Shorter telomeres may increase risk of age-related brain diseases

Shorter protective caps – telomeres – on the chromosomes of certain white blood cells may influence the likelihood of developing age-related brain diseases.

Researchers from Mass General Brigham, Boston, Massachusetts, analysed data from over 350,000 people in the UK BioBank and presented their findings at the American Stroke Association's international conference in Los Angeles, California. Following the participants for 12 years, they found that people who had shorter leukocyte (a type of white blood cell) telomeres had an increased risk of developing brain diseases such as dementia, late-life depression and stroke.

'In a clinical setting, leukocyte telomere length could help identify people who may need more intensive monitoring or preventive measures,' said Dr Tamara Kimball from Massachusetts General Hospital and co-author of the abstract presented at the conference.

Telomeres are protective caps at the end of chromosomes, which prevent chromosome damage. The length of telomeres is influenced by factors that cannot be changed, such as gender and age, as well as factors that can be changed, such as lifestyle choices and environmental factors. Over time, telomeres gradually shorten and reduce their ability to protect chromosomes, leading to cellular ageing.

The researchers found that people with the shortest leukocyte telomere length had an eight percent higher risk of stroke, a 19 percent higher risk of dementia and a 14 percent higher risk of late-life depression.

Commenting on the research, Costantino Iadecola, professor of neurology at Weill Cornell Medicine, New York, who was not a part of the study, said: 'While the link between ageing and stroke, dementia and late-life depression is well established, the finding that telomere shortening in white blood cells can be a sign of ageing, holds significant clinical implications for assessing risks and predicting health outcomes.'

However, the study showed that shorter telomeres were not associated with an increased risk of developing these age-related conditions in people who made healthier lifestyle choices (assessed via a brain score test), such as diet, exercise, and maintaining a healthy body mass index.

Dr Kimball added: 'Adopting healthier lifestyles and improving modifiable risk factor profile may lower the negative effects of shorter leukocyte telomeres. In short, it is never too late to start taking better care of your brain.'

Previous research has indicated a link between DNA modifications and ageing (see BioNews 1074, 1157 and 1212). However, the researchers emphasise the need for further investigation into leukocyte telomere length over time as their findings are yet to be published in a peer-reviewed scientific journal and the results are preliminary.

They further emphasised that they did not find that telomere length is a definitive cause of these age-related brain diseases, yet, healthier lifestyle choices may mitigate the harmful effects associated with shorter telomeres.