Covid accelerated aging

MADRID (EFE)— What does aging mean in relation to brain health? Can stress, isolation, and global disruption leave their mark? A new study suggests that people's brains aged more rapidly due to the COVID-19 pandemic, even among those who were not infected with SARS-CoV-2.

This is the main conclusion of a study conducted with nearly 1,000 people and led by scientists at the University of Nottingham (United Kingdom), which also revealed that brain aging was more pronounced in men and people from disadvantaged sociodemographic backgrounds.

Previous research had already demonstrated links between COVID-19 and molecular characteristics of brain aging and cognitive decline. However, it had not been established whether the pandemic period (regardless of infection status) affected brain aging.

To map this aging, the scientists used machine learning models trained on brain scans from the UK Biobank of 15,334 healthy participants to measure the difference between an individual's predicted brain age and their actual age, known as the brain age gap.

This model was subsequently used to analyze two brain MRIs of 996 healthy individuals, taken at least two years apart. In the control group (564 individuals), both scans were performed before the pandemic, and in the "pandemic" group (432 individuals), one scan was performed before and one after the start of the emergency.

In the second scan, the authors found that the brains of the "pandemic" group had aged an average of 5.5 months faster than those of the control group.

Accelerated brain aging was observed during the pandemic, regardless of whether participants had been infected or not.

However, SARS-CoV-2 infection was associated with a higher rate of acceleration with increasing age.

In their article, the authors note that previous studies confirm that social isolation and perceived loneliness contribute to structural and functional changes in the brain that are expected to drive accelerated brain aging.

What surprised Ali-Reza Mohammadi-Nejad, the study's lead author, was that even people who hadn't had Covid showed a "significant increase" in brain aging rates.

"This really demonstrates how much the experience of the pandemic itself, from isolation to uncertainty, can have affected brain health," the University of Nottingham summarizes in a statement.

Furthermore, the team assessed the participants' cognitive performance using ten tests. They found that accelerated brain aging was associated with decreased cognitive performance, particularly in tests such as mental flexibility and processing speed, only among those infected with SARS-CoV-2.

The authors point out several limitations of the study, such as the inability to determine the duration of these effects and the lack of overall data.

They also highlight that the observed brain aging could be reversible, although this cannot currently be assessed in this cohort.

However, these data emphasize the effect of both indirect and direct exposure to SARS-CoV-2 and the pandemic, underscoring the need for targeted research to improve brain health outcomes in future crises.

Masud Husain, professor of neurology and cognitive neuroscience at the University of Oxford, says that although this analysis has been carried out with great care, caution is needed when interpreting it.

In this regard, it indicates that the difference in brain age between the two groups was, on average, only five months, and the difference in cognitive performance was limited to the total time required to complete one of these tests.

And he questions whether this really makes a significant difference in everyday life, in a statement to the British Science Media Centre, a scientific resource platform for journalists.

At a glance

Acceleration

Researchers at the University of Nottingham note that previous studies have confirmed that social isolation and perceived loneliness contribute to changes in the brain that accelerate aging.

Limitations

They also warn of the limitations of their study, such as the lack of global data.