New research suggests a specific blood test could potentially help identify people at risk of developing Alzheimer’s disease up to a decade before symptoms appear.
The test looks for a protein known as p-tau217, which researchers say could help identify symptom-free older adults who are more likely to later develop cognitive impairment.
The findings were presented at the Alzheimer’s Association International Conference in London.
The study’s lead researcher, Reisa Sperling from the Mass General Brigham Neuroscience Institute in the United States, said the test had previously been used mainly in people already showing symptoms.
“Right now it’s really being utilised in people who already have symptoms of Alzheimer’s disease and are thought to have cognitive impairment due to Alzheimer’s disease,” she said.
“In this study, we are looking at people who do not yet have symptoms of Alzheimer’s disease.”
Researchers analysed data from 2,684 healthy older adults who had taken part in long-running Alzheimer’s studies since 2004.
By last year, 478 of those participants had developed cognitive impairment.
The study found that symptom-free older adults with very high levels of p-tau217 had a 38 per cent risk of developing cognitive impairment within five years.
That risk rose to 78 per cent within 10 years.
“We also found that people who have a very low level of this blood test, p-tau217, were very unlikely to progress over time and were about the same level as people in general as they age over a 10-year period might be at risk for developing impairment,” Sperling said.
Sperling said different levels of p-tau217 appeared to signal different levels of risk, although the highest levels were most strongly linked to other evidence of disease progression.
The test does not currently offer a cure or change the treatment advice given to people who may be at risk.
“At this point, it wouldn’t change what I would tell someone to do. I’d still tell them to eat well, sleep well, exercise a lot and stay engaged. But that’s going to change dramatically if the current prevention trials show clinical benefit,” Sperling said.
However, the test could become an important tool if clinical trials show certain drugs can prevent or delay Alzheimer’s disease.
Researchers say it could help doctors identify people who may be eligible for preventative treatment.
Jessica Langbaum from the Banner Alzheimer’s Institute described the development as a “game changer” in Alzheimer’s research.
“This is really important for people, particularly if we get to a time when there’s one of the treatments that are being tested for Alzheimer’s prevention therapies,” she said.
“If one of those treatments read out having a blood test that can accurately determine who to test and say, yes, this person might be eligible for treatment, I think that’s a real game changer.”
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