Dementia Scotland: Blood test could predict dementia up to 15 years before diagnosis, study shows

The research based on more than 50,000 healthy people from UK Biobank has been labelled a ‘breakthrough’ amid evidence a blood test could predict dementia up to 15 years before diagnosis

A blood test that looks for changes in certain proteins could predict dementia up to 15 years before diagnosis, in research that has been labelled a “breakthrough”.

Scientists have identified 11 proteins that they say are highly accurate – more than 90 per cent – at predicting future dementia.

These proteins, found in the liquid component of blood known as the plasma, are markers for the biological changes that happen in people who have dementia or Alzheimer’s disease.

A nurse holds a test tube containing a blood sample. Picture: Simon Dawson/PA Wire

One such protein – known as GFAP – has previously been identified as a potential biomarker in smaller studies.

The researchers from the University of Warwick and Fudan University in China described their findings, published in the journal Nature Aging, as a “breakthrough”.

Professor Jianfeng Feng, from the University of Warwick’s department of computer science, said this test “could be seamlessly integrated into the NHS and used as a screening tool by GPs”.

More than 90,000 people in Scotland have dementia. Alzherimer Scotland said the degenerative condition was most common in older people, but could affect those in their 40s and 50s or even younger.

There are more than 944,000 people more widely in the UK who have dementia, which is expected to rise to more than a million by 2030.

The researchers said an early diagnosis was critical for those with the condition as there were new drugs that could slow progression of the disease if detected early enough.

Jia You, of Fudan University, said early screening “holds immense significance in pinpointing dementia risks”.

He said: “A notable advantage of plasma protein analysis is that it merely necessitates routine blood tests, similar to those conducted during regular hospital visits or health checks. This simplicity offers a considerable edge over more invasive procedures like lumbar punctures, especially where the targeting population are healthy individuals.”

For the study, thought to be the largest of its kind, the researchers looked at data from more than 50,000 healthy people from UK Biobank, which holds medical and lifestyle records of more than half a million Britons.

They analysed the blood samples from this group collected between 2006 and 2010.

Over a follow-up period of ten to 15 years, more than 1,400 people went on to develop dementia.

By analysing more than 1,400 different proteins in the blood and using artificial intelligence, the researchers found 11 proteins that could accurately predict dementia up to 15 years before diagnosis.

Two new Alzheimer’s drugs – lecanemab and donanemab – are under review by the UK medicines regulator, meaning any ability to confirm the disease early would be crucial for patients who would benefit from this medication, if approved.

Commenting on the study, Dr Richard Oakley, associate director of research and innovation at Alzheimer’s Society, said: “This research looked at proteins in the blood of healthy individuals and followed them up 15 years later and found a common set of proteins in those that went on to develop dementia.

“It’s very early days and lots more work is needed, but this could lay the groundwork for the early prediction of dementia and teach us more about how to provide an early and accurate diagnosis.

“What we need now are blood tests that work in a real-world setting and that can accurately diagnose dementia when someone is starting to show symptoms.

“This is why we’re working with Alzheimer’s Research UK on the Blood Biomarker Challenge which will revolutionise the way dementia is diagnosed.

“The project, which is possible thanks to £5 million in funding raised by players of People’s Postcode Lottery, will gather the information needed to introduce a blood test for dementia into UK healthcare systems.”

Adam Stachura, director of policy, communications and external affairs at Age Scotland, said: "Getting an early diagnosis is extremely important for those living with dementia, their loved ones and their carers. It can really help with getting the right support and care to meet your needs.

"Although this research is still in the very early stages, it is a hopeful sign that a simple blood test can help with a dementia diagnosis. It is a long way from being available to people in Scotland and it’s full benefits are still unknown, but could certainly be helpful for diagnosis in the future."

Dr Sheona Scales, director of research at Alzheimer’s Research UK, added: “We have seen some fantastic progress in the development of blood tests for Alzheimer’s over the last few months. This new study adds to the growing body of evidence that looking at levels of certain proteins in the blood of healthy people could accurately predict dementia before symptoms develop.

“Further studies are needed to understand how these tests and predictive models work with data from more diverse populations.

“The key proteins hallmarks of Alzheimer’s disease – amyloid and tau – also were not included in the analysis, so we don’t know how these proteins would affect the prediction model. And, even when tests show promise in studies like this, they still need to go through regulatory approval before they can be used in a healthcare setting.”

British scientists are separately developing a £10 at-home finger prick blood test for Alzheimer’s amid claims a prototype could be available to trial as early as this year.

The test uses a new technique involving tiny gold “nanoparticles”, which the researchers originally developed as a test for Covid.

Publication of the research results comes as four new medicines were approved for use in Scotland, including a treatment for blood cancer and the first targeted treatment for a rare skin condition.

The Scottish Medicines Consortium (SMC), which advises on newly-licensed medicines for use by NHS Scotland, welcomed the approval of treatments for three different skin conditions, including chronic abscesses and another caused by dialysis.

A medication that targets two types of blood cancers was also approved. However, a potential treatment for a rare cancer was declined by the committee, which said “uncertainties” could still be addressed in future.

New cancer drug, loncastuximab tesirine (Zynlonta) was accepted to treat adult patients with two types of blood cancers – diffuse large B-cell lymphoma and high-grade B-cell lymphoma. The committee also approved difelikefalin (Kapruvia) for treating itchy skin in adult kidney patients who are receiving dialysis.

Dupilumab (Dupixent) was accepted for treating adults with prurigo nodularis (PN), the first targeted treatment for the rare skin condition which causes a rash with intense itching and lumps.

Also approved was secukinumab (Cosentyx), for the treatment of adults with hidradenitis suppurativa, a long-term skin condition that causes abscesses and scarring on the skin. Cabozantinib (Cabometyx) was not recommended for treating adults with a type of cancer called differentiated thyroid carcinoma.

SMC chairman, Dr Scott Muir, said: “The committee is pleased to be able to accept four new medicines for use in NHS Scotland. We know that our decision on dupilumab will be welcomed by patients with prurigo nodularis and their families. This is the first targeted treatment licensed for this very impactful skin condition.