Assessing the Association of the Dietary Inflammatory Index With Stroke Risk and All-Cause Mortality Among Hypertension Patients: A NHANES Cross-Sectional Study (2005-2018)

Objective To investigate the association between the Dietary Inflammatory Index (DII) and stroke risk among hypertensive adults, as well as all-cause mortality post-stroke, utilizing data from the National Health and Nutrition Examination Survey (NHANES). Methods This cross-sectional analysis included 7,590 hypertensive participants (stroke group: N=609; non-stroke group: N=6,981). DII was derived from 28 dietary components. Participants were stratified into DII tertiles: Q1 (lowest), Q2 (moderate), and Q3 (highest). Weighted multivariable logistic regression assessed associations between DII (continuous and categorical) and stroke prevalence. Restricted cubic splines (RCS) evaluated non-linearity. Subgroup analyses identified effect modifiers. Cox proportional hazards regression modeled associations of DII and its components with all-cause mortality in the stroke cohort. Results Stroke patients exhibited significantly higher DII scores than non-stroke controls ( P <0.05). Each 1-unit increase in DII was associated with a 13% elevated stroke risk (Odds Ratio (OR)=1.13, 95%CI: 1.04–1.22, P =0.006). Compared to Q1, Q3 had a 68% higher stroke risk (OR=1.68, 95%CI: 1.22–2.32, P =0.002). RCS confirmed significant non-linearity ( P <0.001). Antihypertensive medication modified this association ( P -interaction =0.042). Among stroke patients, DII demonstrated a U-shaped association with mortality ( P -trend =0.048): Q2 had the lowest mortality, while Q1 and Q3 showed poorer survival. Component analysis revealed higher β-carotene scores associated with increased mortality risk (Hazard Ratio (HR)=1.44, 95%CI: 1.01–2.04), whereas higher vitamin A scores correlated with reduced risk (HR=0.68, 95%CI: 0.47–0.99). Conclusion This cross-sectional study identifies a significant, dose-response association between elevated DII and increased stroke risk in hypertensive adults, suggesting that reducing dietary inflammatory load holds preventive potential. Moreover, β-carotene and vitamin A show opposing associations with post-stroke mortality, reflecting the complexity of nutritional inflammation and informing precision nutrition strategies for stroke.