Epidemiology of dementia in Rochester, Minnesota

Abstract

Objective: To present the results of several retrospective epidemiologic studies of dementia in Rochester, Minnesota. Material and Methods: These studies were done by using the medical records-linkage resources of the Rochester Epidemiology Project. Results: The incidence and prevalence of dementia increase sharply with advancing age. No difference is noted in overall age-adjusted incidence rates by gender. Rochester studies provide the only 25-year time trend analyses of the incidence of dementia in the United States. Time trends over three prevalence dates indicate an increase in prevalence in this community. Survival is decreased among patients with dementing illness. Case-control studies of Alzheimer's disease (AD) show that general medical conditions, previous head injury, thyroid disease, exposure to therapeutic radiation, anesthesia, and blood transfusion are generally not risk factors for AD. Patients with depression may have an increased risk for the development of AD. Sociodemographic factors such as education, occupation, marital status, and type of dwelling were not significantly different among patients with AD and their age- and gender-matched control subjects. Conclusion: The Rochester Epidemiology Project has proved to be an excellent resource for the study of the incidence, prevalence, and risk factors for dementia.