A simple blood test that detects a specific protein linked to Alzheimer’s disease may help predict cognitive decline in older adults up to a decade before symptoms appear.
Researchers found that measuring a blood biomarker called p-tau217 can track the buildup of damaging brain proteins associated with the disease.
In one of the largest studies of its kind, nearly 2,700 cognitively healthy adults with an average age of 70 were tracked for up to ten years.
Individuals with very high p-tau217 levels had an estimated 78% chance of developing cognitive impairment within a decade and roughly a one in three chance within five years.
Even those with moderately elevated levels faced a 45% risk of cognitive decline over the same ten-year period.
The p-tau217 protein is a modified form of tau, which forms tangles in the brain and contributes to memory loss.
The blood test provided risk information beyond what standard brain scans and genetic testing currently offer.
Once validated, such tests could be used to identify candidates for clinical trials of preventive treatments.
They may also help guide monitoring, treatment decisions, and family counseling if therapies are approved for early-stage use.
Researchers cautioned that p-tau217 alone cannot fully predict an individual’s future cognitive health.
Age, genetics, kidney function, and racial background can all influence biomarker levels and overall dementia risk.
The team called for longer studies in more diverse populations to refine these risk estimates.
Identifying at-risk individuals before memory problems emerge could shift the focus toward earlier intervention and prevention.
Earlier detection may fundamentally change how dementia is diagnosed, treated, and potentially avoided.
