The newly proposed dietary index for gut microbiota and its association with the risk of nonalcoholic fatty liver disease: the mediating role of body mass index.

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with dietary habits and the gut microbiota. The dietary index for the gut microbiota (DI-GM) is a newly proposed index that reflects gut microbial diversity based on dietary intake. However, its relationship with NAFLD remains unclear. This study aimed to explore the association between DI-GM and the risk of NAFLD.

METHODS

In this cross-sectional study, we utilized data from the NHANES 2009-2018. Multivariable logistic regression, restricted cubic spline curves (RCS), subgroup analysis, and mediation analysis were used to evaluate the association between DI-GM and the risk of NAFLD.

RESULTS

A total of 4,923 participants were included in the study. According to the fully adjusted model, a significant inverse association was observed between DI-GM and NAFLD (OR = 0.883, 95% CI: 0.835-0.932, P < 0.001). After stratification by quartiles, compared with participants in the first quartile of DI-GM score, those in the fourth quartile had a 36.5% lower odds of developing NAFLD (OR = 0.635, 95% CI: 0.481-0.839, P = 0.002). Mediation analysis revealed that 72.69% of the association between DI-GM and NAFLD was mediated by BMI (P < 0.001). Subgroup analysis suggested that the association between DI-GM and NAFLD might be influenced by race (P for interaction < 0.05). RCS analysis revealed a linear correlation between DI-GM and NAFLD (P for nonlinear = 0.883).

CONCLUSIONS

DI-GM is negatively associated with NAFLD risk, with BMI mediating this relationship and race being a significant influencing factor.