Infectious Disease Outcomes

A large study published in The Lancet, drawing on data from nearly 550,000 adults in Finland and the U.K. over 14 years, finds that obesity is linked to a substantially higher risk of being hospitalized for or dying from infectious diseases, including flu, COVID‑19, pneumonia, gastroenteritis, UTIs and other common infections. Overall, obese adults were about 70% more likely than those with a healthy BMI to be hospitalized with or die from an infection, and those with class 3 obesity (BMI ≥40) had roughly triple the risk of these severe outcomes. Researchers estimate obesity contributed to roughly 9% of infection‑related deaths in 2018, 15% in 2021 and 11% in 2023, with effects seen even in people without diabetes, heart disease or metabolic syndrome and largely unaffected by reported physical‑activity levels. The strongest associations were with skin and soft‑tissue infections, and the authors say the pattern suggests obesity impairs the body’s ability to recover once infected rather than dramatically increasing infection rates themselves. Importantly, obese participants who lost weight reduced their risk of severe infections by about 20%, leading the authors to argue that tackling obesity could prevent up to about one in nine infection‑related deaths worldwide and to call for policies that make healthy food and opportunities for physical activity more accessible.