Cross‐sectional associations between amyloid and tau PET and cognitive performance in Black adults without dementia: Preliminary results from the African Americans Fighting Alzheimer’s in Mid‐life study

Background Few studies have examined amyloid and tau and cognitive performance in samples solely comprised of African American (AA) adults. The African Americans Fighting Alzheimer’s in Mid‐life (AA‐FAIM) study (n = 293 active AA participants) is currently collecting amyloid and tau positron emission tomography (PET) scans. Preliminary cross‐sectional associations between amyloid and tau PET and cognitive performance are presented here. Method N = 55 adults without dementia had amyloid and/or tau PET (n = 48 had amyloid PET; n = 47 had tau PET; n = 40 had both scans). 11C‐Pittsburgh Compound B (PiB) PET quantified cortical β‐amyloid. 18F‐MK‐6240 PET measured tau in entorhinal cortex (EC), medial temporal lobe (MTL), and temporal lobe meta‐ROI. Amyloid and tau PET positivity cut‐points were derived from prior research. Cognitive assessment included immediate and delayed recall (RAVLT) and Trails B. Linear regression tested associations between amyloid and tau PET and cognition. Results In those with both amyloid and tau PET, seven (17.5%) were amyloid and EC tau PET positive (Table 1). Increased amyloid PET DVR and amyloid PET positivity were significantly related to increased tau PET SUVR in models unadjusted and adjusted for age and sex (Figure 1). In the combined sample (n = 40), neither amyloid nor tau PET was significantly related to cognition in models adjusted for age, education, and prior‐test‐exposure (or remote testing when recall was analyzed) (p‐values>.06). In the tau PET sample (n = 47), increased tau in EC and MTL was significantly related to worse immediate recall in adjusted models; in contrast, amyloid was not significantly related to cognition (Table 2) in the amyloid PET sample (n = 48). Associations between PET and cognition were similar following removal of n = 4 MCI participants. Conclusions Preliminary results in this small sample suggest that elevated brain tau is related to verbal‐learning and recall in a sample of AAs without dementia; results related to amyloid did not reach statistical significance. A larger sample size is needed to increase the statistical power to detect associations and improve the precision and comparability of tau and amyloid parameter estimates. Recruitment of more participants for longitudinal PET and cognitive testing is planned to refine characterization of AD‐related change in the AA‐FAIM cohort.