Causal relationship between gut microbiota and dental caries: A Mendelian randomization analysis

The onset of dental caries is associated with multiple factors, including oral microbiota, dietary sugars, the defensive mechanisms of saliva and teeth, oral hygiene practices, and socioeconomic factors. However, its relationship with the gut microbiota remains to be further explored. It remains crucial to establish a definitive causal link between the gut microbiota and the development of dental caries. This study aimed to investigate the causal relationship between gut microbiota and the risk of dental caries, focusing on identifying specific microbial communities potentially implicated in its pathogenesis. Gut microbiota data from genome-wide association studies (GWAS) conducted by the MiBioGen consortium were utilized as the exposure variable, with dental caries as the outcome variable. A Mendelian randomization (MR) approach was employed, leveraging comprehensive, publicly available GWAS summary data from European populations. The primary analytical method was the inverse variance weighted method, supplemented by additional techniques such as the weighted median model, MR-Egger, simple mode, and weighted mode, to ensure the robustness of the results. Heterogeneity was evaluated using Cochran Q test, and potential pleiotropy was assessed through MR-Egger regression. Sensitivity analyses were performed using the leave-one-out method to further validate the findings. The results revealed that a higher relative abundance of Christensenellaceae, FamilyXIII, Ruminococcaceae, and Senegalimassilia was associated with a reduced risk of dental caries. In contrast, a higher relative abundance of Erysipelotrichia, Erysipelotrichales, Pasteurellales, Erysipelotrichaceae, Pasteurellaceae, Methanobrevibacter, Roseburia, and Terrisporobacter was linked to an elevated risk of dental caries. This study provides compelling evidence for a causal relationship between gut microbiota and the development of dental caries, offering novel insights into the potential role of specific gut microbial communities in the pathogenesis of dental caries.