Objective:To investigate the relationship between non-alcoholic fatty liver disease(NAFLD) and hepatic fibrosis and skeletal muscle mass in patients with type 2 diabetes mellitus(T2DM).Methods:A total of 685 T2DM patients diagnosed at the Endocrinology department of Lanzhou University First Hospital, from April 2022 to May 2023, were divided into NAFLD and Non-NAFLD groups, and the NAFLD group was further categorized into fibrosis and non-fibrosis based on aspartate aminotransferase(AST) /alanine aminotransferase(ALT) level. The differences in appendicular skeletal muscle mass(ASM), appendicular skeletal muscle mass index(ASMI), and the prevalence of muscle mass loss were compared across groups. The correlations between ASMI and NAFLD, as well as liver fibrosis were analyzed by binary logistic regression.Results:Among male T2DM patients, those with NAFLD had lower ASMI levels and a higher prevalence of muscle mass reduction compared to non-NAFLD group. Among female T2DM patients, those with NAFLD had lower levels of ASM and ASMI, and a higher prevalence of muscle mass reduction compared to non-NAFLD group. ASMI levels in both male and female T2DM patients were independently negatively correlated with NAFLD risk( OR=-0.696, 95% CI 0.579-0.837; OR=-0.757, 95% CI 0.629-0.911). In NAFLD patients, ASM and ASMI levels were lower in those with liver fibrosis compared to those without fibrosis; however, the prevalence of muscle mass reduction did not differ significantly. Among male NAFLD patients, ASMI levels were independently negatively correlated with the risk of liver fibrosis( OR=-0.726, 95% CI 0.537-0.983), while no correlation was found in female patients. Conclusion:Reduced muscle mass is independently associated with the risk of NAFLD in both male and female T2DM patients. In males, reduced muscle mass is also independently related to the risk of liver fibrosis.

Trimethylamine N-oxide (TMAO) is an intestinal flora metabolite produced in the liver by the oxidation of trimethylamine (TMA) by hepatic enzymes. Recently, it has been found that plasma TMAO levels play an important role in the development and progression of osteoporosis. This review has presented the physiological functions and metabolic processes of TMAO, and its effects on the development and progression of osteoporosis through oxidative stress and inflammation. Plasma TMAO levels are influenced by diet as well as medications, which provides a new perspective and target for the treatment and prevention of osteoporosis.