“Good” HDL cholesterol levels tied to lower COVID-19 risks
Healthy levels of "good" HDL cholesterol are associated with a lower risk of severe COVID-19, said a study posted on medRxiv.
Researchers analyzed records of 317,306 participants in the UK Biobank study, including 869 people who were hospitalized for COVID-19.
Participants with healthy HDL levels were at lower risk of becoming infected with the new coronavirus, and those who did become infected were less likely to be hospitalized.Healthy levels of HDL are at least 40 mg/dL (1 mmol/L) for men and 50 mg/dL (1.3 mmol/L) for women, according to U.S. guidelines.
After taking health behaviors, socioeconomic status and other factors into account, the odds of hospitalization for COVID-19 went down 9% with every 0.2 mmol/L (roughly 8 mg/dL) increase in HDL-cholesterol, the study found.
Earlier studies of Biobank participants found the same inverse relationship between HDL and hospitalizations for other infectious diseases, the authors said.
The study does not prove that HDL itself protects against COVID-19. Still, the authors said, the anti-inflammatory and immune properties of HDL may explain their findings.
Viral load most important factor in transmission
The amount of virus in the noses and throats of COVID-19 patients is the most important factor in determining whether they will infect others, according to a report published in The Lancet Infectious Diseases.
Researchers in Spain studied 282 patients and 753 of their recent close contacts.
While household members most often became infected, the viral load "was the most important factor in determining whether transmission occurred between a case and their contacts," said coauthor Michael Marks of the London School of Hygiene & Tropical Medicine.
"Whether the case was coughing or had other symptoms didn't seem to play a major role," he said, reinforcing that even patients without symptoms need to isolate themselves.
He said health authorities might want to consider more enhanced contact tracing for individuals with higher viral loads. A separate study by UK researchers, which has not yet been peer-reviewed, reported similar findings.