The causality between gut microbiota and functional dyspepsia: a two-sample Mendelian randomization analysis

Introduction: To investigate the potential link between gut microbiota and functional dyspepsia (FD). Methods: : Genome-wide association studies (GWAS) of gut microbiota and FD were used in Mendelian randomization (MR) research. Using the GWAS of 18,340 people, instrumental variables related to gut microbiota as an exposure factor were identified. In a GWAS investigation, 189695 control individuals and 4376 FD patients from Europe were included as outcome variables. The primary analysis technique was inverse variance weighted analysis (IVW). The reliability of MR Analysis results is tested using sensitivity analysis. Results: : TSMR analysis revealed the presence of seven gut microbiota associated to FD. In the IVW method, Order Erysipelotrichales (odds ratio (OR): 1.301; 95% confidence interval (CI): 1.016,1.665;P=0.037),Family Erysipelotrichales (OR:1.301;95%CI:1.016,1.665;P=0.037), Genus Haemophilus (OR:1.236;95%CI 1.059, 1.442;P=0.007), Genus Ruminiclostridium9 (OR:1.422; 95%CI:1.078, 1.877; P=0.013),Genus Lachnospiraceae NK4A 136 group (OR:1.297;95%CI:1.059, 1.589; P=0.012) was positively associated with functional dyspepsia. Class Gammaproteobacteria (OR:0.705;95%CI:0.522,0.952;P=0.022) and Genus Erysipelatoclostridium (OR:0.747;95%CI:0.628,0.888;P=0.001) were found to be inversely related to functional dyspepsia. There was no evidence of pleiotropy or heterogeneity in the sensitivity analysis. Conclusions: : Our research provides evidence for a possible link between FD and a number of gut microbiota. The role that gut microbiota plays in the development of FD requires more investigation.