No independent association between coffee drinking and a subsequent first myocardial infarction in 464 patients was found in a study well controlled for cigarette smoking and five other established "risk factors." Coffee drinking and cigarette smoking are strongly correlated habits. Review of other studies of coffee and coronary heart disease indicates that discrepancies in findings may be related either to cigarette smoking or to selection of control subjects. Coffee drinking is not an established risk factor for myocardial infarction.
Klatsky AL, Friedman GD, Siegelaub AB. Coffee Drinking Prior to Acute Myocardial InfarctionResults From the Kaiser-Permanente Epidemiologic Study of Myocardial Infarction. JAMA. 1973;226(5):540-543. doi:10.1001/jama.1973.03230050018005