title: The determinants of change in patella cartilage volume--a cohort study of healthy middle-aged women.
abstract: OBJECTIVE
  Although cartilage loss occurs with advancing age and is a hallmark of OA, the factors that affect cartilage change are not well established. The aim of this study was to explore the determinants of change in patella cartilage volume over 2 yrs among healthy middle-aged women with no clinical knee OA.
  
  
  METHODS
  One hundred and forty-eight women with no clinical knee OA were recruited from a previous population-based cross-sectional study of healthy women aged 40-67 yrs. MRI was performed at baseline and at 2 yrs, to assess patella cartilage and bone volume. Self-reported exercise was assessed by questionnaire.
  
  
  RESULTS
  Annual loss of patella cartilage volume was 1.6% (95% CI 1.2, 1.9). Age was positively associated with patella cartilage volume loss after adjustment for confounders (P = 0.05). For every 1 mm(3) increase in patella bone volume at baseline, annual cartilage loss was reduced by 8.05 mm(3) (95% CI 12.91, 3.19; P < 0.001). Fortnightly participation in exercise promoting an increased heart and respiratory rate for at least 20 min also tended to be associated with a reduced rate of patella cartilage volume loss (P = 0.09).
  
  
  CONCLUSIONS
  Among middle-aged women with no clinical knee OA, advancing age expedites the rate of patella cartilage volume loss, while increased patella bone volume and exercise participation tends to be associated with a reduction in the rate of patella cartilage volume loss. Interventions targeting modifiable factors, such as physical activity, warrant further investigation as they may help to prevent patellofemoral OA.
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University Medical School, Alfred Hospital, Prahran, Victoria 3181, Australia.
authors.forename: S P
authors.initials: SP
authors.lastname: Wijayaratne
authors.forename: A J
authors.initials: AJ
authors.lastname: Teichtahl
authors.forename: A E
authors.initials: AE
authors.lastname: Wluka
authors.forename: F
authors.initials: F
authors.lastname: Hanna
authors.forename: R
authors.initials: R
authors.lastname: Bell
authors.forename: S R
authors.initials: SR
authors.lastname: Davis
authors.forename: J
authors.initials: J
authors.lastname: Adams
authors.forename: F M
authors.initials: FM
authors.lastname: Cicuttini
mesh_terms: D000375:Aging / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006339:Heart Rate; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology; D010329:Patella / Q000473:pathology*; D012119:Respiration