Why COVID-19 is more deadly in people with obesity—even if they're young

Why COVID-19 is more deadly in people with obesity—even if they're young ‘The stickiest blood I've ever seen’ and other weight-related factors worsen the coronavirus disease Science | AAAS

Since the pandemic began, dozens of studies have reported that many of the sickest COVID-19 patients have been people with obesity. In recent weeks, that link has come into sharper focus as large new population studies have cemented the association and demonstrated that even people who are merely overweight are at higher risk.

For example, in the first metaanalysis of its kind, published on 26 August in Obesity Reviews, an international team of researchers pooled data from scores of peer-reviewed papers capturing 399,000 patients. They found that people with obesity who contracted SARS-CoV-2 were 113% more likely than people of healthy weight to land in the hospital, 74% more likely to be admitted to an ICU, and 48% more likely to die.

A constellation of physiological and social factors drives those grim numbers. The biology of obesity includes impaired immunity, chronic inflammation, and blood that’s prone to clot, all of which can worsen COVID-19. And because obesity is so stigmatized, people with obesity may avoid medical care.

“We didn’t understand early on what a major risk factor obesity was. … It’s not until more recently that we’ve realized the devastating impact of obesity, particularly in younger people,” says Anne Dixon, a physician-scientist who studies obesity and lung disease at the University of Vermont. That “may be one reason for the devastating impact of COVID-19 in the United States, where 40% of adults are obese.”

People with obesity are more likely than normal-weight people to have other diseases that are independent risk factors for severe COVID-19, including heart disease, lung disease, and diabetes. They are also prone to metabolic syndrome, in which blood sugar levels, fat levels, or both are unhealthy and blood pressure may be high. A recent study from Tulane University of 287 hospitalized COVID-19 patients found that metabolic syndrome itself substantially increased the risks of ICU admission, ventilation, and death. ...