title: Associations between dementia/mild cognitive impairment and cognitive performance and activity levels in youth.
abstract: OBJECTIVE
  To study the associations between dementia/mild cognitive impairment (MCI) and cognitive performance and activity levels in youth.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Research volunteers living throughout the United States.
  
  
  METHODS
  A total of 396 persons (mean age 75) who were graduates of the same high school in the mid-1940s.
  
  
  METHODS
  Adolescent intelligence quotient (IQ) scores were gathered from archived student records, and activity levels were determined from yearbooks. A two-stage telephone screening procedure (Modified Telephone Interview for Cognitive Status or Informant Questionnaire on Cognitive Decline in the Elderly followed by Dementia Questionnaire) was used to determine adult cognitive status. Data were analyzed using logistic regression to model the risk of cognitive impairment (dementia/MCI) versus no cognitive impairment as a function of IQ and activity level, adjusting for sex and education.
  
  
  RESULTS
  High adolescent IQ and greater activity level were each independently associated with a lower risk for dementia/MCI (odds ratio (OR) for a 1-standard deviation increase in IQ=0.51, 95% confidence interval (CI)=0.32-0.79; OR for a unit increase in activity=0.32, 95% CI=0.12-0.84). No association was found between sex or education and adult cognitive status in this model.
  
  
  CONCLUSIONS
  High IQ and greater activity levels in youth reduce the risk for cognitive impairments in aging. The mechanism(s) underlying these associations are unknown, but intelligence may be a marker for cognitive/neurological "reserve," and involvement in activities may contribute to "reserve." Early neuropathology and ascertainment bias are also possible explanations for the observed associations.
authors.affiliation: University Memory and Aging Center, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, Ohio 44120, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Fritsch
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Smyth
authors.forename: McKee J
authors.initials: MJ
authors.lastname: McClendon
authors.forename: Paula K
authors.initials: PK
authors.lastname: Ogrocki
authors.forename: Concepcion
authors.initials: C
authors.lastname: Santillan
authors.forename: Janet D
authors.initials: JD
authors.lastname: Larsen
authors.forename: Milton E
authors.initials: ME
authors.lastname: Strauss
mesh_terms: D000293:Adolescent; D000368:Aged; D003071:Cognition; D003072:Cognition Disorders / Q000209:etiology*; D015331:Cohort Studies; D003704:Dementia / Q000209:etiology*; D005260:Female; D006801:Humans; D007360:Intelligence; D007899:Leisure Activities; D008297:Male; D012189:Retrospective Studies