Article from 2022

Telomere shortening, one of the “measures” of biological ageDifferent from chronological age. It is a measure of the body's ageing, based on the effectiveness of the mechanisms that keep cells young and on markers of the functionality of organs and apparatus., appears to be strongly correlated with the risk of COVID-19 mortality. In particular in women, and especially after age 65

What this article is about

• TelomeresEnd parts of the chromosomes. They have the function of making DNA more stable and their length is inversely correlated with ageing. are the end portions of chromosomes, which shorten with each cell replication
• Telomere shortening is linked to various diseases of aging
• A new Spanish study confirms the association between telomere length and COVID-19 mortality, particularly significant for women over 65

Related articles

• COVID, telomeres and DNA damage
• Why do we age? 9 biological causes discovered
• Sirtuins, the 7 genes that make us live longer and better

Telomeres, the “end caps” of chromosomes that shorten with advancing age, could provide valuable information on the risk of developing severe COVID-19 infection. This is the claim of a study conducted by the Carlos III Health Institute in Madrid, which identified a significant association between the length of telomeres and COVID-19 mortality. The effect mainly concerns women aged 65 and over. The research has just been presented at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) in Lisbon, and the authors have published the study abstract (Relative telomere length impact on mortality and survival of COVID-19).

Telomere length as an index of health

Telomeres are small portions of DNA located at the ends of chromosomes. They are a bit like indicators of the cell’s age (although they are not as precise as biological clocks): every time a cell divides, in fact, they shorten, until the point at which, when they are too worn, the cell no longer divides and, damaged, enters a phase called senescence. We have long known (Nature Cell Biology) that the reduction in the length of these components is associated with numerous diseases typical of aging, from cancers to osteoarthritis, up to a higher risk of certain infections.

Studying COVID-19

Today the focus is on COVID: the researchers related the size of the telomeres to the severity of SARS-CoV-2 infection in 608 patients hospitalized during the first wave of the pandemic, in 2020, and therefore not yet vaccinated. Telomere length was measured with blood tests carried out within 20 days of hospital admission. The authors then considered the weight of risk factors and individual characteristics, such as sex, age, smoking and the presence of other diseases. In the study, 75 hospitalized participants, with an average age of 78, died of COVID-19.

Telomeres are the end portions of chromosomes. Every time a cell divides they shorten, until the point at which, when they are too worn, the cell no longer divides and, damaged, enters a phase called senescence.

Shorter telomeres, higher risk

The statistical results, spread over the entire sample, indicate that as telomere length decreases, COVID mortality increases significantly. Analyzing the phenomenon in a stratified way, that is, considering only certain categories of participants, it becomes clear that the effect detected concerns almost exclusively women and, among them, above all those over 65 – the majority, given that the average age of the overall sample is about 68.

In female patients with longer telomeres – and therefore with less cellular aging than the others – the risk of dying within a month was 70% lower, and 76% lower for dying within 3 months. Considering only participants over 65, the risk is about 80% lower. In men, by contrast, no significant association between telomeres and COVID severity was found.

In older women, telomere length is a parameter that could be predictive of the likelihood of very severe COVID infections, as explained by Ana Virseda-Berdices, one of the study coordinators. In men, the lack of statistical significance of the effect could also be masked by other factors, according to the author. For example, it could be due to the presence of pre-existing diseases that worsen the situation in themselves, regardless of the level of cellular aging.

It is not the first time

The processes underlying this phenomenon are not yet known, but today’s work is not the only one to have highlighted it. There are already some studies, including an Italian study by IFOM in Milan and IGM-CNR in Pavia, that show an association between damage to telomeres and susceptibility to serious infections with SARS-CoV-2. In the research by IFOM and CNR, the proposed mechanism concerns the aging of certain lung cells – type II alveolar epithelial cells – which would thus become “easier targets” and allow greater entry of the virus.