People with a faulty gene linked to an increased dementia risk could be twice as likely to get severe Covid-19, according to an Exeter-led study.
Researchers found those of European ancestry who carry the faulty gene, called ApoE4, have a higher chance of developing acute coronavirus symptoms - even when they are not affected by dementia.
Their findings suggest some people may be genetically predisposed to suffer from worse cases of the virus.
David Melzer, Professor of Epidemiology and Public Health at Exeter University, led the research.
He said: “Several studies have now shown that people with dementia are at high risk of developing severe Covid-19.
“This study suggests that this high risk may not simply be due to the effects of dementia, advancing age or frailty, or exposure to the virus in care homes.
The effect could be partly due to this underlying genetic change, which puts them at risk for both Covid-19 and dementia.
Scientists analysed data from the UK Biobank, which collects health and genetic data on 50,000 people.
Their findings, published in the Journal of Gerontology: Medical Sciences, revealed those who carry two faulty copies of the ApoE4 gene are twice as likely to be severely affected by coronavirus than those who don’t.
The number of people of European ancestry thought to have two faulty copies of the ApoE4 gene.
This has been described as an “exciting result” by those who conducted the research.
The study’s co-author, Dr Chia-Ling Kuo from the University of Connecticut School of Medicine, said it will allow scientists to “pinpoint how this faulty gene causes vulnerability to Covid-19” which “could lead to new ideas for treatments.”
Dr Carol Routledge, director of research at Alzheimer’s Research UK, has urged caution when reading the findings.
Dr Routledge said: “We don't yet know how this Alzheimer's risk gene might make people more susceptible to the virus.
"Despite the large study group, only 37 people with the risk gene tested positive for Covid-19, and we must be careful about the conclusions we draw from such small numbers.
“These findings will need to be followed up with further research to see if this link could present avenues for new treatments."
Professor Tara Spires-Jones, deputy director at the Centre for Discovery Brain Sciences at the University of Edinburgh, also stressed the limitations of the study.
An important limitation of the current paper is that this type of observational study cannot prove that the ApoE4 gene is the cause of the observed increased risk of Covid-19. The scientists did a thorough job of trying to control for other things associated with ApoE4 that could account for the risk, but it is still possible that there is an unknown related factor causing the increased risk. >