Obesity Linked to 70% Higher Risk of Severe Infections and Death
A comprehensive new study has revealed that individuals living with obesity face a significantly elevated risk of severe outcomes from infectious diseases. Research involving over 500,000 participants indicates that those with obesity are 70% more likely to be hospitalised or die from infections such as influenza, pneumonia, and Covid-19.
Global Impact and Urgent Policy Needs
The findings, published in the Lancet, suggest that obesity may contribute to approximately 600,000 of the 5.4 million annual deaths from infectious diseases worldwide, accounting for about 11% of such fatalities. Dr Solja Nyberg, the study's first author from the University of Helsinki, warned that as obesity rates continue to climb globally, the number of infection-related hospitalisations and deaths is expected to rise correspondingly.
Dr Nyberg emphasised the critical need for immediate policy interventions: "To mitigate the risk of severe infections and other health complications associated with obesity, there is an urgent demand for strategies that promote healthy living and support weight management. This includes ensuring access to affordable nutritious food and creating opportunities for regular physical activity."
In the interim, she advised that it is "especially important" for people with obesity to stay current with their vaccinations to help protect against preventable diseases.
Study Methodology and Key Findings
The research utilised data from 67,000 adults in Finnish studies and 470,000 adults from the UK Biobank dataset to investigate the correlation between obesity and severe infectious disease outcomes. Participants, with an average age of 42 in Finland and 57 in the UK, had their body mass index (BMI) assessed and were monitored for an average of 13 to 14 years.
The study defined obesity as having a BMI of 30 or higher and compared this group to individuals with a healthy BMI ranging from 18.5 to 24.9. It found that the risk of hospital admission or death from any infectious disease increased progressively with higher body weight.
Underlying Mechanisms and International Variations
Professor Mika Kivimäki of UCL, the study's lead author, proposed that broad biological mechanisms might explain the heightened risk. "It is plausible that obesity compromises the immune system's ability to fend off infectious agents like bacteria, viruses, parasites, or fungi, leading to more severe illness," he stated.
Professor Kivimäki also noted that evidence from trials involving GLP-1 weight-loss drugs aligns with these findings, as reducing obesity appears to lower the risk of serious infections. However, he cautioned that further research is necessary to confirm the specific mechanisms behind these associations.
The study highlighted notable differences in obesity-related infection deaths across countries. In the UK, obesity was linked to about one in six such deaths, while in the US, the proportion rose to one in four. Vietnam reported the lowest rate, with obesity associated with just 1.2% of infection fatalities.
Limitations and Cautions
Funded by Wellcome, the Medical Research Council, and the Research Council of Finland, the research has certain limitations. It relied on observational data, which means it cannot establish causality definitively. Dr Sara Ahmadi-Abhari, a co-author from Imperial College London, urged caution in interpreting the global impact estimates, stating, "They provide a sense of the scale of the problem but should be viewed with prudence."
This study underscores the pressing public health challenge posed by obesity, particularly in the context of infectious diseases, and calls for concerted efforts to address this growing issue through targeted policies and individual health measures.
