12 Feb 2026 • Obesity is not only a cardiometabolic risk factor - it may also substantially heighten vulnerability to severe infections.

In a large multicohort analysis spanning Finland and the UK, investigators report that adults with severe obesity face markedly higher risks of infection-related hospitalisation and mortality across a wide spectrum of pathogens.

Compared with individuals of healthy weight, those with class III obesity (BMI ≥40 kg/m²) had nearly a threefold higher risk of infection-related hospitalisation and death. Even across all obesity classes combined, the pooled hazard ratio for severe infection was 1.7.

The elevated risk was consistent regardless of how adiposity was measured - BMI, waist circumference, or waist-to-height ratio - and extended across acute and chronic infections, including viral and bacterial subtypes.

When researchers applied these risk estimates to Global Burden of Disease data, the implications were striking: an estimated 8.6% of infection-related deaths worldwide in 2018 were attributable to obesity, rising to 15.0% during 2021, amid the COVID-19 pandemic, and remaining elevated at 10.8% in 2023.

Source: The Lancet | Read full story