Can a Blood Test Predict Dementia?

in general 29 July 2016

Can a Blood Test Predict Dementia?

A recent Daily Mail report said "Simple blood test … could predict if you'll suffer dementia."

The story came from a study carried out by researchers from King’s College London and published in the peer-reviewed scientific journal Genome Biology. 

The NHS claims the study received financial support from a number of sources, including InnoMed (Innovative Medicines in Europe), XRGenomics Ltd, Alzheimer’s Research UK, and The John and Lucille van Geest Foundation.

The article is available here.


Taking  samples of muscle and tissue from young and old adults, the study aimed to identify a genetic score that could indicate peoples’ biological age. There was a set of genetic markers that could differentiate between young and old samples.

Using other tissue samples, including blood from people with and without Alzheimer's disease, the authors further tested this "healthy ageing gene score". They found the score was lower in those with Alzheimer's. Overall, this score is suggested as a marker for healthy ageing.  


However, the NHS says “it is important to realise this study is in the early experimental stages and the score has so far only been tested in small groups of people with known disease status. It is not known how well it could predict future disease development. 

“There is also the issue of the psychological impact of being told you are of ‘older’ biological age, or may have a higher risk of dementia or other chronic diseases – especially if there is little you can do to prevent this.”

Media Coverage

The UK media gave the study extensive coverage, and the NHS believes this was generally premature.  They say “the headlines could suggest that people can go to their GP and request a blood test to determine their age and risk of dementia, which is certainly not the case.

“This study is in the early stages and there would be many things to consider before suggesting this could be a screening test.

“The papers largely ignored the issue of whether being told you had a biological age older than your years, or had higher risk of dementia, would be welcome news.”


There are steps you can take to reduce your risk of dementia and other chronic diseases, such as living a healthier lifestyle. The NHS is also inviting people to sign up to take part in trials on NHS Join Dementia Research.

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