PROJECT SUMMARY - Clinical Core (CC) The mission of the UC Davis Alzheimer’s Disease Research Center (UCD ADRC) is to advance the science of healthy brain aging among diverse populations while caring for those affected by dementia. This mission and the work of the Clinical Core (CC) contribute to many of the milestones and goals set forth by the National Alzheimer’s Disease Plan (NAPA). The CC is essential to the UCD ADRC’s mission, in part, by maintaining the Longitudinal Diversity Cohort (LDC), a large, highly diverse group of older adults followed annually through autopsy, and by overseeing the collection of the multiple sources of data obtained from these individuals. This cohort is highly unique among ADRCs in that it includes substantial numbers of older adults from two of the largest underrepresented groups in the U.S.: African Americans (~25% of the cohort) and Hispanics (~25%). This diversity translates into heterogeneity of cognitive trajectories, incident Alzheimer’s disease and related dementias (ADRD), risk factors and lifecourse experiences, and the prevalence of vascular risk factors consistent with community populations, thereby providing a valuable resource for studying both AD and mixed pathologies. The sample is similarly diverse in terms of education (range of 0-20 years), native language, socioeconomic and immigration status, and exposure to adversity. Through primarily community recruitment, the UCD ADRC enrolls cognitively normal and mildly impaired individuals to study cognitive decline and the transition to various stages of disease. This facilitates identification of novel modifiable risk and protective factors and biomarker development, both of which have implications for dementia prevention. All individuals in the LDC are characterized at an uncommonly rich level (well beyond the UDS) that includes neuroimaging and blood biomarkers, annual diagnostic classification, psychometrically rigorous measurement of cognition and daily function (separate from measurements used for diagnosis) and extensive collection of lifecourse sociocultural and behavioral data. The LDC is a well established cohort with extensive data from both active (n=425) and inactive cases (n>950), some with 15+ years of follow-up. All of this data has been integrated into the UCD ADRC database that provides an easily accessible research resource widely utilized by researchers both within and outside of our Center. Data from the LDC has contributed to innovative new research findings in many areas including enhancing our understanding of ethnic/racial disparities in cognitive aging and the contributions of vascular disease to brain health, among many other contributions. In addition, the CC has the added advantage of creating bi-directional translational relationships with epidemiological studies aimed at understanding the complex determinants of ADRD and accelerating the development of effective treatment and prevention across the ADRD spectrum.