title: Relationship between gender, bone mineral density, and disc degeneration in the lumbar spine: a study in elderly subjects using an eight-level MRI-based disc degeneration grading system.
abstract: The study cohort comprised 196 females and 163 males. Lumbar spine bone mineral density (BMD) and magnetic resonance imaging (MRI) were acquired. Females had more severe disc degeneration than males. Lumbar spine lower BMD was associated with less severe disc degeneration. Lumbar disc spaces were more likely to be narrower when vertebral BMD was higher.
  
  
  BACKGROUND
  The purpose of this paper is to study the relationship between gender, BMD, and disc degeneration in the lumbar spine.
  
  
  METHODS
  The study cohort comprised 196 females and 163 males (age range 67-89 years) with no age difference between the two groups. Lumbar spine BMD was measured with dual X-ray densitometry, and MRI was acquired at 1.5 T. A subgroup of 48 males had additional lumbar vertebral quantitative computerized tomography densitometry. Lumbar disc degeneration was assessed using a MRI-based eight-level grading system.
  
  
  RESULTS
  Female subjects had more severe disc degeneration than male subjects. After removing age effect, a positive trend was observed between T-score and severity of lumbar disc degeneration. This was significant in female subjects while not significant in male subjects. Lumbar disc spaces were more likely to be narrowed when vertebral BMD was higher. These observations were more significant in the midlumbar region (L3/4 and L4/5) and less so at the thoracolumbar junction.
  
  
  CONCLUSIONS
  Female subjects tended to have slightly more severe lumbar disc degeneration than male subjects. Lower lumbar spine BMD was associated with less severe disc degeneration.
authors.affiliation: Department of Diagnostic Radiology and Organ Imaging, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, People's Republic of China. yixiang_wang@cuhk.edu.hk
authors.forename: Y-X J
authors.initials: YX
authors.lastname: Wang
authors.forename: J F
authors.initials: JF
authors.lastname: Griffith
authors.forename: H T
authors.initials: HT
authors.lastname: Ma
authors.forename: A W L
authors.initials: AW
authors.lastname: Kwok
authors.forename: J C S
authors.initials: JC
authors.lastname: Leung
authors.forename: D K W
authors.initials: DK
authors.lastname: Yeung
authors.forename: A T
authors.initials: AT
authors.lastname: Ahuja
authors.forename: P C
authors.initials: PC
authors.lastname: Leung
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology*; D001851:Bone Diseases, Metabolic / Q000150:complications / Q000503:physiopathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010024:Osteoporosis / Q000150:complications / Q000503:physiopathology; D012720:Severity of Illness Index; D012737:Sex Factors