U-shaped association between dietary flavonoid and gallstone prevalence with sex-specific effects: Insights from a cross-sectional study.

ObjectiveTo examine the association between dietary flavonoid intake and gallstone prevalence in a representative United States sample using National Health and Nutrition Examination Survey 2017-2018 data.MethodsThis cross-sectional study included 4087 adults aged ≥20 years. Flavonoid intake was assessed using the United States Department of Agriculture Food and Nutrient Database for Dietary Studies and covered 29 flavonoids across six subclasses. Gallstones were defined by self-reported physician diagnosis. Covariates included demographics, lifestyle, and health status. Multivariate logistic regression, weighted quantile sum, quantile g-computation, and Bayesian kernel machine regression models were used to evaluate the individual and combined effects of flavonoids.ResultsGallstone prevalence was 11.00% (n = 475). A U-shaped relationship was observed for total flavonoid intake, with lower intakes negatively and higher intakes positively associated with gallstone prevalence. Among females, higher total flavonoid and flavonol intakes were significantly associated with increased gallstone prevalence. Specific flavonoids, including theaflavins and thearubigins, were associated with gallstone prevalence in females. Both the weighted quantile sum and quantile g-computation models showed a significant positive correlation in the overall population and among females; however, this association was not observed in males. Bayesian kernel machine regression identified flavan-3-ols as a key contributor in females.ConclusionsA U-shaped relationship was observed between total flavonoid intake and gallstone prevalence. Dietary flavonoids, particularly in females, are associated with the prevalence of gallstone, highlighting the need for further research into potential mechanism and consideration of sex in dietary guidelines.