Investigating the genetic causality between periodontitis and intracranial aneurysms: A 2-sample Mendelian randomization study

Previous studies have suggested an association between periodontitis and intracranial aneurysms (IAs). However, it remains unclear whether the association is causal. This study systematically investigated the potential genetic link between periodontitis and IAs, including the formation and rupture of IAs. This study utilized publicly available genome-wide association study summary statistics data for a 2-sample bidirectional Mendelian randomization (MR) analysis. The main statistical analysis method used was inverse variance weighting. The reliability of the results was verified through sensitivity analysis and assessment of the strength of genetic instrumental variables. There was no causal relationship between genetically determined periodontitis and uIAs (odds ratio [OR] = 1.02, 95% confidence interval [CI]: 0.89-1.17, P = .76) or aneurysmal subarachnoid hemorrhage (OR = 0.96, 95% CI: 0.85-1.08, P = .50). In the reverse MR analysis, the increased risk of uIAs or SAH was not statistically significant for an increased risk of periodontitis (uIAs: OR = 0.99, 95% CI: 0.94-1.05, P = .78; aneurysmal subarachnoid hemorrhage: OR = 1.02, 95% CI: 0.96-1.09, P = .51). The results from MR-Egger regression and weighted median method were consistent with the inverse variance weighted method. Sensitivity analysis indicated that horizontal pleiotropy was unlikely to distort the causal estimates. Our study does not support a causal relationship between periodontitis and the formation or rupture of IAs, and vice versa.