title: Incidence of dementia in a population older than 75 years in the United Kingdom.
abstract: BACKGROUND
  Incidence studies have been relatively neglected in psychiatric epidemiology. They are particularly important for dementia, since prevalence rates are affected by length of survival, which itself falls with increasing age and presence of dementia.
  
  
  METHODS
  Two-wave community study of 1195 elderly subjects aged older than 75 years, restudied 2.4 years after a community prevalence study. A two-stage method was used, comprising the Mini-Mental State Examination followed in a stratified sample by the Cambridge Examination for Mental Disorders of the Elderly (CAM-DEX) interview. Incidence rates were based on person-years at risk.
  
  
  RESULTS
  Annual incidence rates for dementia were 2.3% for subjects initially aged 75 to 79 years, 4.6% for ages 80 to 84 years, and 8.5% for ages 85 to 89 years, approximately doubling every 5 years. Rates did not differ significantly by sex, educational level, or social class. Twice as many additional individuals received a diagnosis of minimal dementia not reaching case threshold.
  
  
  CONCLUSIONS
  The findings show high rates of new onset dementia, increasing markedly with age, and suggest rapid acceleration of one or more processes that is common in advanced age.
authors.affiliation: Department of Psychiatry, University of Cambridge, England.
authors.forename: E S
authors.initials: ES
authors.lastname: Paykel
authors.forename: C
authors.initials: C
authors.lastname: Brayne
authors.forename: F A
authors.initials: FA
authors.lastname: Huppert
authors.forename: C
authors.initials: C
authors.lastname: Gill
authors.forename: C
authors.initials: C
authors.lastname: Barkley
authors.forename: E
authors.initials: E
authors.lastname: Gehlhaar
authors.forename: L
authors.initials: L
authors.lastname: Beardsall
authors.forename: D M
authors.initials: DM
authors.lastname: Girling
authors.forename: P
authors.initials: P
authors.lastname: Pollitt
authors.forename: D
authors.initials: D
authors.lastname: O'Connor
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology*; D004522:Educational Status; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D015995:Prevalence; D011569:Psychiatric Status Rating Scales; D012720:Severity of Illness Index; D017678:Sex Distribution; D012923:Social Class; D006113:United Kingdom / Q000453:epidemiology