USC Research Identifies Racial and Ethnic Disparities in Alzheimer’s Brain Protein Markers Among Older Adults

Keck School of Medicine research reveals that Black and Hispanic adults show higher tau protein levels earlier, requiring new Alzheimer’s diagnostic approaches.

By: AXL Media

Published: Mar 14, 2026, 6:25 AM EDT

Source: Information for this report was sourced from Keck School of Medicine of USC

Challenging the Homogeneity of Alzheimer’s Research

For decades, the scientific understanding of Alzheimer’s disease has been predominantly shaped by data from non-Hispanic white populations, a bias that USC researchers are now actively dismantling. A new study published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association utilizes advanced PET brain scans to track the early biological signs of cognitive decline in a diverse cohort. The research team identified that patterns of protein buildup, which serve as the primary diagnostic markers for the disease, do not manifest uniformly across different racial and ethnic groups. This discovery underscores an urgent need for inclusive diagnostic criteria that account for the unique physiological and social realities of diverse communities.

Early Tau Buildup in Minority Populations

The study analyzed data from more than 1,500 cognitively normal or mildly impaired adults through the Health and Aging Brain Study–Health Disparities (HABS-HD). Researchers discovered that Black and Hispanic participants showed elevated levels of tau—a protein that forms tangles and disrupts brain cell communication—within the medial temporal lobe. Critically, this accumulation occurred even in the absence of significant amyloid beta plaques, which are often considered the primary precursor to Alzheimer's in white patients. These findings suggest that the traditional "amyloid-first" model of disease progression may not be a universal standard for predicting memory loss in all populations.

The Complexity of Memory Decline in Black Adults

A significant finding of the USC research is the divergence in how amyloid buildup affects memory performance across groups. While the link between amyloid and memory impairment was strong in non-Hispanic white and Hispanic participants, it was noticeably absent in Black participants. Senior author Dr. Meredith N. Braskie suggested that for Black adults, cognitive decline may be driven by a more complex interplay of factors beyond simple protein tangles. Influences such as vascular health, life-long stress exposure, and socioeconomic determinants likely play a more dominant role in brain health, requiring a broader investigative lens than current biomarker-focused models provide.