COVID-19: Overweight and obese more likely to test positive for the virus

People with a higher body mass index - BMI - are more likely to test positive for the virus that causes COVID-19, a study suggests.

Research by Chaim Sheba Medical Centre in Israel found that people who are overweight - with a BMI between 25 and 29.9 - are 22% more likely to contract the virus.

The figure for people who are obese - with a BMI between 30 and 34.9 - rises to 27%.

For those who are morbidly obese, with a BMI at or above 40, the risk increases by 86%.

Some 26,030 people were tested between 16 March and 31 December last year and 1,178 positive COVID-19 tests were recorded.

Even after age, sex, and other medical conditions were considered, the relationship between BMI and the probability of a person testing positive remained significant, the researchers found.

The study authors concluded: "As BMI rises above normal, the likelihood of a positive SARS-CoV-2 test result increases, even when adjusted for a number of patient variables.

"Furthermore, some of the comorbidities associated with obesity appear to either be associated with an increased risk of infection or to be protective."

People with diabetes were 30% more likely to test positive, while the likelihood was six times greater for those with high blood pressure.

But the risk was reduced for those with a history of stroke (by 39%), ischemic heart disease (by 55%) and chronic kidney disease (by 45%).

The researchers were unable to explain this.

Also, research by the IRCCS Policlinico San Donato research hospital in Italy, has found that abdominal obesity is more important than general obesity in predicting the severity of chest X-ray results in coronavirus patients.

Abdominal obesity is fat around the waist as opposed to general obesity, which is determined by BMI.

Chest X-ray severity scores were calculated by dividing each lung into three zones, with each one scoring a maximum of three points - zero for normal lung performance and three for poor function.

Some 59% of patients with abdominal obesity had a high score, whereas this was true for just 35% of those without abdominal obesity.