Mendelian randomization analysis identifies intestinal flora causally associated with asthma-related infections and pneumonia

The objective of this study is to explore the causal links between the gut microbiota and the vulnerability of patients with asthma to infections and pneumonia. This study utilized summary statistics from a genome-wide association study (GWAS) that covered 211 gut microbial taxa as the exposure. We focused on asthma-related infections and asthma-related pneumonia as the outcomes of interest. To determine the causal effect of gut microbiota on these asthma-related conditions, we conducted Mendelian randomization (MR) analysis using the inverse variance weighted (IVW) method as our primary tool. To ensure the reliability of our findings, we performed a series of sensitivity analyses, including Cochran’s Q test, MR-Egger intercept, MR-PRESSO Global test, and leave-one-out analysis. Furthermore, multiple testing was applied to affirm the robustness of these causal associations. We identified 28 associations that demonstrated indications of causality. After conducting sensitivity analysis and multiple corrections, three causal relationships remained. An increased presence of the genus Oxalobacter (OR = 1.13; CI: 1.06-1.20; p = 0.015) was found to be positively correlated with asthma-related infections. Conversely, a higher abundance of the family Alcaligenaceae (OR = 0.81; CI: 0.72-0.92; p = 0.027) was inversely related to asthma-related infections and pneumonia. Our findings suggest that dysbiosis, or an imbalance in gut microbiota, may be linked to an elevated risk of infection in patients with asthma, thereby enriching our comprehension of this phenomenon.