title: Incidence of dementia in oldest-old with amnestic MCI and other cognitive impairments.
abstract: OBJECTIVE
  To examine the incidence of dementia among the oldest-old people with normal cognition and different types of cognitive impairment.
  
  
  METHODS
  This study included 395 participants without dementia (mean age 93.3 years) from The 90+ Study, a prospective, population-based study of aging and dementia in people aged 90 years and older. The participants had evaluations for dementia every 6 months, and their average follow-up was 2.5 years. We examined the incidence of all-cause dementia in participants stratified into 4 cognitive groups: normal, amnestic mild cognitive impairment (aMCI), nonamnestic mild cognitive impairment (naMCI), and other cognitive impairment (OCI).
  
  
  RESULTS
  Dementia incidence was highest for participants with aMCI (31.4% per year) and OCI (39.9% per year). Participants with naMCI had an incidence of 14.1% per year, and participants with normal cognition had an incidence of 8.4% per year. Dementia incidence was associated with increasing age in both normal and cognitively impaired participants; however, an APOE4 allele was associated with a higher dementia incidence only in participants with baseline cognitive impairment.
  
  
  CONCLUSIONS
  The risk of developing dementia in the oldest-old is high and increases to higher rates when cognitive impairment is present. Similar to results of studies in younger elderly individuals, cognitive impairment and increasing age were related to increased dementia incidence. High dementia incidence rates in the oldest-old individuals, particularly when cognitively impaired, emphasize the need to further study cognitive impairment and dementia in this rapidly expanding age group.
authors.affiliation: Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, USA. cpeltz@uci.edu
authors.forename: Carrie B
authors.initials: CB
authors.lastname: Peltz
authors.forename: María M
authors.initials: MM
authors.lastname: Corrada
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Berlau
authors.forename: Claudia H
authors.initials: CH
authors.lastname: Kawas
mesh_terms: D000369:Aged, 80 and over; D000647:Amnesia / Q000150:complications* / Q000453:epidemiology* / Q000235:genetics; D053327:Apolipoprotein E4 / Q000235:genetics; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000150:complications* / Q000453:epidemiology* / Q000235:genetics; D015331:Cohort Studies; D003704:Dementia / Q000175:diagnosis* / Q000453:epidemiology* / Q000235:genetics; D005260:Female; D006801:Humans; D015994:Incidence; D007802:Language; D008297:Male; D008568:Memory; D009483:Neuropsychological Tests
chemical_list: D053327:Apolipoprotein E4
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