The Indianapolis-Ibadan Dementia Project, established in 1991, is a longitudinal prospective population-based comparative epidemiological study of the prevalence and incidence rates and risk factors for Alzheimer’s disease and other age associated dementias. Enrollment of community-dwelling elderly (age>65 years) African Americans living in Indianapolis and Yoruba living in Ibadan, Nigeria employed the same research design, methods, and investigators (see study description at The first enrollment wave began in 1992 and participants were followed every 2 to 3 years.

Participants were ascertained and evaluated through community centers, clinical and hospital settings as well in community centers and at home. All participants greater than 65 years of age who agreed to participate were screened using measures. Those who failed the screen underwent a more comprehensive clinical evaluation. Medical and family history interview, neuropsychological testing, behavioral and emotional assessments, and functional measures, including collateral informant report, were available for all most participants. Venous blood samples (were collected on all participants. All assessments were conducted in the preferred language of the participant or knowledgeable informant. Finally, all participants were adjudicated by a clinical consensus panel and were classified according to various criteria in place at the time of the clinical data collection Details on diagnosis criteria and process were described in Hendrie et al JAMA 2001.