London, May 26 (IANS): A faulty gene that raises people's risk of dementia may also make them twice as likely to suffer from severe coronavirus infection (Covid-19), warn researchers.

Published in the Journal of Gerontology, Medical Sciences, the study analysed data from the UK Biobank and found a high risk of severe Covid-19 infection among European ancestry participants who carry two faulty copies of the APOE gene (termed ae4e4').

The same faulty gene is already known to increase the risk of developing Alzheimer's disease in old age by up to 14-fold.

Now, the research team has found that carrying these gene mutations doubles the risks of Covid-19 - even in people who had not developed these diseases.

"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," said lead author David Melzer from the University of Exeter in the UK

"The effect could be partly due to this underlying genetic change, which puts them at risk for both Covid-19 and dementia," Melzer stressed.

The team 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 exposed to the high prevalence of the virus in care homes.

However, the new study indicates that a genetic component may also be at play.

The team found that people with the APOE e4e4 genotype were at double the risk of developing severe Covid-19, compared to those with the common e3e3 form of the APOE gene.

The team used data from the UK Biobank study, which collects health and genetic data on 500,000 people.

The majority of people in the population and in the sample size have not yet been exposed to the virus.

In this analysis, 2.36 per cent of participants with European ancestries had the ApoE e4e4 faulty gene, but 5.1 per cent of those who tested positive for Covid-19 had this gene variant, suggesting the risk is doubled.

"This is an exciting result because we might now be able to pinpoint how this faulty gene causes vulnerability to Covid-19. This could lead to new ideas for treatments," said study co-author Dr Chia-Ling Kuo from the University of Connecticut in the US.