A new study suggests obesity increases the risk of dying from COVID-19 by 48% and may make vaccines against the disease less effective, News Medical reported on 26 August.

Conducted by researchers from the University of North Carolina (UNC), the World Bank and Saudi Health Council, the study took data from 75 studies around the world, involving nearly 400,000 patients.

The team found that not only was the risk of death 48% higher for those who were obese (defined as a BMI over 30), but their chance of ending up in a hospital was 113% higher, and the likelihood of being admitted to intensive care was 74% higher.

Published in the journal Obesity Reviews, the study noted that obesity-induced metabolic changes such as inflammation and the impaired ability to use insulin could interfere with the body’s ability to fight infections, including flu and hepatitis. The infection could also lead to uncontrolled blood glucose levels in patients with diabetes, which could impair the immune response.

“Individuals with obesity are also more likely to experience physical ailments that make fighting this disease harder, such as sleep apnea, which increases pulmonary hypertension, or a body mass index that increases difficulties in a hospital setting with intubation,” said Dr Melinda Beck from the University of North Carolina at Chapel Hill.

The researchers urged governments to focus on reducing the prevalence of obesity, such as warning labels on packaged goods that were high in sugar, fat and salt. Limiting the marketing of unhealthy food to children was also important, they said.

In another study, published in Diabetes Care, researchers showed that predominantly black hospitalised COVID-19 patients with metabolic syndrome (a combination of obesity, hypertension, diabetes, and abnormal cholesterol levels) were about five times more likely to be admitted to intensive care and require a ventilator. They were also 3.4 times more likely to die from their infections, News Medical reported.

A third study highlighted how obese people were more likely to contract COVID-19. The study, published in the journal Clinical Infectious Diseases, showed that higher levels of obesity were linked to the increased risk of infection.

The team from South Korea had examined and compared health-weight control subjects and had found that overweight people were 1.1 times more likely to contract the virus, while obese people were 1.3 times more likely to be infected.

Obesity was a growing worldwide health problem and its incidence had tripled since 1975. In 2016, more than 1.9bn adults were overweight, and of these, more than 650M were obese, the World Health Organization (WHO) said.

In the USA, more than one in three adults was considered overweight and about one in 13 adults had extreme obesity.