People with obesity may have a much higher risk of severe illness or death from infectious diseases, according to a large international study published in The Lancet. The researchers found that obesity was linked to a 70 percent higher chance of being hospitalized or dying from infections like influenza, COVID-19, and pneumonia. They say this is a growing and often overlooked public health problem.
The study analysed long-term health data from more than 540,000 individuals drawn from the UK Biobank and multiple population cohorts in Finland. Participants’ body mass index (BMI) was recorded at enrolment, and they were followed for an average of 13-14 years.
The results showed that people with obesity were much more likely to have serious problems from many types of infections. Those with severe obesity had the highest risk, nearly three times greater than people with a healthy BMI.
When researchers applied their data to the world population, they estimated that obesity may have played a role in about 600,000 of the 5.4 million infection-related deaths worldwide in 2023, or roughly 10.8 percent of all such deaths.
The authors warned that these global estimates should be viewed with caution, but they also said the strong link between obesity and infection is hard to ignore, especially as obesity rates keep rising in both developed and developing countries.
The connection between obesity and severe COVID-19 became clear during the pandemic. People with obesity made up a larger share of those hospitalized or who died from the virus. But until now, there was little evidence linking obesity to other infectious diseases.
This new study shows that the risk is not just about COVID-19, but applies to infectious diseases in general.
Although this study did not look at the biological reasons, earlier research points to several possible causes. These include chronic inflammation, immune system changes, and higher rates of conditions such as diabetes and heart disease, all of which can worsen infections.
Lead author Solja Nyberg from the University of Helsinki said that urgent policy action is needed. She warned that as obesity rates rise around the world, the number of hospitalizations and deaths from infections linked to obesity will likely go up too.
She called for public health policies that help people live healthier lives. This includes making nutritious food more affordable, creating safer places for exercise, and offering ongoing support for weight management.
These findings add to the growing evidence that obesity is not just a risk factor for chronic diseases, but also affects how seriously people get sick from infections. As infectious diseases remain a global threat, tackling obesity could be an important, but often overlooked, way to reduce preventable illness and death worldwide.
