Food quality score and the risk of coronary artery disease: a prospective analysis in 3 cohorts

Background: Currently, there are few diet quality assessment tools that are predictive of coronary artery disease (CAD) risk that do not require nutrient analysis and substantial time to administer in clinical settings. Objective: To inform the development of such a tool, we prospectively examined the association between a food-based diet quality score and risk of CAD in 3 separate large US cohort studies. Design: Between 1984 and 2012, 71,415 women (aged 43-63 y in 1984), 42,945 men (aged 40-75 y in 1986), and 93,131 younger women (aged 27-44 y in 1991) without a history of cardiovascular disease were followed up to 28 y. Diet was assessed <= 7 times by using repeated food-frequency questionnaires. We computed the Food Quality Score (FQS) for each individual based on food groups previously associated with less weight gain. A higher score represented a healthier diet. The FQS and CAD association was modeled with the Cox proportional hazard model, controlling for potential confounders. We also compared the magnitude of association with CAD for the FQS and other diet quality scores. Results: We ascertained 6817 incident total CAD events, with 4588 cases of nonfatal myocardial infarction and 2131 fatal CAD events. Comparing top to bottom deciles, pooled RRs of the FQS were 0.61 (95% CI: 0.54, 0.69; P-trend < 0.001) for total CAD. These associations were independent of established cardiovascular disease risk factors including body weight, physical activity, and smoking. The magnitude of the RR for 1 SD of the FQS and CAD was generally similar to established diet scores that require detailed nutrient analysis, including the Alternate Healthy Eating Index-2010, the Dietary Approaches to Stop Hypertension score, and the alternate Mediterranean diet score. Conclusion: A higher food-based diet quality score was associated with lower risk of CAD and was comparable with established diet scores.