Gut Microbiota And Bruxism: A Mendelian Randomization Study

To assess the relationship between gut microbiota and bruxism using Mendelian randomization We utilized genome-wide association study (GWAS) statistical data for gut microbiota from the MiBioGen Alliance consortium (N = 18,340). Sleep bruxism (SB) outcome data were derived from the FinnGen Release R9 (publicly released in April 2022), comprising 12,297 SB cases (defined by ICD-10 diagnostic codes F45.8 and G47.8) and 364,980 controls, with a total sample size of 377,277. Independent genetic loci significantly associated with the relative abundance of 211 gut microbiota taxa (P < 5 × 10⁻⁸) were selected as instrumental variables (IVs). A two-sample Mendelian randomization (MR) analysis was primarily conducted using the inverse-variance weighted (IVW) method, with beta (β) values estimating causal effects between gut microbiota and SB. Sensitivity analyses included the leave-one-out method, Cochran’s Q heterogeneity test, and MR-Egger regression for horizontal pleiotropy assessment to validate result robustness. In the final analysis, five gut microbiota genera associated with bruxism were identified through the inverse-variance weighted (IVW) method. Notably, genus Ruminococcaceae UCG011 and genus Ruminococcus gauvreauii group exhibited protective effects against bruxism. Conversely, three genera were identified as risk factors: genus Coprococcus3, genus Erysipelatoclostridium, and genus Olsenella. Our study demonstrates causal associations between specific gut microbiota and sleep bruxism (SB), offering novel insights into the gut microbiota–SB axis and its underlying mechanisms.