Inverse association between dietary flavonoid intake and nocturia in middle-aged and older adults from NHANES 2007–2010

Nocturia is an increasingly prevalent chronic disease that affects the quality of an individual's life. The prevalence of nocturia exceeds 50% among older adults in the U.S. Inflammation and oxidative stress are considered potential factors affecting nocturia, according to prior research. Flavonoids have attracted considerable interest due to their anti-inflammatory, antioxidant, and anti-aging properties. The association between flavonoid consumption and nocturia has been rarely investigated. For this cross-sectional study, we selected 5926 middle-aged and older adults over 40 from the 2007-2010 National Health and Nutrition Examination Survey (NHANES). Daily dietary flavonoid consumption was assessed through two 24-hour dietary recall interviews and the principal outcome was assessed based on a standardized questionnaire administered by trained interviewers. Weighted multivariate logistic regression and stratified analysis were employed to evaluate the impact of dietary total flavonoid consumption on nocturia. Restricted cubic spline (RCS) was utilized to explore whether there is a non-linear association between total flavonoid intake and nocturia. In addition, we performed weighted logistic regression and weighted quantile sum (WQS) regression by six flavonoid species (isoflavones, anthocyanins, flavan-3-ols, flavanones, flavonoids and flavonols) to estimate a combined mixture sum effect as well as the contribution of each mixture component. Subgroup analysis help us identify heterogeneity in these relationships and enhances the applicability of the research findings across different groups. After fully adjusting for confounders, weighted logistic regression models indicated that dietary flavonoid intake was significantly associated with a decreased prevalence of nocturia (OR: 0.93; 95% CI: 0.88-1.00, P-value = 0.036). This trend remained significant in the analysis stratified by quartile level of flavonoid intake. RCS analysis demonstrated an inverse linear correlation between total flavonoid consumption and nocturia. Analysis conducted through quartile stratification of six flavonoid species and WQS regressions showed that anthocyanins, flavan-3-ols, and flavonols were crucial elements. Within these subclasses, Peonidin in anthocyanins, Catechin and Theaflavin-3,3'-digallate in flavan-3-ols, and Isorhamnetin, Kaempferol, and Quercetin in flavonols were also investigated and may have contributed significantly. Our study revealed an inverse association between dietary flavonoid intake and nocturia in middle-aged and older adults, and anthocyanins, flavan-3-ols and flavonols were protectively associated with nocturia.