TUESDAY, Aug. 15, 2006 (HealthDay News) -- An occasional cup of coffee might trigger first heart attacks in some people, a new study suggests.
"One cup or less of coffee per day may set off heart attacks in people with a sedentary lifestyle or with three or more risk factors for heart disease," said study author Ana Baylin, an assistant professor in the Department of Community Health at Brown University, in Rhode Island.
This latest finding will most likely keep the coffee debate percolating among health experts. Previous research has suggested that coffee does not raise heart risks, and might even protect against high blood pressure and diabetes. As a matter of fact, only decaffeinated coffee has been shown to possibly boost the chances of cardiovascular trouble.
Baylin and her colleagues from Harvard's School of Public Health looked at 503 nonfatal heart attack cases that occurred between 1994 and 1998 in Costa Rica. Their study, expected to be published in the September issue of Epidemiology, found light (one cup daily) and moderate (two to three cups daily) coffee consumption was linked to a higher incidence of first, nonfatal heart attacks when compared with heavy (four cups or more daily) coffee consumption. Most people in the study reported drinking two to three cups of coffee per day.
"We don't know, but think it may be caffeine, because that is the active component in coffee that we know increases sympathetic nerve activity, which raises blood pressure," Baylin speculated.
She stressed the study focused only on the short-term effects of coffee; the researchers only looked at the first hour after coffee was consumed. "The acute effect of coffee as a trigger for heart attack is modified by habitual consumption. People who drink it regularly are still at risk. Only heavy drinkers are not at risk," she said.
And, she cautioned, the findings don't apply to the general population, only for people who are already at risk for heart attacks. Some risk factors include high blood pressure, high cholesterol, obesity, diabetes and smoking. "People who don't have these risk factors don't need to limit their coffee intake," she said.
Dr. Robert Eckel, immediate past president of the American Heart Association, said he is "unconvinced" about the coffee-heart attack link. "Most heart attacks occur in the morning, a time that might coincide with coffee consumption for the once-a-day drinker," he noted, adding that the small size of the study and low number of cardiac events reported also pointed up the need for further research.
"There were only nine cases of heart attack in the one-cup-or-less-a-day group. Like any other study, it's observation and association, although [the study] might give rise to further research," he said.
Also, it's unclear why heavy coffee drinkers would be immune from the effect, Eckel added.
Like most of the research on coffee, "this is all opinion and theory, [there's] nothing one could say that would be convincing here," Eckel said.
It may be "people with more heart disease are more at risk for that occasional cup of coffee, but this study doesn't prove that. There may be an effect, but there's no validation or reproducibility," he said.
More information
For more on how drinking coffee might raise your heart attack risk, go to the American Heart Association.
