Alzheimer's disease: biomarkers differ for African Americans vs whites

  • Morris JC & al.
  • JAMA Neurol
  • 7 Jan 2019

  • curated by Susan London
  • Clinical Essentials
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  • Compared with their white counterparts, African American older adults with varied cognitive statuses had lower cerebrospinal fluid (CSF) levels of the Alzheimer’s disease (AD) biomarkers total tau and phosphorylated tau181.

Why this matters

  • Racial differences may provide information about race-specific pathophysiology and suggest a need to adjust values for race.

Key results

  • No racial differences seen:
    • MRI cerebral ischemic lesions.
    • Cortical standardized uptake value ratios for Pittsburgh compound B.
    • CSF amyloid-β42 levels.
  • Among individuals with a family history of dementia, mean adjusted total hippocampal volumes were lower for African American participants vs white participants (6418.26 vs 6990.50 mm3; P<.001>
  • African American participants had lower CSF levels of:
    • total tau (293.65 vs 443.28 pg/mL; P<.001 and>
    • phosphorylated tau181 (53.18 vs 70.73 pg/mL; P<.001>
  • In stratified analysis, only APOE ε4-positive participants showed significant racial differences in CSF total tau, phosphorylated tau181.

Expert comment

  • In an editorial, Lisa L. Barnes, PhD, writes, "There are not yet enough numbers to say anything definitive about the association of biomarkers with race. The scientific community will need many more people working in this space to obtain credible numbers."

Study design

  • Cross-sectional cohort study of 1255 community-dwelling adults (13.8% African American) with mean age 70.8 years.
  • Two-thirds had normal cognitive status; one-third had AD mild cognitive impairment or early AD dementia.
  • Main outcomes: hippocampal volumes, global cerebral amyloid burden, CSF biomarker levels.
  • Funding: National Institute on Aging; National Center for Advancing Translational Sciences.


  • Potential residual confounding.
  • Only 2 races studied.
  • Unknown generalizability.