By estimating the age of people’s brains based on MRI scans and using machine learning, a team led by UCL researchers in England has identified several risk factors for a prematurely aging brain. Poor heart health is one of them.
They found that poor heart health at age 36 predicted greater brain age later in life, while men also tended to have older brains than women of the same age .
The findings were published in The Lancet Healthy Longevity.
People of the same age had brains of very different ages
Older brain age was associated with slightly poorer scores on cognitive tests and also predicted increased brain shrinkage (atrophy) over the next two years, suggesting that brain age may be an important clinical marker for people at risk of cognitive decline or other diseases related to brain health.
“We found that despite the fact that the people in this study were all of very similar actual ages, there was a very large variation in the age predicted by the computer model of their brains,” said Professor Jonathan Schott, lead author of the study.
“We hope that this technique could one day be a useful tool for identifying people at risk of accelerated aging so that they can be offered early, targeted prevention strategies to improve their brain health,” says the professor, quoted by Medical Xpress.
A lifetime study
The researchers applied an MRI-based machine learning model to estimate the brain age of participants in the Alzheimer’s Research UK-funded Insight 46 study, led by Professor Schott.
Study participants are drawn from the 1946 British Birth Cohort of the Medical Research Council National Survey of Health and Development (NSHD). Because the participants were part of the study throughout their lives, the researchers were able to compare their current brain age with various factors throughout their lives.
The participants were all between 69 and 72 years old, but their estimated brain ages ranged from 46 to 93 years.
The researchers were able to explain about a third of the variability in brain age by looking at different factors throughout the participants’ lives.
What did poor heart health reveal?
People with poor heart health at age 36 or 69 had poorer brain health, as did those with cerebrovascular (related to blood flow and blood vessels in the brain) disease identified on MRI. This aligns with an earlier study led by Professor Schott, which found that high blood pressure at age 36 predicted poorer brain health later in life.
The study found no association between childhood cognitive function, education level or socioeconomic status and a prematurely aging brain.
The researchers also found that older brain age was associated with a higher concentration of neurofilament light protein (NfL) in the blood. Increased NfL is thought to occur due to nerve cell damage and is increasingly recognized as a useful marker of neurodegeneration.
Poor heart health in youth affects us in old age
“The Insight 46 study is helping to reveal more about the complex relationship between the different factors that influence people’s brain health throughout life,” said Dr Sara Imarisio, from Alzheimer’s Research UK.
“Using machine learning, the researchers in this study found even more evidence that poor heart health in middle age is linked to greater brain shrinkage in old age. We are incredibly grateful to the dedicated group of individuals who have given their entire lives to science, making this research possible,” she concluded.