Project Summary Black Americans are twice as likely to develop Alzheimer’s disease (AD) than White Americans. The biopsychosocial determinants of cognitive function, an early-stage component of the AD continuum, are less understood in the Black population. Allostatic load (AL), an indicator of multisystem (e.g., nervous, cardiovascular) physiological dysregulation driven by chronic psychosocial stress, may be one determinant of poor cognitive function. The neighborhood is an emerging social determinant of cognitive function that may be especially relevant for Black Americans given historical systems of socioeconomic and residential disadvantage. Neighborhood disadvantage together with perceived neighborhood stressors may exacerbate AL, to the detriment of cognitive function for midlife and older Black adults. The overall research objective is to examine the relationship between AL and cognitive function and whether this association is impacted by both neighborhood disadvantage [i.e., neighborhood socioeconomic status (SES) and Black-White segregation] and perceived neighborhood stressors (i.e., high disorder and low social cohesion) within Black midlife and older adults. Secondary, longitudinal data will come from the 2006-2016 waves of the Health and Retirement Study, a nationally representative study of health among the midlife and older (>50 years of age) US adult population. Specific aims for this project include: (Aim 1) testing the relationship between AL and cognitive function using baseline linear regression and growth curve models; (Aim 2) examining the moderating roles of neighborhood SES and Black-White segregation on the relationship between AL and cognitive function to predict baseline cognitive function and change over time using cross-sectional linear regression models and growth curve models; and (Aim 3) analyzing the association between AL, perceived neighborhood stressors, and cognitive function in baseline linear models and growth curve models stratified by levels of (1) neighborhood SES and (2) Black-White segregation. The positive impact of the proposed research will be an increased understanding of complex, multifactorial social-environmental and biological determinants of cognitive function among Black Americans. Furthermore, by mentoring underrepresented students at Xavier University of Louisiana I will contribute to increasing diversity in the aging research pipeline and expanding my university’s population health and aging research capacity.