Incidence and Risk Factors of Dementia in a Rural Area

ABSTRACT

OBJECTIVES: To survey the incidence and risk factors of dementia on a rural elderly cohort. METHODS: Two follow-up studies in 2000 and 2003 were done on 966 non-demented elderly residents who participated in 1st wave in 1996. A two-phase study was conducted using the Korean version of Psychogeriatric Assessment Scale in phase I and the diagnostic interview according to DSM-III R criteria by psychiatrists in stage II. RESULTS: Of the 966 elderly residents who had not dementia in 1996 prevalence study, 592 residents in 2nd wave and 508 residents in 3rd wave completed the incidence study. Dementia was incident in 96 residents. The annual incidence rates per 1000 persons were 27.2 (CI:22.2-33.2). Annual incidence rates were rapidly raised from 10.6 (CI:5.3-21.2) in the age range 65-69 years to 88.9 (CI:55.3-143) in the age range 85+. Older age was a risk factor of dementia (p<0.05), and Education was a preventive factor of dementia (p<0.001). But, female, history of depression, alcohol use history and tobacco use history were not risk factors. CONCLUSION: The annual incidence rates in Korea were higher than those of other countries. High percentage of no educated person (58.8%) in this community may be related to the higher incidence rates. Weighting to sex and age in normal elderly population in Korea at 2003, The annual incidence rates of dementia per 1000 persons were 25.2, and the numbers of newly incident elderly persons every year were approximately hundred thousand.