Causal relationship between irritability and asthma: a bidirectional two-sample Mendelian randomization study

IntroductionPrevious studies have suggested a relationship between bad mood and asthma. Therefore, in this study, a two-sample Mendelian randomization (MR) method was used to explore the correlation between irritability and asthma.Material and MethodsRelevant instrumental variables (IVs) were extracted from the aggregated data of the genome-wide association studies (GWAS) database. Inverse-variance weighting (IVW) and weighted median (WME) were used for the MR analysis to evaluate the causal relationship between irritability and asthma using odds ratios (ORs) and the corresponding 95% confidence intervals (CIs), respectively. The "leave-one-out" method was used for sensitivity analysis.ResultsThe results of IVW analysis using random-effects models suggested that irritability increased the risk of asthma (OR = 1.954, 95% CI = 1.188-3.214, p = 0.008). The results of WME were consistent with this observation (OR = 1.934, 95% CI = 1.100-3.400, p = 0.021). Additionally, gastroesophageal reflux disease (GERD) might account for approximately 40% of the relationship between irritability and asthma. The sensitivity analysis revealed the stability of the results.ConclusionThe causal relationship between irritability and asthma was analyzed through MR analysis. Irritability increased the risk of asthma. GERD might play an important mediating role in this relationship.