The Associations Between Dietary Flavonoid Intake and Neurodegenerative Diseases Risk: A Cross-Sectional Study.

The incidence of neurodegenerative diseases (NDs), primarily Alzheimer's disease and Parkinson's disease, has been steadily increasing, constituting a significant global public health challenge. This study aims to evaluate the associations between dietary flavonoid intake and the risk of NDs. Data from 13,573 participants in the National Health and Nutrition Examination Survey (NHANES) were analyzed. Weighted logistic regression, receiver operating characteristic (ROC) curve analysis, weighted restricted cubic splines, subgroup analysis, and sensitivity analysis were employed to assess the associations. Overall, higher total flavonoid intake was associated with lower odds of NDs after adjustment for demographic, socioeconomic, lifestyle, and clinical covariates (Q4 vs. Q1: OR = 0.52, 95% CI: 0.31-0.90). Among flavonoid subclasses, flavones (Q4 vs. Q1: OR = 0.49, 95% CI: 0.30-0.79) and flavonols (Q4 vs. Q1: OR = 0.53, 95% CI: 0.33-0.86) showed the strongest inverse associations. In addition, restricted cubic spline analyses demonstrated significant non-linear relationships, with the lowest odds of NDs observed at intake levels of approximately 432 mg/day for total flavonoids, 1.7 mg/day for flavones, and 29 mg/day for flavonols. These findings suggest that moderate intake of flavonoids, particularly flavones and flavonols, may contribute to the observed inverse association between flavonoid intake and NDs.