title: Nontraditional risk factors combine to predict Alzheimer disease and dementia.
abstract: OBJECTIVE
  To investigate whether dementia risk can be estimated using only health deficits not known to predict dementia.
  
  
  METHODS
  A frailty index consisting of 19 deficits not known to predict dementia (the nontraditional risk factors index [FI-NTRF]) was constructed for 7,239 cognitively healthy, community-dwelling older adults in the Canadian Study of Health and Aging. From baseline, their 5-year and 10-year risks for Alzheimer disease (AD), dementia of all types, and survival were estimated.
  
  
  RESULTS
  The FI-NTRF was closely correlated with age (r2 > 0.96, p < 0.001). The incidence of AD and dementia increased exponentially with the FI-NTRF (r2 > 0.75, p < 0.001 over 10 years). Adjusted for age, sex, education, and baseline cognition, the odds ratio of dementia increased by 3.2% (p = 0.021) for each deficit (that was not known to predict dementia) accumulated, outperforming the individual cognitive risk factors. The FI-NTRF discriminated people with AD and all-cause dementia from those who were cognitively healthy with an area under the receiver operating characteristic curve of 0.66 ± 0.03.
  
  
  CONCLUSIONS
  Comprehensive re-evaluation of a well-characterized cohort showed that age-associated decline in health status, in addition to traditional risk factors, is a risk factor for AD and dementia. General health may be an important confounder to consider in dementia risk factor evaluation. If a diverse range of deficits is associated with dementia, then improving general health might reduce dementia risk.
authors.affiliation: Department of Medicine, Dalhousie University, Halifax, Canada.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Song
authors.forename: Arnold
authors.initials: A
authors.lastname: Mitnitski
authors.forename: Kenneth
authors.initials: K
authors.lastname: Rockwood
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000453:epidemiology*; D002170:Canada / Q000453:epidemiology; D003071:Cognition; D003704:Dementia / Q000175:diagnosis* / Q000453:epidemiology*; D004522:Educational Status; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors