Abstract
BACKGROUND: The gut-retina axis, an emerging area of research, has uncovered the bidirectional link between the intestines and retina, offering new insights into ophthalmic disease management. Diabetic retinopathy (DR), a common diabetes complication with a digestive-related connection, lacks large-sample retrospective studies on the impact of gut microbiota-related diets. The association between the Dietary Index for Gut Microbiota (DI-GM) and DR requires further investigation. METHODS: 1,285 diabetic patients from the National Health and Nutrition Examination Survey (NHANES) spanning the years 2009 to 2018 were analyzed. DI-GM, based on 14 foods or nutrients intake, served as the exposure variable. Associations were assessed via Spearman correlation, weighted logistic regression, restricted cubic spline (RCS) analysis, and subgroup analyses. RESULTS: Spearman analysis revealed predominantly inverse correlations among DI-GM components. After adjusting for confounders, each 1-point increase in DI-GM was associated with a 12% lower DR risk (OR = 0.88, 95% CI 0.78-0.99, P = 0.039). The Q4 DI-GM exhibited a 67% reduced DR risk compared to Q1 (OR = 0.33, 95%CI 0.12-0.88, P = 0.028). RCS analysis identified a nonlinear dose-response relationship (P-nonlinearity < 0.01), with rapid risk reduction at DI-GM < 4 and diminishing returns thereafter. Subgroup analyses indicated that most subgroup associations showed no statistically significant differences (interaction P > 0.05), except for participants with long-standing diabetes, without hypertension and BMI < 25 (OR = 0.55, 95%CI: 0.33-0.93, P = 0.03). CONCLUSIONS: Higher DI-GM scores are linked to lower DR risk, supporting dietary optimization (e.g., increased whole grains/vegetables, reduced processed meat) as a potential strategy for DR prevention through gut microbiota modulation. These findings advance gut-retina axis theory and provide actionable dietary guidelines for diabetes complications.