PARIS (BLOOMBERG) - Obese and overweight people are at high risk of suffering severe cases of Covid-19, according to a French study that sheds light on the pandemic's burden.

The research, presented at a conference this week, shows how carrying extra pounds puts patients at risk of more serious disease and death.

Only one in every 10 people who end up in intensive care with Covid-19 were in a range of healthy weight, the study found.

Researchers led by Francois Pattou, the head of Lille University Hospital's general and endocrine surgery department in France, found that about half of the 124 intensive-care patients with Covid-19 in a sample they studied were obese and most of the remaining ones were overweight.

By contrast, only a quarter suffered from obesity and another quarter were overweight in a control group of several hundred patients admitted to intensive care for reasons unrelated to the pandemic.

People with a body mass index of 30 or more were considered obese, matching international thresholds from the World Health Organisation and the US Centers for Disease Control and Prevention.

"The increased risk posed by this virus to people living with obesity could not be clearer," Pattou said.

"Our data show that the chances of increasing to more severe disease increases with BMI, to the point where almost all intensive care Covid-19 patients with severe obesity will end up on a ventilator."

As many as 87 per cent of patients who were severely obese required a ventilator to continue breathing, Pattou and colleagues found.

The findings will be presented at the European and International Congress on Obesity.