A magnetic resonance imaging scan (pictured, artificially coloured) of the brain can detail the risk of memory loss and other cognitive difficulties.Credit: Zephyr/SPL
Telltale features in standard brain images can reveal how quickly a person is ageing, a study of more than 50,000 brain scans has shown1.
Pivotal features include the thickness of the cerebral cortex — a region that controls language and thinking — and the volume of grey matter that it contains. These and other characteristics can predict how quickly a person’s ability to think and remember will decline with age, as well as their risk of frailty, disease and death.
Although it’s too soon to use the new results in the clinic, the test provides advantages over previously reported ‘clocks’ — typically based on blood tests — that purport to measure the pace of ageing, says Mahdi Moqri, a computational biologist who studies ageing at Harvard Medical School in Boston, Massachusetts.
“Imaging offers unique, direct insights into the brain’s structural ageing, providing information that blood-based or molecular biomarkers alone can’t capture,” says Moqri, who was not involved in the study.
The results were published today in Nature Aging.
Slowing the clock
Genetics, environment and disease all affect the speed of biological ageing. As a result, chronological age does not always reflect the pace at which time takes its toll on the body. Researchers have been racing to develop measures to fill that gap.
Ageing clocks could be used early in life to assess an individual’s risk of age-related illness, when it might still be possible to intervene. They could also aid testing of treatments aimed at slowing ageing, by providing a marker to track the effects of the intervention in real time.
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A host of candidate clocks has emerged in the scientific literature — and in direct-to-consumer advertising — over the past decade. Many of these were developed by feeding reams of data, such as measurements of the levels of molecules found in the blood, into computer algorithms that determine which parameters are linked with ageing. Often, the reasons underlying these correlations are unclear.
To develop an improved clock, Ethan Whitman, who studies brain ageing at Duke University in Durham, North Carolina, and his colleagues began with a remarkable study of more than 1,000 people born in Dunedin, New Zealand, between April 1972 and March 1973, who have been periodically assessed since birth by researchers. In the most recent of those assessments, participants’ brains were scanned using magnetic resonance imaging.
Whitman’s team fed measurements made from 860 of those brain images into their algorithm and had it look for correlations between the brain-scan data and what the team called the pace of ageing, a measure that incorporates data from all the Dunedin participants’ age-related declines in cardiovascular, metabolic and immune function, as well as other physiological measures.