Researchers from the University of California San Diego have found that diabetes is linked to changes in measurable biological signals in the blood that are associated with Alzheimer's disease and brain damage in Latino adults. The study, published on April 23, 2026 in Alzheimer's & Dementia: The Journal of the Alzheimer's Association, suggests that metabolic health may play an important role in shaping future dementia risk.
"Diabetes is usually discussed in terms of heart disease or kidney problems, but our findings show it may also be closely connected to changes in the brain," said Hector González, PhD, corresponding author and professor in the Department of Neurosciences at UC San Diego School of Medicine. "These biological signals in the blood give us early clues about processes that could eventually lead to Alzheimer's disease."
The study followed more than 6,000 middle-aged and older Latino adults from several U.S. cities with large Latino populations, including San Diego, as part of a 15-year community health research project. Researchers examined whether people with diabetes — or with higher long-term blood sugar levels — showed changes in blood-based indicators linked to Alzheimer's disease and nerve cell damage.
They found that individuals with diabetes had higher levels of blood signals associated with abnormal tau, a protein that normally helps support nerve cells in the brain but becomes harmful in Alzheimer's disease by forming tangles that disrupt brain function. Participants with diabetes also showed lower levels of a blood signal related to amyloid, a protein that can build up in the brain and form sticky plaques that interfere with communication between brain cells. Similar patterns were also observed in people with elevated blood sugar levels even if they had not been diagnosed with diabetes.
"These blood-based indicators don't diagnose Alzheimer's disease," added Kevin González, first author and a postdoctoral fellow in the Department of Neurosciences at UC San Diego School of Medicine, "but they can help us identify who may be on a higher-risk path years before memory problems appear."
Latino communities experience some of the highest rates of diabetes in the U.S. and often face barriers to early diagnosis and treatment. Previous studies suggest that treating diabetes may lower the risk of Alzheimer's disease, raising the possibility that better blood sugar control could also reduce the harmful brain-related changes seen in this study.
Because these signals can be measured through a simple blood draw, this approach may offer a more accessible way to monitor brain health than brain scans or spinal fluid tests, particularly in communities with limited access to specialty care.
The researchers plan to explore whether improving diabetes management can slow or reverse these blood-based changes and reduce long-term dementia risk.
"If we can identify risk earlier and act sooner," Kevin González said, "we may be able to change the course of Alzheimer's disease and reduce health disparities in Latino communities."
Link to full study: https://doi.org/10.1002/alz.71223
Additional co-authors on the study include: Judy Pa, PhD; Sarah Banks, PhD; Katherine J. Bangen, PhD; Douglas Galasko, MD; Natasha Z. Anita, PhD, and Freddie Márquez, PhD, from UC San Diego School of Medicine. Wassim Tarraf, PhD, from Wayne State University. Linda C. Gallo, PhD, and Ariana Stickel, PhD, from San Diego State University. Paola Filigrana, PhD, and Carmen R. Isasi, MD, from Albert Einstein College of Medicine. Martha Daviglus, MD, and Fernando D. Testai, MD, from University of Illinois in Chicago. Melissa Lamar, PhD, from University of Illinois in Chicago and Rush University Medical Center. Charles DeCarli, MD, from University of California, Davis.
The study was funded, in part, by the National Institute of Aging (R01AG075758, R56AG048642, RF1AG054548, and RF1AG061022)
Authors report no conflicts of interest.
