According to a study in Thursday's New England Journal of Medicine that women under the age of 50 are twice as likely to die from heart attacks than their male counterparts. CBS News Health Correspondent Dr. Emily Senay reports.
The discovery by Yale University researchers suggests that biological factors -- not differences in medical care -- largely explain why heart attacks are more deadly for women.
This study, like many others, found that women's heart attacks in general are more likely to be fatal. Seventeen percent of female heart attack victims die while still in the hospital, compared with 12 percent of males.
However, when the researchers broke the numbers down by age, they came to the surprising conclusion that the difference results entirely from a much higher death rate among the younger victims.
Under age 50, when heart attacks are especially rare among women, just 3 percent of male victims die, compared with 6 percent of females. By age 75, the death rate for both sexes is about equal, around 19 percent.
Researchers don't have all the answers to explain this disparity, but they do note that the women in this study had different symptoms, more complications and lower usage of treatments than the men - all which may play a role in heart disease.
While this may be part of the story, the new work suggests that biology is probably a more important factor.
The study, directed by Dr. Viola Vaccarino, was based on a review of the records of 384,878 heart attack victims between 1994 and 1998. It was published in Thursday's issue of the New England Journal of Medicine.
"Probably biological mechanisms play a major role, but we need to look at the big picture and take into account all aspects of the women and their care," Vaccarino said. "Heart disease is the No. 1 killer of women, even among younger women, less than 65."
In earlier work, the Yale team and other researchers found that women wait hours longer after a heart attack before going to the hospital, then are treated less aggressively than men. That delay, which allows further damage to the oxygen-starved heart, results partly because women tend to experience less painful heart attack symptoms. Sometimes they feel only pressure or a burning feeling, not crushing pain.
The researchers also noted that younger female victims are more likely than men to have other health problems, such as diabetes, high blood pressure and heart failure.
In an accompanying editorial, Dr. Laura F. Wexler of the University of Cincinnati called the discovery "striking and new."
"Do these women have some especially potent risk factor, or do they lack a protective factor that is normally present in women?" she asked.
Typically heart disease afflicts women about a decade later in life than men, probably because the female hormone estrogen protects their hearts through young and middle age. Those who are struck at an early age ay have differences in the way their bodies use this hormone.
Another study in the journal, directed by Dr. Judith S. Hochman of St. Luke's-Roosevelt Hospital Center in New York City, looked at 12,142 men and women who had bad heart attacks, milder ones or severe chest pain.
In all three categories, women were up to twice as likely to suffer serious complications. Among those who had heart attacks, the women were 50 percent more likely to die within 30 days.