Drinking up to six daily cups of coffee -- or more -- may not boost heart disease risk, new research shows.
Heart disease is a leading killer of U.S. men and women. Past studies on heart disease and coffee have been inconsistent, write Esther Lopez-Garcia, PhD, and colleagues in Circulation.
Lopez-Garcia works in Spain at the Universidad Autonoma de Madrid’s medical school. Her new study, done in collaboration with Harvard Medical School, checks data from two long-term U.S. health studies.
“These data do not provide any evidence that coffee consumption increases the risk of coronary heart disease,” the researchers write.
“Likewise, we found no association for consumption of total caffeine, decaffeinated coffee, or tea,” they add.
Long-Term Coffee Habits
Lopez-Garcia and colleagues studied data from the Health Professionals Study and the Nurses’ Health Study.
The Nurses’ Health Study started in 1976. The Health Professionals Follow-Up Study started 10 years later. Upon enrollment, participants had no history of heart disease and were in their mid- 40s to early 50s, on average.
About 44,000 men and more than 84,400 women took part. They updated their health information every two years. Every two to four years, they also completed dietary questionnaires, including information on coffee consumption.
Coffee intake ranged from less than one monthly cup to at least six daily cups. Filtered coffee was the most common type of coffee drunk by participants.
Tracking Heart Disease
Here are the combined heart disease statistics for 20 years of the Nurses’ Health Study and 14 years of the Health Professionals Follow-Up Study:
Men: 1,449 nonfatal heart attacks and 724 fatal cases of coronary heart disease. Women: 1,561 nonfatal heart attacks and 693 fatal cases of coronary heart disease.
The researchers adjusted for a long list of factors, including participants’ age, smoking, physical activity, alcohol use, hormone therapy (for women), body mass index (BMI), parents’ heart attack history, aspirin use, vitamin E supplement use, and history of high blood pressure, high cholesterol, and diabetes.
The point of those adjustments was to focus only on coffee and heart disease. After making those adjustments, the researchers found no higher risk of heart disease among coffee drinkers, even for those who reported drinking six or more daily cups of coffee.
“These results provide strong evidence against the hypothesis that coffee consumption increases the risk of coronary heart disease,” write Lopez-Garcia and colleagues.
The study also shows no links between heart disease and consumption of caffeine, decaffeinated coffee, or tea. The study cautions that the results pertain to filtered coffee and might be different in nonfiltered or "French press" coffee.
However, frequent coffee drinkers were more likely to be smokers. Smoking can drive up heart risks and other health problems.
Thirty percent of the men and more than half of the women who drank at least six daily cups of coffee also smoked cigarettes, the researchers note. That pattern may explain why some past studies have linked coffee intake to heart risks, write Lopez-Garcia and colleagues.
By Miranda Hitti, reviewed By Ann Edmundson, MD
SOURCES: Lopez-Garcia, E. Circulation, May 2, 2006; vol 113. News release, American Heart Association.