Media release

From: Springer Nature

Neuroscience: COVID pandemic linked to faster brain ageing in UK adults

Rates of brain ageing accelerated during the COVID-19 pandemic, even among those who did not get infected with SARS-CoV-2, suggests a study of nearly 1,000 UK adults published in Nature Communications. The study, which used UK Biobank data, found that accelerated brain ageing was more pronounced in males and those from deprived socio-demographic backgrounds regardless of whether they had been infected with SARS-CoV-2.

Previous research has shown links between COVID-19 and molecular signatures of brain ageing and cognitive decline. However, it has yet to be established how both the pandemic itself (separate from infection status), and SARS-CoV-2 infection, affected brain ageing amongst the general population.

To map brain ageing, Ali-Reza Mohammadi-Nejad, Stamatios Sotiropoulos, Dorothee Auer and colleagues used machine learning models, trained on UK Biobank brain scans of 15,334 healthy participants, to measure the difference between an individual’s predicted brain age and their real age, known as the brain age gap. This model was then used to analyse two magnetic resonance image scans of the brains of 996 healthy participants in the UK, taken at least 2 years apart. In the control group (564 individuals), both scans took place before the pandemic and in the ‘Pandemic’ group (432 individuals), one scan came from before and the other after the onset of the pandemic.

The authors found that by the second scan, approximately three years later, the brains of participants from the ‘Pandemic’ group had aged on average 5.5 months faster than the control group. Accelerated brain ageing over the period of the pandemic was observed regardless of whether the participants had been infected; however, SARS-CoV-2 infection was linked to an increased rate of acceleration as participant age increased. This brain ageing effect was also observed to be more pronounced in males and for individuals experiencing socioeconomic disadvantage such as lack of employment, low levels of income, poor health, and lower levels of education. Additionally, the authors assessed the cognitive performance of participants using ten cognitive tests taken at the time of both scans. They found that accelerated brain ageing was associated with a decline in cognitive performance — particularly in tests such as mental flexibility and processing speed — solely amongst those infected with SARS-CoV-2, as opposed to the wider Pandemic group.

The authors note several limitations with the study, such as an inability to determine how long these effects may last and a lack of global data. They also highlight that the observed brain ageing may be reversible, although this cannot currently be tested in this cohort. However, these data emphasise the effect of both indirect and direct exposure to SARS-CoV-2 and the pandemic, highlighting the need for targeted research to improve brain health outcomes in future public health crises.