Our biological age may predict dementia risk better than birth date

Aging is not just about counting candles on a cake. While chronological age marks time, biological age reveals how your body is truly holding up. The two don’t always align. You might be 60 on paper but have the organs and cells of someone far younger – or older.

This difference can carry real consequences, especially for brain health. According to a major new study, people with higher biological ages than their chronological ones may face a greater risk of developing dementia.

The findings shed light on how our internal aging patterns could shape long-term cognitive outcomes.

This research gains urgency in the face of global dementia rates, which continue to climb. With longer life expectancies, understanding how to age healthily becomes more important than ever. And this study offers a new lens through which to view prevention and early detection.

Biological age may signal dementia risk

Chronological age is simple – your age based on birthdate. Biological age is more complex. It reflects how your body’s systems perform relative to typical aging. It draws on health indicators like lung function, blood pressure, cholesterol levels, and even blood cell activity.

While this study does not prove causation, it reveals a compelling association between advanced biological age and dementia.

That’s important, because it suggests biological age may be a useful warning sign for cognitive decline. It also raises hope – because biological age is more responsive to change than the passage of time.

“With the rising impact of dementia around the world, identifying risk factors and implementing preventive measures is essential,” said study author Dr. Yacong Bo of Zhengzhou University in China.

“While none of us can change our chronological age, we can influence our biological age through lifestyle factors such as diet and exercise.”

Faster aging and higher dementia risk

The researchers examined 280,918 individuals from a large UK database. At the start of the study, the average participant was 57 years old.

Importantly, none had dementia when they joined the research. These individuals were then tracked for 14 years on average, allowing the team to observe who developed dementia and how biological age might relate to that outcome.

During the study period, 4,770 participants were diagnosed with dementia. Among those who developed the disease, their average chronological age was 65.

But their average biological age stood at 55, suggesting their bodies had aged beyond their actual years. In contrast, people who did not develop dementia had an average chronological age of 57 and a biological age closer to 45.

These differences reflect more than numbers – they may signal stress on vital systems like the brain, heart, and immune system.

How biological age was measured

To calculate biological age, the researchers used two distinct methods. Both factored in key aging biomarkers like lung efficiency, cholesterol, and blood pressure. But they also looked at deeper blood indicators, such as average red cell size and white blood cell count.

These tests offer insight into how the body’s internal systems – like metabolism, immunity, kidney and liver function, and cardiovascular health – are aging. When these systems wear out faster than normal, they may place the brain under greater stress.

When grouped by biological age, the participants with the oldest biological profiles were about 30% more likely to develop dementia compared to those with the youngest profiles.

These results accounted for other variables like smoking, education, and baseline age, suggesting that biological age remained a strong predictor.

Faster aging linked to brain shrinkage

The researchers didn’t stop at statistical risk. They also looked at brain imaging to find structural evidence of damage. People with advanced biological age showed signs of reduced gray matter volume – a known marker in many forms of dementia, including Alzheimer’s disease.

“These brain structure changes explain some, but not all, of the association between advanced biological age and dementia,” Bo said.

“These results support the hypothesis that advanced biological age may contribute to the development of dementia by causing a widespread change in brain structures.”

The structural thinning of the brain may help explain why faster-aging bodies tend to suffer cognitive problems earlier. However, it also points to other unknown factors that may link the two.

Healthy living may reduce dementia risk

While we cannot pause time, this study hints that we might influence how our bodies age. Biological age appears more flexible than chronological age. That means good habits – like regular movement, plant-forward eating, low stress, and avoiding tobacco – could lower our biological age over time.

The authors emphasize this point. “While none of us can change our chronological age, we can influence our biological age,” Bo said. This opens a promising window for public health efforts that target modifiable risk factors.

The study also raises new questions: Could slowing biological aging delay or prevent cognitive diseases? Would earlier screening based on biological age allow for better treatment or care? These are paths future research may explore.

Limitations of the study

The researchers acknowledged some limitations of their study. Participants in the UK database were generally more health-conscious than the wider population.

This could skew the findings toward lower dementia risk overall, meaning the real-world numbers might differ. Still, the consistent patterns between biological age and cognitive decline remain relevant.

Importantly, this work was supported by both the Henan Province and Zhengzhou city governments in China, highlighting the growing international interest in brain aging research.

Learn more about brain health

To better understand brain conditions and healthy aging, resources like BrainandLife.org offer science-backed information.

Managed by the American Academy of Neurology, this platform connects patients, caregivers, and medical professionals with expert advice. The site includes articles, podcasts, and books covering topics from migraine to Alzheimer’s.

In summary, how fast your body ages may shape how well your mind holds up. And as this new research shows, staying biologically younger might offer powerful protection.

The study is published in the journal Neurology.

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