A higher BMI increases the risk of hospitalisation or death following a respiratory tract infection, according to an analysis published in JAMA.
Body mass index (BMI) has a J-shaped associations with overall mortality and with many cause-specific deaths. In addition, during the Covid-19 pandemic it became clear that being overweight increases the risk of Covid-19-related hospitalisations. Nevertheless, whether or not there is a relationship between BMI and other respiratory infections, viral or otherwise, is less clear.
In the current study, researchers used data from the UK Biobank, to explore the relationship between body mass index and the risk of hospitalisation for, or death from, respiratory infections. The team focused not only on Covid-19 but both upper and lower respiratory tract infections (RTIs). Researchers excluded participants with a chronic respiratory disease or previous hospitalisations for infectious respiratory diseases. Modelling assessed the association between BMI categories of 14 – 24.9, 25 – 29.9 (the reference point), 30-34.9, and 35-60.
BMI and hospitalisation
Data was available for 476, 176 participants (median age = 58 years, 54% female) and the mean BMI was 27.4. Participant follow-up occurred over an average of 11.8 years.
During follow-up, 20,302 individuals were hospitalised or died of severe infectious respiratory diseases. For Covid-19, the fully adjusted hazard ratios (HRs) ranged from 0.66 for those with a BMI of 14 – 24.9, to 2.27 (95% CI 1.73 – 2.97) for the highest category (e.g., 35 – 60). For a lower RTI, HRs ranged from 0.94 to 1.68 among those in the highest BMI category. A similar trend was seen for upper RTIs.
The authors suggest the implementation of approaches to reduce obesity and target vaccinations for respiratory infections in those with an elevated BMI.