PREVALENCE OF ALZHEIMERS-DISEASE AND DEMENTIA IN 2 COMMUNITIES - NIGERIAN-AFRICANS AND AFRICAN-AMERICANS

Objective: This article reports on a prevalence study of dementia and Alzheimer's disease among two groups of subjects with the same ethnic background but widely differing environments. Method: The study was co nducted among residents aged 65 years and older in two communities: Yo rubas (N=2,494) living in Ibadan, Nigeria, and African Americans (N=2, 212 in the community and N=106 in nursing homes) living in Indianapoli s, Indiana. The study design consisted of a screening stage followed b y a clinical assessment stage for selected subjects on the basis of th eir performance on the screening tests. Results: The age-adjusted prev alence rates of dementia (2.29%) and Alzheimer's disease (1.41%) in th e Ibadan sample were significantly lower than those in the Indianapoli s sample, both in the community-dwelling subjects alone (4.82% and 3.6 9%, respectively) and in the combined nursing home and community sampl es (8.24% and 6.24%, respectively). The prevalence rates of dementia a nd Alzheimer's disease increased consistently with advancing age in bo th study groups. Conclusions: To the authors' knowledge, this is the f irst study, using the same research method at the two sites, to report significant differences in rates of dementia and Alzheimer's disease in two different communities with similar ethnic origins.