Several genetically determined traits are associated with Covid-19 susceptibility and severity, finds a study by UK researchers.
Epidemiological studies have previously suggested that individuals with co-morbid conditions including diabetes, chronic lung, inflammatory and vascular disease, are at higher risk of adverse Covid-19 outcomes.
The new study by researchers at the Queen Mary University of London found that genetically predicted Covid-19 is significantly associated with an 11 per cent increased risk of phlebitis and thrombophlebitis.
Phlebitis means inflammation of a vein, while thrombophlebitis is an inflammatory process that causes a blood clot to form and block one or more veins, usually in the legs.
A 10 per cent increased risk of blood clots in the leg and a 12 per cent increased risk of blood clots in the lung was also found.
"The results from our study add valuable information for the identification and stratification of individuals at increased Covid-19 risk and other complications after infection. Our findings could have further significance for individuals with long-Covid complications," said Dr Eirini Marouli, Lecturer in Computational Biology at QMUL.
"In addition to that, we found that general Covid-19 susceptibility was associated with an increased risk of blood clots in leg and lung; factors involved in Covid-19 mortality," Marouli added.
For the study, a Phenome-wide (PheWAS) analysis was conducted in up to 400,000 European ancestry individuals.
The team also found associations with traits including increased counts of lymphocytes -- a type of white blood cell known to play a crucial role in viral infections, blood clots, thrombocytopenia -- lower platelet count, common in severe cases of Covid infection, poor lung function -- a significant reason for mortality and hospitalisation, and obesity -- high visceral fat adiposity.
The findings will help identify patients at high risk of SARS-CoV-2 infection, as well as stratify the relative risk of Covid-19 patients. Further work is also required to better understand the biological and clinical value of these findings, including long-term complications after infection, the researchers said.