Scientists have long known that growing older is one of the biggest risk factors for dementia. However, not everyone ages in the same way.
Some people remain mentally sharp well into old age, while others develop memory problems and cognitive decline much earlier.
A new study from researchers at King’s College London suggests that the “real age” of a person’s body may be more important than the number of birthdays they have celebrated.
The study found that people whose biological age is older than their actual chronological age are more likely to develop dementia, especially vascular dementia, and may develop the disease at a younger age.
The research was published in the journal Alzheimer’s & Dementia and analyzed health information from more than 220,000 participants in the UK Biobank database.
Researchers also discovered that when advanced biological aging was combined with a high genetic risk for dementia, the danger became much greater.
In particular, people carrying two copies of the APOE ε4 gene variant and showing signs of faster biological aging were up to 10 times more likely to develop dementia compared to the average participant.
Dementia is a broad term used to describe conditions that affect memory, thinking, and daily functioning. Alzheimer’s disease is the most common type, but vascular dementia, which is linked to reduced blood flow in the brain, is also very common.
Currently, nearly one million people in the United Kingdom are living with dementia, and experts expect that number to rise sharply over the coming decades as populations age.
Although aging remains the strongest risk factor, scientists say dementia is not simply an unavoidable part of getting older.
Research suggests that many cases may be delayed or even prevented by reducing certain risk factors such as smoking, poor diet, physical inactivity, obesity, high blood pressure, and social isolation.
The new study focused on something called biological aging.
Unlike chronological age, which simply counts years, biological age estimates how old the body appears internally based on physical and chemical changes inside cells and tissues.
To measure biological aging, the researchers used a “metabolomic aging clock.”
This clock uses blood samples to study metabolites, which are tiny molecules produced during metabolism. Metabolism is the process the body uses to turn food into energy and perform other important functions.
Changes in the levels of these metabolites can provide clues about how healthy the body is and how quickly it is aging.
Scientists compared each participant’s biological age with their chronological age to calculate something called “MileAge delta.”
If someone’s biological age was older than expected, it suggested their body was aging faster than normal.
The researchers then tracked who later developed dementia.
Nearly 4,000 participants developed dementia during the study period.
The analysis showed that people with biological ages significantly older than their actual ages had a much greater risk of developing dementia over time.
For vascular dementia, the risk increase was especially large. People with accelerated biological aging had around a 60% higher risk of developing vascular dementia.
Overall dementia risk was about 20% higher among people whose biological age was substantially older than expected.
The researchers also found that biological aging and genetic risk appeared to work mostly independently.
This means that both genes and the body’s aging processes may separately contribute to dementia risk.
According to lead researcher Dr. Julian Mutz, the findings suggest that biological aging measurements may help identify people at risk before symptoms begin.
He explained that blood-based aging tests may eventually become useful tools for prevention and early screening.
One reason the findings are exciting is that biological aging may be more modifiable than genetic risk.
While people cannot change the genes they inherit, they may be able to influence biological aging through healthier lifestyles, better medical care, and reducing harmful risk factors.
The study also highlights the growing interest in blood-based testing for brain diseases.
Compared to brain scans or spinal fluid tests, blood tests are far less invasive, easier to perform, and potentially more affordable for large populations.
Researchers believe metabolomic aging clocks could eventually help doctors identify high-risk individuals for dementia prevention studies or clinical trials.
The findings may also help scientists better understand why some people develop dementia earlier than others.
However, the researchers caution that the study only shows associations and does not prove that faster biological aging directly causes dementia.
Future studies will be needed to determine whether slowing biological aging could actually reduce dementia risk.
Still, experts say the large study size and strong results make the findings important.
The research suggests that looking beyond chronological age may give doctors a much clearer picture of long-term brain health.
If future research confirms these findings, simple blood tests measuring biological age could someday become part of routine health screening to help identify people at risk of dementia long before symptoms appear.
If you care about dementia, please read studies that eating apples and tea could keep dementia at bay, and Olive oil: a daily dose for better brain health.
For more health information, please see recent studies what you eat together may affect your dementia risk, and time-restricted eating: a simple way to fight aging and cancer.
The study was published in Alzheimer’s & Dementia.
