Causal relationship between gut microbiomes and migraine: a Mendelian randomization study

While observational studies have found a correlation between gut microbiomes and migraine, the causal relationship remains elusive. Our study aims to fill this gap by performing an in-depth statistical investigation of the causal relationship between gut microbiomes and migraine using Mendelian randomization design.
We identified gut microbiomes genetic instrumental variables (IVs) using The Dutch Microbiome Project. These IVs were then used to evaluate previously reported migraine GWAS with sample sizes 599,356 individuals also of European ancestry. To assess pleiotropy and heterogeneity in the MR analysis, we employed several statistical methods including MR-Egger_intercept, MR-PRESSO, MR-Egger, and inverse variance weighted (IVW) in Cochran's Q-test. Additionally, we used MR-egger, weighted median, IVW, simple mode and weighted mode for MR analysis. The effect of single nucleotide polymorphisms (SNPs) on SNP bias was also tested.