Obese people are 70 per cent more likely to die from an infectious disease, concerning new research reveals

People who are obese are 70 per cent more likely to be hospitalised or die from an infectious disease, with the link now accounting for one in six deaths in the UK, a landmark report reveals. 

With obesity increasing among children and adolescents, the authors say without significant change, obesity will continue to contribute to the burden of chronic conditions including diabetes, heart disease and cancer. 

‘Our findings suggests that people living with obesity are significantly more likely to become severely ill or to die from a wide range of infectious diseases. 

‘As obesity rates are expected to rise globally, so will the number of deaths and hospitalisations from infectious diseases linked to obesity,’ warns study author Dr Solja Nyberg. 

‘To reduce the risk of severe infections, as well as other health issues linked with obesity, there is an urgent need for policies that help people stay healthy and support weight loss, such as access to affordable healthy food and opportunities for physical activity.’ 

The public health expert added it’s imperative for obese people to get all recommended vaccinations to minimise the risk of contracting a potentially life-threatening disease. 

During the pandemic, countries with the highest level of overweight people, such as the UK and the US, had the highest death rates.

And whilst the correlation between obesity and mortality rates from Covid was ‘clear and compelling,’ until now it was unclear whether obesity had the same effect on infectious diseases in general. 

The study, published in medical journal The Lancet, analysed data from over 67,000 adults in two studies in Finland and over 470,000 adults in the UK. 

At the beginning of the study, participants’ body mass index (BMI) – a measure of body fat based on height and weight – was recorded, with a BMI of 30 or over classed as obese. 

The participants, who were around 42 years old at the start of the study, were followed for 14 years on average. 

They found people with obesity were 70 per cent more likely to be hospitalised or die from any infectious disease compared to those of a healthy weight.

The risk was found to steadily increase with body weight, with those classed as severely obese, with a BMI of 40 or over, at three times the risk of healthy participants. 

Using this data, the researchers predict that up to 11 per cent of infection-related deaths worldwide could ‘potentially be prevented by eliminating obesity.’  

They studied 10 common infectious diseases in more detail and found that for almost all of these – including flu, Covid, pneumonia, urinary tract infections (UTIs) and respiratory infections – obese people were more at risk of severe complications. 

However, obesity did not appear to increase the risk of severe HIV or tuberculosis. 

 Professor Mika Kivimäki, an expert in social epidemiology at University College London and study lead, said: ‘Our finding that obesity is a risk factor for a wide range of infectious diseases suggests that broad biological mechanisms may be involved. 

‘It is plausible that obesity weakens the immune system’s ability to defend against the infectious bacteria, viruses, parasites or fungi, therefore resulting in more serious diseases.’ 

He added that evidence from GLP-1 weight loss drugs, including now household names Wegovy and Ozempic, fit with this finding, as reducing obesity also appears to lower the risk of severe infections, heart disease and even some cancers. 

‘That said, additional research is required to confirm the mechanisms underlying these associations ,’ the professor concluded.  

The researchers then applied these estimates to global data and found that obesity was linked to one in 10 infection-related deaths worldwide in 2023. 

In the US, obesity was linked to a quarter of infectious disease deaths, whilst in the UK the number sat at around one in six. 

Vietnam, by contrast, had the lowest level of overweight in the population and the lowest infectious disease death rate – with obesity linked to just 600 out of 50,500 infectious disease deaths. 

Dr Sara Ahmadi-Abhari, from Imperial College London who conducted the analyses on the global burden of disease, said: ‘Estimates of the global impact give a sense of how large the problem may be, but they should be interpreted with caution.’ 

This is because data is not always accurate, particularly in low-income countries. 

They concluded: ‘Obesity should receive greater attention in public health strategies aimed at preventing severe infections. 

‘Effective implementation of evidence-based weight loss interventions and stronger integration of obesity considerations into vaccination programmes for high-risk groups could help reduce the burden of severe infections and related mortality.’ 

It comes as new research suggests that excess weight is the ‘major driving force’ between 61 commonly occurring and potentially life-threatening conditions including kidney disease osteoarthritis and diabetes.

Currently, at least nine million people in the UK live with two or more long-term conditions that could be prevented by losing weight. Two in three Britons are now classed as overweight or obese. 

The arrival of GLP-1 drugs has transformed obesity treatment, offering dramatic weight loss and other health benefits that were largely out of reach with diet and exercise alone. 

But, experts have warned the benefits of weight loss jabs may be short-lived once treatment ends, with the majority of users regaining the weight inside two years of stopping treatment. 

 Obesity has been linked to at least 13 types of cancer and is the second biggest cause of the disease in the UK, according to Cancer Research. It has also fuelled a 39 per cent rise in type 2 diabetes among under-40s, with 168,000 young Britons now living with the condition.