SARS-CoV-2 is associated with changes in brain structure in UK Biobank.
Level 3 - non-randomized controlled study
Longitudinal non-randomized controlled cohort study with pre- and post-infection MRI scans.
PubMed 35255491 · doi:10.1038/s41586-022-04569-5
What was done
Researchers investigated longitudinal magnetic resonance imaging (MRI) changes in 785 UK Biobank participants aged 51 to 81 years scanned twice. Between scans, 401 participants tested positive for SARS-CoV-2 (mean of 141 days between diagnosis and second scan) and 384 served as controls. The availability of pre-infection imaging allowed comparison of longitudinal changes while controlling for pre-existing baseline status.
What was found
Compared to controls, SARS-CoV-2 cases showed a significantly greater reduction in grey matter thickness and tissue contrast in the orbitofrontal cortex and parahippocampal gyrus, greater changes in markers of tissue damage in regions functionally connected to the primary olfactory cortex, a greater reduction in global brain size, and greater cognitive decline between scans. These effects persisted after excluding 15 hospitalized patients. The abstract reported no numerical effect sizes, percentages, or p-values.
Why it matters
Using pre-infection baseline imaging, this study demonstrates that even mild SARS-CoV-2 infection is associated with measurable structural brain changes in limbic and olfactory regions and cognitive decline.
Limits
The cohort was restricted to older adults (aged 51–81 years) and may not generalize to younger individuals. The abstract does not provide exact effect sizes or numerical statistics. The mean follow-up of 141 days leaves it unknown whether these structural and cognitive changes persist long-term or are reversible.
Cited by
- supports A UK Biobank longitudinal MRI preprint study of nearly 800 subjects found significant gray matter atrophy in the olfactory cortex and memory/learning brain regions following SARS-CoV-2 infection, including in non-hospitalized mild cases.