Indianapolis Ibadan Epidemiological Study of Dementia
The Indianapolis-Ibadan Dementia Project, established in 1991, is a prospective population-based comparative epidemiological study of the prevalence, incidence rates and risk factors for Alzheimer's disease and other age associated dementias. The project enrolled community-dwelling elderly (age > 65 years) African Americans living in Indianapolis and Yoruba living in Ibadan, Nigeria, employing the same research design, methods, and investigators. It initially reported significantly lower prevalence rates of disorders in the Yoruba compared to the African Americans. In subsequent waves of the study (1994-1995, 1997-1998) incidence rates, rates of newly diagnosed cases, were also found to be significantly lower in the Yoruba. In genetic studies, the frequency of the APOE ε4 allele was about the same in the two groups, but there was a differential effect of APOE ε4 on Alzheimer’s disease risk between the two cohorts with the APOEe4 risk being much weaker in Yoruba. A major conclusion of the study was that the environment, particularly factors which increased risk for cardiovascular disease also play a major role in the etiology of dementia/Alzheimer Disease and are potentially preventable. More than 100 papers have been published in major journals during the past two decades using data from this study. A complete list of published manuscripts is included on the Publications page. A summary of research design can be found on the Documentation page.
Analyses for genome wide association study (GWAS) for African Americans are being conducted in collaboration with Dr. Denis Evans of Rush University in Chicago and Dr. Phillip De Jager at the Broad Institute in Cambridge. In April 2011 the project was approved for a genome wide association analysis for the Yoruba carried out by the Center for Inherited Diseases Research at Johns Hopkins. GWAS data for African American participants can be obtained from the Alzheimer’s Disease Genetics Consortium (http://www.adgenetics.org/). GWAS data for Ibadan participants can be obtained from dbGap (https://www.ncbi.nlm.nih.gov/gap/).
