LOS ANGELES — Researchers at the Keck School of Medicine of USC published a study on June 17, 2026, indicating that cognitively impaired Hispanic adults showed lower amyloid buildup compared to non-Hispanic white adults with similar genetic risk factors for Alzheimer's disease.

The study analyzed brain imaging and clinical data from 17,017 older adults, including 1,427 Hispanic participants, across five studies related to aging and Alzheimer's disease. The findings appeared in the journal Alzheimer's & Dementia: The Journal of the Alzheimer's Association.

The researchers found that greater amyloid buildup in the brain was associated with cognitive impairment or carrying the APOE ε4 gene variant in both Hispanic and non-Hispanic white participants. However, Hispanic participants generally exhibited lower amyloid levels when compared to non-Hispanic white participants who had the same cognitive and genetic characteristics. Among individuals with the APOE ε4 gene variant, Hispanic participants with normal cognition or mild impairment showed lower amyloid levels than their non-Hispanic white counterparts.

Non-Hispanic white participants carrying the APOE ε4 gene variant were more than four times as likely to show amyloid pathology, while Hispanic participants with the variant were about two and a half times as likely. Cally Xiao, lead author and researcher at the Keck School of Medicine, said, "APOE ε4 is a major Alzheimer's disease genetic risk factor, but our results suggest its relationship to amyloid buildup may be more nuanced in Hispanic populations. This work is important because it may influence how we interpret risk, understand cognitive decline, and ultimately design or apply treatments across diverse communities."

Xiao said, "These findings do not mean that Hispanic adults are at lower risk for dementia. In fact, Hispanic populations face a higher overall burden of dementia. Instead, our results suggest that cognitive impairment in Hispanic older adults may not always be driven by amyloid in the same way, and that other biological, vascular, or social factors may also be important." Arthur W. Toga, director of the Stevens Neuroimaging and Informatics Institute, said, "Alzheimer's disease is complex, and the path to cognitive decline may not look identical for every population. To move toward more precise and equitable care, we need research that reflects that complexity."

The authors accounted for age, sex, education, and cognitive performance by using Centiloid values to compare brain amyloid burden. They also noted that vascular health and other medical conditions may contribute to differences in amyloid burden but do not fully explain them. The study authors indicated that additional research is necessary, including larger samples of Hispanic participants, more detailed information on Hispanic origin and ancestry, and longitudinal data to track amyloid changes over time.