| Objective To employ Mendelian randomization (MR) to explore the association between the gut microbiome (GM) and bone mineral density (BMD). Methods GM and BMD GWAS data were selected from the IEU GWAS database at the University of Bristol. Inverse variance weighted (IVW), weighted median estimator (WME), and MR-Egger regression for two-sample MR analysis were used. Odds ratios (ORs) were used to evaluate the causal relationship between GM and BMD. Results The results showed a causal relationship between GM and BMD. Among them, the genera bacteroides, streptococcus, and the families ruminococcaceae UCG002 and ruminococcaceae UCG005 might be protective factors for BMD, while the genera gordonibacter, oxalobacter, and thermoanaerobacter might be potential risk factors for BMD. In addition, there might be unknown gut microbiota that were potential threats to BMD. Conclusion We conducted a comprehensive assessment using Mendelian randomization to investigate the causal effect of 211 gut microbiota species (from phylum to genus level) on BMD. The results suggest that bacillus spp., streptococcus lactis, streptococcaceae UCG002, and streptococcaceae UCG005 may serve as protective factors for BMD. On the other hand, gordonella spp., clostridium oxalicum spp., and tethanella spp. may act as potential risk factors for BMD. Additionally, there might be unidentified intestinal flora that poses a potential threat to BMD. These findings support the influence of gut microbiota on BMD and provide valuable insights into specific flora that warrant further investigation. |