BRAIN scans could be used to identify people at risk of early death and cognitive decline, according to results of a study involving more than 600 Scots.

Neuroscientists programmed computers to predict a person's "brain age" using a combination of MRI scans and machine learning algorithms, which measure brain volume by estimating the overall loss of grey and white matter.

When the technique was tested using MRI scans taken from 669 adults in Scotland, all aged 73 at the time, the researchers found that the greater the difference between a person’s brain age and their actual age, the higher their risk of poor mental and physical health - and even early death.

Participants with "older brains" performed worse on standard physical measures for healthy ageing, including grip strength, lung capacity and walking speed, and were statistically more likely to have died before the age of 80.

The study, led by Imperial College London in collaboration with neuroscientists from Edinburgh University, is published today in the journal of Molecular Psychiatry. The researchers stress that while the technique is a long way from being used in clinical practice, they are hopeful it might one day be used as a screening too to help identify those at risk of cognitive decline and premature death, providing an opportunity for early intervention.

Lead author Dr James Cole, of ICL's department of medicine, said: “We've come up with a way of predicting how old someone is based on an MRI scan of their brain. Our approach uses the discrepancy between their chronological age and what we call their brain-predicted age as a marker of age-related atrophy in the brain.

"If your brain is predicted to be older than your real age than that reflects something negative may be happening.”

The researchers suggest that the technique could eventually be adapted as a screening tool in a similar way to Body Mass Index (BMI) weight checks, giving GPs and other health practitioners a quick way of detecting whether a patient has a healthy brain age.

Dr Cole added: “In the long run it would be great if we could do this accurately enough so that we could do it at an individual level. Someone could go to their doctor, have a brain scan and the doctor could say 'your brain is 10 years older than it should be’, and potentially advise them to change their diet or lifestyle or to start a course of treatment. However, at the moment, it's not sufficiently accurate to be used at that sort of individual level.”

Participants for the study were drawn from the Lothian Birth Cohort 1936, a long-term cognitive ageing study involving a group of adults all born in 1936 who completed the Scottish Mental Survey as children in 1947.

Professor Ian Deary, who leads the Lothian Birth Cohort 1936 project, said: "This study clearly shows how a group of people who are about the same chronological age do differ when one looks at aspects of their bodies; biologically, they are ageing at different rates.

"We already knew in the Lothian Birth Cohort 1936 that those whose epigenetic clock was ageing more slowly tended to live longer. This new set of findings tells us that those whose brain structure appears younger than their actual age also tend to have longer to live."