title: The associations between parity, other reproductive factors and cartilage in women aged 50-80 years.
abstract: OBJECTIVE
  Sex hormones and reproductive factors may be important for osteoarthritis (OA). The aim of this study was to describe the associations of parity, use of hormone replacement therapy (HRT) and oral contraceptives (OCs) with cartilage volume, cartilage defects and radiographic OA in a population-based sample of older women.
  
  
  METHODS
  Cross-sectional study of 489 women aged 50-80 years. Parity, use of HRT and OC was assessed by questionnaire; knee cartilage volume and defects by magnetic resonance imaging and knee joint space narrowing (JSN) and osteophytes by X-ray.
  
  
  RESULTS
  Parity was associated with a deficit in total knee cartilage volume [adjusted β=-0.69 ml, 95% confidence interval (CI) -1.34, -0.04]. Increasing parity was associated with decreasing cartilage volume in both the tibial compartment and total knee (both P trend <0.05). Parity was also associated with greater cartilage defects in the patella compartment [adjusted odds ratio (OR)=2.87, 95% CI=1.39, 5.93] but not other sites. There was a consistent but non-significant increase in knee JSN (OR=2.78, 95% CI=0.75, 10.31) and osteophytes (OR=1.69, 95% CI=0.59, 4.82) for parous women. Use of HRT and/or OC was not associated with cartilage volume, cartilage defects or radiographic change.
  
  
  CONCLUSIONS
  Parity (but not use of HRT or OC) is independently associated with lower cartilage volume primarily in the tibial compartment and higher cartilage defects in the patella compartment in this population-based sample of older women.
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Australia. Shuying.Wei@utas.edu.au
authors.forename: S
authors.initials: S
authors.lastname: Wei
authors.forename: A
authors.initials: A
authors.lastname: Venn
authors.forename: C
authors.initials: C
authors.lastname: Ding
authors.forename: J
authors.initials: J
authors.lastname: Martel-Pelletier
authors.forename: J-P
authors.initials: JP
authors.lastname: Pelletier
authors.forename: F
authors.initials: F
authors.lastname: Abram
authors.forename: F
authors.initials: F
authors.lastname: Cicuttini
authors.forename: G
authors.initials: G
authors.lastname: Jones
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002358:Cartilage, Articular / Q000473:pathology*; D003276:Contraceptives, Oral; D003430:Cross-Sectional Studies; D005260:Female; D020249:Hormone Replacement Therapy / Q000706:statistics & numerical data*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000473:pathology*; D054850:Osteophyte / Q000000981:diagnostic imaging; D010298:Parity; D011859:Radiography
chemical_list: D003276:Contraceptives, Oral