Mendelian randomization study on causal relationship between gastroesophageal reflux disease and bronchial asthma
Objective To investigate the causal relationship between gastroesophageal reflux disease(GERD)and different phenotypes of asthma based on Mendelian randomization(MR).Methods The dataset was pooled by genome-wide association studies(GWAS),in which the GERD data contained 602 604 cases,the unspecified asthma data contained 156 078 cases,139 591 cases of obesity-associated asthma,138 474 cases of pediatric asthma,140 308 cases of allergic asthma and 136 633 cases of eosinophilic asthma.The inverse va-riance weighting method was used as the main method of MR analysis,and the weighted median method,sim-ple model,weighted models and MR-Egger conducted the supplement,and the sensitivity analysis was carried out to assess the stability of the results.Results The MR analysis showed that unspecified asthma(OR=1.61,95%CI:1.45-1.77,P<0.01),obesity-related asthma(OR=2.40,95%CI:1.98-2.90,P<0.01),Childhood asthma(OR=1.56,95%CI:1.25-1.94,P<0.01)and allergic asthma(OR=1.47,95%CI:1.25-1.74,P<0.01)present the forward cause effect,but eosinophilic asthma had no causal relation with GERD(OR=1.31,95%CI:0.95-1.81,P=0.10).The sensitivity analysis showed that the horizontal pleiot-ropy and heterogeneity in the results did not exist.Conclusion GERD could lead to an increased risk of un-specified asthma asthma,obesity-associated asthma,pediatric asthma and allergic asthma,while the effect on eosinophilic asthma is not significant.