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Illiteracy and the incidence of Alzheimer's disease in the Yonchon County survey, Korea

Published online by Cambridge University Press:  01 May 2008

Jun-Young Lee
Department of Psychiatry, Seoul National University Boramae Hospital, Korea
Sung Man Chang
Department of Psychiatry and Behavioral Science, Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Korea
Hong-Suk Jang
Department of Psychiatry, Incheon Medical Center, Korea
Jae Seung Chang
Department of Psychiatry, Seoul Municipal Eunpyeong Hospital, Korea
Guk-Hee Suh
Department of Psychiatry, Hallym University College of Medicine, Hangang Sacred Heart Hospital, Korea
Hee-Yeon Jung
Department of Psychiatry, Seoul National University Boramae Hospital, Korea
Hong-Jin Jeon
Department of Psychiatry and Behavioral Science, Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Korea
Maeng Je Cho*
Department of Psychiatry and Behavioral Science, Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Korea
Correspondence should be addressed to: Maeng Je Cho, Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul, 110-744, Korea. Phone: +82 2 20723155; Fax: +82 2 7447241. Email:


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.

Research Article
Copyright © International Psychogeriatric Association 2008

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