Coffee Drinking and Myocardial Infarction

Abstract

To the Editor.— Much of the letter by Jick et al concerns our attempt to explain the variation among studies. As our Table 4 clearly indicated, the listing of proportions of heavy coffee-drinkers in various studies was made without precise equilibration of the number of cups of coffee drunk per day. Many persons who answered yes to the question Have you usually, in the past year, drunk more than cups of coffee per day? may have imprecisely interpreted the query as six or morecups per day? Therefore, we thought that the comparison was appropriate. However, we now agree that a strict interpretation categorizes our positive responders as drinking seven or more cups of coffee per day. Such categorization is closer to Paul's1200 or more cups per month group that included only 7% of controls. The new Framingham Heart Study data, presented by Jick et al, suggest