Associations between an inflammatory diet index and severe non-alcoholic fatty liver disease: a prospective study of 171,544 UK Biobank participants

BACKGROUND: Although non-alcoholic fatty liver disease (NAFLD) is linked to inflammation, whether an inflammatory diet increases the risk of NAFLD is unclear. This study aimed to examine the association between the Energy-adjusted Diet Inflammatory Index (E-DII) score and severe NAFLD using UK Biobank. METHODS: This prospective cohort study included 171,544 UK Biobank participants. The E-DII score was computed using 18 food parameters. Associations between the E-DII and incident severe NAFLD (defined as hospital admission or death) were first investigated by E-DII categories (very/moderately anti-inflammatory [E-DII <  - 1], neutral [E-DII - 1 to 1] and very/moderately pro-inflammatory [E-DII > 1]) using Cox proportional hazard models. Nonlinear associations were investigated using penalised cubic splines fitted into the Cox proportional hazard models. Analyses were adjusted for sociodemographic, lifestyle and health-related factors. RESULTS: Over a median follow-up of 10.2 years, 1489 participants developed severe NAFLD. After adjusting for confounders, individuals in the very/moderately pro-inflammatory category had a higher risk (HR: 1.19 [95% CI: 1.03 to 1.38]) of incident severe NAFLD compared with those in the very/moderately anti-inflammatory category. There was some evidence of nonlinearity between the E-DII score and severe NAFLD. CONCLUSIONS: Pro-inflammatory diets were associated with a higher risk of severe NAFLD independent of confounders such as the components of the metabolic syndrome. Considering there is no recommended treatment for the disease, our findings suggest a potential means to lower the risk of NAFLD.