Diabetes-related foot disease and sarcopenia-related traits: evidence from US and Chinese cohorts and mendelian randomization

BACKGROUND: High-quality evidence examining the relationship between diabetes-related foot diseases (DFD) and sarcopenia-related traits (SRTs) remains limited. AIMS: To investigate whether DFD is associated with an increased risk of SRTs. METHODS: We analyzed data from 48,831 participants in the National Health and Nutrition Examination Survey (NHANES) and China Health and Retirement Longitudinal Study (CHARLS). Adjusted logistic regression models were used to assess the cross-sectional association between DFD and SRTs. From the CHARLS, 9,093 participants without baseline SRTs were followed up to examine the longitudinal associations between DFD and SRTs. Generalized linear models were used to evaluate correlations and trend effects. Mendelian randomization (MR) analysis was conducted to explore potential causal relationships. RESULTS: In the NHANES cross-sectional analysis, we observed significant associations between DFD and sarcopenia indicators (strength, assistance with walking, rising from a chair, climbing stairs, and falls score, odds ratios [OR]: 2.59, p < 0.001; lean body mass, OR: 3.04, p < 0.001). DFD demonstrated a significant correlation with sarcopenia indicators (Short Physical Performance Battery [SPPB] score, OR:1.71, p < 0.001; grip strength, OR: 2.48, p < 0.001) in the CHARLS (2011) baseline analysis. In the 2015 CHARLS follow-up analysis, DFD remained significantly associated with the SPPB score (relative risk: 1.32, p < 0.05) and grip strength (relative risk: 1.33, p = 0.001). MR findings were consistent with a causal contribution of diabetic neuropathy and diabetic circulatory complications to lower muscle strength and slower gait speed. CONCLUSIONS: This study established DFD as an independent risk factor for SRTs and may accelerate the onset of sarcopenia relative to diabetes mellitus.