People with a genetic mutation associated with an increased risk of dementia may also be twice as likely to develop severe COVID-19 symptoms, according to a large-scale study.
Researchers at the University of Exeter and the University of Connecticut analysed data from the UK Biobank, which collects health and genetic data on 500,000 people.
They found high risk of severe COVID-19 infection among European ancestry participants who carry two faulty copies of the APOE gene, termed e4e4.
One in 36 people of European ancestry have two faulty copies of this gene, and this is known to increase risks of Alzheimer’s disease up to 14-fold and also increases risks of heart disease.
Now, the research team has found that carrying these gene mutations “doubles the risk” of developing a severe form of COVID-19 – even in people who had not developed these diseases.
Professor David Melzer, who led the team, 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.”
The findings follow the news from the Office of National Statistics that dementia is main underlying condition for COVID-19 deaths.
It said that of the 33,841 COVID-19-related deaths that occurred in March and April in England and Wales, the most common pre-existing condition for people dying from the virus was dementia and Alzheimer’s disease, with 6,887 deaths (20.4% of the total).
The research team has previously found that people with dementia are three times more likely to get severe COVID-19, yet they are not one of the groups advertised to shield – or shelter in place – on health grounds.
Part of the increased risk effect may have been exposure to the high prevalence of the virus in care homes, but the new study, published in the Journal of Gerontology: Medical Sciences, indicates that a genetic component may also be at play.
However, Dr Routledge, director of Research at Alzheimer’s Research UK, urged caution when interpreting the findings.
She 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.
“This study analysed data from participants with European ancestry so the findings may not be relevant to other groups and it is important for other studies to look into COVID-19 risk for people with a different genetic background.
“The COVID-19 outbreak is having a particularly strong impact on many people with dementia and their families. It is essential that people with dementia have the support they need to minimise their risk of being exposed to the virus.”