title: Sex differences in the association between body mass index and total hip or knee joint replacement resulting from osteoarthritis.
abstract: OBJECTIVE
  To examine the association between body mass index (BMI) and osteoarthritis (OA) leading to total hip (THR) or knee (TKR) joint replacement.
  
  
  METHODS
  Case-control study design. All patients still living in Iceland who had had a THR or TKR resulting from OA before the end of 2002 were invited to participate. First-degree relatives of participating patients served as controls. A total of 1473 patients (872 women) and 1103 controls (599 women), all born between 1910 and 1939 and who had answered a questionnaire including questions about height and weight, were analysed. A randomly selected sample, representative of the Icelandic population, was used as a secondary control group.
  
  
  RESULTS
  The OR, adjusted for age, occupation and presence of hand OA, for having a THR was 1.1 (95% CI 0.9 to 1.5) for overweight men and 1.7 (95% CI 1.0 to 2.9) for obese men. The OR for having a TKR was 1.7 (95% CI 1.1 to 2.6) for overweight men and 5.3 (95% CI 2.8 to 10.1) for obese men. The OR for having a THR was 1.0 (95% CI 0.8 to 1.3) for overweight women and 1.0 (95% CI 0.6 to 1.5) for obese women. The OR for having a TKR was 1.6 (95% CI 1.1 to 2.2) for overweight women and 4.0 (95% CI 2.6 to 6.1) for obese women.
  
  
  CONCLUSIONS
  This study supports a positive association between high BMI and TKR in both sexes, but for THR the association with BMI seems to be weaker, and possibly negligible for women.
authors.affiliation: Department of Orthopaedics, Clinical Sciences Lund, Lund University, Sweden. Jonas.Franklin@med.lu.se
authors.forename: J
authors.initials: J
authors.lastname: Franklin
authors.forename: T
authors.initials: T
authors.lastname: Ingvarsson
authors.forename: M
authors.initials: M
authors.lastname: Englund
authors.forename: L S
authors.initials: LS
authors.lastname: Lohmander
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D015992:Body Mass Index; D016022:Case-Control Studies; D005190:Family; D005260:Female; D006801:Humans; D007055:Iceland; D008297:Male; D009765:Obesity / Q000150:complications; D009784:Occupational Diseases / Q000209:etiology* / Q000601:surgery; D016017:Odds Ratio; D015207:Osteoarthritis, Hip / Q000209:etiology* / Q000601:surgery; D020370:Osteoarthritis, Knee / Q000209:etiology* / Q000601:surgery; D050177:Overweight / Q000150:complications; D012044:Regression Analysis; D018570:Risk Assessment / Q000379:methods; D012737:Sex Factors