title: Prevalence of degenerative imaging findings in lumbar magnetic resonance imaging among young adults.
abstract: METHODS
  A cross-sectional imaging study of young adults.
  
  
  OBJECTIVE
  To investigate the prevalence of disc degeneration (DD) and displacement, anular tears, and Modic changes in lumbar magnetic resonance imaging (MRI) among young adults.
  
  
  BACKGROUND
  Although low back pain in young adulthood is common, the prevalence of spinal MRI findings at this age remains virtually unknown.
  
  
  METHODS
  The study population was a subcohort of the Northern Finland Birth Cohort 1986. Subjects living within 100 km of Oulu (n = 874) were invited to participate in lumbar MRI at 20 to 22 years of age (mean: 21.2 years). Degree of DD, type of Modic changes, and presence of disc bulges, herniations, high intensity zone (HIZ) lesions, and radial tears at all lumbar levels were assessed.
  
  
  RESULTS
  Three hundred twenty-five women and 233 men (n = 558) attended the MR imaging. DD was significantly more frequent in men (54% vs. 42%, P = 0.005), as was multiple DD (21% vs. 14%, P = 0.036). The prevalences of disc bulges and radial tears were 25% and 9.1%, respectively, without gender differences. HIZ lesions were more common among women than men (8.6% vs. 4.3%, P = 0.046), whereas herniations were significantly more common among men (5.6% vs. 2.5%, P = 0.047). Only 2 disc extrusions were observed, one in each gender. All degenerative disc findings were more common at the L5-S1 level except HIZ lesions, which were most likely at L4-L5. The prevalence of the Modic changes was 1.4%, without gender difference, type I being more common than type II. Typically, Modic changes were located adjacent to a DD Grade 4 disc and at the 2 lowest levels.
  
  
  CONCLUSIONS
  Almost half of young Finnish adult aged 21 years had at least one degenerated disc, and a quarter had a bulging disc. Modic changes and disc herniations were, however, relatively rare.
authors.affiliation: Department of Physical and Rehabilitation Medicine, Institute of Clinical Sciences, University of Oulu, Oulu, Finland.
authors.forename: Jani
authors.initials: J
authors.lastname: Takatalo
authors.forename: Jaro
authors.initials: J
authors.lastname: Karppinen
authors.forename: Jaakko
authors.initials: J
authors.lastname: Niinimäki
authors.forename: Simo
authors.initials: S
authors.lastname: Taimela
authors.forename: Simo
authors.initials: S
authors.lastname: Näyhä
authors.forename: Marjo-Riitta
authors.initials: MR
authors.lastname: Järvelin
authors.forename: Eero
authors.initials: E
authors.lastname: Kyllönen
authors.forename: Osmo
authors.initials: O
authors.lastname: Tervonen
mesh_terms: D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007403:Intervertebral Disc / Q000473:pathology*; D007405:Intervertebral Disc Displacement / Q000175:diagnosis* / Q000453:epidemiology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015995:Prevalence; D011859:Radiography; D013122:Spinal Diseases / Q000175:diagnosis / Q000453:epidemiology; D055815:Young Adult