Shorter Telomeres Linked to Higher Risk of Dementia and Stroke

Biological Aging Doesn’t Doom Brain Health, Study Finds

A connection between the length of protective caps on our chromosomes and the development of debilitating brain conditions has emerged, but lifestyle choices may offer a powerful buffer against these risks, new research suggests.

Telomere Length and Brain Disease

Researchers have discovered an association between shorter telomeres – the protective coverings on the ends of chromosomes – and an increased likelihood of dementia and stroke. The study, published Wednesday in the journal Neurology, analyzed genetic data from over 356,000 participants in the UK Biobank.

Telomeres act like the plastic tips on shoelaces, preventing chromosomes from unraveling. They naturally shorten each time cells divide, providing a measure of biological age, which can differ significantly from chronological age.

Participants were categorized based on telomere length in their white blood cells. Over an average of seven years, nearly 26,000 individuals developed dementia, stroke, or depression. Those with the shortest telomeres experienced 5.8 cases of these conditions per 1,000 person-years, compared to 3.9 cases per 1,000 for those with the longest telomeres.

The analysis revealed that individuals with shorter telomeres were 11% more likely to develop one of these brain diseases, even after accounting for other known risk factors. Specifically, they faced an 8% increased risk of stroke, a 19% increased risk of dementia, and a 14% increased risk of late-life dementia.

Lifestyle as a Protective Factor

Importantly, the increased risk associated with short telomeres disappeared in individuals who adopted healthier lifestyle habits.

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.

—Dr. Christopher Anderson, Associate Professor of Neurology at Harvard Medical School

According to the Alzheimer’s Association, more than 6.7 million Americans are living with Alzheimer’s disease in 2024, a number projected to rise to nearly 13 million by 2050. (Alzheimer’s Association, 2024)

Anderson emphasized that these results suggest healthy behaviors could slow cellular aging and reduce the incidence of these diseases, particularly in those at higher risk.

Study Limitations and Future Research

Researchers caution that the study demonstrates an association, not a direct cause-and-effect relationship, between telomere length and brain health. Further investigation is needed to fully understand the underlying mechanisms.

While biological age is a significant factor, maintaining a healthy lifestyle remains a crucial step in protecting brain health throughout life.