1 PROJECT SUMMARY 2 The overarching goals of the African Americans Fighting Alzheimer’s in Midlife (AA-FAIM) renewal are to 3 promote timely and valid detection of Alzheimer’s disease (AD) and related dementias (ADRD) in Black 4 populations and to increase inclusion of Black adults in ADRD research. Being racialized as Black in the US is 5 associated with twice the risk of cognitive decline and ADRD relative to non-Hispanic whites. Yet, because Black 6 Americans are substantially under-recruited and under-represented in ADRD research, gaps remain in our 7 understanding of the generalizability of prevailing theories of preclinical AD pathophysiology (e.g. the amyloid 8 hypothesis) to Black patients. To address these gaps, we must obtain essential biomarker data from Black 9 participants and improve inclusion of Black participants, examining recruitment/retention with scientific rigor. In 10 Aim 1, we will explore the relevance of preclinical amyloidosis in predicting cognitive decline in a Black cohort, 11 comparing models considering roles of (a) preclinical AD pathology, (b) vascular risk factors, (c) psychosocial 12 factors, and (d) cognitive markers in predicting cognitive decline in a cohort of 400 Black adults. Aim 2 will 13 examine the association between plasma Aß42/40 and Amyloid PET positivity (PET A+) and test the 14 chronicity/EAOA (estimated age of amyloid onset) model of preclinical AD in Black participants. We will 15 investigate associations between plasma Aß42/40 and concurrent PET A+, and assess whether longer amyloid 16 chronicity and/or earlier EAOA are associated with accelerated cognitive decline. Aim 3 examines factors 17 associated with successful enrollment and retention. We will assess patterns of perceptions and beliefs relative 18 to an emerging model of participant engagement, and explore model constructs’ efficacy in predicting 19 prospective participation decisions. With renewed investment in the AA-FAIM cohort, we will continue 20 contributing to an emerging understanding of preclinical ADRD in a minoritized population. Moreover, we can 21 further leverage our participants’ contributions by partnering with teams seeking access to these unique data.