A study by the Karolinska Institutet in Sweden has investigated the potential of blood biomarkers to predict the occurrence of Alzheimer’s disease and other dementias in a real-world setting.
Previous research has suggested that biomarkers such as tau217, Neurofilament Light (NfL), and Glial Fibrillary Acidic Protein (GFAP) could be useful in diagnosing early dementia, but most studies recruited only patients who were already seeking advice on cognitive issues.
In the new study, published by Nature Medicine, more than 2,100 older adults without dementia were tracked over a 16-year period. Of six blood-based biomarkers linked to Alzheimer’s disease, elevated levels of four – p-tau181, p-tau217, NfL, and GFAP – were significantly associated with higher risk of developing dementia.
Participants with higher levels of these biomarkers at the start of the study were more likely to be diagnosed with dementia years later. The strongest individual predictor was p-tau217, which has recently been recognized as a key indicator of Alzheimer’s. When combined with NfL or GFAP, the ability to predict dementia improved even further.
“Our findings imply that if an individual has low levels of these biomarkers, their risk of developing dementia over the next decade is minimal,” said senior author Davide Vetrano.
However, while the markers reliably identified people unlikely to develop dementia – showing a negative predictive value of over 90 percent – they were less reliable at confirming who would go on to develop the disease. For instance, even the best-performing combinations yielded positive predictive values of only around 43 percent.
“These biomarkers are promising, but they are currently not suitable as standalone screening tests to identify dementia risk in the general population,” said Vetrano. Still, the researchers say they could be valuable in community settings to identify those who are unlikely to develop dementia and reduce unnecessary testing.
Corresponding author Giulia Grande said, “Further research is needed to determine how these biomarkers can be effectively used in real-world settings, especially for elderly living in the community or in primary health care services."
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