title: Longitudinal associations between adiposity and change in knee pain: Tasmanian older adult cohort study.
abstract: OBJECTIVE
  The aim of this study was to describe the longitudinal relationship between adiposity and change in knee pain.
  
  
  METHODS
  A total of 1099 participants aged 50-79 were randomly selected from the local community in Southern Tasmania, of which 767 were followed up on average 5.1 years later. Knee pain was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at each time point. Consistent knee pain was defined as knee pain at all three time-points. The five pain subscales were grouped into weight-bearing pain and non-weight-bearing pain according to the nature of pain. Body fat and lean mass were assessed using dual energy x-ray absorptiometry (DXA).
  
  
  RESULTS
  Baseline body mass index (BMI) and body fat mass were deleteriously associated with consistent knee pain over follow-up. BMI was consistently associated with increases in weight-bearing and non-weight-bearing pain. Fat mass was associated with an increase in non-weight-bearing pain. In mixed-model analyses, WOMAC total pain score was associated with BMI (β = 1.27) and body fat mass (β = 1.17). The association of lean mass was not significant after adjustment for fat mass.
  
  
  CONCLUSIONS
  BMI is the most consistent correlate of knee pain in older adults. Fat mass is associated with non-weight-bearing knee pain suggesting systemic mechanisms are involved.
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania 7000, Australia.
authors.forename: Xingzhong
authors.initials: X
authors.lastname: Jin
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania 7000, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia; Arthritis Research Institute, 1st Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China. Electronic address: Changhai.Ding@utas.edu.au.
authors.forename: Changhai
authors.initials: C
authors.lastname: Ding
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania 7000, Australia.
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania 7000, Australia.
authors.forename: Benny
authors.initials: B
authors.lastname: Antony
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania 7000, Australia.
authors.forename: Laura L
authors.initials: LL
authors.lastname: Laslett
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania 7000, Australia.
authors.forename: Leigh
authors.initials: L
authors.lastname: Blizzard
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: Flavia
authors.initials: F
authors.lastname: Cicuttini
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania 7000, Australia.
authors.forename: Graeme
authors.initials: G
authors.lastname: Jones
mesh_terms: D015502:Absorptiometry, Photon; D050154:Adiposity / Q000502:physiology*; D000368:Aged; D015992:Body Mass Index; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D050177:Overweight / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D010146:Pain / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology
keywords: Adiposity; Body mass; Knee pain; Longitudinal study