Obesity Linked to 1 in 10 Infection Deaths Globally, Study Reveals Deeper Immunological Impact

Global - Ekhbary News Agency

Obesity Linked to 1 in 10 Infection Deaths Globally, Study Reveals Deeper Immunological Impact

A landmark international study has shed critical light on the alarming connection between obesity and heightened susceptibility to severe infections, revealing that the condition is linked to one in ten infection-related deaths worldwide. Published in the prestigious journal The Lancet on February 9, these findings underscore that obesity is not merely a risk factor for metabolic diseases but also a crucial determinant of immune response and health outcomes in the face of pathogens.

Researchers meticulously analyzed data from over half a million individuals across the UK and Finland, discovering that people with obesity are 70% more likely to be hospitalized with or die from severe infections compared to their non-obese counterparts. This stark correlation persisted even after accounting for factors such as metabolic syndrome or diabetes, socioeconomic status, and physical activity levels, reinforcing obesity's status as an independent risk factor.

Mechanisms of Impact: Why Obesity Heightens Vulnerability

Dr. Mika Kivimäki, the study's senior author and an epidemiologist at University College London, elucidated that "people with obesity may find it harder to fight off infections." He further explained that extra body fat can compromise the immune system in several ways, including impairing lymphatic function, reducing lung function, and escalating long-term low-grade inflammation. The lymphatic system plays a vital role in maintaining fluid balance and transporting and training immune cells, while compromised lung function can impede the clearance of respiratory pathogens.

Moreover, Professor Nikhil Dhurandhar, a nutritional sciences professor at Texas Tech University not involved in the new research, noted that fat tissue and the immune system are deeply intertwined. Precursor cells that develop into fat cells can behave like immune cells, and some fat cells actively secrete pro-inflammatory substances. This chronic, low-grade inflammation can exhaust the immune system, diminishing its capacity to respond effectively to new threats.

Exacerbation During the COVID-19 Pandemic

The link between obesity and infection risks became particularly prominent during the COVID-19 pandemic. In 2021, a significant 15% of all infection hospitalizations and deaths were associated with obesity. This observation prompted Kivimäki's team to investigate whether the coronavirus posed a unique danger to individuals with obesity or if the risk extended to all types of infections. The study concluded that the heightened risk indeed spans across bacterial, viral, fungal, and parasitic infections.

The research also demonstrated a dose-response relationship: the greater the degree of obesity, the higher the risk. Individuals with a Body Mass Index (BMI) between 30 and 34.9 faced a 50% higher risk of infection, hospitalization, or death compared to those with BMIs under 30. This risk doubled for those with a BMI of 35 to 39.9 and tripled for those with a BMI of 40 or above. Crucially, participants who lost or gained weight after their initial measurements saw their severe infection risk correspondingly drop or rise, suggesting a potential reversibility in this relationship.

Obesity as a Chronic Disease: Challenges and Solutions

While the study's observational nature precludes definitive proof of causation, the evidence strongly suggests that obesity contributes to immune dysfunction. This dysfunction may render individuals with obesity less responsive to vaccinations, leaving them more vulnerable. Additionally, obesity is linked to a lack of sensitivity to the hormone leptin, which regulates body weight and appetite and also possesses an immune-protective role.

Professor Dhurandhar emphasized, "Obesity is a disease. It's a chronic disease. It's not a matter of willpower; it’s not a matter of discipline." This perspective is crucial in understanding the formidable challenges of weight loss and maintenance. However, the advent of drugs like semaglutide (GLP-1 agonists) may facilitate weight loss for some. While trials hint at these medications reducing infection risk, Kivimäki cautioned that individuals taking these drugs often lose muscle mass alongside fat. This muscle loss could have negative implications for the immune system, as muscle tissue provides glutamine, an amino acid vital for some immune cells, and produces the anti-inflammatory compound interleukin-6.

Kivimäki concluded, "In our future research, we want to better understand why obesity raises the risk of severe infections, and, importantly, what can be done to reduce that risk." This study reinforces the urgent need to address obesity not just as a risk factor for cardiovascular disease and diabetes, but as a critical determinant of global immune health.

Ekhbary News Agency