While men suffer more heart attacks than women, women have a 20 percent higher prevalence of stable angina, according to a new study that conflicts with conventional medical wisdom.

Angina is a common and serious heart problem. It’s caused by inadequate oxygen to the heart, which can lead to chest pain or discomfort on exertion that typically goes away with rest. The condition can result from partially blocked heart arteries or decreased flexibility of the cardiac arteries.

“When one looks at typical symptoms of angina, one finds that they are as common in women as men,” said study lead researcher Dr. Harry Hemingway, a professor of clinical epidemiology at University College London Medical School in Great Britain. “In fact, they are slightly more common in women than men right across 31 countries, and we didn’t know that before,” he added.

Because heart attacks are more common in men than women, Hemingway said doctors “have assumed the same thing to be the case for other forms of coronary heart disease. The main other form of heart disease is angina.”

For the new study, Hemingway and his colleagues collected data from 74 studies involving 401,315 people living in 31 countries, including the United States. The prevalence of angina varied from country to country. Among women, the prevalence varied from 0.73 percent to 14.4 percent, with an average of 6.7 percent. Among men, it varied from 0.76 percent to 15.1 percent, for an average of 5.7 percent, the study found.

While risk factors for heart disease, such as smoking, differed from country to country, once the researchers compensated for those risk factors, they found that the prevalence of angina was still higher among women. In fact, the prevalence of angina was 20 percent higher overall among women than men.

The study findings are published in the March 25 issue of the journal Circulation.

“Doctors and the general public should realize that out there in the real world, men and women experience these symptoms with a similar frequency,” Hemingway said. “When someone sees their doctor with symptoms of angina, the sex of the patient is not the most important factor.”

While the study doesn’t show that women with angina are under-diagnosed or under-treated, Hemingway thinks that, overall, women with heart disease are less likely to receive appropriate treatment.

“This is consistent with many observations which suggest that women with suspected or confirmed heart disease are less likely to go for further investigation or treatment,” Hemingway said. “This study shows that that general issue may be even more important than we suspected.”

One expert on women and heart disease isn’t surprised that angina is more common among women.

“This is something we’ve always believed — that there was an excess of angina symptoms in women,” said Dr. Nieca Goldberg, medical director of the Women’s Health Program at New York University Medical Center.

Angina used to be considered a benign symptom in women, added Goldberg, who’s the author of Dr. Nieca Goldberg’s Complete Guide to Women’s Health. “Maybe that’s the thing that sent us on the wrong pathway that women didn’t have heart disease,” she said.

“Just because women don’t have as many heart attacks as men, we have to recognize that angina is something that’s limiting women from having a good quality of life,” she said.

(Source: Harry Hemingway, M.D., professor of clinical epidemiology, University College London Medical School, Great Britain; Nieca Goldberg, M.D., medical director of the Women’s Health Program, New York University Medical Center, New York City, and author, Dr. Nieca Goldberg’s Complete Guide to Women’s Health; March 25, 2008, Circulation)