Association between the dietary index for gut microbiota and cardiometabolic multimorbidity: the mediating role of systemic immune-inflammation index and systemic inflammatory response index

Sihan Hu¹jiayuan song²Hui Jiang^3*Baojian Wei^4*Hui Wang^4*

• ¹Guangxi Medical University, Nanning, China
• ²Changchun University of Chinese Medicine, Changchun, Jilin Province, China
• ³School of Nursing, Shandong First Medical University, Tai'an, Shandong Province, China
• ⁴School of Nursing, Shandong First Medical University, School of Nursing, Shandong First Medical University, Tai'an, Shandong Province, China

Objective: This study aims to investigate the association between the Dietary Index for Gut Microbiota (DI-GM) and the risk of Cardiometabolic Multimorbidity (CMM), with a focus on the mediating role of systemic inflammatory markers, including Systemic Immune-Inflammation Index (SII) and Systemic Inflammatory Response Index (SIRI). Methods: A cross-sectional analysis was conducted on 17,388 eligible participants from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2020. Weighted logistic regression model was used to evaluate the association between DI-GM, SII, SIRI and CMM.Restricted cubic spline (RCS) regression model was used to explore potential nonlinear relationship between three variables and the risk of CMM. Mediation analysis was performed to assess the potential mediating effects of SII and SIRI on the association of DI-GM and CMM. We also constructed subgroup analysis and sensitivity analysis.Results: Higher DI-GM scores were significantly associated with a reduced risk of CMM (OR=0.94, 95% CI: 0.91-0.98, P = 0.001). Higher Ln-SII and Ln-SIRI were significantly associated with an increased risk of CMM (OR=1.45, 95% CI: 1.28-1.65, P < 0.001; OR=1.87, 95% CI: 1.69-2.07, P < 0.001). Subgroup analysis indicated that the protective effect of DI-GM on CMM was more pronounced among individuals with higher education levels (P for interaction < 0.05). Mediation analysis revealed that SII and SIRI partially mediated the association between DI-GM and CMM, accounting for 8.3% and 18.1% of the total effect, respectively (P < 0.001). Sensitivity analysis indicated the robustness of the results.The findings suggested that a diet promoting gut microbiota health, as measured by DI-GM, was associated with a lower risk of CMM, partially mediated by reduced systemic inflammation.These results strongly emphasize the potential of gut microbiota to reduce the risk of CMM from a dietary perspective and the underlying mechanisms behind this potential, providing new strategies for clinical prevention and treatment of CMM.