Researchers at Karolinska Institutet have shown how some specific biomarkers in the blood of cognitively healthy elderly people can predict the development of dementia up to ten years before diagnosis.

A new study published in Nature Medicine has examined the ability of specific biomarkers to predict dementia, including Alzheimer’s disease, in cognitively healthy older adults up to ten years before actual diagnosis. Among the biomarkers were p-tau217, Neurofilament Light (NfL) and Glial Fibrillary Acidic Protein (GFAP).

Samples from over 2,000 people

Previous research has indicated that these biomarkers could be helpful in early dementia diagnosis, but most studies have been conducted on people who have already sought care for cognitive disorders, such as memory problems. 

To assess the predictive value of biomarkers in the general population, a larger population-based study was required.

This study analyzed blood samples from just over 2,100 people over the age of 60. It was led by researchers at the Aging Research Center at Karolinska Institutet in collaboration with SciLifeLab and the Royal Institute of Technology in Stockholm. 

The participants were followed over time to see if they developed dementia. At a follow-up ten years later, 17 percent of the participants had developed dementia. The accuracy of the biomarkers used in the study was found to be up to 83 percent.

“These are promising results, especially considering the large time interval between testing and diagnosis. It shows that it is possible to reliably identify individuals who will develop dementia and those who will remain healthy,” says Giulia Grande , assistant professor at the Department of Neurobiology, Care Sciences and Society , Karolinska Institutet, and the study’s first author. 

Promising biomarkers

“Our results also suggest that if an individual has low levels of these biomarkers, the risk of developing dementia in the next decade is minimal. This could therefore provide reassuring news to people who are concerned about their cognitive health, as it rules out dementia,” says Davide Vetrano , associate professor at the same department and the study’s senior author. 

At the same time, the study shows that the positive predictive values ​​for the biomarkers were low, meaning that elevated levels alone are not sufficient to identify which individuals will actually develop dementia within the next ten years. The authors therefore advise against using the biomarkers as a screening tool in the population at this time. 

– The biomarkers are promising, but are currently not suitable for use as independent screening tests to identify dementia risk in cognitively healthy people, says Davide Vetrano.

The researchers noted that it is a combination of the three most relevant biomarkers – p-tau217 with NfL or GFAP – that could improve predictive accuracy. 

“More research is needed to understand how these biomarkers can be used effectively in real-life healthcare settings, especially for asymptomatic older adults,” says Giulia Grande. 

– We are now moving forward with investigating whether the combination of the three biomarkers together with other clinical, biological or functional information can improve the possibility of using them as a screening tool in the population.

The study was primarily funded by the Swedish Research Council, the Swedish Brain Foundation and the strategic research initiative in epidemiology and biostatistics at Karolinska Institutet. The researchers declare that there are no conflicts of interest.

Publication

“Blood-based biomarkers of Alzheimer’s disease and incident dementia in the community” , Giulia Grande, Martina Valletta, Debora Rizzuto, Xin Xia, Chengxuan Qiu, Nicola Orsini, Matilda Dale, Sarah Andersson, Claudia Fredolini, Bengt Winblad, Erika J. Laukka, Laura Fratiglioni & Davide L. Vetrano. Nature Medicine , online 26 March 2025, doi: 10.1038/s41591-025-03605-x.