Perceived racism, cardiovascular disease risk, and neurocognitive aging

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There is increasing knowledge that racism makes us sick. Black Americans are twice as likely as White Ameri- cans to have Alzheimer’s disease (AD) independent of genetic risk. Despite this knowledge, little is known about whether and how chronic experiences of racism contribute to medial temporal hippocampal (MTH) and prefrontal-executive system integrity, systems that exhibit profound neurodegeneration in AD. Although comor- bid illnesses and socioeconomic status contribute to the AD health disparity, disparities remain. This highlights a critical unmet need for understanding social and societal contributors to disparities in brain health. A major contributor to health inequities in the U.S. is chronic stress due to the cumulative effects of racism over the life- time. Although the negative impact of chronic stress on the MTH and prefrontal systems is well known, less understood is the impact of chronic interpersonal and institutional/structural racism, unique and salient forms of chronic stress in Black Americans, on neurocognitive integrity of these brain systems. Since perceived racism contributes to health disparities in cardiovascular disease (CVD) risk factors, which are also risk factors for AD, perceived racism should have a significant impact also on the AD health disparity. In support of this, our pre- liminary data show that perceived racism in older Black women predicts future subjective memory decline, which was in part mediated by depressive symptoms, and that greater perceived social discrimination predicts poorer memory and lower amygdala and hippocampal head volumes in older adults. Despite this knowledge, the cumulative impact of racism on neurocognitive integrity in Black seniors remains unknown. The objective of this application is to investigate the impact of racism on neurocognitive MTH-memory and prefrontal-executive system integrity in Black seniors and to examine potentially underlying biological mechanisms. Our central hy- pothesis is that cognitively healthy Black seniors who have experienced higher levels of chronic racism will show greater CVD risk (Aim 1) and poorer MTH and prefrontal integrity (Aim 2) than those who have experi- enced fewer instances of racism over the lifetime. We further hypothesize that CVD risk and mental health will mediate (i.e., explain) the relationship between perceived racism and neurocognitive integrity (Exploratory Aim). Perceived interpersonal racism will be assessed with a structured interview and institutional/structural racism based on racial residential segregation. Ten-year CVD risk will be assessed using the 2013 Atheroscle- rotic CVD (ASCVD) risk algorithm, with lipid and other biomarkers obtained from a fasting blood test and blood pressure from ambulatory blood pressure monitoring. Neurocognitive MTH and prefrontal system integrity will be examined using a cognitive assessment of episodic memory and executive function, respectively, and struc- tural MRI. Further, we will use structural equation modeling to examine interrelationships between racism, CVD risk, mental health, and neurocognitive integrity. Addressing this knowledge gap is critical for developing new health policies and biobehavioral and social interventions for healthy aging.