HAI Book 2025 - Flipbook - Page 700
Robinson, Talia
174
Characterizing associations with Aβ burden in non-Hispanic Black
participants across US POINTER and A4/LEARN cohorts
Talia Robinson1, Kathryn Papp1, Theresa Harrison2, Laura Baker3, Heather Snyder4, Reisa
Sperling1, Rebecca Amariglio1, Susan Landau2, A4 STUDYTEAM4, US POINTER Study Group4
Brigham and Women’s Hospital, Boston, MA, US
University of California Berkley, Berkley, CA, US
3
Wake Forest University, Winston-Salem, NC, US
4
Alzheimer’s Association, Chicago, IL, US
1
2
Background: In clinical trials with low representation from diverse populations, selection bias and cohort effects
may contribute to differences in AD biomarker results, impacting generalizability to other cohorts and the larger
population. Lower amyloid (Ab) among non-Hispanic Black (NHB) relative to non-Hispanic White (NHW)
participants was reported in the A4/LEARN trial, driven by lower A´ in NWB APOEe4 carriers. Here, we examine
generalizability of biomarker findings in NHBs by expanding this work to the US POINTER Imaging sub-study.
Methods: Cognitively unimpaired NHB and NHW participants from US POINTER and A4/LEARN with baseline PET
data were included (Table 1). Global A´ (quantified in centiloids; CLs) was assessed using [18F]florbetapir in
A4/LEARN and [18F]Florbetaben in US POINTER. Demographic data, APOE genotype, cardiovascular risk (CV-risk)
factors (body mass index; BMI, systolic blood pressure; SBP), and Preclinical Alzheimer9s Cognitive Composite
(PACC) were collected. Regression models analyzed A´ burden in NHW/NHBs, and associations of demographic,
cv-risk, and APOEε4 status on A´ in NHW/NHBs adjusting for relevant demographics.
Results: US POINTER and A4/LEARN NHBs differed demographically and in CV-risk, but not in A´ burden,
%APOEε4+, or PACC score (Table 1). A´ was not associated with sex, BMI, or SBP in either cohort or ethnoracial
group. Lower A´ in NHB relative to NHW was replicated in US POINTER (p = .01), as was the differential impact of
APOEe4 status on Ab burden, with lower A´ in e4+NHBs relative to e4+NHWs (p < .01; Figure 1).
Conclusion: Despite demographic and cv-risk differences across cohorts, NHBs were similar in A´ and
APOEe4status. Lower Ab burden in NHB compared to NHW individuals was driven by ApoE4 carriers, but CV-risk
was not related to A´ in either NHB or NHW individuals, suggesting that AD-related genetic risk is a stronger
driver than CV-risk of ethnoracial group differences in A´.
HAI2025 - 700
