A cross-sectional population-based study on senile dementia in a rural city.

All residents aged 65 or over in a rural city (n=5340) were studied with a self-administered questionnaire on psychiatric symptoms, physical health status, medical history, and environmental factors. After the screening, the clinical diagnosis of senile dementia was made by psychiatrists. The overall prevalence was 4.0% among responders staying at home (201/4969). The prevalence increased with age for both males and females and tended to be higher for females than males. The multilogistic analysis of the above variables showed that in the cerebrovascular type, stroke and inactive physical status might be risk factors for both gender groups. For the Alzheimer's type, age and inactive physical status might be risk factors. For overall dementia, age, stroke, and inactive physical status might be risk factors.