A warning has been issued by scientists as new research suggests that even a mild case of Covid-19 could increase the risk of developing Alzheimer’s disease. The study, published in Nature Medicine, found that the virus could alter brain proteins associated with the condition, sparking public health concerns.
The research involved analysing blood samples from 1,252 UK participants, half of whom had tested positive for Covid. The study found significant changes in brain biomarkers linked to Alzheimer’s disease in those who had contracted the virus.
According to Medical News, scientists measured levels of beta-amyloid (Aβ40, Aβ42), pTau-181, NfL, and glial fibrillary acidic protein (GFAP), which are all markers of Alzheimer’s disease. They also assessed the brain health of participants using neuroimaging data and testing cognitive function.
It was found that those who had Covid-19 displayed significant changes in brain biomarkers associated with Alzheimer’s disease. Covid positive participants had a reduced ratio of Aβ42:Aβ40, which is often linked to Alzheimer’s pathology.
The team found increased levels of pTau-181, a protein associated with tau tangles in the brain, and elevated NfL levels, which indicated neuronal damage in Covid patients. And GFAP, a marker of astrocyte activation and neuroinflammation, was also higher in those who had Covid.
These changes are said to be on par with four years of natural aging or 60 percent of the impact of carrying one APOE-ε4 allele, a genetic marker associated with a higher risk of Alzheimer’s disease. This adds to previous evidence that viral infections could heighten dementia risks.
The study’s authors stated: “SARS-CoV-2 infection was associated with biomarkers associated with β-amyloid pathology: reduced plasma Aβ42:Aβ40 ratio and, in more vulnerable participants, lower plasma Aβ42 and higher plasma pTau-181. The plasma biomarker changes were greater in participants who had been hospitalized with Covid-19 or had reported hypertension previously.
“We showed that the changes in biomarkers were linked to brain structural imaging patterns associated with Alzheimer’s disease, lower cognitive test scores and poorer overall health evaluations. Our data from this post hoc case–control matched study thus provide observational biomarker evidence that SARS-CoV-2 infection can be associated with greater brain β-amyloid pathology in older adults.”
They further commented: “While these results do not establish causality, they suggest that SARS-CoV-2 (and possibly other systemic inflammatory diseases) may increase the risk of future Alzheimer’s disease.”