Number of new cases of dementia decreasing for African-Americans but not Africans

http://www.eurekalert.org/pub_releases/2015-08/iu-sn080415.php

Public Release: 4-Aug-2015
Study: Number of new cases of dementia decreasing for African-Americans but not Africans
Indiana University

An Indiana University and Regenstrief Institute study is the first to report significantly decreased incidence rates over two decades for Alzheimer's disease and other dementias in African-Americans. The study is also the first to show that the incidence rate of these conditions in Africans was unchanged over the same period.

In African-Americans in Indianapolis, dementia incidence rates declined significantly from 1992 to 2011. However, there was no noteworthy change in dementia incidence in older Yoruba of Ibadan, Nigeria, according to the prospective community-based study of the two populations published online ahead of print in the peer-reviewed Alzheimer's & Dementia: Journal of the Alzheimer's Association.

"The reason for the significant decline in new cases of Alzheimer disease and other dementias in the African-Americans we studied is not yet entirely clear but we believe it may be possible that medications for cardiovascular conditions contributed to the decline," said study first author Sujuan Gao, Ph.D., professor of biostatistics at Indiana University School of Medicine. "This explanation is supported by the fact that prior to the study both groups had similar rates of elevated blood pressure, which had been recognized and treated in the Indianapolis participants but not in those in Ibadan."

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While the rate of new cases of dementia decreased in Indianapolis over the two decades, the African-Americans enrolling at the midpoint of the project in 2001 had significantly higher rates of medical conditions including diabetes, hypertension and stroke and as well as higher treatment rates for these conditions than the African-Americans who entered the project in 1992.

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