Alzheimer's disease biomarkers in Black and non‐Hispanic White cohorts: A contextualized review of the evidence

Abstract

Black Americans are disproportionately affected by dementia. To expand our understanding of mechanisms of this disparity, we look to Alzheimer's disease (AD) biomarkers. In this review, we summarize current data, comparing the few studies presenting these findings. Further, we contextualize the data using two influential frameworks: the National Institute on Aging–Alzheimer's Association (NIA‐AA) Research Framework and NIA's Health Disparities Research Framework. The NIA‐AA Research Framework provides a biological definition of AD that can be measured in vivo. However, current cut‐points for determining pathological versus non‐pathological status were developed using predominantly White cohorts—a serious limitation. The NIA's Health Disparities Research Framework is used to contextualize findings from studies identifying racial differences in biomarker levels, because studying biomakers in isolation cannot explain or reduce inequities. We offer recommendations to expand study beyond initial reports of racial differences. Specifically, life course experiences associated with racialization and commonly used study enrollment practices may better account for observations than exclusively biological explanations.

Moving beyond disclosure: Stages of care in preclinical Alzheimer's disease biomarker testing

“…Data has shown that biomarker changes in AD can vary between Blacks and Whites, and similar biomarker profiles can be associated with divergent cognitive function. 37 To date, it is unknown how frequently biomarker testing of asymptomatic persons is pursued in clinical practice. Surveys conducted prior to the approval of amyloid PET scans for clinical use found that a majority of dementia specialists planned to use them to identify asymptomatic persons at risk for AD dementia, 38 while others would be reluctant to share results for fear of negative psychosocial outcomes.…”

“…The limited inclusiveness of biomarker research raises concerns about the validity of biomarker data in these populations. Data has shown that biomarker changes in AD can vary between Blacks and Whites, and similar biomarker profiles can be associated with divergent cognitive function 37 …”

“…There is a pressing need for research in more diverse populations to make evidence about safety and prognosis more generalizable. The data used for current prognostic models largely come from non‐Hispanic White study participants, and may not be applicable to other racially and ethnically minoritized groups 37 . Similarly, safety outcomes after disclosure among general clinical populations may not be the same as the participants in biomarker research studies.…”

What Influences the Willingness of Blacks and African Americans to Enroll in Preclinical Alzheimer’s Disease Biomarker Research? A Qualitative Vignette Analysis

“…The limited inclusiveness of biomarker study samples raises concerns about the validity and reliability of biomarker data in underrepresented groups [ 19 ]. Data shows that biomarker changes in AD can vary between Black/African American and White populations, and similar biomarker profiles can be associated with divergent cognitive function [ 20, 21 ]. The current lack of reliable biomarker data for underrepresented groups limits the diagnostic, prognostic, and therapeutic validity of biomarkers for clinical use in these populations, and has the potential to further exacerbate health disparities [ 9 ].…”

Tau Beats Amyloid in Predicting Brain Atrophy in Alzheimer Disease: Implications for Prognosis and Clinical Trials

“…Furthermore, individual factors modify the relationship between tau accumulation and cognition, with younger age, female sex, higher educational attainment, and higher baseline cortical thickness all associated with increased resistance against the deleterious effect of pathology on cognitive performance (30). Some studies suggest that the relationship between tau, neurodegeneration, and cognition may also vary with race and ethnicity as proxies for social determinants of health (31), though much more work on diverse cohorts is needed to better understand these relationships. Finally, the development of biomarkers that measure common non-AD pathologies (e.g., vascular lesions, TDP43, and a-synuclein aggregates) will be critical for achieving a more adequate prognosis, as these processes are highly prevalent in patients with AD (32) and contribute significantly to neurodegeneration and cognitive decline.…”