title: Factors influencing longitudinal change in knee cartilage volume measured from magnetic resonance imaging in healthy men.
abstract: OBJECTIVE
  To determine whether the amount of joint cartilage in healthy, middle aged men is stable or changes over time, and what factors may influence this.
  
  
  METHODS
  In a cohort study, 28 healthy men (70% of the original cohort; mean (SD) age, 51.9 (12.8) years) had baseline knee magnetic resonance imaging (MRI) of their dominant knee and repeat MRI of the same knee approximately 2.0 years later. Knee cartilage volume was measured at baseline and follow up. Risk factors assessed at baseline, including sex hormones and metabolic bone markers, were tested for their association with change in knee cartilage volume over time.
  
  
  RESULTS
  Mean (SD) reduction in tibial cartilage volume per year was 162 (93) microl. This represented a 2.8% reduction in total tibial articular cartilage per year (95% confidence interval, 0.2% to 5.5%). Tibial cartilage loss was associated with serum free testosterone level, independently of age, body mass index, baseline tibial cartilage volume tibial plateau area, and total bone mineral content. Overall, testosterone accounted for 14.5% (partial r2) of the variation in change in tibial cartilage volume. There was a trend towards a positive association between tibial cartilage loss and urinary N-telopeptide cross-links of type I collagen (Ntx) (p = 0.057).
  
  
  CONCLUSIONS
  Further studies will be required to determine whether hormonal manipulation or treatment with antiresorptive drugs will reduce the risk of knee osteoarthritis in men in later life.
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University - Central and Eastern Clinical School, Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia.
authors.forename: F
authors.initials: F
authors.lastname: Hanna
authors.forename: P R
authors.initials: PR
authors.lastname: Ebeling
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: R
authors.initials: R
authors.lastname: O'Sullivan
authors.forename: S
authors.initials: S
authors.lastname: Davis
authors.forename: A E
authors.initials: AE
authors.lastname: Wluka
authors.forename: F M
authors.initials: FM
authors.lastname: Cicuttini
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015992:Body Mass Index; D001835:Body Weight; D015519:Bone Density; D016723:Bone Remodeling; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D015444:Exercise / Q000502:physiology; D006728:Hormones / Q000097:blood; D006801:Humans; D007719:Knee Joint; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D013739:Testosterone / Q000097:blood
chemical_list: D015415:Biomarkers; D006728:Hormones; D015675:Osteocalcin; D013739:Testosterone