Dietary index for gut microbiota is associated with stroke among US adults†

Aims: Emerging evidence underscores the diet–microbiota–gut–brain axis as vital to brain health. The dietary index for gut microbiota (DI-GM), quantifying diet quality linked to gut microbiota diversity, reflects healthier gut microbiota with higher scores. Therefore, this study was designed to explore the unclear association between DI-GM and stroke. Methods: A cross-sectional analysis was conducted using data from 48 677 participants aged ≥20 years in the National Health and Nutrition Examination Survey (NHANES). Demographic and dietary data were collected, and multivariable weighted logistic regression analysis was performed to evaluate the association between the DI-GM and stroke. Additionally, restricted cubic spline (RCS), subgroup analyses, and receiver operating characteristic (ROC) curve were conducted. Results: In participants aged ≥20 years, the odds ratio (OR) was 0.96 (95% CI: 0.92–1.00, P = 0.075) in the crude model, but after adjustment, the OR was 0.93 (95% CI: 0.89–0.98, P = 0.003), while higher beneficial to gut microbiota scores were consistently associated with lower stroke prevalence with ORs of 0.87 (95% CI: 0.83–0.90, P < 0.001) in the crude model and 0.88 (95% CI: 0.83–0.93, P < 0.001) after adjustment. Among participants aged 20–29 years, no significant association was observed. For those aged ≥30 years, higher DI-GM and beneficial to gut microbiota scores were associated with lower stroke prevalence, with DI-GM showing ORs of 0.93 (95% CI: 0.89–0.97, P < 0.001) in the crude model and 0.93 (95% CI: 0.89–0.98, P = 0.003) after adjustment, and beneficial to gut microbiota scores showing ORs of 0.82 (95% CI: 0.79–0.86, P < 0.001) in the crude model and 0.88 (95% CI: 0.83–0.93, P < 0.001) after adjustment. RCS indicated a linear relationship between DI-GM and stroke. Conclusion: The DI-GM was inversely and linearly associated with stroke prevalence, particularly in adults aged 30 years and above.