Research into caffeine and heart disease is dogged by inconclusive and contradictory findings.
Researchers at the University Of Maryland School Of Medicine reviewed 10 studies investigating the link between coffee consumption and coronary heart disease. Two studies found a link, one found the evidence inconclusive, and seven discovered no link at all. Of the two studies in the first group, the Boston Collaborative Drug Surveillance Program study showed a 60% higher risk of heart attack among hospital patients who drank one to five cups of coffee a day, and a 120% higher risk among drinkers of six or more cups, compared to nondrinkers, The second study, of male medical students at the Johns Hopkins Medical Institutions, showed a two to threefold greater risk of coronary heart disease among coffee drinkers.
But both studies proved to be flawed. In the Boston study, the coffee drinking subjects who had had heart attacks were compared to a non-coffee drinking control group with other disease, but as it turned out, the control group might as well have consumed large amounts of coffee in the past. The Johns Hopkins study did not look at other factors that may increase the risk of their disease, such as high fat diet, lack of exercise, job stress, and personality.
A study of 14,500 men and women in Tromso, Norway, showed that blood cholesterol and triglyceride levels were higher among coffee drinkers (as much as 14% higher in people who drank nine or more cups of coffee a day). But recent analysis by the authors of these findings suggested that the coffee drinkers also tended to smoke, consume more fats, and lead sedentary lives. “Coffee drinking”, they conducted, “may therefore indicate an unhealthy life style”. Still, that caffeine on its own raises cholesterol levels remains unproven.
The sole heart problem definitely pegged to caffeine is irregular heartbeats, or arrhythmias, and people subject to such irregularity should stay away from caffeine, particularly if they are recovering from a heart attack.
Article extracted from this publication >> July 22, 1988
