[A study of the factors involved in the onset of senile dementia].

Cohort studies were made regarding 1,300 elderly was born before 1918, who were living in a city of Osaka Prefecture in 1979 and were confirmed not to be demented: the fourth survey made in the 13th year thereafter, 1992, showed the following results: 1. The prevalence of senile dementia of Alzheimer's type (SDAT) increased with age, but that of cerebrovascular dementia (VD) did not. 2. The prevalence of female SDAT was remarkably higher with age. 3. The incidence of senile dementia was 0.92%. 4. The results of multi-variate analysis showed the onset of VD and SDAT to be deeply connected with age, blood pressure, the degree of drinking, salt intake and age, inactive ADL, blood pressure respectively.