Since inception of the study in 1992, over 6,000 participants have enrolled in the Washington Heights and Inwood Community Aging project (WHICAP). The cohort participants were nondemented initially, 65 years of age or older, and comprised of non‐Hispanic whites (32%), African Americans (28%), and Caribbean Hispanics from the Dominican Republic (44%). During each assessment, participants received a neuropsychological test battery, medical interview, and were re‐consented for sharing of genetic information and autopsy. A consensus diagnosis was derived for each participant by experienced clinicians based on NINCDS‐ADRDA criteria for possible, probable, or definite AD, or moderate or high likelihood of neuropathological criteria of AD. Every individual with whole‐exome sequencing has at least a baseline and one follow‐up assessment and examination, and for those who have died, the presence or absence of dementia was determined using a brief, validated telephone interview with participant informants: The Dementia Questionnaire (DQ) and the Telephone Interview of Cognitive Status (TICS).
Over the length of the project, WHICAP have identified environmental, health-related and genetic risk factors of disease and predictors of disease progression by collecting longitudinal data on cognitive performance, emotional health, independence in daily activities, blood pressure, anthropometric measures, cardiovascular status and selected biomarkers in this elderly, multi-ethnic cohort. Biomarker studies include lipids, amyloid peptides, sex hormones, homocysteine, insulin and C-reactive protein (CRP), and MRI in these elderly participants. WHICAP have reported that the rates of disease and the frequency of disease risk factors vary across ethnic groups, and have identified one of the largest, multi-ethnic groups of incident LOAD cases.