Lower Prevalence of Asymptomatic Alzheimer's Disease Among Healthy African Americans

Ann Neurol. 2024 Sep;96(3):463-475. doi: 10.1002/ana.26960. Epub 2024 Jun 25.

Abstract

Objective: Alzheimer's disease (AD) is believed to be more common in African Americans (AA), but biomarker studies in AA populations are limited. This report represents the largest study to date examining cerebrospinal fluid AD biomarkers in AA individuals.

Methods: We analyzed 3,006 cerebrospinal fluid samples from controls, AD cases, and non-AD cases, including 495 (16.5%) self-identified black/AA and 2,456 (81.7%) white/European individuals using cutoffs derived from the Alzheimer's Disease Neuroimaging Initiative, and using a data-driven multivariate Gaussian mixture of regressions.

Results: Distinct effects of race were found in different groups. Total Tauand phospho181-Tau were lower among AA individuals in all groups (p < 0.0001), and Aβ42 was markedly lower in AA controls compared with white controls (p < 0.0001). Gaussian mixture of regressions modeling of cerebrospinal fluid distributions incorporating adjustments for covariates revealed coefficient estimates for AA race comparable with 2-decade change in age. Using Alzheimer's Disease Neuroimaging Initiative cutoffs, fewer AA controls were classified as biomarker-positive asymptomatic AD (8.0% vs 13.4%). After adjusting for covariates, our Gaussian mixture of regressions model reduced this difference, but continued to predict lower prevalence of asymptomatic AD among AA controls (9.3% vs 13.5%).

Interpretation: Although the risk of dementia is higher, data-driven modeling indicates lower frequency of asymptomatic AD in AA controls, suggesting that dementia among AA populations may not be driven by higher rates of AD. ANN NEUROL 2024;96:463-475.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease* / cerebrospinal fluid
  • Alzheimer Disease* / diagnosis
  • Alzheimer Disease* / epidemiology
  • Amyloid beta-Peptides* / cerebrospinal fluid
  • Asymptomatic Diseases
  • Biomarkers* / cerebrospinal fluid
  • Black or African American*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Peptide Fragments / cerebrospinal fluid
  • Prevalence
  • White People
  • tau Proteins* / cerebrospinal fluid

Substances

  • tau Proteins
  • Amyloid beta-Peptides
  • Biomarkers
  • amyloid beta-protein (1-42)
  • Peptide Fragments