Composite dietary antioxidant index is inversely associated with all-cause, cardiovascular and cancer mortality in adults with hyperlipidemia

To explore the association between the Composite Dietary Antioxidant Index (CDAI) and all-cause, cardiovascular disease (CVD), and cancer mortality in U.S. adults with hyperlipidemia, and to assess the potential mediating role of inflammation-related biomarkers in this association. 25,383 patients with hyperlipidemia from the 2001-2018 National Health and Nutrition Examination Survey (NHANES) were included. The association between CDAI and mortality was assessed using weighted Cox regression models, Kaplan-Meier survival curves, subgroup analyses, and sensitivity analyses. Mediation analysis evaluated the roles of leucocytes, neutrophils, monocytes, lymphocytes, and the systemic inflammatory response index (SIRI). A total of 3,810 all-cause deaths, 1,218 CVD deaths, and 883 cancer deaths were recorded during the follow-up period. Fully adjusted models showed that highest CDAI (Q4 group) compared to the lowest quartile (Q1) was associated with a lower risk of all-cause (HR = 0.79, 95% CI: 0.68-0.91, P = 0.001), CVD (HR = 0.73, 95% CI: 0.55-0.96, P = 0.026) and cancer (HR = 0.72, 95% CI: 0.55-0.93, P = 0.011) mortality. The protective effect of vitamin E on the risk of death was most significant. The results of subgroup and sensitivity analyses were robust. Inflammatory indicators mediated the association between CDAI and mortality, with a range of changes from 1.11% to 4.12%. Higher CDAI, especially vitamin E intake, was independently associated with a significant reduction in all-cause, CVD, and cancer mortality in hyperlipidemic patients. Inflammation may partially mediate this association, with a modest mediation effect.