Composite Dietary Antioxidant Index and Cardiovascular Diseases and All-cause Mortality in Iranian Adults: A Prospective Cohort Study

BACKGROUND AND AIMS:Antioxidants are known to combat oxidative stress, a key factor in the development of cardiovascular diseases(CVDs) and mortality. In the current study, we aimed to prospectively investigate the relationship between the composite dietary antioxidant index(CDAI) and the incidence of CVDs and mortality in the Iranian population. METHODS AND RESULTS:This study was conducted within the framework of the Tehran Lipid and Glucose Study(TLGS) among 5048 adults≥30 years, selected from the third and fourth phases of the TLGS. Dietary intake was assessed using a validated food frequency questionnaire, and the CDAI was calculated based on intakes of vitamins A, C, E, selenium, zinc, and manganese from food sources. A multivariable Cox proportional hazard regression model was used to estimate the risk CVDs, coronary heart disease(CHD), stroke, and mortality across CDAI tertiles. Median(interquartile) of CDAI score for all participants was -0.69(-3.12, 2.43). During 9-year follow-up period, 357 cases of CVDs(7.10%) and 131 cases of all-cause mortality(2.60%) were ascertained. In the multivariable adjusted model, the CVDs risk reduced across the tertiles of CDAI(HR = 0.60; 95%CI:0.40-0.89; P-trend = 0.013). Also, a one SD increase in CDAI score was associated with reduced risk of CVDs(HR = 0.77; 95%CI:0.64-0.93; P-trend = 0.007) and CHD(HR = 0.78; 95%CI:0.64-0.95; P-trend = 0.016). No significant associations were found between the CDAI score and the incidence risk of stroke and mortality. CONCLUSION:The findings of this study showed that a higher CDAI score is associated with a lower risk of CVDs in Iranian adults. However, there is no significant relationship between the CDAI score and risk of mortality and stroke.