The Sleep Connection: Exploring the Role of Composite Dietary Antioxidant Index in Sleep Quality Based on NHANES 2007-2014

<b><i>Background</i></b> : Growing evidence has highlighted the critical role of oxidative stress in the pathogenesis of sleep problems. The Composite Dietary Antioxidant Index (CDAI), a holistic metric designed to assess the cumulative antioxidant capacity of dietary components, may be intricately linked to sleep quality. This study aimed to investigate the association between CDAI and sleep parameters using data from the National Health and Nutrition Examination Survey (NHANES). <b><i>Methods</i></b> : Participants with complete data on CDAI, sleep parameters, and other essential covariates were included in this study. Weighted multivariable linear or logistic regression models were employed to examine the association between CDAI and sleep parameters (sleep duration, sleep trouble, and sleep disorder). Subgroup analyses, smooth curve fitting, threshold/saturation effect analyses, and sensitivity analyses were conducted to characterize the association's features. <b><i>Results</i></b> : A total of 10,491 participants were finally included in the analysis. After adjusting for all potential covariates, higher CDAI levels were associated with increased sleep duration (CDAI_T3 vs. CDAI_T1, β=0.16, 95% CI: 0.08-0.24), while exhibiting no significant correlation with sleep trouble (CDAI_T3 vs. CDAI_T1, OR=1.03, 95% CI: 0.88-1.20) or sleep disorder (CDAI_T3 vs. CDAI_T1, OR=1.01, 95% CI: 0.79-1.28). Subgroup analyses and interaction tests indicated a more pronounced association among individuals with depression (P interaction<0.0001) and those taking sleep-modulating medications (P interaction=0.0014). Smooth curve fitting analyses identified an inverted "L"-shaped association between CDAI and sleep duration, with the inflection point of CDAI determined to be 3.2. Within this threshold, each 1-unit increase in CDAI was associated with a 0.04-hour (95% CI: 0.02-0.05) increase in sleep duration, whereas no association was observed beyond this point. Finally, sensitivity analyses, which excluded individuals with extreme energy intakes or depression, confirmed a consistent and robust association between CDAI and sleep duration. <b><i>Conclusion</i></b> : The association between CDAI and sleep duration exhibits a positive, inverted "L"-shaped pattern with a saturation effect. Further prospective or longitudinal cohort studies with larger sample sizes and longer follow-up periods are needed to evaluate its practical value for clinical interventions.