The vast majority of global coronavirus deaths occurred in nations with high levels of obesity, according to a report linking overweight populations with more severe coronavirus-related illness and mortality.

The report, by the World Obesity Federation, found that 88 percent of deaths due to covid-19 in the first year of the pandemic were in countries where more than half of the population is classified as overweight, which it defines as having a body mass index (BMI) above 25. Obesity, generally defined as BMI above 30, is associated with particularly severe outcomes.

Among the nations with overweight populations above the 50 percent threshold were also those with some of the largest proportions of coronavirus deaths — including countries such as Britain, Italy and the United States. Some 2.5 million people have died around the world of covid-19, more than 517,000 of which were in the United States.

In some cases, the correlations between coronavirus severity and weight are also tied to racial and ethnic inequality. In the United States, “Hispanic and non-Hispanic Black adults have a higher prevalence of obesity and are more likely to suffer worse outcomes from COVID-19,” according to the Centers for Disease Control and Prevention.

The report found that in countries where less than half of the adult population is classified as overweight, the likelihood of death from covid-19 was about one-tenth of the levels in countries with higher shares of overweight adults. A higher BMI was also associated with increased risk of hospitalization, admission to intensive or critical care and the need for mechanically assisted ventilation.

In Britain, overweight coronavirus patients were 67 percent more likely to require intensive care, and obese patients three times likelier.

Prime Minister Boris Johnson, who was hospitalized and required oxygen therapy after contracting the disease last spring, has campaigned in recent months for Britons to lose weight to reduce health risks and support the country’s overburdened National Health Service.

Speaking last year, Johnson said he had long struggled with his weight and was “too fat” when he was sickened with the disease that has claimed more than 124,000 lives in the United Kingdom. He is often spotted out running near his home in central London alongside his personal trainer.

The World Obesity Federation findings were near-uniform across the globe, the report said, and found that increased body weight was the second greatest predictor after old age of hospitalization and higher risk of death of covid-19.

As a result, the London-based federation urged governments to prioritize overweight people for coronavirus testing and vaccinations.

The United Nations warned in 2020 that obesity is a “global pandemic in its own right.”