Why the Increase in Heart Attack Rates Among Women?

Each year, about 1.2 million Americans suffer heart attacks, and roughly 40 percent die from them. Men, in general, are at an increased risk of heart attack, at least until women reach menopause and lose the protective effect of the estrogen hormone, when the risk among genders becomes almost equal. But a new study shows the gender gap has also narrowed between middle-aged men and women—meaning that either hormonal influence isn’t protecting women in midlife as well as in the past or that not enough emphasis is being given to women’s cardiovascular health.

The new study, published in the Archives of Internal Medicine, analyzed national survey data on more than 8,000 men and women aged 35 to 54 from 1988 through 1994 and from 1999 through 2004. Researchers looked at heart attack rates and compared those scores using a tool called Framingham coronary risk score, which takes into account age, cholesterol levels, blood pressure and smoking history, and predicts the risk of a having a heart attack in 10 years. In both time periods, men had more heart attacks than women, but the rates of men improved from 2.5 percent in the earlier period to 2.2 percent in the latter time frame; women’s rates increased from 0.7 percent to 1 percent.

Over the two study periods, the men’s cardiovascular risk factors improved or remained stable, whereas the only risk factor that improved in women was high-density lipoprotein levels. Lead author Dr. Amytis Towfighi, assistant professor of clinical neurology at the University of Southern California and chairwoman of the neurology department at Rancho Los Amigos National Rehabilitation Center, says this suggests that precursors to heart disease, such as high blood pressure and high cholesterol, are not assessed or treated as aggressively in women. “There have been several studies that have found women have their risk factors checked less frequently than men,” she said. “When they are checked, women are less likely to receive medication than men. And when they receive medication, their symptoms are not as controlled as much as men.”

Towfighi says societal changes may also play a role. With more women in the work force, job demands may be attributing to their rising rates of obesity and diabetes and limiting their ability to exercise and follow a healthful diet. “People didn’t think that women in that age group were at high risk for heart disease and stroke,” she said. “But I suspect that with growing rates of obesity, women aren’t as protected as much as they have been in the past.”

In the second study published in the same journal, researchers examined trends in the risk of death after heart attack among 916,380 men and women who had a heart attack between 1994 and 2006. They found that survival rates following a heart attack improved in both men and women during that time, with the biggest improvements seen in women. “We found that the number of younger women who die in the hospital after a heart attack, compared with men in the same age group, has narrowed over the last few years,” said researcher Dr. Viola Vaccarino, director of the Emory Program in Cardiovascular Outcomes Research and Epidemiology.

Women under the age of 55 had a 52.9 percent reduction in the risk of death over the time period, whereas men of the same age had a 33.3 percent reduction. However, the gender difference became progressively smaller in older men and women. The researchers theorized that the decrease might be the result of better diagnosis and management of heart problems among women compared with men. “Such improvement may be due to better recognition and management of coronary heart disease and its risk factors in women before the acute MI event, as suggested by the narrowing in the sex difference in previous revascularization,” they wrote.

In an accompanying editorial, Dr’s Sabine Oertelt-Prigione and Vera Regitz-Zagrosek, of Charité Universitatsmedizin in Berlin, say that while the improvements described in both studies “indicate that we are on the right track,” they also support the use of more aggressive risk assessment for the prevention of heart attack, especially for women. “Much needs to be done,” they wrote.