To better understand risk factors for Alzheimer's disease and vascular dementia, demographic, medical, and other epidemiological factors were compared for 83 African American women with Alzheimer's disease and 46 with vascular dementia, Overall, the risk factor profiles for Alzheimer's disease and vascular dementia were similar to those in other studies. However, Alzheimer's patients had a high frequency of hypertension and a relatively high frequency of diabetes mellitus. The presence of such risk factors raises the possibility that there is a vascular component to the dementia in these African-American women with Alzheimer's disease. Neuropathological studies are needed to help answer this question.