A simple blood draw might one day tell you your risk of memory problems decades before they happen — a breakthrough that researchers at Mass General Brigham are calling a critical step forward in the fight against Alzheimer's disease.
Scientists led by the Mass General Brigham Neuroscience Institute analyzed blood samples from 2,684 cognitively healthy older adults across North America, Japan, and Australia. They found that people with very high levels of a protein marker called p-tau217 faced a 38% chance of developing cognitive impairment within five years and a 78% chance within ten years. About 478 participants in the study eventually developed cognitive impairment.
The research, published in the journal JAMA and presented at the Alzheimer's Association International Conference, is notable because it followed people over time rather than just measuring differences at a single moment. Participants had their blood tested and brain scans taken when they enrolled, then received annual checkups to track their cognitive health. The earliest participants joined in 2004, with follow-ups continuing through 2025.
The test predicted risk even when accounting for other known risk factors, including genetic markers and plaques that show up on brain scans. Lead author Rachel F. Buckley, a cognitive neuroscientist, said the study stands out because it estimated individual risk levels using data from six different groups, creating a large and varied dataset that still showed consistent results.
Senior author Reisa Sperling, a neurologist, said the long-term goal is to make predicting memory decline as routine as checking cholesterol to predict heart attacks. But she emphasized that doctors don't yet recommend these tests for people without symptoms, since effective treatments to slow or prevent decline are still limited. Today, medical advice remains unchanged: exercise regularly, maintain a healthy diet, and prioritize sleep.
The hope is that as new drugs targeting the disease continue to be tested, these blood tests could help identify which people would benefit most from early intervention. "Today, p-tau217 can help identify people at high risk for future Alzheimer’s dementia for participation in prevention trials," Sperling noted. The test recently received federal clearance, and researchers are now working to validate their findings in broader populations and over longer time periods.