A Study on the Prevalence of Dementia and its Related Factors in the Rural Elderly

ABSTRACT

For the purpose of investigation of prevalence, etiology and its related factors of the dementia in the rural elderly, the author examined 650 elderly people aged 60 years or more via cluster sampling by using a door to door 2 phase design from June 1992 to July 1992. The cognitive impairment was assessed by MMSEK in the first screening phase, and in the second phase 252 people in the dementia suspected group (MMSEK score 24) were taken to the clinical examination for the diagnosing dementia. The results were as follows; 1. The prevalence rate of dementia was 21.3% in the rural elderly, and was higher in females (31.1%) than in males (10.7%) (p<0.01). 2. The prevalence rates of dementia in males aged 60-69, 70-79 and over 80 were 4.1%, 16.7% and 50.0% respectively and those in female were 8.7%, 49.3%, 72.2% respectively. The rates increased significantly with increasing age in both sexes (p<0.01). 3. The prevalence rates of the mild, moderate and severe dementia were 8.4%, 9.3% and 3.6% respectively and increased significantly with increasing age in females (p<0.001). 4. The proportional distribution of dementia type by etiological classification was 63.6% senile dementia of Alzheimer's type, 17.7% vascular dementia, 10.4% mixed dementia, 4.2% alcoholic dementia, 1.0% posttraumatic dementia and 3.1% for others. 5. In multiple logistic regression analysis for affecting factors of the dementia, the significant variables were level of physical activity, age, education and sex. The Odds ratios in factors were low level of physical activity 6.0 x (95% CI 2.4-15.1), age over 70 4.8 x (95% CI 2.2-10.7), no formal education 3.9 x (95% CI 1.1-13.8), and female sex 2.2 x (95% CI 1.0-5.0).