Nov. 1, 2004 -- Coffee and cigarettes are a common combination for many people, but the pairing may compromise the heart, say Greek researches.
Scientists had already found that coffee and cigarettes, each taken alone, affect the heart and represent modifiable risk factors. They each can increase the stiffness of arteries, which has been shown to be associated with an increased risk of heart disease.
The new study, which comes from researchers including Charalambos Vlachopoulos, MD, of the cardiology department at Athens Medical School, shows that when taken together, smoking and caffeine can interact, and together they produce negative effects on the heart.
Vlachopoulos and colleagues conducted two tests.
First, they studied 24 healthy men and women in their early 30s who were all current smokers and coffee drinkers. None were taking heart medications or oral contraceptives, all had normal blood pressure, and none had diabetes or high cholesterol levels.
Participants fasted from cigarettes and coffee for at least 12 hours before each of four sessions, which involved either smoking one cigarette for five minutes or drinking two cups of coffee followed an hour later by smoking a cigarette. For comparison, some participants were given caffeine-free coffee followed an hour later by a sham cigarette.
The researchers found the greatest increase in arterial stiffness occurred in participants who drank coffee and smoked cigarettes in the same session.
The second test was organized differently but had similar results.
This time, the scientists studied a larger group -- 160 people. As in the first test, all participants were healthy and were not taking heart medications or oral contraceptives.
The researchers divided participants into four groups: smokers who drink coffee, smokers who don't drink coffee, nonsmokers who drink coffee, and nonsmokers who don't drink coffee.
Again, the greatest degree of arterial stiffness and abnormal blood flow occurred in the coffee-drinking smokers. In both tests, being male or female didn't have an effect on the significant interactions between coffee and cigarettes.
Taken together, the combined effect of coffee and cigarettes appears to be greater than their individual impact, the researchers say.
"Given the frequent combination of smoking and caffeine intake, these effects on arterial function may have important implications for human health," write the researchers in the Nov. 2 issue of the Journal of the American College of Cardiology.
Because the study focused on young, healthy people, the findings might not extend directly to other groups, say the researchers.