Assessment of Racial Disparities in Biomarkers for Alzheimer Disease

Abstract

IMPORTANCE Racial differences in molecular biomarkers for Alzheimer disease may suggest race-dependent biological mechanisms.OBJECTIVE To ascertain whether there are racial disparities in molecular biomarkers for Alzheimer disease.

Complex interactions underlie racial disparity in the risk of developing Alzheimer's disease dementia

“…One study further reported a significant race by APOE ε 4 interaction for both CSF t‐tau and p‐tau, 12 suggesting that the racial disparities in these biomarkers, and hence in the more downstream clinical changes, may depend on APOE ε4 status, consistent with our current findings. Specifically, both biomarker studies 11,12 are cross‐sectional with mean ages from 67.5 to 71.5 years, close to the younger end of the baseline age in the current study where we found that AAs had a lower risk of AD dementia mostly in APOE ε 4 positive participants with a low BMI. Putting all these together, our independent findings on the APOE ε 4 ‐dependent racial disparity in the risk of AD are consistent with the latest biomarker findings.…”

“…One study further reported a significant race by APOE 4 interaction for both CSF t-tau and p-tau, 12 suggesting that the racial disparities in these biomarkers, and hence in the more downstream clinical changes, may depend on APOE 4 status, consistent with our current findings. Specifically, both biomarker studies 11,12 Inherited Alzheimer Network (DIAN) trials, 33 and the Alzheimer's Prevention Initiative (API) trial 34 are ongoing. Primary prevention trials are currently planned.…”

“…Lack of biomarkers and cause of death (for those who died) in the UDS prevents us from directly linking the racial disparity in biomarkers to that in the risk of pathologically confirmed AD. Finally, although our findings are consistent with most recent biomarker reports 11,12 and autopsy studies, 18 the underlying mechanisms of the racial differences remain poorly understood. The fundamental question of whether AD, as currently defined, is the same disease between AAs and whites remains open.…”

“…Importantly, these biomarker changes are all clinically relevant because in cognitively normal elderly individuals, a high level of t-tau and p-tau and a high ratio of CSF ttau/A 42 or a high level of cerebral A burden as shown by PET imaging predict the rate of longitudinal cognitive decline and the conversion to early symptomatic AD. 15,32 The established predictability of clinical/cognitive outcomes by CSF biomarkers, especially t-tau and p-tau, coupled with two most recent independent biomarker studies of racial disparity which reported that the CSF t-tau and p-tau were lower in AAs versus whites, 11,12 may partially explain the racial differences in the risk of AD dementia. One study further reported a significant race by APOE 4 interaction for both CSF t-tau and p-tau, 12 suggesting that the racial disparities in these biomarkers, and hence in the more downstream clinical changes, may depend on APOE 4 status, consistent with our current findings.…”

The importance of diversity in cognitive neuroscience

“…A few studies have also focused on race and ethnicity differences in biomarkers of Alzheimer's disease. For example, older African Americans have a twofold increase in amyloid beta deposition, but lower concentrations of tau in cerebrospinal fluid compared with Whites, though the latter was found to only be true in participants who were APOE ε4 allele positive . Controlling for cerebrospinal fluid markers of amyloid beta, researchers found that cognitive dysfunction in African Americans was more associated with white matter hyperintensity burden and less associated with tau markers compared with Whites.…”