Imagine that a simple blood test at 45 or 50 years old could reveal a risk of
Alzheimer’s disease decades before the first memory lapses. This is the scenario that American researchers are beginning to draw, by focusing not on brain proteins, but on more discreet players: blood platelets.
A study published in early November 2025 in the journal
Neurologyled by the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases (UT Health San Antonio) and the NYU Grossman School of Medicine, analyzed theplatelet aggregation of 382 adults aged approximately 56 years, from the Framingham Heart Study, all free of dementia. The results suggest a future
early detection of Alzheimer’s in midlife, but with several gray areas.
A platelet blood test to detect Alzheimer’s in mid-life
Vascular dysfunction refers to a disorder in the functioning of blood vessels, which can have a variety of causes, ranging from the formation of abnormal blood clots, atherosclerosis, inflammation, diabetes, high blood pressure, smoking and age. Since the 1960s, specialists have suspected a vascular component of Alzheimer’s: up to 75% of patients also present vascular lesions, and around 25% of vascular dementias after the age of 75 show an amyloid pathology. But the underlying mechanisms remain poorly understood.
“We believe that since platelets are easy to obtain in the blood, they could potentially be part of midlife screening to identify at-risk individuals and apply preventive interventions targeting platelet-related inflammation.” indicated Professor Sudha Seshadri, professor of neurology and lead author. In other words, this type of platelet blood test could one day become part of quarantine health checks.
What platelets reveal at midlife
The new study analyzed 382 dementia-free participants, with an average age of 56, enrolled in the Framingham Heart Study, an ongoing, long-term community-based observational study conducted among residents of Framingham, Massachusetts, since 1948. So the scientists looked for an association between platelet aggregation and actual biomarkers of Alzheimer’s disease in midlife. The researchers measured, using a laboratory test, the tendency of blood platelets to aggregate, then compared this data to amyloid and tau PET scans and brain MRI taken one to two years later.
The results showed a positive link: People whose platelets clump more tightly also tend to have higher levels of amyloid and tau proteins in the brain, characteristic of Alzheimer’s disease. However, this connection is not the same for everyone.
“This correlation appears in people whose platelet activity is lowest under the experimental conditions used.explains Professor Alexa Beiser, professor of biostatistics at the Boston University School of Public Health, who has worked with Framingham data for decades and played a fundamental role in the statistical analysis of the study. “In this group, greater platelet aggregation correlated with greater amounts of amyloid and tau protein on brain scans. In people with higher platelet activity, this correlation is less clear.”.
Not yet an in-office screening, but a strong lead
The scientists nevertheless concluded that circulating platelets in the blood could provide early clues to Alzheimer’s risk – perhaps decades before symptoms appear – with data suggesting that certain characteristics of platelets in midlife may be linked to early brain changes associated with the disease.
“Our study highlights the need to further explore the role of platelet inflammation in disorders related to brain aging, and in particular in Alzheimer’s disease and related dementias.,” explained Prof. Jaime Ramos-Cejudo, first author.This could open up new perspectives for intervention, several years before symptoms appear. We believe platelets may be a critical link between vascular dysfunction and brain inflammation“.
The authors recall that high platelet aggregation in mid-life, in Framingham, had already been linked to an increased risk of dementia over twenty years. For now, this is a statistical link, not a Alzheimer’s blood test
usable routinely.