Obesity is contributing to a substantial number of deaths from infectious diseases, with new research indicating it may drive one in six such fatalities globally, as published by The Independent.
In the UK, obesity accounted for 7,300 out of 42,000 infection-related deaths in 2023, while worldwide figures suggest it was a factor in 0.6 million out of 5.4 million deaths that year.
With almost a third of UK adults—28 per cent—estimated to be obese, experts warn that this condition significantly raises the risk of hospital admission or death from infectious diseases such as flu, pneumonia, gastroenteritis, and urinary tract infections. People with obesity are 70 per cent more likely to be admitted or die from an infection, while those with severe obesity face three times the risk, and the trend is set to worsen if obesity levels continue to rise.
Professor Naveed Sattar, a co-author of the study from the University of Glasgow, explained that obesity may increase infection risk by altering blood flow, lung expansion, and immune function. “It can affect how well the immune system works – for instance, by altering the gut microbiome, limiting how fully the lungs expand, and even changing how much virus a person is exposed to,” he said. “Obesity also stretches tissues in ways that reduce blood flow to the skin, making infections more likely, and skin folds can make some areas harder to keep clean.”
The research, published in the Lancet medical journal, analysed data from over 540,000 people in Finland and the UK, including more than 470,000 adults from the UK Biobank. Participants’ body mass index was tracked for an average of 13 to 14 years, and using risk estimates from 925 bacterial, viral, parasitic, and fungal diseases, the study found obesity linked to one in 10 infection-related deaths globally in 2023.
However, obesity did not appear to increase the risk of severe HIV or tuberculosis, and the connection to serious infections was not explained by obesity-related chronic conditions like type 2 diabetes, being observed in patients both with and without such illnesses.
Professor Mika Kivimaki of University College London, who led the study, stated: “Our findings suggest that obesity weakens the body’s defences against infections, resulting in more serious diseases. People may not get infected more easily, but recovery from infection is clearly harder.”
The study authors concluded there is an urgent need for policies that help people stay healthy and support weight loss. Experts suggest that weight loss drugs, already taken by an estimated 1.6 million people in the UK, could help reduce the health risks of obesity.
Professor Sattar noted that separate large-scale trials show these medications meaningfully reduce deaths from infections compared to a placebo. Dr Earim Chaudry, an NHS GP, added that weight loss jabs can have “positive effects on patients’ blood sugar levels, cholesterol and cardiorespiratory health” alongside weight loss, and the research supports the benefits of expanding weight-management services and medications.
