A new blood test that measures levels of a specific protein biomarker may be able to predict the risk of developing Alzheimer's disease up to 10 years before cognitive symptoms become apparent, according to a study published in The Journal of the American Medical Association. The research, conducted by Harvard-affiliated scientists, focused on the biomarker p-tau217, which is linked to the buildup of tau proteins in the brain associated with memory loss.
In a large-scale analysis involving nearly 2,700 cognitively healthy adults with an average age of 70, researchers tracked participants for up to a decade. The findings indicated that individuals with very high levels of p-tau217 had an approximately 78% chance of experiencing cognitive impairment within 10 years, and a roughly 33% chance within five years. Those with moderately elevated levels still faced a 45% risk over a decade.
Researchers believe this blood test could revolutionize how dementia risk is assessed, similar to how cholesterol tests are used to estimate heart disease risk. Dr. Jeremy Koppel, co-director of the Litwin-Zucker Center, noted the test's potential for early diagnosis and for understanding the progression of Alzheimer's disease. While the biomarker alone cannot definitively predict an individual's future, it provides significant predictive information, potentially surpassing that of standard brain scans and genetic testing in certain contexts.
Rachel Buckley, the study's lead author and an associate professor of neurology at Harvard Medical School, stated that the evidence suggests dementia risk can be detected years before memory problems emerge. She highlighted the potential for such tests to aid in recruiting participants for clinical trials aimed at preventing cognitive decline. In the future, these tests could also guide monitoring and treatment decisions for patients and families once preventative or early-stage treatments become available.
Scientists caution that other factors, including age, genetics, kidney function, and racial background, can influence biomarker levels and overall dementia risk. The research team emphasized the need for further, longer-term studies involving more diverse populations to refine these risk estimates. Maria Carrillo, chief science officer at the Alzheimer’s Association, underscored that targeting the disease in its silent, pre-symptomatic stage offers the greatest potential for future treatments to have a significant impact on preventing or slowing dementia.