Obesity drives one in ten infectious disease deaths

A new study reveals a significant link between obesity and the severity of infectious diseases. Researchers found that just over one in ten deaths globally from infectious diseases – approximately 0.6 million out of 5.4 million in 2023 – can be attributed to obesity.

The Weight of Infection

The research, published in The Lancet, demonstrates that individuals with obesity face a 70% higher risk of hospitalization or death from infection compared to those with a healthy weight. This increased risk escalates with higher body mass index (BMI). those with a BMI of 40 or higher experienced three times the risk of severe infection.

Did You Know? The study analysed data from over 540,000 participants in the UK and Finland, tracking them for an average of 13-14 years.

Professor Mika Kivimaki, lead author from University College London (UCL), explained that obesity is already known to contribute to chronic conditions like diabetes and cardiovascular disease. “Here we have found robust evidence that obesity is also linked to worse outcomes from infectious diseases, as becoming very ill from an infection is markedly more common among people with obesity.”

Broad Impact Across Illnesses

The study encompassed 925 different infectious diseases, including bacterial, viral, parasitic, and fungal infections. For common illnesses like flu, Covid-19, pneumonia, gastroenteritis, and urinary tract infections, individuals with obesity were more likely to require hospitalization or succumb to the illness. However, the research did not find a correlation between obesity and severe cases of HIV or tuberculosis.

Expert Insight: This study underscores that obesity isn’t simply a risk factor for chronic diseases, but also directly impacts the body’s ability to fight off infections, potentially leading to more severe outcomes even if the initial infection isn’t more easily contracted.

Researchers determined that the link between obesity and severe infection remained consistent regardless of how obesity was measured – whether by BMI, waist circumference, or waist-to-height ratio. Importantly, the association persisted even when accounting for pre-existing obesity-related conditions and lifestyle factors like physical activity.

Looking Ahead

The study suggests that weight loss could mitigate some of this risk, with obese individuals who lost weight showing a roughly 20% reduction in the risk of severe infections. As Dr. Solja Nyberg of the University of Helsinki noted, rising global obesity rates are likely to translate into increased hospitalizations and deaths from obesity-related infectious diseases.

Addressing this trend may require policies promoting healthy lifestyles, including access to affordable nutritious food and opportunities for physical activity. Maintaining up-to-date vaccinations is also particularly important for individuals with obesity.

The researchers also noted that estimates of the global impact should be interpreted cautiously, as data on infection-related deaths and obesity are not always accurate, particularly in countries with limited resources.

Frequently Asked Questions

What is a healthy BMI range according to this study?

A healthy BMI range, as defined in the study, is between 18.5 and 24.9.

Did the study find obesity increased the risk of getting infections?

The study found that obesity did not necessarily increase the risk of *getting* infected, but it did make recovery from infection more difficult and increased the risk of hospitalization or death.

Which countries showed the highest percentage of infection-related deaths attributable to obesity?

The researchers estimated that in the UK, one in six (17%) infection-related deaths can be attributable to obesity, and 26% in the US.

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