Much has been said about the risk factors that make someone especially vulnerable to the novel coronavirus. They include being older than 65, having diabetes, a chronic lung condition or moderate to severe asthma, among others.

But studies are showing the condition that might make someone most at risk of COVID-19, the disease caused by the coronavirus, is obesity.

Indeed, it might be the most-significant risk factor after only age, particularly among younger adults who might think they are otherwise safe from serious illness. New studies are showing that obese individuals are at greater risk even when chronic conditions like diabetes or asthma are absent and the individual is otherwise healthy.

The United States has one of the highest obesity rates in the world. About 42% of American adults are considered obese, or nearly 80 million people.

One study examined risk factors for 4,000 COVID-19 patients treated by NYU Langone Health early in the pandemic. The researchers noted that obesity appeared to be a more important risk factor than a range of health problems, such as diabetes or high blood pressure, in predicting who will require hospitalization.

Researchers at Langone also found obese patients under age 60 were twice as likely to be hospitalized.

Meantime, studies in Europe and Asia have found some of the same associations. A study by Chinese scientists shows obese individuals during the coronavirus outbreak are at twice the risk of pneumonia.

It’s a troubling trend to physicians and a reminder that obese younger people are as much at risk as many older Americans.