Stroke and dementia as well as late-life depression are more common in people who have a biomarker of aging called short leukocyte telomere length, according to a study published on June 11, 2025, online in Neurology®, the medical journal of the American Academy of Neurology. The good news is that this relationship was not found in people with healthy lifestyle habits, such as eating healthy and maintaining low cholesterol and blood pressure.
The study does not prove that shorter telomeres cause these brain diseases; it only shows an association.
Our findings support the potential benefits of working to improve your risk factors such as maintaining a healthy weight, limiting alcohol and getting enough sleep and exercise in reducing the risk of age-related brain disease even in people who are already showing signs of damaging biological aging.”
Christopher D. Anderson, MD, MMSc, study author of Harvard Medical School in Boston, Massachusetts, and Fellow of the American Academy of Neurology
Telomeres are protective caps at the end of chromosomes. They shorten each time cells divide, making them key biomarkers of biological aging, reflecting the cumulative biological stresses a person has experienced. This study looked at the length of telomeres in white blood cells, called leukocytes.
For the study, researchers analyzed records of 356,173 people in the United Kingdom with an average age of 56 who had information on the length of their leukocyte telomeres and about their risk factors such as diet and smoking. The participants were divided into three groups based on how long their telomeres were: short, medium or long.
The researchers also looked at a modified Brain Care Score that evaluates risk factors associated with stroke, dementia and late-life depression. On a 19-point scale, people with scores of 15 points or higher were considered to have good brain care and people with scores of 10 or lower were considered to have poor brain care.
Then researchers looked to see whether participants developed any of three age-related brain diseases: stroke, dementia and late-life depression during an average of seven years of follow-up. During that time, 25,964 people developed at least one age-related brain disease.
Those with the shortest telomeres had 5.82 cases of the brain diseases per 1,000 person-years, compared to 3.92 cases per 1,000 for those with the longest telomeres. Person-years represent both the number of people in the study and the amount of time each person spends in the study.
When researchers adjusted for other factors that could affect the risk of brain diseases, such as age, high blood pressure and smoking, they found that people with short telomeres were 11% more likely to develop at least one of the three brain diseases than people with long telomeres.
But when researchers looked at the Brain Care Scores, they found that people with short telomeres who had high Brain Care Scores did not have a higher risk of developing the brain diseases.
“These results suggest that healthy lifestyle behaviors could delay the aging of our cells and reduce the frequency of these diseases, especially in people who are greater risk,” Anderson said.
A limitation of the study was that only people of European ancestry were included, so the results may not apply to other groups.
The study was supported by the American Heart Association-Bugher Foundation Centers of Excellence in Hemorrhagic Stroke Research, the National Institutes of Health and the Massachusetts General Hospital McCance Center for Brain Health.
Source:
Journal reference:
Kimball, T. N., et al. (2025). Association of Leucocyte Telomere Length With Stroke, Dementia, and Late-Life Depression. Neurology. doi.org/10.1212/wnl.0000000000213794.