Effect of Dietary Flavonoids on Circadian Syndrome: A Population-Based Cross-Sectional Study.

Background: Altering the dietary patterns can potentially decrease the likelihood of metabolic syndrome and circadian syndrome (CircS), but it remains unclear which types of flavonoid compounds are responsible for these effects, particularly among nationally representative populations. Thus, we conducted a cross-sectional study to investigate the impact of flavonoid intake on CircS. Methods: The study included 9212 noninstitutionalized adults from two survey cycles (2007-2008 and 2009-2010) of the National Health and Nutrition Examination Survey (NHANES). Data on six dietary flavonoids were collected through a 24-hr dietary recall, including isoflavones, anthocyanidins, flavan-3-ols, flavanones, flavones, and flavonols. All statistical analyses were weighted to account for the complex survey sampling design to generate nationally representative estimates. Multivariable logistic regression and propensity score matching (PSM) were performed to control for potential confounders and assess the association between the six flavonoids and risk of short sleep. Results: After adjusting for all covariates, only individuals with high intake of total flavanones exhibited a 28% [odds ratio (OR) = 0.72, 95% confidence interval (CI) = 0.64-0.83, P < 0.001] decrease in the risk of CircS. The results obtained through PSM were consistent with this finding (OR = 0.70, 95% CI = 0.61-0.80, P < 0.001). Total flavanone intake displayed a linear dose-response relationship with the likelihood of CircS (P for interaction = 0.448). Conclusions: Our findings suggest that high dietary intakes of flavanones have beneficial effects on reducing the risk of CircS.