The effects of coffee on myocardial infarction are uncertain. We hypothesize that coffee in the presence of predisposing factors can induce a cascade of events that, through sympathetic nervous activation, can induce the onset of myocardial infarction.
We recruited 503 incident cases of nonfatal myocardial infarction between 1994 and 1998 in Costa Rica. We used a case-crossover design to calculate relative risks (RRs) and 95% confidence intervals (95% CIs).
The RR of myocardial infarction in the hour after coffee intake was 1.49 (95% CI = 1.17–1.89). Occasional coffee drinkers (≤1 cup/day, n = 103) had a RR of myocardial infarction of 4.14 (2.03–8.42), moderate coffee drinkers (2–3 cups/day, n = 280) had a RR of 1.60 (1.16–2.21), and heavy coffee drinkers (≥4 cups/d, n = 120) had a RR of 1.06 (0.69–1.63; P = 0.006, test of homogeneity). Patients with 3 or more risk factors (n = 101) had a RR of myocardial infarction of 2.10 (1.30–3.39), whereas patients with fewer than 3 risk factors (n = 396) had a RR of 1.39 (1.04–1.82; P = 0.15, test of homogeneity); and RR was 1.72 (1.30–2.30) among sedentary patients compared with 1.07 (0.66–1.72) among nonsedentary (P = 0.10, test of homogeneity).
The findings indicate that coffee intake may trigger myocardial infarction. The association is particularly strong among people with light/occasional intake of coffee (≤1 cup/day), with sedentary lifestyle, or with 3 or more risk factors for coronary heart disease.
From the *Department of Community Health, Brown University, Providence, Rhode Island; †Department of Epidemiology; Harvard School of Public Health, Boston, Massachusetts; ‡Department of Nutrition; Harvard School of Public Health; §Department of Epidemiology, School of Public Health, University of Alabama at Birmingham; and ¶Centro Centroamericano de Población, Universidad de Costa Rica.
Submitted 10 January 2006; accepted: 29 March 2006.
Supported by grants HL071888 and HL60692 from the National Institutes of Health. Dr Baylin was supported by AHA fellowship 0425810T from the American Heart Association.
Editors’ note:A commentary on this article appears on page 495.
Correspondence: Ana Baylin, Department of Community Health, Brown University, Box G-H1, Providence, RI 02912. E-mail: Ana_Baylin@brown.edu.