title: Role of Osteoarthritis, Comorbidity, and Pain in Determining Functional Limitations in Older Populations: European Project on Osteoarthritis.
abstract: To evaluate the role of comorbidity and pain in the association between hip/knee osteoarthritis (OA) with self-reported as well as performance-based functional limitations in a general elderly population.
  
  
  
  We analyzed the data of 2,942 individuals, ages between 65 and 85 years, who participated in the European Project on Osteoarthritis, which was made up of 6 European cohorts (from Germany, Italy, The Netherlands, Spain, Sweden, and the UK). Outcomes included self-reported physical function measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the participants' performance-based physical function was evaluated using the walking test.
  
  
  
  While comorbidity did not affect the significant association between hip/knee OA and physical function limitations found in the participants, pain reduced the effect of OA on self-reported physical function, and it cancelled the effect of OA on the walking test. Obesity, anxiety, depression, and cardiovascular diseases were associated with the worst WOMAC scores. Obesity, cognitive impairment, depression, peripheral artery disease, and stroke were associated with the worst walking times.
  
  
  
  These findings demonstrate that while comorbidity is strongly and independently associated with functional limitations, it does not affect the OA-physical function association. Hip/knee OA is associated with self-reported impairment in physical function, which was only partially mediated by pain. Its association with physical function, as evaluated by the walking test, was instead completely mediated by pain.
authors.affiliation: University of Padua, Padua, Italy.
authors.forename: Sabina
authors.initials: S
authors.lastname: Zambon
authors.affiliation: National Research Council, Neuroscience Institute-Aging Branch, Padua, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Siviero
authors.affiliation: University of Ulm, Ulm, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Denkinger
authors.affiliation: National Research Council, Neuroscience Institute-Aging Branch, Padua, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Limongi
authors.affiliation: Universidad Autonoma de Madrid, Madrid, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Victoria Castell
authors.affiliation: EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Suzan
authors.initials: S
authors.lastname: van der Pas
authors.affiliation: Universidad Autonoma de Madrid, Madrid, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Otero
authors.affiliation: University of Southampton, Southampton General Hospital, Southampton, UK.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Edwards
authors.affiliation: University of Ulm, Ulm, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Peter
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Pedersen
authors.affiliation: Universidad Autonoma de Madrid, Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Sánchez-Martinez
authors.affiliation: University of Southampton, Southampton General Hospital, Southampton, UK.
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Dennison
authors.affiliation: National Research Council, Neuroscience Institute-Aging Branch, Padua, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Gesmundo
authors.affiliation: EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Schaap
authors.affiliation: EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Dorly J H
authors.initials: DJ
authors.lastname: Deeg
authors.affiliation: EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Natasja M
authors.initials: NM
authors.lastname: van Schoor
authors.affiliation: National Research Council, Neuroscience Institute-Aging Branch, Padua, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Maggi
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005060:Europe; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D015207:Osteoarthritis, Hip / Q000453:epidemiology* / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000453:epidemiology* / Q000503:physiopathology; D010146:Pain / Q000209:etiology*