Prevalence, incidence, prognosis and risk factors of dementia.

The epidemiological evidence on the dementing illnesses suggests that dementia poses an important public health problem. Estimates of the prevalence of dementia indicate that in the twelve countries of the European Community 1.5 to 2.5 million people may be suffering of the disease. The available data on the incidence suggest that in these countries 200,000 to 250,000 people are newly hospitalized yearly for dementia. Fruitful epidemiological approaches to identify preventable causes of the dementing illnesses may include incidence studies across populations, family studies, and risk factors studies using Creutzfeldt-Jakob disease as a model for dementia of the Alzheimer type.