Association between nonalcoholic fatty liver disease and stroke: a cross-sectional study

Background: Emerging evidence suggests a potential association between nonalcoholic fatty liver disease (NAFLD) and stroke risk, but data from US outpatient populations remain inconclusive. This study aimed to evaluate this association in a nationally representative adult cohort. Methods: A cross-sectional analysis was conducted using data from the National Health and Nutrition Examination Survey (NHANES) cycles 1999–2020. NAFLD was defined by the United States Fatty Liver Index (≥30). Stroke history was self-reported. Multivariable logistic regression models adjusted for sociodemographic factors, metabolic syndrome, and survey weights. Subgroup and sensitivity analyses were performed to assess robustness. Results: Among 13 422 participants (mean age 47.141 years; 50.948% female), 40.426% had NAFLD. Stroke prevalence was significantly higher in the NAFLD group (4.087 vs. 2.215%, P < 0.001). NAFLD was independently associated with stroke in unadjusted (OR 1.804, 95% CI 1.508–2.157, P < 0.001) and demographically adjusted models (OR 1.420, 95% CI 1.171–1.721, P < 0.001). In Model 3, after adjusting for metabolic syndrome, the association was not statistically significant (OR 1.193, 95% CI 0.958–1.485, P = 0.116). In the subgroup analysis, the association between the two diseases was significant in participants aged 50–65 years (OR 1.654, 95% CI 1.044–2.622) and those without hypertension (OR 2.077, 95% CI 1.211–3.328). The connection remained significant in models applying inverse probability weighting (OR 1.611, 95% CI 1.400–1.853, P < 0.001) and continued to exist after non-Hispanic Black participants were excluded (OR 1.290, 95% CI 1.006–1.656, P = 0.045). Conclusions: This study reveals a significant association between NAFLD and stroke, especially in adults aged 50–65 and those without hypertension. These findings suggest that NAFLD is associated with vascular risk; further prospective research is needed to determine whether it should be incorporated into cardiovascular risk assessments. Longitudinal research is needed to confirm whether treating NAFLD reduces stroke incidence.