysis (OR 3.0; 95 % CI 1.227-7.333).
  
  
  CONCLUSIONS
  This longitudinal study demonstrated the significant association between vertebral osteophyte and incidence of mild LBP in initially asymptomatic and radiologically normal subjects. These data provide the additional information concerning the pathology of LBP, but further study is needed to clarify the clinical relevance.
authors.affiliation: Orthopaedic Surgery, Japanese Self Defense Forces Hospital, Ikejiri, Setagaya-ku, Tokyo, Japan. drsamusio@world.ocn.ne.jp
authors.forename: Osamu
authors.initials: O
authors.lastname: Nemoto
authors.forename: Akira
authors.initials: A
authors.lastname: Kitada
authors.forename: Satoko
authors.initials: S
authors.lastname: Naitou
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Tsuda
authors.forename: Keitarou
authors.initials: K
authors.lastname: Matsukawa
authors.forename: You
authors.initials: Y
authors.lastname: Ukegawa
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D055959:Intervertebral Disc Degeneration / Q000000981:diagnostic imaging / Q000453:epidemiology*; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008137:Longitudinal Studies; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000453:epidemiology*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D008889:Military Personnel; D011859:Radiography; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires