Dunedin Study researchers have developed a new tool that can tell how fast someone is aging by looking at a snapshot of their brain.
Called DunedinPACNI, the tool was created by scientists from Otago, Duke and Harvard universities.
From a single MRI brain scan, it can estimate your risk in midlife for chronic diseases that typically emerge decades later.
The researchers found that in older people, the tool could identify whether someone may be more likely to develop dementia or other age-related diseases years before symptoms appear, when they might have a better shot at slowing the course of disease.
That information could help prevention and early intervention efforts to support long-term health and wellbeing, positive aging, and reduce the burden of age-related diseases, such as dementia.
Dunedin Study researcher Professor Ahmad Hariri, of Duke's Department of Psychology and Neuroscience, says Study data collected in midlife was used to capture how fast people are aging, which is "helping us predict diagnosis of dementia among people who are much older".
The Study is the most detailed study of human health and development in the world. It follows the lives of 1037 babies born at Queen Mary Maternity Hospital in Dunedin between April 1, 1972 and March 31, 1973.
Every few years, Study researchers look for changes in the Study Members' blood pressure, body mass index, glucose and cholesterol levels, lung and kidney function and other measures - even gum recession and tooth decay.
They used the overall pattern of change across these health markers over nearly 20 years to generate a score for how fast each person was aging.
DunedinPACNI was trained to estimate this rate of aging score using only information from a single brain MRI scan that was collected from 860 Study Members when they were 45 years old.
Researchers found that Dunedin Study members with faster PACNI scores (indicating faster aging) were more likely to have poorer health, and poorer physical and cognitive functioning.
The researchers then worked with studies with older people in the United States and United Kington to test the new PACNI tool on more than 50,000 brain scans.
They found that faster PACNI was associated with increased risk of developing chronic diseases (e.g. heart attacks, strokes), increased likelihood of being diagnosed with dementia over time, and even increased mortality.
Moana Theodore
Study Director Professor Moana Theodore says the research is a great example of how the University of Otago and the Dunedin Study are at the forefront of world-leading aging research alongside international collaborators.
"If we can predict ageing, especially in mid-life, with these types of tools, then we may be able to intervene earlier to stop or slow down the progression of age-related diseases like dementia," she says.
"The science would not be possible without the 50-plus year contribution of the Study members and their families."
"If we can predict ageing, especially in mid-life, with these types of tools, then we may be able to intervene earlier to stop or slow down the progression of age-related diseases like dementia." - Study Director Professor Moana Theodore
Faster aging and higher dementia risk
Recently published in the journal Nature Aging, results across the data sets found people who were aging faster by this measure performed worse on cognitive tests and showed faster shrinkage in the hippocampus, a brain region crucial for memory.
More soberingly, they were also more likely to experience cognitive decline in later years.
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.
Using PACNI in overseas studies with older people, the researchers found that those with faster aging scores were more frail and more likely to experience age-related health problems such as heart attacks, lung disease or strokes.
The fastest agers were also 18 per cent more likely to be diagnosed with a chronic disease within the next several years compared with people with average aging rates.
Even more alarming, they were also 40 per cent more likely to die within that timeframe
than those who were aging more slowly, the researchers found.
"The link between aging of the brain and body are pretty compelling," Professor Hariri says.
The correlations between aging speed and dementia were just as strong in other demographic and socioeconomic groups than the ones the model was trained on, including a sample of people from Latin America, as well as UK participants who were low-income or from ethnic minority communities.
"It seems to be capturing something that is reflected in all brains."
This work is important because people worldwide are living longer. In the coming decades, the number of people over age 65 is expected to double, reaching nearly one fourth of the world's population by 2050.
"But because we live longer lives, more people are unfortunately going to experience chronic age-related diseases, including dementia."
Dementia's economic burden is already huge. Research suggests that the global cost of Alzheimer's care, for example, will grow from US$1.33 trillion in 2020 to US$9.12 trillion in 2050 -- comparable or greater than the costs of diseases like lung disease or diabetes that affect more people.
Effective treatments for Alzheimer's have proven elusive. Most approved drugs can help manage symptoms but fail to stop or reverse the disease.
One possible explanation for why drugs haven't worked so far is they were started too late, when the Alzheimer's proteins that build up in and around nerve cells have already done too much damage.
"Drugs can't resurrect a dying brain," Professor Hariri said.
But 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.
In addition to predicting risk of dementia over time, DunedinPACNI may also help scientists better understand why people with certain risk factors, such as poor sleep or mental health conditions, age differently.
More research is needed to advance DunedinPACNI from a research tool to something that has practical applications in healthcare.
But in the meantime, the team hopes the tool will help researchers with access to brain MRI data measure aging rates in ways that aging clocks based on other biomarkers, such as blood tests, can't.
"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," Professor Hariri says.
