Health Farm

-- For a disease with no cure, why should anyone care that a new blood test could tell us if we’re on track to develop dementia?

For starters, an accurate test could speed up dementia research by identifying those at risk of Alzheimer’s who might be suitable for clinical trials aimed at preventing or delaying the development of the disease. A test might even encourage people to live healthier lifestyles, which is shown to lower the risk of Alzheimer’s by a third, even when it runs in the family.

Alzheimer’s is the most common cause of dementia, affecting more than 520,000 people in the UK, mostly over-65, and millions around the world.

Damaging clumps of protein start to accumulate in the brains of people up to 20 years before they develop memory loss and confusion – the characteristics of Alzheimer’s.

Costly positron emission tomography (PET) brain scans are currently the only way to detect the presence of accumulated protein in the brain.

But researchers from Washington University School of Medicine, in St Louis, Missouri, are on the cusp of a blood test that may do the job of expensive brain scans.

Researchers measured levels of one protein, called amyloid beta, in the blood of 158 adults aged over 50 to see if the protein’s presence matched levels found in brain scans. It did, but only 88% of the time – which isn’t sufficiently accurate for a diagnostic test.

But when researchers combined this information with two other risk factors for Alzheimer’s – an age of over 65 and people with a genetic variant called APOE4, which at least triples the risk of the disease – the accuracy of the blood test improved to 94%.

That’s good enough for a viable screening initiative.