A blood test may predict if apparently healthy older adults are likely to develop Alzheimer’s symptoms in the next five or 10 years, researchers reported Wednesday. The scientists behind the new study stress that it’s too soon for healthy people to seek out the so-called p-tau217 test, which is currently used to help diagnose whether people experiencing cognitive problems have Alzheimer’s or another disorder.

Understanding the Study

The new findings showed that symptom-free older adults who harbored very high levels of p-tau217 had a 38% risk of developing cognitive impairment over five years. That risk grew to 78% by 10 years. The research was published in JAMA and presented at the Alzheimer’s Association International Conference in London.

According to Dr. Reisa Sperling of the Mass General Brigham Neuroscience Institute, the study’s senior author, the information could be reassuring or terrifying, but for now, it’s a potential tool to speed drug development by helping to identify and enroll high-risk people into studies of possible Alzheimer’s treatments or preventive strategies.

The Mass General Brigham team analyzed data from 2,684 older adults who were healthy when they’d joined some long-running Alzheimer’s studies, receiving the p-tau217 blood test at enrollment and yearly cognitive checkups. Between the earliest enrollment in 2004 and last year, about 478 had developed cognitive impairment.

Implications and Next Steps

While different intermediate levels of p-tau217 signaled progressive risk, only the very highest level seemed to correlate with other evidence about that tipping point. Scientists not involved in the study praised it but also offered some reasons to be cautious, noting that only a small fraction of study participants had been tracked for a full decade, so there’s less confidence in the 10-year risk estimate than the five-year risk estimate.

The predictions could be clouded by other factors — older people may be at risk of dying from something else, or have heart-related problems that can cause vascular dementia rather than Alzheimer’s. Despite these considerations, the new work has provided a crucial piece of the puzzle in understanding and potentially predicting Alzheimer’s disease.

Original reporting: 40/29 / KHBS (NW Arkansas) — read the source article.