New Tool Predicts How Fast Someone Is Aging

Scientists at Duke, Harvard, and the University of Otago in New Zealand have developed a novel tool that can tell how fast someone is aging. From a single MRI brain scan, the tool can estimate the risk in midlife for chronic diseases that typically emerge decades later. In older people, the tool can predict whether someone will develop dementia or other age-related diseases years before symptoms appear.

“What's really cool about this is that we've captured how fast people are aging using data collected in midlife,” explained Ahmad Hariri, senior author of the study published in Nature Aging. “And it’s helping us predict diagnosis of dementia among people who are much older.”

Several algorithms have been developed to measure how well a person is aging. But most of these “aging clocks” rely on data collected from people of different ages at a single point in time, rather than following the same individuals as they grow older, Hariri explained.

The challenge, he added, is to come up with a measure of how fast the process is unfolding that isn’t confounded by environmental or historical factors unrelated to aging. To do that, the researchers drew on data gathered from some 1,037 people who have been studied since birth as part of the Dunedin Study.

The new tool, named DunedinPACNI, was trained to estimate this rate of aging score using only information from a single brain MRI scan that was collected from 860 Dunedin Study participants when they were 45 years old. Next the researchers used it to analyze brain scans in other datasets from people in the U.K., the U.S., Canada and Latin America. Across data sets, they found that people who were aging faster by this measure performed worse on cognitive tests and showed faster shrinkage in the hippocampus.

Those who the tool deemed to be aging the fastest when they joined the study were 60% more likely to develop dementia in the years that followed. They also started to have memory and thinking problems sooner than those who were aging slower.

The researchers also found that people whose DunedinPACNI scores indicated they were aging faster were more likely to suffer declining health overall, not just in their brain function. People with faster aging scores were more frail and more likely to experience age-related health problems such as heart attacks, lung disease or strokes.

In the future, the new tool could make it possible to identify people who may be on the way to Alzheimer's sooner, and evaluate interventions to stop it—before brain damage becomes extensive, and without waiting decades for follow-up.