The Composite Dietary Antioxidant Index is Associated With Common Non-communicable Diseases: The Mediation and Joint...

Purpose: To evaluate the associations between composite dietary antioxidant index (CDAI) and common non-communicable diseases (NCDs) and explore the potential effects of inflammatory indices in these associations. Methods: We included 20,097 adults from the National Health and Nutrition Examination Survey 2003-2018. Multivariable logistic regressions were applied to evaluate the associations between CDAI and common NCDs. Mediation analysis was used to explore the role of inflammatory indices in the associations. Results: Higher CDAI was associated with a downward trend in the incidence of obesity, cardiovascular disease (CVD), chronic respiratory diseases, and chronic kidney disease (CKD) (p for trend < 0.05). The association between CDAI and CVD was influenced by C-reactive protein (CRP), red blood cell width (RDW), and neutrophil to lymphocyte ratio (NLR), with mediated proportions of 3.490%, 5.173%, and 2.351%, respectively. NLR partially contributed to the link between CDAI and CKD, with a mediating ratio of 2.746%. Additionally, we observed additive interactions between CDAI and CRP (RERI (95% CI): 0.282 (0.070, 0.494), AP (95% CI): 0.539 (0.088, 0.991), as well as RDW on CVD (RERI (95% CI): 0.318 (0.124, 0.511), AP (95% CI): 0.717 (0.217, 1.218)). There also appeared to be a weak multiplicative interaction between CDAI and RDW on CVD (p-int = 0.049). Conclusion: Our investigation ascertained that CDAI was related to common NCDs. Moreover, inflammatory indices played an important role in the associations between CDAI and NCDs.