Association Between Dietary Index for Gut Microbiota and Sarcopenic Obesity in Middle‐Aged and Elderly Population: The Mediation Role of Hepatic Steatosis Index

ABSTRACT This study aims to assess the association between the Dietary Index for Gut Microbiota (DI‐GM) and sarcopenic obesity (SO) in middle‐aged and elderly populations, and to evaluate whether the Hepatic Steatosis Index (HSI) acts as the mediation in this relationship. A cross‐sectional analysis was conducted on 3746 participants from the National Health and Nutrition Examination Survey (NHANES) database from 2011 to 2018. Weighted multivariate linear and logistic regression models were used to explore the association between DI‐GM and the prevalence of SO, DI‐GM and HSI, and HSI and the prevalence of SO. Restricted cubic spline (RCS) analysis was used to assess the potential nonlinear relationship between DI‐GM and SO. Subgroup analyses were performed to evaluate the consistency of this relationship across different demographic groups. Additionally, mediation analysis was conducted to explore whether there existed a potential association between DI‐GM, HSI, and SO. Among the 3746 participants included in the study, 369 (9.8%) were diagnosed with SO. After adjusting for all covariates by weighted multivariate logistic regression, each unit increase in DI‐GM was associated with a 15% decrease in the prevalence of SO [Model 3: OR = 0.85, 95% CI (0.76, 0.95), p = 0.006]. When DI‐GM was categorized into quartiles, the results remained significant [Model 3: OR = 0.47, 95% CI (0.30, 0.75), p = 0.002]. Further analysis indicated that the protective effect of DI‐GM was primarily attributed to the Beneficial gut microbiota score (BGMS). RCS analysis revealed a significant linear relationship between DI‐GM and SO ( p > 0.05). Subgroup analysis demonstrated the robustness of this association across various subgroups. Mediation analysis showed that 17.8% of the association between DI‐GM and SO was mediated by HSI ( p < 0.05). DI‐GM is significantly inversely associated with the prevalence of SO in the aging population, and HSI partially mediates this association.