title: Lifetime risk and age at diagnosis of symptomatic knee osteoarthritis in the US.
abstract: OBJECTIVE
  To estimate the incidence and lifetime risk of diagnosed symptomatic knee osteoarthritis (OA) and the age at diagnosis of knee OA based on self-reports in the US population.
  
  
  METHODS
  We estimated the incidence of diagnosed symptomatic knee OA in the US by combining data on age-, sex-, and obesity-specific prevalence from the 2007-2008 National Health Interview Survey, with disease duration estimates derived from the Osteoarthritis Policy (OAPol) Model, a validated computer simulation model of knee OA. We used the OAPol Model to estimate the mean and median ages at diagnosis and lifetime risk.
  
  
  RESULTS
  The estimated incidence of diagnosed symptomatic knee OA was highest among adults ages 55-64 years, ranging from 0.37% per year for nonobese men to 1.02% per year for obese women. The estimated median age at knee OA diagnosis was 55 years. The estimated lifetime risk was 13.83%, ranging from 9.60% for nonobese men to 23.87% in obese women. Approximately 9.29% of the US population is diagnosed with symptomatic knee OA by age 60 years.
  
  
  CONCLUSIONS
  The diagnosis of symptomatic knee OA occurs relatively early in life, suggesting that prevention programs should be offered relatively early in the life course. Further research is needed to understand the future burden of health care utilization resulting from earlier diagnosis of knee OA.
authors.affiliation: Brigham and Women's Hospital, Harvard University, and Boston University School of Public Health, Boston, MA 02115, USA. elosina@partners.org
authors.forename: Elena
authors.initials: E
authors.lastname: Losina
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Weinstein
authors.forename: William M
authors.initials: WM
authors.lastname: Reichmann
authors.forename: Sara A
authors.initials: SA
authors.lastname: Burbine
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Solomon
authors.forename: Meghan E
authors.initials: ME
authors.lastname: Daigle
authors.forename: Benjamin N
authors.initials: BN
authors.lastname: Rome
authors.forename: Stephanie P
authors.initials: SP
authors.lastname: Chen
authors.forename: David J
authors.initials: DJ
authors.lastname: Hunter
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Suter
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Jordan
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Katz
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003430:Cross-Sectional Studies / Q000639:trends; D005260:Female; D006801:Humans; D008136:Longevity; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000453:epidemiology*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology