Background Previous studies have presented skeletal muscle loss was associated with diabetes mellitus (DM) and non-alcoholic fatty liver disease (NAFLD). However, whether the presence of NAFLD could influence the association between skeletal muscle mass and DM was still unknown. The aim of the present study was to investigate the relationship of skeletal muscle mass with diabetes in Chinese middle-aged and older community population, and whether the association could be effected by NAFLD. Methods A cross-sectional study of 5,626 residents aged 45 and above in Changfeng community in Shanghai were conducted. Skeletal muscle mass (SMM) was detected by dual-energy X ray absorption (DXA) and calculated as ASM% [appendicular skeletal muscle mass (ASM) (kg) /body weight*100%]. Liver fat content (LFC) was measured using a quantitative ultrasound method. Multivariate logistic regression analyses were conducted to investigate the association between ASM% quartiles with DM. Results With ASM% decreasing, fasting blood glucose (FBG), 2-hour postprandial blood glucose (2hBG) and Homeostasis model assessment for insulin resistance (HOMA-IR) as well as LFC increased in both genders, and the prevalence of diabetes and NAFLD also increased. Spearman analysis showed ASM% was negatively correlated with FBG, 2hBG and LFC. Stepwise logistic regression analysis showed after multiple adjustments, ASM% quartile was negatively associated with the risk of diabetes only in male, but not in female. Subgroup analysis found the ASM% quartiles remained negatively correlated with the risk of diabetes in male non-NAFLD population, but not in NAFLD population. When stratified by LFC quartiles, the results was similar. After multivariate adjustments, low ASM% was negatively correlated with the risk of diabetes only in the first and second LFC quartile in male, and the association remained insignificant in each LFC quartile in female. Conclusions Skeletal muscle mass was negatively associated with the risk of diabetes in male population but not in female. The presence of NAFLD weakened this association. The results suggested stratified management of diabetes should be considered according to skeletal muscle mass and the presence of NAFLD.

Background Previous studies have presented osteoporosis and sarcopenia frequently occur concomitantly in elderly. Type I collagen carboxyl-terminal peptide β (β-CTX) usually increases in osteoporosis. However, the relationship between β-CTX and muscle mass remains unclear. This study aimed to explore the association between serum β-CTX and the risk of sarcopenia in elderly inpatients. Methods 228 patients > 65 years were recruited in this cross-sectional study. Dual-energy X-ray scanning (DXA) was used to access skeletal muscle and bone mass. Skeletal muscle mass index (SMI) was defined as appendicular skeletal muscle mass (ASM) divided by height2. Serum markers of bone remodeling were detected by electrochemical immunofluorescence assay. Results Serum concentration of β-CTX as well as the prevalence of osteoporosis were higher in low SMI group than in the normal SMI group. Correlation analysis showed that serum β-CTX levels negatively correlated with SMI and bone mass. Across the quartiles of serum β-CTX, total skeletal muscle mass (TSM), ASM, SMI, total bone mass (TBM) and bone mass at various sites including the limbs, spine and pelvis decreased significantly, wherea the prevalence of low SMI and osteoporosis increased. Logistic regression analysis showed the higher quartiles of serum β-CTX had an increased risk of low SMI and osteoporosis, compared to the lowest quartile (the third and fourth quartiles for low SMI and the fourth quartile for osteoporosis). Conclusions With increasing serum β-CTX levels, muscle and bone mass decreased in Chinese elderly inpatients. Serum β-CTX was positively associated with the risk of osteoporosis and muscle loss.