Association between Dietary Index for Gut Microbiota (DI-GM) and non-alcoholic fatty liver disease (NAFLD): Evidence from NHANES 1999-2018.

Background and objectives: Gut microbiota and liver are closely linked, and disruption of the gut-liver axis has been associated with various conditions, including non-alcoholic fatty liver disease (NAFLD). The Die-tary Index for Gut Microbiota (DI-GM), a recently developed measure of gut microbiota variety, has not been researched in connection with NAFLD.

Methods and study design: We conducted a cross-sectional analysis of 12,910 eligible participants aged ≥20 years from the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2018 by adjusting for covariates. Dietary recall data were used to calculate the DI-GM (including components beneficial and unfavorable to gut microbiota). Multiple logistic regression and subgroup analyses were used.

Results: A total of 12,910 patients were included in the study, of whom 4673 (36.2%) were identified as NAFLD. Each point increase in DI-GM was associated with an 8% decrease in the prevalence of NAFLD (OR = 0.92, 95% CI = 0.90, 0.94, p <0.001), the associations remained significant after adjusting for potential confounders (OR = 0.92, 95% CI = 0.89, 0.95, p <0.001). After grouping DI-GM, in the fully adjusted model, participants with DI-GM ≥ 6 were significantly negatively associated with the prevalence of NAFLD (OR = 0.71, 95% CI = 0.61, 0.82, p <0.001) compared to participants with DI-GM ≤3 group with adjustment for potential confounders. After subgroup analyses and sensitivity analyses, the relationship between DI-GM and NAFLD remained robust.

Conclusions: Our findings indicate an inverse association between the newly proposed DI-GM and the presence of NAFLD in adult Americans, offering a novel perspective on NAFLD research.