Modifiable lifestyle factors and risk of intracranial aneurysm: A univariate and multivariate Mendelian randomisation study.

The aim of this study was to assess the potential causal relationship between lifestyle factors and intracranial aneurysms (IAs) using a two-sample Mendelian randomization (MR) approach. The study used a pooled dataset from a genome-wide association study that covered information on 24 lifestyle factors, intracranial aneurysm cases, subarachnoid hemorrhage, and unruptured aneurysms. Five MR methods were applied for analysis by selecting single nucleotide polymorphisms as instrumental variables, with the inverse variance weighting method as the main method. To ensure the stability of the results, horizontal multiple validity tests, sensitivity analyses, and inverse MR were performed, and genetically determined exposure factors were adjusted by multivariate MR. Several lifestyle factors were found to have a significant genetic causal effect on the occurrence and development of intracranial aneurysms. For example, lamb intake, smoking initiation, number of cigarettes smoked per day, length of television viewing, and fatigue were identified as genetic risk factors and strongly associated with aneurysm rupture, whereas red wine intake showed some genetic protection against intracranial aneurysms and similarly affected aneurysm rupture. Sensitivity analyses and inverse MR verified the robustness of these results. After adjusting for exposure factors, multivariate MR confirmed daily smoking and smoking initiation as risk factors for intracranial aneurysms, unruptured aneurysms, and subarachnoid hemorrhage, whereas red wine intake was a genetically protective factor against intracranial aneurysms and subarachnoid hemorrhage. This MR analysis revealed a genetic causal link between specific lifestyle factors and intracranial aneurysms, emphasizing the need for further studies to confirm these findings and explore their mechanisms.