These days, we know that it's not the number on our birthday cake that counts, but rather our biological age. Our brain health is an important part of that.
Researchers suggest that isolation and ongoing uncertainty during the various lockdowns during the pandemic may have sped up brain ageing across the country.
Based on the brain scans of UK Biobank participants, the research reveals an average of "5.5-month deviation of brain age gap" after the pandemic. This essentially means that brain age rose by almost six months, which may lead to faster cognitive decline with age.
This deviation applied to all participants, even those who did not catch the virus during the pandemic.
These findings, published in Nature, came from brain ageing models trained using data from over 15,000 healthy people. The models were then applied to almost 1,000 participants of the UK Biobank study, a long-term project that monitors the health of middle-aged and older adults.
Half underwent brain scans before the pandemic, and the rest afterwards. From this, the researchers found that the pandemic had "significantly" accelerated brain ageing.
Those infected with Covid-19 performed more poorly on cognitive tests when reassessed after the pandemic, with scans showing a drop in certain cognitive abilities, including mental flexibility and processing speed.
Brain ageing was also particularly accelerated in men, older people, and those from deprived backgrounds.
Dr Ali-Reza Mohammadi-Nejad, lead author on the study, was surprised by the results. He said: "It really shows how much the experience of the pandemic itself, everything from isolation to uncertainty, may have affected our brain health."
While this study was published only this week, it's supported by several others that highlight the impact of social isolation on communities.
"Research shows that chronic social disconnection and sustained stress can impair memory, emotional regulation, and executive functioning," says Joanna Konstantopoulou, a health psychologist, pointing to studies led by researchers at Brigham Young University and the University of Chicago.
"Women may have fared better thanks to behavioural and physiological differences. For example, psychologically, we are more likely to maintain social contact and talk about our experiences. Biologically, the hormone oestrogen helps regulate the HPA axis, the system in the brain and body that controls how we respond to stress," she says.
"When this system is overwhelmed for too long, we often see fatigue, poor concentration, and emotional strain, but oestrogen appears to buffer some of that," she says, highlighting studies in Nature Reviews Immunology.
"These findings underline that brain health isn’t only shaped by illness, it’s shaped by how we live, connect, and cope under pressure.”
So, what comes next? Will it be possible to reverse these developments and lower our biological age? "We can't test whether the changes we saw will reverse, but it's certainly possible, and that's an encouraging thought," said Dorothee Auer, a professor of neuroimaging and a senior author of the study.
