People with obesity 70% more likely to be hospitalised by or die from infection, study finds | Obesity

People with obesity 70% more likely to be hospitalised by or die from infection, study finds | Obesity

February 10, 2026 discoverhiddenusacom Health

People living with obesity face a significantly heightened risk of severe illness and death from infectious diseases. Recent research suggests individuals with obesity are 70% more likely to be hospitalized or die from infection and approximately one in ten infection-related deaths worldwide may be linked to the condition.

A Broadened Understanding of Risk

This study, published in the Lancet, expands on observations made during the Covid-19 pandemic, which indicated a higher risk for those with obesity. Researchers sought to determine if this increased vulnerability extended to a wider range of infectious diseases. The study analyzed data from over 500,000 adults – 67,000 in Finland and 470,000 in the UK – tracking them for an average of 13 to 14 years.

The Scope of the Problem

The research encompassed common infections like flu, pneumonia, gastroenteritis, and urinary tract infections, in addition to Covid-19. Findings indicate that obesity may already be a contributing factor in as many as 600,000 of the 5.4 million annual deaths from infectious diseases globally. The risk increased as body weight increased, with a BMI of 30 or higher defining obesity in the study.

Did You Know? The study followed participants for an average of 13 to 14 years, with the average age at the start of the study being 42 in Finland and 57 in the UK.

Why Obesity Increases Vulnerability

Professor Mika Kivimäki, of UCL, suggested that obesity may weaken the immune system’s ability to fight off infections caused by bacteria, viruses, parasites, or fungi. Evidence from trials involving GLP-1 weight-loss drugs supports this idea, as reducing obesity appears to lower the risk of severe infections. However, researchers emphasize that further investigation is needed to fully understand the underlying mechanisms.

Geographical Variations

The proportion of infection-related deaths linked to obesity varied by country. In the UK, approximately one in six infectious disease deaths were associated with obesity, while in the US, that figure rose to one in four. Vietnam showed the lowest proportion, with obesity linked to just 1.2% of infection deaths.

Expert Insight: This research highlights a complex interplay between metabolic health and immune function. The findings suggest that addressing obesity isn’t solely about chronic disease prevention, but also about bolstering the body’s defenses against immediate threats like infectious illnesses.

What Could Happen Next

If global obesity rates continue to rise, as currently projected, the number of hospitalizations and deaths from infectious diseases linked to obesity is also likely to increase. A possible next step could involve the implementation of policies focused on promoting healthy lifestyles, including access to affordable, nutritious food and opportunities for physical activity. Further research is also needed to confirm the biological mechanisms connecting obesity and increased infection risk.

Frequently Asked Questions

What infectious diseases were considered in the study?

The study considered a range of infectious diseases, including flu, pneumonia, gastroenteritis, urinary tract infections, and Covid-19.

How was obesity defined in this research?

Obesity was defined as having a Body Mass Index (BMI) of 30 or higher.

Did the study prove that obesity *causes* increased infection risk?

The research relied on observational data and, according to Dr. Sara Ahmadi-Abhari of Imperial College London, estimates of global impact “should be interpreted with caution,” as the study could not confirm a causal relationship.

Given these findings, how might public health strategies need to evolve to address the growing link between obesity and infectious disease vulnerability?