The Relationship Between Flavonols Intake and Stroke in the Elderly: NHANES (2007-2010 and 2017-2018)

Background Stroke is a common fatal and disabling disease in the elderly. We investigated the correlation and potential benefits of dietary intake of flavonoid compounds and their subclasses in elderly stroke patients. Methods This study utilized data from the National Health and Nutrition Examination Survey (NHANES) from 2007–2010 and 2017–2018. Flavonoids intake was calculated based on food frequency questionnaires (FFQ) through a 24-hour dietary recall. Multivariable logistic regression analysis was employed to explore the relationship between flavonoids intake and their subclasses with stroke prevalence. Restricted cubic splines (RCS) were used to investigate the nonlinear relationship between flavonols subclasses and stroke. Multivariable logistic regression models were used to evaluate the association between flavonols intake and stroke among all participants and across different flavonols subgroups. Bayesian kernel machine regression (BKMR) was introduced to assess the overall effect of flavonols intake levels on the risk of stroke status. Considering the relatively high correlation among flavonols subclasses, we further implemented a hierarchical variable selection method, performing 50,000 iterations using the Markov Chain Monte Carlo algorithm. We then calculated the conditional posterior inclusion probability (condPIP). Results Including 3,806 elderly stroke patients, the study revealed an inverse relationship between dietary flavonoids and their subclasses and stroke prevalence. After adjusting for potential confounders, it was found that higher quartiles of flavonols intake were associated with lower stroke prevalence. Specifically, with each unit increase in flavonols (Q4) intake, the odds of stroke in the elderly decreased by 61% (OR = 0.390, 95% CI [0.209–0.728]; P  = 0.005). Similar results were observed for the subclasses of flavonols. Subgroup analyses indicated that age and poverty index ratio (PIR) were effect modifiers in the relationship between flavonols intake and stroke. We further examined the intake levels of dietary flavonols subclasses such as isorhamnetin, kaempferol, myricetin, and quercetin and their association with stroke status stratified by population characteristics. In addition to age and PIR, hyperlipidemia and body mass index (BMI) were found to be the most common significant influencing factors in the relationship between flavonols subclasses and stroke prevalence. Furthermore, RCS revealed a “U”-shaped nonlinear relationship between flavonols, including their quercetin and kaempferol subclasses, and stroke, whereas the relationship between stroke and myricetin was linear. Our study also assessed the overall impact of dietary flavonols subclasses on stroke in the elderly and the interrelationships among these subclasses. The results consistently indicated a negative joint effect of flavonols subclass mixtures on the risk of stroke in the elderly. When evaluating the impact of individual flavonols subclasses on stroke outcomes, a potential dose-response relationship was observed, with increasing intake of myricetin being associated with a decreased risk of stroke. Conclusion These results emphasize that adhering to an increased dietary intake of flavonoid compounds, particularly flavonols and their subclasses such as myricetin, can significantly reduce the prevalence of stroke among the U.S. elderly population. This offers potential benefits for stroke patients, especially among elderly individuals aged 60–70 and those with higher incomes.