Pandemic accelerated brain ageing in uninfected people, study finds
People’s brains aged more rapidly during the pandemic, even among those who were not infected with COVID-19, new research has found.
The study found that structural changes in brain scans pointed to accelerated ageing, with an average brain age gap of 5.5 months among people exposed to the pandemic compared with controls.
The brain age gap refers to the difference between a person’s predicted brain age—based on imaging—and their actual chronological age.
UK researchers used longitudinal neuroimaging data from 15,334 healthy adults in the UK Biobank, with an average age of 63.
Fewer than 4 per cent of participants were hospitalised, and all had tested negative within three weeks of infection.
The findings were then applied to 996 healthy participants (average age 58.8), each of whom had two MRI brain scans—either both taken before the pandemic or one before and one after the emergence of SARS-CoV-2.
Accelerated brain ageing was most pronounced in older adults, men and those from socioeconomically deprived backgrounds—particularly individuals with lower education and employment levels or poorer overall health—regardless of COVID-19 infection status.
A more pronounced brain age gap in infected participants suggested a complex pattern of decline, with infection-related factors compounding ageing in older people.
The researchers wrote: “This supports the concept of brain resilience loss leading to faster cognitive decline, consistent with existing neurodegeneration and dementia research and recent epigenetic models.”
Accelerated brain ageing was associated with reduced cognitive performance—mental functions such as memory, attention and problem-solving—only in participants who had tested positive for COVID-19.
The team said the study “highlights the pandemic’s significant impact on brain health, beyond direct infection effects, emphasising the need to consider broader social and health inequalities.”
Other factors during the pandemic, such as lower physical activity, poorer diet and increased alcohol consumption, may also have contributed.
Among participants who completed cognitive tests before and after the pandemic began, only those who contracted COVID-19 between the two scans showed signs of cognitive decline, including reduced flexibility and slower processing speed.
In others, the level of brain ageing may not have been sufficient to impair cognition.
“Some changes do not trigger symptoms, and some others take many years for any symptom to be manifested,” said lead author Ali-Reza Mohammadi-Nejad of the University of Nottingham.
Meanwhile, Mahdi Moqri of Harvard Medical School said the study “really underlines how significant the pandemic environment was for mental and neurological health.”
He added that it is not yet known whether these brain ageing effects are reversible, since the analysis was based on only two scan points.
