A new study suggests that people with shorter protective caps at the ends of their chromosomes, called telomeres, may have a higher risk of developing age-related brain diseases such as stroke, dementia, and late-life depression.
The study, presented at the American Stroke Association’s International Stroke Conference 2025, analyzed data from over 356,000 participants in the UK Biobank and provides new insights into the role of biological aging in brain health.
What Are Telomeres and Why Do They Matter?
Telomeres are caps at the ends of chromosomes that protect genetic material from damage. Over time, telomeres shorten as cells divide, which is a natural part of aging. However, shorter telomeres have been linked to a higher risk of age-related diseases.
In this study, researchers focused on leukocyte telomere length—the telomere length of white blood cells—which is considered a marker of biological aging.
Telomere length is influenced by both genetic factors (such as ancestry and gender) and lifestyle choices. Poor lifestyle habits, chronic stress, and environmental factors like pollution can accelerate telomere shortening, potentially increasing the risk of diseases.
Study Findings: Telomere Length and Brain Disease Risk
Researchers followed participants for a median of 12 years to see whether shorter telomeres were linked to the development of stroke, dementia, or late-life depression. Their findings showed that:
- People with the shortest leukocyte telomeres had an
- 8% higher risk of stroke
- 19% higher risk of dementia
- 14% higher risk of late-life depression
- Overall, those with the shortest telomeres had an 11% greater risk of developing at least one of these brain diseases compared to those with longer telomeres.
This suggests that shorter telomeres may act as a biological warning sign of age-related brain diseases. However, the study also found that telomere length does not directly cause these diseases—instead, it serves as an indicator of cellular aging and underlying health issues.
The Role of Lifestyle in Reducing Risk
An important part of the study examined whether healthy lifestyle choices could offset the risks associated with shorter telomeres. Participants were given a Brain Care Score, a measure of factors such as diet, exercise, blood pressure, and social connections. The results showed:
- Among people with poor lifestyle habits (low Brain Care Score), shorter telomeres significantly increased the risk of stroke, dementia, and late-life depression by 11%.
- Among people with healthier habits (high Brain Care Score), shorter telomeres were NOT linked to a higher risk of brain diseases.
This finding highlights the power of lifestyle choices in protecting brain health, even for those with biological risk factors like shorter telomeres. “It is never too late to start taking better care of your brain,” said study lead author Dr. Tamara Kimball, a researcher at Massachusetts General Hospital.
Implications for Health and Future Research
This study reinforces that aging plays a direct role in the risk of major brain diseases. While telomere shortening is a marker of aging, it does not mean someone will definitely develop stroke or dementia.
Instead, lifestyle interventions—such as exercise, a healthy diet, and social engagement—could help slow the impact of aging on the brain.
Dr. Costantino Iadecola, a neurology professor at Weill Cornell Medicine, noted that different parts of the body age at different rates, with the immune system and brain closely connected. He emphasized that longer telomeres in white blood cells may indicate a lower risk of brain diseases, supporting the idea that maintaining overall health can help protect brain function.
Review and Limitations
This study provides strong evidence that telomere length can serve as a biological marker for brain health, but it has some limitations:
- It focused only on people of European ancestry, so the findings may not apply to other ethnic groups.
- Telomere length and lifestyle factors were measured only at the start of the study, meaning changes over time were not accounted for.
- Leukocyte telomere length may not represent telomere length in other parts of the body, such as the brain.
Despite these limitations, the study provides valuable insights into how aging affects brain health and highlights the importance of preventive measures.
Conclusion: A Holistic Approach to Brain Health
Rather than focusing on drugs to alter telomere length, the researchers suggest a holistic approach—centered on healthy lifestyle choices—to reduce the risk of stroke, dementia, and depression.
By maintaining a healthy diet, staying physically active, managing stress, and staying socially engaged, individuals may be able to counteract the effects of aging and protect their brain health for longer.
This study adds to growing evidence that while we cannot change our genetics, we can take steps to improve our long-term brain health.
If you care about depression, please read studies about how dairy foods may influence depression risk, and B vitamins could help prevent depression and anxiety.
For more information about mental health, please see recent studies that ultra-processed foods may make you feel depressed, and extra-virgin olive oil could reduce depression symptoms.
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