title: Cognition and incident dementia hospitalization: results from the atherosclerosis risk in communities study.
abstract: OBJECTIVE
  Cognitive decline is a defining feature of dementia. We sought to determine if a single baseline cognitive test score or change in test score over time is more strongly associated with risk of dementia hospitalization. We also sought to compare short- and long-term dementia risk.
  
  
  METHODS
  Prospective cohort study of 9,399 individuals from the Atherosclerosis Risk in Communities Study (median 10 years of follow-up). Cognition was assessed at two time points (6 years apart) using three tests: Delayed Word Recall Test (DWRT), Digit Symbol Substitution Test (DSST), and Word Fluency Test. Dementia hospitalizations were determined using ICD-9 codes.
  
  
  RESULTS
  Baseline cognitive test scores were associated with both short-term and long-term risk of dementia. The association of 6-year change in cognitive test score with dementia risk was stronger than that of individual test scores at a single visit [change from highest to lowest tertile, DWRT: hazard ratio = 6.45 (95% confidence interval = 1.80-23.08); DSST: hazard ratio = 10.94 (95% confidence interval = 3.07-38.97)].
  
  
  CONCLUSIONS
  In this community-based population, 6-year changes in cognitive scores were more strongly associated with risk of incident dementia hospitalization than baseline scores, although single DWRT and DSST scores were predictive. Our findings support the contention that cognitive changes may precede clinical dementia by a decade or more.
authors.affiliation: Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA. andrea.christman@gmail.com
authors.forename: Andrea L C
authors.initials: AL
authors.lastname: Schneider
authors.forename: Rebecca F
authors.initials: RF
authors.lastname: Gottesman
authors.forename: Thomas
authors.initials: T
authors.lastname: Mosley
authors.forename: Alvaro
authors.initials: A
authors.lastname: Alonso
authors.forename: David S
authors.initials: DS
authors.lastname: Knopman
authors.forename: Josef
authors.initials: J
authors.lastname: Coresh
authors.forename: A Richey
authors.initials: AR
authors.lastname: Sharrett
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Selvin
mesh_terms: D015984:Causality; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D002537:Intracranial Arteriosclerosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment; D015996:Survival Rate; D014481:United States / Q000453:epidemiology