Objective:

Determine whether tau-PET findings generalize to Black and Latino participants who continue to be underrepresented in dementia research.

Background:

Tau-PET neuroimaging is increasingly used to diagnose, stage, and assess response to disease-modifying treatments in individuals with Alzheimer disease, yet studies evaluating tau PET applications have predominantly been completed in non-Hispanic White (nHW) participants. 

Design/Methods:

Community-dwelling Black and Latino participants completed MRI, and amyloid- (PiB or florbetapir) and tau- (flortaucipir) PET brain imaging as part of a longitudinal study of memory and aging. Global and regional tau-PET standardized uptake value ratios (normalized to the cerebellar crus) were determined in Black and Latino participants and compared with findings in nHW participants, 1:1-matched for age, sex, education, and global Clinical Dementia Rating®. Conditional logistic modeling compared 47 regions of interest, adjusted for false discovery rate. Relevant associations between flortaucipir retention and clinical outcomes were assessed using Spearman rank correlations. 

Results:

105 Black (mean 71.3±11.0 years-old, 65% female, 34% cognitively impaired), 37 Latino (mean 65.2±8.2 -years-old, 51% female, 22% cognitively impaired) and 142 matched nHW participants completed neuroimaging. Tau-PET burden was similar between matched cohorts (Black and nHW participants, mean SUVR: 1.37±0.41 vs 1.32±0.36, p=0.20; Latino and nHW participants, mean SUVR: 1.30±0.41 vs 1.27±0.29, p=0.69). Lower flortaucipir uptake was noted in the caudate (p=0.02), putamen (p=0.03), and pallidum (p=0.02) of Black vs nHW participants. Global flortaucipir retention increased with age (Black: Rho=0.223; nHW: Rho=0.243; p<0.05), amyloid Centiloids (Black: Rho=0.649; Latino: Rho=0.474; nHW: Rho=0.693; p<0.01), and cognitive impairment (i.e., Clinical Dementia Rating® Sum-of-Box scores, Black: Rho=0.53; Latino: Rho=0.489; nHW: Rho=0.533; p<0.01).

Conclusions: