How fast are you aging? Brain scans reveal hidden clues

Aging doesn’t look the same for everyone. Most people know someone who seems to age faster or slower than others. One person may still run marathons in their 70s, while another starts struggling with memory and energy in their 50s.

This aging discrepancy raises a basic question: Is there a way to actually measure how fast someone is aging?

Scientists from Duke University, Harvard University, and the University of Otago in New Zealand have created a tool that uses a single brain scan to estimate how quickly your body and mind are aging. And it does this while you’re still in midlife, before major health problems show up.

“The way we age as we get older is quite distinct from how many times we’ve traveled around the sun,” said Ahmad Hariri, professor of psychology and neuroscience at Duke University.

Aging clues hidden in a single scan

The new tool, called DunedinPACE Neuroimaging or DunedinPACNI, can be used with a standard MRI brain scan. It gives doctors and researchers a read on your aging pace and potential risk for chronic diseases long before symptoms appear.

This kind of early warning system could give people a chance to make changes that might actually slow or prevent serious health problems.

“What’s really cool about this is that we’ve captured how fast people are aging using data collected in midlife,” Hariri said. “And it’s helping us predict diagnosis of dementia among people who are much older.”

Why most aging clocks get it wrong

Many “aging clocks” already exist, but they mostly rely on things like blood tests or genetic markers collected from people of various ages at one point in time. That approach can be misleading.

According to Hariri, things that look like faster aging may simply be because of differences in exposure to things such as leaded gasoline or cigarette smoke that are specific to their generation. “We need to figure out how we can monitor aging in an accurate way.”

The new model avoids that problem by using data from a rare and detailed dataset: the Dunedin Study. This long-term project has followed more than 1,000 people born in Dunedin, New Zealand, between 1972 and 1973.

Brain scans predict rates of aging

Researchers have been tracking the participants’ physical and mental health for over 50 years. Every few years, the study measured things like blood pressure, cholesterol, glucose, body mass index, kidney and lung function – even gum health.

By analyzing how these markers changed over time, the researchers created a personalized aging rate for each participant.

The team trained DunedinPACNI to predict that rate of aging based only on brain scans taken when the participants were 45. Once the model was trained, it was tested on other datasets from the U.S., U.K., Canada, and Latin America.

Your brain keeps the score

The results held up across different groups. People who were aging faster, according to the tool, performed worse on cognitive tests, experienced faster shrinkage of the hippocampus – the brain’s memory center – and faced a higher risk of cognitive decline.

In one sample of 624 older adults, those who were aging the fastest had a 60% higher chance of developing dementia and started showing symptoms earlier than their slower-aging peers.

When the team first saw the results, they were amazed. “Our jaws just dropped to the floor,” Hariri said.

More than just the brain

The tool also revealed a strong link between brain aging and overall physical decline. People with high aging scores were more likely to suffer from heart disease, lung issues, strokes, and other chronic illnesses.

These individuals were 18% more likely to be diagnosed with a major disease and 40% more likely to die in the next few years compared with people aging at an average pace.

“The link between aging of the brain and body are pretty compelling,” Hariri said.

The model worked just as well across different racial and socioeconomic groups, including low-income and non-white participants in the U.K. and people in Latin America. “It seems to be capturing something that is reflected in all brains,” Hariri said.

Aging populations, growing problems

Globally, the number of people over 65 is expected to double by 2050. That means more people will deal with diseases like Alzheimer’s, which already cost the world $1.33 trillion in 2020 and could climb to $9.12 trillion by mid-century.

“But because we live longer lives, more people are unfortunately going to experience chronic age-related diseases, including dementia,” Hariri said.

Current Alzheimer’s drugs don’t stop or reverse the disease – they mostly manage symptoms. One reason they may not work well is that they’re given too late. “Drugs can’t resurrect a dying brain,” Hariri said.

That’s where a tool like DunedinPACNI could change things. If doctors can spot who’s at higher risk earlier, they could try new treatments while there’s still time to protect the brain.

Scans may identify causes of faster aging

Besides tracking dementia risk, the tool could help explain why certain factors – like poor sleep or mental health problems – seem to make people age faster.

“We really think of it as hopefully being a key new tool in forecasting and predicting risk for diseases, especially Alzheimer’s and related dementias, and also perhaps gaining a better foothold on progression of disease,” Hariri said.

“More research is needed to advance DunedinPACNI from a research tool to something that has practical applications in healthcare,” said Ethan Whitman, a Ph.D. student in clinical psychology at Duke and the study’s first author.

In the meantime, the researchers hope others will use the tool in studies that already have brain scan data but lack long-term health tracking. It could open a new window into how we age – and how we might slow the process down.

The full study was published in the journal Nature Aging.

Image Credit: Ethan Whitman, Duke University

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