title: Illiteracy and the incidence of Alzheimer's disease in the Yonchon County survey, Korea.
abstract: BACKGROUND
  This study aims to establish the incidence rates of Alzheimer's disease (AD) and to understand the relations between illiteracy and AD in the Korean Yonchon survey cohort.
  
  
  METHODS
  A community-based, dementia-free cohort of 966 people aged 65 years and older was followed up for an average of 5.4 +/- 1.60 years to detect incident AD cases using a two-phase procedure. Age-specific incidence rates were calculated using a person-years approach with Poisson distribution confidence intervals. Data were analyzed using the Cox proportional hazards model to find the hazard ratio of illiteracy.
  
  
  RESULTS
  The participating percentage of the survivors was 86.4% and 74 subjects were diagnosed with AD. Incidence rates per 1000 person-years were 20.99 (95% CI 16.48 to 26.35) for AD. The hazard ratio of illiteracy was 1.78 (95% CI 1.08 to 2.93) adjusted for age, sex, educational level. AD developed more rapidly with aging in the illiterate group than in the literate group.
  
  
  CONCLUSIONS
  Illiteracy is associated with a higher risk of AD and the risk increases with age.
authors.affiliation: Department of Psychiatry, Seoul National University Boramae Hospital, Korea.
authors.forename: Jun-Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Sung Man
authors.initials: SM
authors.lastname: Chang
authors.forename: Hong-Suk
authors.initials: HS
authors.lastname: Jang
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Chang
authors.forename: Guk-Hee
authors.initials: GH
authors.lastname: Suh
authors.forename: Hee-Yeon
authors.initials: HY
authors.lastname: Jung
authors.forename: Hong-Jin
authors.initials: HJ
authors.lastname: Jeon
authors.forename: Maeng Je
authors.initials: MJ
authors.lastname: Cho
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology*; D015331:Cohort Studies; D004522:Educational Status; D005260:Female; D005500:Follow-Up Studies; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007723:Korea / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012307:Risk Factors; D017678:Sex Distribution; D011795:Surveys and Questionnaires