People living with obesity are 70 per cent more likely to be hospitalised or die from infectious diseases, with nearly one in 10 infection- deaths worldwide linked to the condition, according to a major international study.

Higher risk across common infections

The research, which analysed data from over 500,000 people, found that obesity significantly increases the risk of severe illness or death from infections such as flu, pneumonia, gastroenteritis, urinary tract infections and Covid-19.

Researchers estimate that obesity may already be a contributing factor in around 600,000 of the 5.4 million deaths caused by infectious diseases globally every year — about 11 per cent of the total.

Findings from long-term studies

The study used data from two large cohorts: about 67,000 adults from Finland and nearly 470,000 adults from the UK Biobank. Participants were followed for an average of 13 to 14 years, with body mass index (BMI) assessed at the start.

People with obesity — defined as a BMI of 30 or above — had a 70 per cent higher risk of hospital admission or death from any infectious disease compared to those with a healthy BMI.

The findings were published in The Lancet.

Experts warn problem may worsen

Dr Solja Nyberg of the University of Helsinki, the study’s first author, warned that the impact could intensify as global obesity rates continue to rise. She stressed the urgent need for public policies that promote healthy diets, physical activity and access to affordable nutritious food.

She also emphasised that people living with obesity should remain up to date with vaccinations to reduce the risk of severe infections.

Immune response may be affected

Lead author Prof Mika Kivimäki of University College London said obesity may weaken the immune system’s ability to fight bacteria, viruses and other pathogens. He added that early evidence suggests weight-loss treatments could also reduce infection severity, though more research is needed.

The study noted variations between countries, with obesity linked to one in six infection deaths in the UK and one in four in the US, while rates were far lower in countries such as Vietnam.