title: Cognition, even in the normal range, predicts disability: cross-sectional and prospective analyses of a population-based sample.
abstract: OBJECTIVE
  To determine if the modified mini-mental state examination (3MS) predicts functional status and if any effect on function is observed within the normal range of cognition.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Community-dwelling older adults in the Canadian province of Manitoba sampled in 1991 and followed in 1996.
  
  
  METHODS
  Baseline sample of 1751 adults aged 65+ from a representative registry. Five years later, 1028 participants remained in the community and had no missing data.
  
  
  METHODS
  The 3MS, age, gender, education, living arrangements, self-rated health, and depressive symptoms were self-reported. Functional status was assessed using the Older Americans Resource Survey, which was dichotomized into no/mild disability versus moderate/severe disability.
  
  
  RESULTS
  Baseline 3MS score predicted baseline functional status. This effect was a gradient across the entire 3MS score, extending into the normal range with no apparent threshold. In logistic regression models, the unadjusted odds ratio (OR, 95% confidence interval) for the association of 3MS score with disability was 0.94 (0.93, 0.95); the adjusted OR was 0.96 (0.95, 0.98) in models including age, gender, education, and other covariates. Baseline 3MS score also predicted functional status 5 years later: The unadjusted OR for disability was 0.94 (0.92, 0.95); the adjusted OR was 0.97 (0.95, 0.99). Again, the risk of functional impairment at time 2 was a gradient effect, extending into the normal range of baseline 3MS score.
  
  
  CONCLUSIONS
  The 3MS predicts functional decline, and this effect is a gradient effect. These results support the hypothesis that cognition is a continuum in risk.
authors: Section of Geriatric Medicine, Department of Medicine, and the Centre on Aging, University of Manitoba, Canada.
authors: Philip D
authors: PD
authors: St John
authors: School of Public Health and Health Systems, University of Waterloo, Canada.
authors: Suzanne L
authors: SL
authors: Tyas
authors: Vancouver Island Health Authority, Canada.
authors: Patrick R
authors: PR
authors: Montgomery
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D010054:Brief Psychiatric Rating Scale / Q000592:standards*; D003072:Cognition Disorders / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D003704:Dementia / Q000175:diagnosis; D004185:Disability Evaluation; D005260:Female; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008350:Manitoba; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D012307:Risk Factors; D012680:Sensitivity and Specificity
keywords: activities of daily living (ADL); cognition; cognitive impairment; disability; functional impairment; mild cognitive impairment (MCI); mini-mental state examination (MMSE); no dementia (CIND)