Your brain isn’t necessarily the same age as the rest of you. Now, it may be possible to predict how quickly a person’s brain will age throughout life based on tests taken when they are 3 years old.
A person’s biological age may be a better indicator of their health than their chronological age. Brain age can be measured using brain scans and machine learning to determine if a person’s brain looks older or younger than the average healthy brain for people of the same age.
To find out if brain age might reveal anything about a person’s health in midlife, Max Elliott at Duke University in North Carolina and his colleagues assessed the brains of 869 adults in New Zealand who have undergone regular medical and cognitive testing since they were 3 years old.
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When the volunteers, all aged between 43 and 46, underwent MRI brain scans, the team found that their brain ages ranged from 23 to 71. Those with older brain ages performed worse on tests of cognition, memory and IQ.
The researchers also measured things like cholesterol and blood sugar levels to estimate the biological age of the volunteers’ bodies. They found that this was loosely linked to brain age, but not totally. “There are some people who have a very advanced brain age whose bodies seem to be ageing slowly, and vice versa,” says Elliott. However, the team found that those who had the highest scores on cognitive tests when they were 3 years old went on to have the youngest-looking brains (bioRxiv, ).
This suggests we might be able to tell who is at risk of accelerated brain ageing early in life, says Elliott. He hopes that predicting brain ageing earlier in life could allow treatments for conditions like dementia to be started sooner. This means they might have a better chance of working.
James Cole at King’s College London cautions that it will be difficult to make predictions based on a 3-year-old’s test results. “Acceleration or delay could be positive or negative,” says Cole. “If a 60-year-old has a brain that looks 70, that’s bad, but if a 3-year-old has a brain that looks 5, that might be a good thing.”
The team also asked other researchers to guess how old the volunteers were based on photos of their faces. Again, the responses varied hugely, with estimates coming in 20 years above and below their actual age. Those who looked older also had older brain ages. “It suggests that the outward signs of ageing are reflected by the internal signs of ageing,” says Cole.
That doesn’t mean that all older-looking individuals will be on their way to dementia, says Elliott.
We don’t yet have a way to treat brain ageing, but given the known benefits to the brain of healthy eating and exercise, these aren’t a bad place to start. “Ageing is a complex interaction of genes and environment,” says Cole. “The environmental factors are likely to be things like stress levels, diet, how much physical exercise people get and how much they use their brains,” he says.
