High dietary antioxidant intake linked to lower risk of myocardial infarction: a nested case-control study

Abstract Background In developing nations, myocardial infarction (MI) remains a significant contributor to deaths from sudden cardiac arrest, with diet playing a key role in its incidence through oxidative stress mechanisms. Although the connection between the Dietary Antioxidant Index (DAI) and cardiovascular diseases has been demonstrated in some studies, the relationship between DAI and MI has not been extensively explored. Therefore, this research aims to investigate this association. Methods We conducted a nested case-control study involving 156 MI cases and 312 healthy controls, utilizing data from the Fasa Adults Cohort Study (FACS), a population-based study of individuals aged 35–70 residing in Fasa, Iran, with 11,097 participants included at baseline. The DAI was determined by normalizing the intake values of six dietary vitamins and minerals, adjusting by subtracting the global mean, and then dividing by the global standard deviation. MI diagnosis was established by an experienced cardiologist using electronic medical records. Conditional logistic regression was employed to examine the association between DAI and MI. Results There were no significant differences between the case and control groups in terms of age (P = 0.96), gender distribution (P = 0.98), and education level (P = 0.38). In a multiple conditional logistic regression analysis, after adjusting for key variables—including body mass index (BMI), smoking status, education level, and serum levels of triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC), fasting blood sugar (FBS), saturated fatty acids (SFA), and polyunsaturated fatty acids (PUFA)—an inverse association was found between DAI and the risk of myocardial infarction (MI) [adjusted Odds Ratio (Adj OR) = 0.88, 95% Confidence Interval (CI): 0.85–0.92; P