title: Prevalence of reported knee pain over twelve years in a community-based cohort.
abstract: OBJECTIVE
  To describe the temporal patterns of knee pain in a community-based cohort over 12 years.
  
  
  METHODS
  Data on self-reported knee pain at 4 time points over 12 years were analyzed in participants from the Chingford Women's Study of osteoarthritis (OA) and osteoporosis. Pain status was defined as any pain in the preceding month and pain on most days in the preceding month. This status was used to classify participants according to pain patterns of asymptomatic, persistent, incident, or intermittent pain. Multinomial logistic regression was used to identify baseline predictors for each pain pattern.
  
  
  RESULTS
  Among the 489 women with complete followup data, the median age at baseline was 52 years (interquartile range [IQR] 48-58 years), the median body mass index (BMI) was 24.39 kg/m(2)  (IQR 22.46-27.20), and 11.7% of the women had a Kellgren/Lawrence radiographic OA severity grade of ≥2 in at least one knee. Among subjects reporting any pain in the preceding month versus those reporting pain on most days in the preceding month, 9% versus 2% had persistent pain, 24% versus 16% had incident pain, and 29% versus 18% had intermittent pain. A higher BMI was predictive of persistent pain (odds ratio [OR] 1.14, 95% confidence interval [95% CI] 1.04-1.25) and incident pain (OR 1.10, 95% CI 1.02-1.18). The presence of radiographic knee OA was predictive of persistent pain (OR 3.70, 95% CI 1.34-10.28; P = 0.012), and reported knee injury was predictive of both persistent pain (OR 4.13, 95% CI 1.34-12.66; P = 0.013) and intermittent pain (OR 4.25, 95% CI 1.81-9.98; P = 0.001).
  
  
  CONCLUSIONS
  Significant variability in the temporal fluctuation of self-reported knee pain was seen in this community-based prospective study over a period of 12 years, with few women consistently reporting knee pain at each time point. Distinct baseline predictors for each pain pattern were identified and may explain the observed heterogeneity of self-reported knee pain when pain status is measured at only one time point.
authors.affiliation: University of Oxford, Oxford, UK.
authors.forename: A
authors.initials: A
authors.lastname: Soni
authors.forename: A
authors.initials: A
authors.lastname: Kiran
authors.forename: D J
authors.initials: DJ
authors.lastname: Hart
authors.forename: K M
authors.initials: KM
authors.lastname: Leyland
authors.forename: L
authors.initials: L
authors.lastname: Goulston
authors.forename: C
authors.initials: C
authors.lastname: Cooper
authors.forename: M K
authors.initials: MK
authors.lastname: Javaid
authors.forename: T D
authors.initials: TD
authors.lastname: Spector
authors.forename: N K
authors.initials: NK
authors.lastname: Arden
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007717:Knee / Q000000981:diagnostic imaging*; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000453:epidemiology*; D010146:Pain / Q000000981:diagnostic imaging / Q000453:epidemiology*; D010147:Pain Measurement; D015995:Prevalence; D011859:Radiography; D012720:Severity of Illness Index