Stroke, dementia, and depression are more common in people with short telomeres.

Telomeres, the gene-protecting structures located at the ends of chromosomes considered a biological marker of aging, could determine our risk of stroke, dementia, and depression in old age.

A study published in the scientific journal ' Neurology ' has found that people with short leukocyte telomere length are more likely to suffer from these diseases as they age.

However, the most encouraging finding is that this risk is not seen in those who lead a healthy lifestyle.

This team from Brigham and Women's General Hospital in Massachusetts (USA) analyzed the relationship between telomere length, which decreases with age or exposure to unhealthy environments, and the risk of age-related brain diseases.

He analyzed the telomeres of more than 356,000 people in the United Kingdom, with an average age of 56, and compared them with their lifestyle and brain health over a seven-year follow-up.

People with the shortest telomeres had more cases of brain diseases: 5.82 per 1,000 person-years, compared to 3.92 among those with the longest telomeres. After adjusting the data for age, hypertension, smoking, and other factors, it was concluded that having short telomeres carries an 11% higher risk of developing at least one of these brain diseases.

But the researchers also analyzed the participants' lifestyle habits using a tool called the Brain Care Score (BCS), which assesses factors such as diet, sleep, exercise, blood pressure, cholesterol, and emotional health. They found that people with short telomeres but a healthy lifestyle were not at greater risk for these diseases.

"These results indicate that it's possible to protect our brains from accelerated aging by taking care of our habits, even if biological signs of deterioration already exist," explains Christopher D. Anderson , author of the study and a neurologist at Harvard Medical School.

"Reducing risk factors like weight and alcohol consumption, as well as getting more sleep and exercise, can help reverse the risk of age-related brain diseases, even in people who already show signs of biological aging," adds lead author Tamara Kimball . " In short, it's never too late to start taking better care of your brain ."

Although the study doesn't prove that short telomeres directly cause brain diseases, it does show a clear association between cellular aging and brain risk. It also highlights that maintaining good habits can offset the effects of biological aging.

An important limitation of the study is that it only included people of European descent, so further research is needed to confirm whether the results apply to other populations.