Revealing the Association Between Total and Subclass Flavonoid Intakes and the Prevalence of Asthma in U.S. Adults.

Asthma is a prevalent chronic respiratory disease in the U.S., and individuals with severe asthma impose a substantial economic burden on the healthcare system. Flavonoids have been shown to play a critical role in the prevention of various diseases. However, previous research has not specifically explored the relationship between flavonoid intake and asthma prevalence. To address this gap, we analyzed data from the NHANES (National Health and Nutrition Examination Survey) and FNDDS (Food and Nutrient Database for Dietary Studies), involving 14,520 qualified U.S. adult participants, using statistical and machine learning models. Multivariate logistic regression models, restricted cubic spline model analysis, and quantile-based g-computation mixture analysis revealed that a higher total flavonoid intake was associated with a significantly lower risk of asthma, and the reverse relationship was nonlinear. Quantile-based g-computation mixture analysis also revealed that flavonoid subclasses flavanones, anthocyanidins, and flavonols have a major contribution to the reverse relationship. Additionally, the stratified models also indicated that the participants with a higher flavonoid intake had a lower risk of being diagnosed with asthma. The effect of total flavonoid intake on asthma prevalence varied by racial groups (