Covid may increase the risk for high cholesterol for up to a year after infection, two recent studies suggest, prompting some doctors to take a closer look at the apparent trend.
"It's something that we need to pay more attention to," said Dr. Ashish Sarraju, a cardiologist with the Preventive Cardiology and Rehabilitation section at the Cleveland Clinic, adding that the latest research is "provocative."
One study, published in The Lancet Diabetes & Endocrinology earlier this month, found that people with a prior Covid infection had a 24% increased risk for high cholesterol levels.
"These are people who never had cholesterol problems before," said Dr. Ziyad Al-Aly, an author of the study and a clinical epidemiologist at Washington University in St. Louis. "Now, all of a sudden, they started having problems weeks and months after Covid-19."
He looked at new diagnoses of high cholesterol among 51, 919 people who had Covid from March 2020 through January 2021, the period before vaccines were widely available. The participants were patients who had sought care within the Department of Veterans Affairs. The majority were white men in their early 60s.
Compared with 2.6 million people who did not have Covid during the same time frame, the patients who got Covid were more likely to have high levels of triglycerides and LDL cholesterol, the so-called bad kind of cholesterol, up to a year later. They were also more likely to have lower levels of the "good" HDL cholesterol.
A second study, published in The Lancet Infectious Diseases in late December, had similar findings, though notably, in a much younger group of people.
Researchers in Switzerland compared the cholesterol levels of 177 members of the Swiss military who had Covid in 2020 with 251 others who had not been infected. The average age of the participants was 21.
The Covid group ended up with higher cholesterol levels, said author Patricia Schlagenhauf, a professor in the department of global and public health at the University of Zurich. They also had higher body mass indexes after Covid.
"The fact that these young people have a significantly higher cholesterol, higher LDL and higher BMI points to a metabolic disorder," she said.
Sarraju, of the Cleveland Clinic, has made similar observations.
"We certainly have seen patients who have had Covid come in with elevated BMI or metabolic issues," he said.
Why a respiratory virus like Covid may lead to high cholesterol is unclear. Ongoing inflammation could play a role. But the participants in these studies were also ill during the first wave of Covid cases, when people were largely staying home.
There were "changes in behavior, including diet and lack of exercise" that could be a factor in the higher cholesterol levels, said Dr. Glenn Hirsch, chief of cardiology at National Jewish Health in Denver. He said his team has seen increases in the risk for many conditions following Covid, including diabetes, cardiovascular disease and kidney disease.
"It seems like this is something that should be tracked closer," Sarraju said.
As of Wednesday, more than 101 million Covid cases had been reported in the United States since the beginning of the pandemic.