# Association of the Composite Dietary Antioxidant Index with All‐Cause, Cancer, and Cardiovascular Mortality: A Prospective Cohort Study

## TL;DR

This study found that moderate intake of dietary antioxidants is linked to lower cancer and cardiovascular mortality over 10 years.

## Contribution

The study introduces the Composite Dietary Antioxidant Index and evaluates its association with long-term mortality outcomes.

## Key findings

- Higher CDAI levels were linked to significantly lower cardiovascular mortality in the second and third quartiles.
- Moderate antioxidant intake showed reduced cancer mortality, though the effect weakened after full adjustment.
- The highest CDAI quartile did not show a significant link to all-cause mortality.

## Abstract

Oxidative stress is a major contributor to chronic diseases such as cardiovascular disease (CVD) and cancer, and antioxidants may play a protective role. However, the link between overall dietary antioxidant intake, measured using the Composite Dietary Antioxidant Index (CDAI), and long‐term health outcomes remains unclear. This prospective cohort study investigated the association between CDAI and cause‐specific mortality, including CVD and cancer, as well as all‐cause mortality and CVD incidence, using data from 6484 adults (mean age: 48.38 years, 39.98% male) in the Mashhad Stroke and Heart Atherosclerosis Disorder (MASHAD) cohort. Dietary intake was evaluated using a validated food frequency questionnaire, and CDAI was calculated from six dietary antioxidants. Participants were followed for 10 years. Kaplan–Meier survival analysis showed that individuals in the third and fourth quartiles of CDAI had significantly lower cancer mortality (p = 0.011) and cardiovascular mortality (p = 0.021). Multivariable Cox regression revealed a significant inverse association between CDAI and cardiovascular mortality in the second (OR = 0.531; 95% CI: 0.391–0.884) and third (OR = 0.535; 95% CI: 0.321–0.892) quartiles, but not in the fourth (OR = 0.847; 95% CI: 0.537–1.337). Higher CDAI was also linked to lower cancer mortality in crude (OR = 0.424; 95% CI: 0.224–0.802), first (OR = 0.384; 95% CI: 0.198–0.747), and second (OR = 0.398; 95% CI: 0.202–0.785) models, though this association weakened after full adjustment (OR = 0.469; 95% CI: 0.165–1.331). No significant link was found between the highest CDAI quartile and all‐cause mortality (p > 0.05). Overall, these findings suggest that moderate antioxidant intake may offer protective effects, particularly for cardiovascular outcomes.

This prospective cohort study investigates the relationship between the Composite Dietary Antioxidant Index (CDAI) and cause‐specific as well as all‐cause mortality. Higher CDAI levels were significantly associated with reduced cardiovascular and cancer mortality, though associations weakened after full adjustment. The findings support the potential role of antioxidant‐rich diets in lowering long‐term health risks, particularly cardiovascular mortality.