Obesity linked to higher hospitalisation and death risk from infections

New research suggests that obesity significantly increases the risk of severe illness and death from infectious diseases, with more than one in 10 infection-related deaths worldwide potentially linked to excess weight.

An analysis of health data from more than 540,000 people in the UK and Finland found that people living with obesity (BMI of 30 or higher) had a 70 per cent higher risk of being hospitalised or dying from infections compared with those at a healthy weight.

The study, published in The Lancet, found that the risk rose sharply with increasing BMI, with people with a BMI of 40 or higher facing around three times the risk of severe infection.

Higher body weight was linked to worse outcomes across a wide range of infections, including influenza, COVID-19, pneumonia, gastroenteritis and urinary tract infections.

The association remained even among people living with obesity who did not have related conditions such as diabetes or heart disease and could not be explained by lifestyle factors such as physical activity.

Using global mortality data, the researchers estimate that obesity contributed to around 600,000 of the 5.4 million infectious disease deaths worldwide in 2023. The proportion of infection-related deaths linked to obesity was estimated at 17 per cent in the UK and 26 per cent in the US, although the authors caution that global estimates are less reliable in low-resource settings.

The study also found that weight loss was associated with a lower risk of severe infections, with people who lost weight experiencing around a 20 per cent reduction in risk compared with those who did not.

The authors warn that as obesity rates continue to rise globally, hospitalisations and deaths from infections linked to obesity are likely to increase, highlighting the importance of supportive public health policies and keeping vaccinations up to date.