Even without catching COVID, the pandemic may have quietly aged your brain

What does it mean to grow older, not just in years, but in terms of brain health? Can stress, isolation, and global disruption leave their mark on people’s minds?

The findings of this new study, which are published in Nature Communications, showed that people who lived through the Covid-19 pandemic showed signs of faster brain aging over time than those scanned entirely before it. The changes were most noticeable in older individuals, in men, and in people from more disadvantaged backgrounds.

Only participants who were infected by Covid-19 between their scans showed a drop in certain cognitive abilities, such as mental flexibility and processing speed. This may suggest that the pandemic’s brain aging effect, on its own (without infection) may not cause symptoms. Also, the authors highlight that the observed brain aging may be reversible.

The study was led by a team of experts from the University’s School of Medicine and was supported by the National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Centre and the Medical Research Council (MRC) DEMISTIFI program.

Dr Ali-Reza Mohammadi-Nejad led the study, he said: “What surprised me most was that even people who hadn’t had Covid showed significant increases in brain aging rates. It really shows how much the experience of the pandemic itself, everything from isolation to uncertainty, may have affected our brain health.”

The research team looked at longitudinal brain scans from nearly 1,000 healthy adults, taken as part of the UK Biobank study. Some participants had scans before and after the pandemic; others, only before. Using advanced imaging and machine learning, the researchers estimated each person’s “brain age” — how old their brain appeared to be compared to their actual age.

The brain age model was developed using brain scans from over 15,000 healthy individuals, without comorbidities, allowing the researchers to build an accurate model for estimating brain age.

“This study reminds us that brain health is shaped not only by illness, but by our everyday environment,” said Dorothee Auer, Professor of Neuroimaging and senior author on the study. “The pandemic put a strain on people’s lives, especially those already facing disadvantage. We can’t yet test whether the changes we saw will reverse, but it’s certainly possible, and that’s an encouraging thought.”

Stamatios Sotiropoulos, Professor of Computational Neuroimaging, and co-lead author added: “The longitudinal MRI data acquired before and after the pandemic from the UK Biobank gave us a rare window to observe how major life events can affect the brain.”