As studies have continuously advanced, cross-linking interplay between various organs in aging individuals have continuously emerged as research hotspots. The role of gut microbiota in bone aging-related diseases, including osteoporosis, osteoarthritis, and intervertebral disc degeneration, has been extensively probed. This review first summarized the inseparable association between gut microbiota and osteoporosis, osteoarthritis, and intervertebral disc degeneration, which then explored potential mechanisms of gut-X axis through neuromodulation (microbiota-gut-brain-bone axis), immunomodulation (Th17 and Treg balance), endocrine regulation (gut-derived hormones and 5-HT), metabolite-mediated regulation (SCFAs), bacterial extracellular vesicles, and changes in microbial niche and gut microbiome-associated biomarkers. Moreover, potential intervention strategies including diet, probiotics, fecal microbiota transplantation, and physical activity were summarized to enhance clinical translation applicability. This review creatively exhibited integrated concept of “gut-X axis” to explore common, patterned mechanisms underlying “gut-bone axis”, “gut-joint axis”, and “gut-disc axis”. Furthermore, it delves into potential mechanisms by which this shared pattern regulates bone aging-related diseases and prospectively outlines therapeutic strategies for bone aging based on this axis.

This review presents crucial role and regulatory significance of gut-X axis modes in common bone-aging related diseases. By anchoring the gut-X axis as intervention targets, the thinking of gut microbiota and its related metabolites in basic studies and clinical prevention and treatment of bone aging-related diseases might be expanded, and its clinical application transformation and development could be innovated.