Obesity is an important risk factor of COVID-19

Yale Medicine physicians explain how obesity may heighten the chance of severe disease.


People who are aged over 60 years and people who have underlying medical conditions such as diabetes, heart disease, respiratory disease, or hypertension are among those who are at greater risk of developing severe or critical illness if infected with the virus. Besides that, a new study suggests that obesity—even among younger people—is emerging as a significant concern.

Ania Jastreboff, MD, Ph.D., a Yale Medicine endocrinologist and obesity medicine physician, said, “It looks like the excess weight itself is problematic, not just the other health conditions it causes. Early data support that obesity is an independent risk factor, meaning that if you control for diabetes, heart problems, hypertension, and other medical conditions, obesity—itself a chronic disease—may potentially be the unifying disease involved in exacerbating COVID-19.”

One of the studies from New York suggested that obesity was a stronger factor predicting hospitalization for COVID-19 than high blood pressure, diabetes, or cancer—or even pulmonary, kidney, or coronary disease. Another study, which considered hospitalized COVID-19 patients under age 60 in New York City, found that individuals who have obesity were twice as likely to be hospitalized and even more likely to require critical care than those who do not have it.

Albert Ko, MD, a Yale Medicine infectious disease specialist and an epidemiologist at Yale School of Public Health, said, “To say certain races and ethnicities have a higher proportion of obesity would be too superficial. These are associations. What we need to know is, what is obesity that makes people more likely to die from COVID-19? Do they get infected more easily? Is it something about their immune response? We know that people who have obesity have worse outcomes for many different diseases, but is there something special about COVID?”

Kevan Herold, MD, a Yale Medicine endocrinologist and immunobiologist, said, “Medical experts haven’t pinned down why obesity seems to make COVID-19 worse, but there are numerous theories. One reason may be related to the fact that obesity can cause a state of chronic, low-grade inflammation.”

“The more severe manifestations of COVID-19 seem to be related to an inflammatory state, which suggests there may be some link, but we don’t understand why. This is a rapidly moving field, with more data starting to come in.”

“Furthermore, obesity can complicate COVID-19 treatment. For instance, many hospitalized patients benefit from being in a prone position (lying on their stomach, which is believed to help open airways), but obesity can make this difficult.”

Dr. Jastreboff says“We’ve been ignoring obesity as a chronic disease. Now we are faced with COVID-19, and we see that the pathophysiology of obesity may be exacerbating the severity of it.”

“For those who have obesity, there are small steps they may take to help manage weight, including finding ways to fit movement and physical exercise into the day or cooking at home.”

“But experts say that obesity is not just a matter of overeating and exercising too little. Genetics, environment, dietary composition, and metabolic changes are all contributors to excess weight and obesity. That’s why compassion and understanding, as well as interventions, such as treatment with anti-obesity medications, surgery, or other therapeutic options, are critical for patients with obesity. And if we can help these individuals early on, perhaps we can help quell the overall severity of COVID-19.”


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