DALLAS, June 1 -- During the first hour after using cocaine, the user's risk of heart attack increases nearly 24 times, according to the first large study of the long-suspected relationship between cocaine and heart disease. The research is reported in today's Circulation: Journal of the American Heart Association.
"Cocaine significantly increases the risk of heart attack in individuals who are otherwise at low risk," says Murray A. Mittleman, M.D., Dr. P.H., of the Institute for Prevention of Cardiovascular Disease at Beth Israel Deaconess Medical Center in Boston, who headed the research project.
"The average age of people in the study who suffered heart attacks soon after using cocaine was only 44," Mittleman notes. "That's about 17 years younger than the average heart attack patient. Of the 38 cocaine users who had heart attacks, 29 had no prior symptoms of heart disease."
Research over the past decade has suggested a strong cause-and-effect relationship between cocaine use and heart attacks and strokes. But this is the first study to examine the direct and devastating short-term effects of cocaine on the heart.
Known as the Determinants of Myocardial Infarction Onset Study, the research was carried out between 1989 and 1996 at 64 medical centers across the United States and included interviews with 2,664 men and 1,282 women who had suffered a non-fatal heart attack. The individuals ranged in age from 20 to 92. Thirty-eight individuals reported cocaine use in the prior year, and nine reported use of the drug within 60 minutes before their heart attacks.
Mittleman notes that cocaine users are more likely to be male and to smoke cigarettes. Smoking is a major risk factor for heart attack. These two variables were accounted for in assessing whether cocaine use increases the risk for heart attack.
"More research is definitely needed," Mittleman says. "We'd like to learn more about the difference that gender and frequency of use may make in cocaine-associated risk."
The researchers plan a similar study to examine the relationship between stroke and cocaine.
"Studying the mechanisms by which cocaine triggers heart attack may provide insights into how other factors, such as stress, or sudden exertion, may also trigger heart attacks and strokes," says Mittleman.
Researchers suggest several ways that cocaine may trigger a heart attack. Cocaine can cause a sudden rise in blood pressure, heart rate and contractions of the left ventricle (or pumping chamber) of the heart. These effects can increase the risk of a heart attack. Cocaine also tightly squeezes, or constricts, the coronary arteries that feed blood to the heart. If the artery constricts, blood flow to the heart and brain can be obstructed, causing a heart attack or stroke.
More than 30 million Americans are believed to have tried cocaine, and an estimated 5 million are regular users, so an understanding of the drug's associated heart-disease risk is an important public health issue, says Mittleman.
"As the public learns more about the huge risk involved in using cocaine, we hope fewer people will want to experiment with this truly dangerous drug," says Mittleman. "In addition, we hope that drug education campaigns may use this information about the magnitude of the heart-disease risk associated with cocaine use to prevent individuals from becoming first-time users." Co-authors are David Mintzer; Malcolm Maclure, Sc.D.; Goeffrey Tofler, M.B.; Jane Sherwood, R. N.; and James Muller, M.D.
Media advisory: Dr. Mittleman can be reached at 617-632-7653 or reporters may contact the communication office at Beth Israel Deaconess at 617-667- 4431. (Please do not publish telephone numbers.)