Association of triglyceride-glucose index and atherogenic index of plasma with sarcopenia across different glucose metabolism states: the mediating role of oxidative stress and chronic inflammation

BACKGROUND: The triglyceride-glucose (TyG) index and the atherogenic index of plasma (AIP) serve as biomarkers representing broad metabolic risks, and they are easy to obtain and cost-effective. However, there is a lack of extensive research investigating the relationship between these two metabolic markers and sarcopenia across various glucose metabolism statuses. METHODS: Data were obtained from the NHANES 2011-2016. A weighted logistic regression model was conducted to assess the relationships between AIP, TyG, and sarcopenia across all participants and subgroups categorized by glucose metabolism status. Restricted cubic spline analysis was applied to investigate their dose-response patterns. Additionally, mediation analysis was performed to explore the mediating influence of oxidative stress and chronic inflammation on the observed associations. Furthermore, the diagnostic accuracy of TyG and AIP in predicting sarcopenia was evaluated using receiver operating characteristic curve analysis. RESULTS: = 0.5283) and sarcopenia. Furthermore, positive AIP and TyG and sarcopenia associations were significant in the normal glucose metabolism population, while not in pre-diabetes and diabetes populations. The associations of AIP and TyG with sarcopenia were significantly mediated via oxidative stress (5.9-18.3%) and chronic inflammation (5.9-18.9%), respectively. The area under curves (95% CI) of the AIP and TyG index for sarcopenia prediction were 0.7660 (0.7376, 0.7945) and 0.7648 (0.7361, 0.7935), respectively. CONCLUSION: In individuals with normal glucose metabolism, elevated AIP and TyG indices show a positive correlation with the occurrence of sarcopenia, and this relationship is partially mediated by the inflammation and oxidative stress present in the individual. Maintaining optimal glycemic and lipid metabolism is crucial for the primary prevention of sarcopenia and related diseases.