New Blood Test May Forecast Alzheimer’s Risk
Researchers have announced that a blood test could determine whether healthy older adults might develop Alzheimer’s symptoms in the next five to ten years. This finding could be, well, a double-edged sword—providing either comfort or anxiety. Still, it presents an opportunity to accelerate drug trials by pinpointing individuals at high risk who may participate in treatment studies.
Large clinical trials are already underway to see if certain medications can potentially prevent or at least delay this devastating disease. If one of these treatments proves effective, doctors will need a straightforward method to identify patients who might benefit from such interventions.
However, the scientists behind this recent study emphasize caution. They advise healthy individuals against rushing to take the p-tau217 test, which is mainly used to diagnose whether someone with cognitive issues has Alzheimer’s or another condition. “It’s better to wait until you have options,” said Dr. Reisa Sperling, a key author of the study. “Right now, I’d still recommend focusing on healthy habits: eat well, sleep well, exercise, and stay engaged.”
Findings reveal that older adults without symptoms but with elevated p-tau217 levels have a 38% chance of developing cognitive impairment within five years, with that number climbing to 78% over a decade.
This research was unveiled at the Alzheimer’s Association International Conference in London and published in JAMA.
The exact causes of Alzheimer’s remain elusive, though it is marked by the accumulation of amyloid plaques and tau tangles in the brain. The p-tau217 test assesses tau levels that relate to the extent of amyloid buildup, hinting at potential tangle formation, according to Sperling.
The team analyzed data from 2,684 older adults initially healthy when enrolled in long-term Alzheimer’s studies. They underwent p-tau217 testing at enrollment and annual cognitive assessments. Out of the sample, around 478 participants showed cognitive decline over the years.
On the other hand, participants with low p-tau217 levels faced minimal risk of cognitive impairment over five to ten years.
There’s a puzzling aspect to predicting Alzheimer’s: many individuals with high amyloid levels never develop dementia. Some experts suggest that accumulating amyloid leads to abnormal tau formations, resulting in cognitive symptoms.
Sperling highlighted that this new blood test can provide insights into an individual’s progression in this complex process. It appears that while varying p-tau217 levels indicate a gradual risk increase, only the highest levels align with significant clinical data about the tipping point.
Some scientists not affiliated with the study praised its potential but advised caution. For instance, the follow-up duration for many participants was limited to under a decade, which diminishes confidence in the longer-term risk predictions. Additionally, other health issues may complicate outcomes, creating uncertainty in projections for Alzheimer’s risk.
Drs. Suzanne Schindler and David Wolk expressed in a commentary that while the blood tests aren’t refined enough yet for tailored predictions, the findings contribute significantly to the overall understanding of the disease.
Interest in the blood test is already building, with individuals citing family histories of Alzheimer’s as a reason to pursue it. Jessica Langbaum from the Banner Alzheimer’s Institute feels it’s premature for widespread testing but acknowledges the importance of these findings. A reliable predictive blood test could be transformative—assuming effective treatments emerge to aid individuals before symptoms show.
