Summary: New research suggests the Covid-19 pandemic may have accelerated brain ageing in the general population, including people who were never infected. Longitudinal brain scans from nearly 1,000 adults indicate that older adults, men, and people from socioeconomically disadvantaged backgrounds experienced the largest changes.
Although measurable declines in cognitive processing speed and mental flexibility were seen only among participants who contracted Covid-19 between scans, the study highlights how a major societal stressor such as a pandemic can leave detectable effects on brain structure and estimated brain age. Importantly, the authors note that these brain-age changes could be reversible.
Key findings:
- Accelerated brain ageing: The pandemic period was associated with faster increases in estimated brain age, even in people without documented SARS-CoV-2 infection.
- Groups most affected: The pattern of accelerated brain ageing was strongest in older participants, men, and individuals from more deprived socio-demographic backgrounds.
- Cognitive effects: Reduced cognitive performance correlated with accelerated brain ageing only in those who had been infected with Covid-19 between scans.
- Possible recovery: The researchers highlight that the observed changes in brain ageing may not be permanent and could diminish over time.
Source: University of Nottingham
Overview
A research team led by the University of Nottingham used longitudinal MRI data to examine whether the Covid-19 pandemic affected brain ageing beyond the effects of infection. Using advanced neuroimaging and machine-learning models trained on a large healthy cohort, the investigators estimated each participant’s “brain age” — a prediction of how old the brain appears structurally relative to chronological age. Comparing scans taken before and after the pandemic onset revealed a measurable impact on brain-age trajectories.
The study, published in Nature Communications, analysed two MRI scans for an independent set of 996 healthy participants drawn from the UK Biobank. Participants were grouped either as controls, with both scans obtained before the pandemic, or as the pandemic group, with one scan before and one after the pandemic began. Crucially, the brain-age prediction models were developed from a separate cohort of 15,334 healthy individuals, giving a robust baseline for estimating deviations between predicted brain age and chronological age.
After matching participants for baseline brain-age gaps and a range of health markers, the authors found that the pandemic group exhibited a greater increase in brain-age gap at the second time point compared with controls. On average, the pandemic group showed a 5.5-month larger deviation in brain-age gap at follow-up. This pattern persisted regardless of whether an individual had documented SARS-CoV-2 infection, indicating an effect linked to the broader experience of the pandemic itself.
The effect was not uniform across the sample: males and people from more deprived socio-demographic backgrounds showed more pronounced increases in brain-age gap. Cognitive testing revealed that only participants who had a Covid-19 infection between scans showed measurable declines in processing speed and cognitive flexibility that correlated with accelerated brain ageing.
Lead author Dr Ali-Reza Mohammadi-Nejad commented that the most striking result was the increase in brain-age rates among people who had never had Covid-19, suggesting the social, psychological, and environmental stresses of the pandemic — including isolation, uncertainty, and disruption to daily life — may have taken a toll on brain health.
Senior author Professor Dorothee Auer emphasized the broader implication: brain health is shaped not only by disease, but by everyday environmental and social conditions. The research team notes it is still unknown whether the observed brain-age changes will fully reverse, but the possibility of recovery is encouraging and highlights the need for continued monitoring and support for vulnerable groups.
About this research
Author: Emma Thorne
Source: University of Nottingham
Contact: Emma Thorne – University of Nottingham
Image credit: Neuroscience News
Original research: Accelerated brain ageing during the COVID-19 pandemic — Ali-Reza Mohammadi-Nejad et al., Nature Communications (open access)
Abstract (summary)
This study used longitudinal neuroimaging from the UK Biobank to investigate how the Covid-19 pandemic affected estimated brain age. Machine-learning models trained on hundreds of multi-modal imaging features from 15,334 healthy participants were applied to 996 independent participants with two MRI scans. Comparing those scanned before and after the pandemic onset with controls scanned only before the pandemic, researchers found accelerated brain ageing associated with the pandemic period, with an average 5.5-month larger brain-age gap at follow-up in the pandemic group. The effect was stronger in males and people from deprived backgrounds, and cognitive decline correlated with brain-age acceleration only in participants who experienced Covid-19 infection. The findings underscore the pandemic’s broader impact on brain health and the importance of addressing social and health inequalities when considering long-term neurological outcomes.