Causal association between asthma and periodontitis: A two‐sample Mendelian randomization analysis

Abstract Background A unified view of whether asthma and periodontitis interact and the direction of action is not found in previous studies. Therefore, in this article, we will elucidate bidirectional causality by two‐sample Mendelian randomization (MR). Methods We obtained summary‐level data for asthma and periodontitis from the massive GWAS databases of several publicly available. Meanwhile, it will ensure no confounders like smoking using the Phenoscanner website to have a search over each SNP. The F statistic value of each SNP is calculated as more significant than 10. This MR analysis mainly used five MR methods: MR‐Egger, weighted median, inverse variance weighted (IVW), simple mode, and weighted mode. As a result, we performed heterogeneity and horizontal pleiotropy tests. Results We have found supporting evidence to verify the hypothesis that asthma may be a protective factor for periodontitis (IVW OR = 0.34; 95% CI = [0.132,0.87]; p = 0.025). The consistent impact direction is shown when additional asthma GWAS dataset are used (MR‐Egger OR = 0.118; 95%CI = [0.016,0.883]; p = 0.04). There is no evidence of a causal effect of periodontitis at the risk of asthma in the reverse analysis ( p > 0.05). Conclusions Our analysis found that people with asthma may have a lower risk of periodontitis than those without. This MR analysis could have significant implications for the clinical process and future research.