[Epidemiology of dementias in the middle-aged and elderly].

The authors analyze clinico-epidemiologic and statistical data on the incidence and nosological distribution of organic dementias in urban population of advanced age (60 years and over), including their correlation with the sex and age of the examined groups of population. The authors have determined parameters of the "registered" morbidity (0.7 per 1,000 individuals aged 60 years and over) and the incidence (3.9 per 1,000 individuals aged 60 years and over) of debilitating processes of old age, i. e., actual prevalence of dementia in people of advanced age. Organic dementia (moderate and severe) was detected in 4.0% of elderly people (4.1%--males, 4%--females). Furthermore, mild dementia was identified in 1.5% of elderly individuals. The follow-up findings (6-9 years after the first examination) of the same urban population demonstrated prognostic significance of mild dementia states with regard to the development of clinically manifest dementia.