EPIDEMIOLOGY OF ALZHEIMERS-DISEASE

Epidemiologic studies of disease fall into two large categories: descr iptive and analytic. Both approaches have been used in studies of deme ntia and Alzheimer's disease (AD). The prevalence of dementia in perso ns age 65 and older in North America is approximately 6 to 10%, with A D accounting for two-thirds of these cases. If milder cases are includ ed, the prevalence rates double. Only age and family history of dement ia are consistently associated with AD in all studies, but putative pr otective agents such as estrogen, NSAIDs, and vitamin E are undergoing clinical trials.