Image of Heidi M. Blanck, Ph.D.

High body mass index, or BMI, is known to be a top risk factor for severe COVID-19, and a major new study has confirmed the link between BMI and the need for invasive mechanical ventilation and death from the disease.

Among more than 148,000 U.S. adult participants with COVID-19, people whose BMI was closest to the threshold between being considered to have a clinically healthy weight and being considered to be overweight had the lowest risk of severe COVID-19. Risk then increased with higher BMI, reported Heidi M. Blanck, Ph.D., an expert in obesity with the National Center for Chronic Disease Prevention and Health Promotion of the Centers for Disease Control and Prevention.

In contrast to previous studies that found almost no tie between obesity and COVID-19 severity among older patients, this study found that adults aged 65 years and older who were overweight or obese were more likely to require invasive mechanical ventilation. What’s more, obesity and severe obesity in this age group was a risk factor for hospitalization and death. (This association was also particularly strong among adults aged 65 years or younger.)

The findings highlight the need for intensive management of COVID-19–associated illness, Blanck and colleagues wrote. It is thought that obesity causes chronic inflammation that disrupts immune and blood clotting responses to pathogens, as well impaired lung function. These effects may be responsible for poor COVID-19 disease outcomes, they explained. 

Data for this study were obtained from PHD-SR, a large, hospital-based, all-payer database. One half of adult COVID-19 patients in the analysis had obesity, compared with 43% in the total PHD-SR sample and 42% nationally, “suggesting that adults with COVID-19–associated illness and obesity might commonly receive acute care in emergency departments or hospitals,” the researchers wrote.

In related news:

Metabolic health should be a priority in the post-pandemic era, physicians say  Obesity is the “No. 1 communicable health disease of our time” and needs to be addressed in a post-pandemic era, say the editors of medical journal The Lancet. The phenomenon of widespread obesity in the U.S. took off in the 1990s, and the COVID-19 pandemic has underscored its role in adverse health outcomes, they wrote in a recent editorial. “With now in excess of 115 million infections and more than 2.5 million deaths from COVID-19 reported worldwide, many of which occurred in people with poor metabolic health, COVID-19 has sent the world a wake-up call about its inaction on metabolic diseases,” the authors wrote. “In the post-COVID-19 era, metabolic health must be a priority, with obesity taking center stage,” they concluded.