Obesity Linked to 70% Higher Risk of Hospitalisation or Death from Infections: Study

People living with obesity face a significantly higher risk of severe outcomes from infectious diseases, with new research suggesting they are 70 per cent more likely to be hospitalised or die from an infection. The condition is now linked to nearly one in 10 infection-related deaths worldwide.

The findings, based on data from more than 500,000 adults, show that excess body weight substantially increases the risk of serious illness and death from a wide range of infections, including influenza, pneumonia, gastroenteritis, urinary tract infections and Covid-19.

Researchers estimate that obesity may already contribute to around 600,000 of the 5.4 million global deaths caused by infectious diseases each year — roughly 11 per cent of the total.

While obesity was known to worsen Covid-19 outcomes during the pandemic, evidence linking obesity to infectious diseases more broadly had been limited. To address this gap, researchers analysed data from 67,000 adults in Finland and 470,000 participants from the UK Biobank. Participants were tracked for an average of 13 to 14 years, with BMI measurements taken at the start of the study.

Published in The Lancet, the study found that individuals with obesity — defined as a BMI of 30 or higher — had a 70 per cent higher risk of hospital admission or death from infectious diseases compared to those with a healthy BMI between 18.5 and 24.9. The risk increased progressively with higher body weight.

The study also highlighted country-level differences. Obesity was linked to about one in six infectious disease deaths in the UK and one in four in the US, while Vietnam reported the lowest proportion, at 1.2 per cent.

The authors cautioned that the research was observational and could not establish a direct cause-and-effect relationship. Dr Sara Ahmadi-Abhari of Imperial College London, a co-author of the study, said global estimates should be interpreted carefully, despite highlighting the scale of the issue.

The research was funded by Wellcome, the Medical Research Council and the Research Council of Finland.

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