title: Association of slower walking speed with incident knee osteoarthritis-related outcomes.
abstract: OBJECTIVE
  To determine whether slower walking speed was associated with an increased risk of incident hip and knee osteoarthritis (OA)-related outcomes.
  
  
  METHODS
  After providing informed consent, community-dwelling participants in the Johnston County Osteoarthritis Project completed 2 home-based interviews and an additional clinic visit for radiographic and physical evaluation. One thousand eight hundred fifty-eight noninstitutionalized residents ages ≥ 45 years living for at least 1 year in 1 of 6 townships in Johnston County, North Carolina, completed the study's questionnaires and clinical examinations at baseline and at followup testing. Walking time was assessed using a manual stopwatch in 2 trials over an 8-foot distance, and walking speed was calculated as the average of both trials. For the hip and knee, we examined 3 outcomes per joint site: radiographic OA (weight-bearing anteroposterior knee radiographs, supine anteroposterior pelvic radiographs of the hip), chronic joint symptoms, and symptomatic OA. Covariates included age, sex, race, education, marital status, body mass index, number of self-reported chronic conditions diagnosed by a health care provider, number of prescriptions, depressive symptoms, self-rated health, number of lower body functional limitations, smoking, and physical activity.
  
  
  RESULTS
  Faster walking speed was consistently associated with a lower incidence of radiographic (adjusted odds ratio [OR] 0.88, 95% confidence interval [95% CI] 0.79-0.97) and symptomatic knee OA (adjusted OR 0.84, 95% CI 0.75-0.95); slower walking speed was associated with a greater incidence of these outcomes across a broad range of different clinical and radiographic OA outcomes.
  
  
  CONCLUSIONS
  Slower walking speed may be a marker for incident knee OA, but other studies must confirm this finding.
authors.affiliation: Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Jama L
authors.initials: JL
authors.lastname: Purser
authors.forename: Yvonne M
authors.initials: YM
authors.lastname: Golightly
authors.forename: Qiushi
authors.initials: Q
authors.lastname: Feng
authors.forename: Charles G
authors.initials: CG
authors.lastname: Helmick
authors.forename: Jordan B
authors.initials: JB
authors.lastname: Renner
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Jordan
mesh_terms: D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D015994:Incidence; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009657:North Carolina; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology*; D017063:Outcome Assessment, Health Care; D011859:Radiography; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D016138:Walking / Q000502:physiology*