Smoking raises female heart attack risk.

Smoking raises female heart attack risk

Smoking cigarettes causes about half of all coronary artery disease cases among young and middle-aged women in the United States, according to a Harvard University study released last week.

The study also showed that women who stopped smoking drastically reduced their chances of developing coronary artery disease and that no level of smoking was safe for women. In addition, several other risk factors, such as diabetes and hypertension, were found to significantly increase a woman smoker's chances of developing coronary artery disease, which includes fatal and nonfatal heart attacks and periodic chest pain, or angina.

"Cigarette smoking is the single most avoidable risk factor for heart attacks in young and middle-aged women,' says the study's principal author, Walter C. Willett of the Harvard School of Public Health.

For many years, studies showed that smoking among men--but not among women--was associated with coronary artery disease. But researchers now say the studies looking only at women were flawed because the samples were too small. In recent years, the association among women has been established. And according to the researchers, the Harvard study is the largest study to report the association, which shows that men and women smoking the same number of cigarettes have about the same chance of developing coronary artery disease.

In 1976, Frank E. Speizer and his Harvard colleagues began tracking the health and lifestyle status of about 120,000 married registered nurses, all women between 30 and 55 years of age, in what became known as the Nurses Health Study. Nurses were chosen, Willett says, because the researchers thought they would give accurate reports and would be representative of the U.S. female population for that age group. In fact, 30 percent of the group in 1976 smoked cigarettes, which was comparable to the proportion of smokers in the same age group among U.S. women.

Among women who smoked 25 or more cigarettes daily, about 81 percent of deaths from coronary artery disease were attributed to smoking. That same group was 5.4 times more likely to have fatal heart attacks than nonsmokers. In addition, the 25-or-more group was 5.8 times more likely to have nonfatal heart attacks than nonsmokers and 2.6 times more likely to have angina.

In contrast to current smokers, former smokers had the same rate of coronary artery disease as women who had never smoked. "If you stop smoking, the risk of disease decreases in a matter of days,' Willett says, because many effects of smoking, such as clotting of blood, will stop almost immediately.

The Harvard study, which appeared in the NOV. 19 NEW ENGLAND JOURNAL OF MEDICINE, also found that women who smoked one to four cigarettes daily were 2.4 times more likely to have coronary artery disease than nonsmokers. About 58 percent of the cases in this group were attributed to smoking.

When the researchers looked at several risk factors in combination with smoking, the results were dramatic. Hypertensive smokers were 22.2 times more likely to develop coronary artery disease than nonsmokers without hypertension. For smokers with high cholesterol, the figure was 18.9, and for smokers with diabetes, it was 22.3.

During the next year, Willett and his colleagues plan to write about 30 additional papers based on the Nurses Health Study and will examine such topics as diet and coronary artery disease and risks associated with stroke. Eventually, they want to determine whether the nurse will listen to the advice provided by the articles.