{"id":659644,"date":"2026-06-26T16:49:22","date_gmt":"2026-06-26T16:49:22","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/659644\/"},"modified":"2026-06-26T16:49:22","modified_gmt":"2026-06-26T16:49:22","slug":"17000-brain-scans-reveal-surprising-ethnic-differences-in-alzheimers-biology","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/659644\/","title":{"rendered":"17,000 Brain Scans Reveal Surprising Ethnic Differences in Alzheimer\u2019s Biology"},"content":{"rendered":"

\"Centiloid<\/a>The Centiloid scale allows researchers to combine and analyze amyloid PET imaging data from multiple sources that used different tracers, scanners, and acquisition times. Credit: Stevens INI<\/p>\n

A large analysis of brain imaging and clinical data from more than 17,000 older adults is revealing a more complex picture of Alzheimer\u2019s disease risk across populations.<\/p>\n

As new Alzheimer\u2019s drugs increasingly target amyloid plaques in the brain, researchers are working to understand whether the biology behind the disease is the same for everyone. A new study suggests the answer may be more complicated than previously thought.<\/p>\n

Analyzing brain imaging and clinical data from more than 17,000 participants across five major aging and Alzheimer\u2019s studies, researchers at the USC Mark and Mary Stevens Neuroimaging and Informatics Institute (Stevens INI) found that Hispanic participants generally had lower amyloid levels than non-Hispanic white participants with similar cognitive status and genetic risk factors. The findings were published in Alzheimer\u2019s & Dementia: The Journal of the Alzheimer\u2019s Association.<\/p>\n

Amyloid plaques are a key hallmark of Alzheimer\u2019s disease, and APOE \u03b54 is the strongest common genetic risk factor for developing the late-onset form of the disorder. While both groups showed higher amyloid levels when carrying APOE \u03b54 or experiencing cognitive impairment, the association appeared weaker among Hispanic participants.<\/p>\n

\u201cAPOE \u03b54 is a major Alzheimer\u2019s disease genetic risk factor, but our results suggest its relationship to amyloid buildup may be more nuanced in Hispanic populations,\u201d said Cally Xiao, PhD, the study\u2019s lead author and a researcher at the Stevens INI. \u201cThis work is important because it may influence how we interpret risk, understand cognitive decline, and ultimately design or apply treatments across diverse communities.\u201d<\/p>\n

Leveraging Global Alzheimer\u2019s Data<\/p>\n

The project relied in part on the Global Alzheimer\u2019s Association Interactive Network (GAAIN), a data sharing platform created at the Stevens INI with support from the Alzheimer\u2019s Association. GAAIN enables scientists to find, explore, and connect large datasets from studies of Alzheimer\u2019s disease, related dementias, and aging from around the world.<\/p>\n

Through GAAIN, the researchers identified studies that reported amyloid PET scan results using the Centiloid scale, a standardized system that allows amyloid measurements to be compared across different imaging tracers, scanners, and research sites.<\/p>\n

The team gathered data from five major research efforts: the Anti-Amyloid Treatment in Asymptomatic Alzheimer\u2019s study, the Alzheimer\u2019s Disease Neuroimaging Initiative, the Health and Aging Brain Study\u2013Health Disparities, the Imaging Dementia\u2013Evidence for Amyloid Scanning study, and the Standardized Centralized Alzheimer\u2019s and Related Dementias Neuroimaging initiative.<\/p>\n

Combining these datasets allowed the researchers to identify trends that may have been difficult to detect within any individual study.<\/p>\n

\u201cThis is exactly the kind of work GAAIN was built to enable,\u201d said Arthur W. Toga, PhD, director of the Stevens INI and senior author of the study. \u201cWhen researchers can identify compatible datasets, connect across studies, and conduct analyses at a scale that no one group could achieve independently, we gain a much clearer view of Alzheimer\u2019s disease. That is especially important when we are trying to understand how disease biology may differ across populations that have historically been underrepresented in research.\u201d<\/p>\n

Comparing Amyloid Burden Across Populations<\/p>\n

The analysis included 17,017 older adults, of whom 1,427 identified as Hispanic. Researchers used Centiloid scores to measure amyloid burden while accounting for factors such as age, sex, education, and cognitive performance.<\/p>\n

Across the full study population, people with mild cognitive impairment or dementia tended to have higher amyloid levels than cognitively healthy participants. Carrying the APOE \u03b54 variant was also associated with greater amyloid burden in both Hispanic and non-Hispanic white participants.<\/p>\n

Even so, Hispanic participants consistently showed lower average amyloid levels than non-Hispanic white participants across diagnostic categories. Among APOE \u03b54 carriers, Hispanic adults with either normal cognition or mild cognitive impairment also had lower amyloid levels than their non-Hispanic white counterparts.<\/p>\n

The researchers also found that APOE \u03b54 had a weaker association with amyloid pathology among Hispanic participants. Non-Hispanic white carriers of APOE \u03b54 were more than four times as likely to show evidence of amyloid pathology, while Hispanic carriers were about two and a half times as likely.<\/p>\n

\u201cThese findings do not mean that Hispanic adults are at lower risk for dementia,\u201d Xiao said. \u201cIn 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.\u201d<\/p>\n

Implications for Alzheimer\u2019s Treatment and Research<\/p>\n

The findings come as anti-amyloid therapies are becoming an increasingly important part of Alzheimer\u2019s treatment. Because these drugs are designed to target amyloid plaques in the brain, understanding how amyloid burden relates to cognitive decline and genetic risk in different populations could have important implications for patient care.<\/p>\n

The researchers emphasize that further studies are needed, including larger groups of Hispanic participants, more detailed information about ancestry and Hispanic origin, and long-term data tracking changes in amyloid levels and cognition.<\/p>\n

They also note that vascular health and other medical conditions may help explain some of the observed differences, although those factors do not appear to account for the findings entirely.<\/p>\n

\u201cAlzheimer\u2019s disease is complex, and the path to cognitive decline may not look identical for every population,\u201d Toga said. \u201cTo move toward more precise and equitable care, we need research that reflects that complexity. Large-scale data resources such as GAAIN are helping make that possible.\u201d<\/p>\n

Reference: \u201cAssociation of cognitive impairment and APOE \u03b54 with Centiloids in Hispanic and non-Hispanic White cohorts\u201d by Cally Xiao, Tyler Ard, Ganna Blazhenets, Renaud La Joie, Ioannis Pappas, Arthur W. Toga, the Alzheimer\u2019s Disease Neuroimaging Initiative, and the Health and Aging Brain Study (HABS-HD) Study Team, 11 June 2026, Alzheimer\u2019s & Dementia.
DOI: 10.1002\/alz.71586<\/a><\/p>\n

Data used in the research were obtained through GAAIN, which is funded by the Alzheimer\u2019s Association and powered by the Laboratory of Neuro Imaging at the USC Stevens Neuroimaging and Informatics Institute. The study was supported by the Global Alzheimer\u2019s Association Interactive Network initiative of the Alzheimer\u2019s Association, grant SG-20-678486-GAAIN2.<\/p>\n

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