Coffee linked to heart attack in some

A cup of coffee could be enough to trigger a first-time heart attack in some vulnerable people. Researchers from Brown University in Providence, Rhode Island, USA, studied 503 adults who suffered a first heart attack between 1994 and 1998. They questioned them about their coffee intake and overall diet in the hours and days before the heart attack. They also collected information on patients' medical history, background and lifestyle habits. It was found that among those who typically drank less than one cup of coffee a day, the risk of heart attack in the hour after drinking a cup was four times higher than would be expected. Similarly, moderate coffee drinkers - those who had two or three cups per day - showed a 60 percent higher-than-expected risk. Hence, among middle-aged and older adults, light to moderate coffee drinkers had an elevated risk of heart attack in the hour after having a cup of coffee. This was particularly the case when a coffee drinker got less of regular exercise or had three or more risk factors for heart disease - such as diabetes, high blood pressure and smoking. On the other hand, there was no risk of having a heart attack among people who were heavy coffee drinkers, downing four or more cups per day. The difference may be that these coffee devotees build up a tolerance to the cardiovascular effects of caffeine. The findings suggest that light or moderate coffee drinkers who are already at risk of heart attack should consider giving up the beverage. The findings add to the confusion that's been brewing about the health effects of coffee. For example, a recent large study of adults found no association between heavy consumption of coffee - at least the filtered kind - and heart disease. But another study suggested that the heart effects of coffee might depend on the genetics - researchers found an elevated heart attack risk only among coffee drinkers with a particular variant of a gene that helps metabolise caffeine. The jolt of caffeine may boost nervous system activity and blood pressure enough to rupture a pre-existing fatty deposit, or plaque, on the artery walls. When this happens, blood flow to the heart can be obstructed, causing a heart attack. There were limitations to the study - patients were asked to recall their coffee intake in relation to the heart attack. In addition, it's well known that heart attack risk naturally rises in the morning, a time when most coffee drinkers have at least one cup. However, that would not explain why heavy coffee drinkers seem immune to the effects. Instead, they suspect that heavy consumers develop a complete tolerance to the short-term cardiovascular effects of caffeine, whereas light to moderate drinkers remain susceptible.