Severe COVID-19 shares genetic links with several medical conditions -- including COPD and diabetes -- that also increase people's risk for serious illness from the virus, a study published Thursday found.
Genetic variants associated with severe COVID-19, which cause some people to experience worse symptoms than others, are also linked with known risk factors for serious illness from the disease, the data, published Thursday by the journal PLOS Genetics, showed.
These genetic variants, or permanent changes in the DNA make-up of the genes sometimes called mutations, are also found in people with blood clot issues, Type 2 diabetes, and heart disease, the researchers said.
There were also genetic links between severe COVID-19 and neutropenia -- or an abnormally low concentration of neutrophils, which make up white blood cells -- for people of African and Hispanic ancestry but not those of European ancestry, they said.
"The nature of the associations brought to light how the virus pushes on a pressure point in the human immune system," study co-author Dr. Katherine Liao said in a press release.
As a result, the immune system has a "constant balancing act of fighting infection while maintaining enough control so that it does not also become an autoimmune process, attacking self," said Liao, an associate professor of medicine at Brigham and Women's Hospital in Boston.
As with other viral diseases, some people with COVID-19 experience it more severely than others, according to the Centers for Disease Control and Prevention.
Previous research has identified certain variants in specific human genes -- including some linked with dementia -- that are also associated with a person experiencing more severe COVID-19.
Identifying these shared variants could improve understanding of COVID-19 and illuminate potential new paths for treatment, according to Liao and her colleagues.
The findings of this study are based on an analysis of genetic information linked with electronic health record data for more than 658,000 military veterans in the United States.
Researchers used a technique called phenome-wide association study, which allowed them to examine links between genetic variants often found in veterans who experienced severe COVID-19 and those associated with a broad selection of medical conditions.
Genetic variants associated with COVID-19 that are also associated with known risk factors for the disease include those linked with venous embolism and thrombosis, or blood clots, as well as Type 2 diabetes and ischemic heart disease, the data showed.
All are known to raise the risk for severe COVID-19, and blood clots are a common complication in those who develop severe illness from the virus.
In addition, the respiratory conditions idiopathic pulmonary fibrosis and chronic alveolar lung disease, both of which cause life-threatening breathing problems, share genetic links with severe COVID-19, the researchers said.
However, other respiratory infections, including the flu, and chronic obstructive pulmonary disease, or COPD, do not share genetic links to severe COVID-19, according to the researchers.
Some genetic variants associated with severe COVID-19 were also associated with reduced risk for autoimmune conditions, such as psoriasis and lupus.
The findings highlight the need to carefully weigh various aspects of the immune system when developing new treatments for COVID-19, the researchers said.
"One thing that stood out to us was the high number of immune-mediated conditions that shared genetic architecture with severe manifestations of COVID-19," Liao said.