Association between the Dietary Inflammatory Index and Metabolic Dysfunction-Associated Fatty Liver Disease and Hepatic Fibrosis: A Cross-sectional Analysis using NHANES 2017-2020

Background Dietary inflammation plays an important role in the progression of metabolic dysfunction-associated fatty liver disease (MAFLD). However, research on the association between dietary inflammation and MAFLD, particularly its associated fibrosis, remains limited. The Dietary Inflammatory Index (DII) is an effective tool for quantifying dietary inflammation. This study aimed to investigate the association between DII, MAFLD, and hepatic fibrosis using data from the National Health and Nutrition Examination Survey (NHANES). Methods Data were obtained from the 2017–2020 NHAENS. Participants were divided into four groups according to DII quartiles. The prevalence of MAFLD and hepatic fibrosis was compared among these groups after applying sampling weights. Multivariate logistic regression analyses were used to evaluate the association between DII and MAFLD with or without hepatic fibrosis. Subgroup analyses explored potential interactions between DII and other covariates. Restricted cubic spline (RCS) analysis was performed to assess the potential nonlinear relationship between DII and the risk of MAFLD and hepatic fibrosis. Results A total of 7,500 participants were included in the study. A statistically significant difference in the prevalence of MAFLD and hepatic fibrosis was observed across the DII quartile groups (P < 0.05). A moderate DII was associated with the highest risk of MAFLD without hepatic fibrosis (OR: 1.57, 95% CI: 1.26–1.97 ), while a higher DII was linked to an increased risk of MAFLD with hepatic fibrosis (OR: 1.87, 95% CI: 1.41–2.49 ). Subgroup analysis revealed a higher risk of MAFLD (OR: 2.34, 95% CI: 1.19–4.63) and hepatic fibrosis (OR: 1.87, 95% CI: 1.41–14.83) in women who had never consumed alcohol and were in the highest DII quartile Q4. Additionally, individuals in Q2 with a high BMI (> 30 kg/m2) were also at elevated risk of MAFLD (OR: 2.31, 95% CI: 1.19–4.50) and hepatic fibrosis (OR: 2.12, 95% CI: 1.40–3.21). RCS analysis demonstrated a significant nonlinear relationship, with an inflection point at a DII of 2.20 for the risk of MAFLD and hepatic fibrosis (P for non-linearity < 0.01). Conclusion Our research shows that DII is closely associated with the risks of MAFLD and hepatic fibrosis, exhibiting a significant nonlinear dose-dependent relationship. As DII increases, the risk of hepatic fibrosis gradually emerges.