Coffee use prior to myocardial infarction restudied: heavier intake may increase the risk

Because of conflicting evidence about the relation of coffee use to coronary artery disease, the authors conducted a new cohort study of hospitalizations among 101,774 white persons and black persons admitted to Kaiser Permanente hospitals in northern California in 1978-1986. In analyses controlled for eight covariates, use of coffee was associated with higher risk of myocardial infarction (p = 0.0002). Compared with nondrinkers of coffee, the following relative risks (RRs) were found: at 1-3 cups/day, RR = 1.14 (95% confidence interval (CI) 0.91-1.42); at 4-6 cups/day, RR = 1.42 (CI 1.10-1.84), p = 0.007; and at greater than 6 cups/day, RR = 1.41 (CI 1.00-1.99), p = 0.05. The relation remained significant when also controlled for blood cholesterol, blood glucose, blood pressure, and adiposity, singly or combined. Tea use was unrelated to myocardial infarction; neither coffee nor tea was related to other coronary diagnoses. Although causality remains unestablished and uncertainty remains, the authors conclude that 1) these data suggest a weak independent relation of coffee use to acute myocardial infarction, not mediated by an effect on blood cholesterol; and 2) persons at risk of myocardial infarction should consider limitation of coffee intake to less than 4 cups/day.