BACKGROUND:

Basic science, clinical observation, and epidemiologic studies have all contributed to an emerging body of evidence on the potential role of flavonoids, a group of polyphenolic compounds with antioxidant properties, in the prevention of cardiovascular disease. However, the few existing studies on flavonoids or its food sources have provided inconsistent results, usually focusing on the primary prevention of coronary heart disease mortality. The study used the small grant mechanism (R03) to analyze previously collected data.

DESIGN NARRATIVE:

The investigators examined whether flavonoid intake was associated with the risk of incident CVD, and whether specific food sources of flavonoids--including tea, onions, apples, red wine, and other foods--were associated with the risk of incident CVD. The investigators processed and analyzed previously collected data of 39,876 middle-aged and older women free of CVD; the Women's Antioxidant Cardiovascular Study (WACS), a prospective study of 8,171 middle-aged and older women with pre-existing CVD or more than three coronary risk factors; the Normative Aging Study (NAS), a prospective study of 2,280 middle-aged and older men; and the Boston Area Health Study (BAHS), a case-control study of first nonfatal myocardial infarction in men and women aged less than 76 years. Using data from semiquantitative food frequency questionnaires administered in each study, the investigators determined individual intake of flavonoids and its food sources. Unlike previous studies, they examined flavonoids in relation to both the primary and secondary prevention of incident cardiovascular disease (CVD), consisting of confirmed cases of nonfatal myocardial infarction (Ml), nonfatal stroke, revascularization procedures, and CVD death.