The incidence of Alzheimer?s disease and related dementia (ADRD) is higher in African Americans and Hispanics than in non-Hispanic Whites, but data Arab Americans have been virtually absent from research on brain and cognitive aging. The unique ethnic experiences of this understudied group have the potential to clarify knowledge of ADRD disparities related to race/ethnicity, immigrant and social factors. The proposed project leverages the first prevalence study of ADRD among Arab Americans (AG057510) to examine brain mechanisms underlying links between sociocultural risk/protective factors and ADRD. The proposed study will test the overarching hypothesis that sociocultural experiences influence ADRD via brain health. The following specific aims will be accomplished by obtaining structural MRI and blood-based AD biomarker data in the Detroit-Aging and Memory Project (D-AMP), which obtains high-quality ADRD phenotypes and genetic data on those aged 65+ from a representative sample of 600 Arab Americans, as well as panel participants (N=330) from the Social Relations Study (SRS), to compare to samples of non-Arab whites in the same geographic area. Our specific aims are: 1) Quantify differences in brain aging among Arab Americans and Whites in metro-Detroit and determine the contribution of brain health to group differences in ADRD; 2) Determine the contribution of immigrant/cultural factors to brain aging among Arab Americans; 3) Characterize the influence of social relations on brain aging and cognitive health among Arab Americans and Whites. The first of its kind, the proposed study will characterize brain aging in older Arab Americans, clarify racial/ethnic disparities in brain and cognitive aging, and reveal mechanisms underlying links between sociocultural factors and ADRD. This knowledge is critical for the development and evaluation of prevention and intervention strategies, cultural tailoring of such efforts to ensure efficacy in different sociocultural groups and to eliminate disparities.