Elevated body mass index is associated with an increased risk of infectious disease admissions and mortality: a mendelian randomization study. (May 2021)

• Record Type: Journal Article
• Authors: Butler-Laporte, G.; Harroud, A.; Forgetta, V.; Richards, J.B.
• Is Part Of: Clinical microbiology and infection. Volume 27:Number 5(2021)
• Page Start: 710
• Page End: 716
• Publication Date: 2021-05
• Subjects: Body mass index -- Infections -- Mendelian randomization -- Mortality -- Obesity -- Sepsis; Medical microbiology -- Periodicals; Diagnostic microbiology -- Periodicals; Communicable diseases -- Periodicals; Infection -- Periodicals; 616.01
• DOI: 10.1016/j.cmi.2020.06.014
• Languages: English
• ISSNs: 1198-743X

Abstract

Abstract: Objective: The effect of body mass index (BMI) on the risk of infectious diseases admissions and mortality is unclear and is difficult to study given the risks of confounding variables. Methods: We used genome-wide association studies (GWASs) with mendelian randomization (MR) to obtain causal inference of BMI on the following infectious diseases outcomes: hospital admissions for pneumonia, sepsis, urinary tract infections, skin and soft tissue infections (SSTIs) or all-cause infections. For patients with pneumonia and sepsis, we also analysed their 28-day and 90-day mortalities. The UK Biobank (UKB) cohort ( n > 500 000) provided data for GWASs on infectious diseases. The GIANT consortium ( n = 681 265) GWAS was used to identify single-nucleotide polymorphisms (SNPs) associated with BMI. Results: Genetically increased BMI, by one standard deviation, was associated with higher rates of admission due to all infectious disease. The effect was most important for SSTIs (OR: 1.11, 95%CI: 1.09, 1.12). Increasing BMI by one standard deviation was associated with higher pneumonia mortality, especially at 28 days (OR: 1.03, 95%CI: 1.01, 1.05). BMI was not clearly associated with sepsis mortality, although interpretation of the results was limited by a small sample size. There were consistent findings in sensitivity analysis performed by removing highly pleiotropic SNPs and multivariate MR including type-2 diabetes mellitus, estimated glomerular filtration rate, high-density lipoprotein, educational attainment, and a history of smoking. Conclusions: Increased BMI was associated with increased risk of admission for infectious disease and mortality. While the pathophysiology behind this phenomenon remains unknown, increasing BMI may influence immune dysregulation.