title: Osteoarthritis prevalence and modifiable factors: a population study.
abstract: BACKGROUND
  This study's objectives were to investigate the prevalence of self-reported knee and hip osteoarthritis (OA) stratified by age and sex and to examine the association of modifiable factors with knee and hip OA prevalence. The study was conducted using randomly sampled data gathered from four communities in the province of Alberta, Canada.
  
  
  METHODS
  A large adult population sample (N = 4733) of individuals ≥18 years were selected. Health-related information was collected through telephone interviews and community measurement clinics for which a sub-sample (N = 1808) attended. Participants self-reported OA during telephone interviews. Clinic interviews further assessed if the diagnosis was made by a health care professional. Statistical analyses compared prevalence of OA between sexes and across age categories. Associations between modifiable factors for OA and the prevalence of knee and hip OA were assessed using binary logistic regression modelling.
  
  
  RESULTS
  Overall prevalence of self-reported OA in the total sample was 14.8 %, where 10.5 % of individuals reported having knee OA and 8.5 % reported having hip OA. Differences in prevalence were found for males and females across age categories for both knee and hip OA. In terms of modifiable factors, being obese (BMI >30 kg/m2) was significantly associated with the prevalence of knee (OR: 4.37; 95 % CI: 2.08,9.20) and hip (OR: 2.52; 95 % CI: 1.17,5.43) OA. Individuals who stand or walk a lot, but do not carry or lift things during their occupational activities were 2.0 times less likely to have hip OA (OR: 0.50; 95 % CI: 0.26,0.96). Individuals who usually lift or carry light loads or have to climb stairs or hills were 2.2 times less likely to have hip OA (OR: 0.45; 95 % CI: 0.21,0.95). The odds of having hip OA were 1.9 times lower in individuals consuming recommended or higher vitamin C intake (OR: 0.52; 95 % CI: 0.29,0.96). Significant differences in prevalence were found for both males and females across age categories.
  
  
  CONCLUSIONS
  The prevalence of knee and hip OA obtained in this study is comparable to other studies. Females have greater knee OA prevalence and a greater proportion of women have mobility limitations as well as hip and knee pain; it is important to target this sub-group.
authors.affiliation: Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, 2308, Australia. ronald.plotnikoff@newcastle.edu.au.
authors.forename: Ronald
authors.initials: R
authors.lastname: Plotnikoff
authors.affiliation: School of Public Health, University of Alberta, Edmonton, AB, Canada. nandinikaru@gmail.com.
authors.forename: Nandini
authors.initials: N
authors.lastname: Karunamuni
authors.affiliation: School of Public Health, University of Alberta, Edmonton, AB, Canada. lytvyak@ualberta.ca.
authors.forename: Ellina
authors.initials: E
authors.lastname: Lytvyak
authors.affiliation: Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, 2308, Australia. chrismpenfold@gmail.com.
authors.forename: Christopher
authors.initials: C
authors.lastname: Penfold
authors.affiliation: School of Public Health, University of Alberta, Edmonton, AB, Canada. dps2@ualberta.ca.
authors.forename: Donald
authors.initials: D
authors.lastname: Schopflocher
authors.affiliation: Fred Hutchinson Cancer Research Center Seattle, Washington, USA. iimayama@fhcrc.org.
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Imayama
authors.affiliation: Centre for Nursing and Health Studies, Athabasca University, Athabasca, AB, Canada. sjohnson@athabascau.ca.
authors.forename: Steven T
authors.initials: ST
authors.lastname: Johnson
authors.affiliation: School of Public Health, University of Alberta, Edmonton, AB, Canada. kim.raine@ualberta.ca.
authors.forename: Kim
authors.initials: K
authors.lastname: Raine
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000416:Alberta; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006621:Hip Joint; D006801:Humans; D007719:Knee Joint; D017770:Lifting; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D059352:Musculoskeletal Pain / Q000453:epidemiology; D009765:Obesity / Q000150:complications*; D015207:Osteoarthritis, Hip / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D020370:Osteoarthritis, Knee / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D011187:Posture; D015995:Prevalence; D057566:Self Report; D012737:Sex Factors; D014815:Vitamins / Q000008:administration & dosage / Q000627:therapeutic use; D016138:Walking
chemical_list: D014815:Vitamins; D001205:Ascorbic Acid