title: Does mild cognitive impairment affect the occurrence of radiographic knee osteoarthritis? A 3-year follow-up in the ROAD study.
abstract: OBJECTIVE
  To determine whether mild cognitive impairment (MCI) increases the risk of occurrence or progression of radiographic knee osteoarthritis (KOA) in a general population.
  
  
  METHODS
  Population-based cohort study.
  
  
  METHODS
  Residents in mountain and seaside areas of Wakayama Prefecture, Japan.
  
  
  METHODS
  1690 participants (596 men, 1094 women; mean age 65.2 years old) were enrolled from the large-scale cohort for the Research on Osteoarthritis (OA)/osteoporosis Against Disability (ROAD) study initiated in 2005 to investigate epidemiological features of OA in Japan. Of these, 1384 individuals (81.9%; 466 men, 918 women) completed the second survey including knee radiography 3 years later.
  
  
  METHODS
  Radiographic KOA was defined as Kellgren-Lawrence (KL) grade ≥ 2 using paired x-ray films. Incidence of KOA during follow-up defined on radiographs as KL grade ≥2, progression of KOA defined as a higher KL grade (either knee) at follow-up compared with baseline. MCI defined as a summary mini-mental state examination (MMSE) score ≤23. Associations between MCI and incidence or progression of KOA were analysed.
  
  
  RESULTS
  The annual cumulative incidence of KOA was 3.3%; for progression of OA it was 8.0%. On logistic regression analysis adjusted for age, gender, regional differences, body mass index, grip strength (worse side), smoking, alcohol consumption, regular exercise and history of knee injury, baseline MMSE summary score was significantly associated with the incidence of KOA (+1 MMSE score; OR 0.83, p=0.010). Baseline MCI was also significantly associated with the incidence of KOA (vs non-occurrence of KOA; OR 4.90, p=0.027). There was no significant association between MMSE scores, the presence of MCI and progression of KOA (+1 MMSE score; OR 0.96, p=0.232; vs non-progression of KOA; OR 1.38, p=0.416).
  
  
  CONCLUSIONS
  MCI significantly increases the risk of incident radiographic KOA, but not the progression of KOA.
authors.affiliation: Department of Joint Disease Research,  22nd Century Medical and Research Center,  the University of Tokyo, Tokyo,  Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Yoshimura
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Muraki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Oka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Kozo
authors.initials: K
authors.lastname: Nakamura
authors.forename: Sakae
authors.initials: S
authors.lastname: Tanaka
authors.forename: Toru
authors.initials: T
authors.lastname: Akune