TUESDAY, May 12, 2009 (HealthDay News) -- Estrogen has long been implicated as being heart protective in premenopausal women, and a new study suggests that having just the right amount of estrogen might be helpful for men as well.
The study, in the May 13 issue of the Journal of the American Medical Association, found that men with heart failure who had the lowest levels of estrogen had about four times the risk of dying as men with average levels and that men with the highest levels of estrogen had more than twice the risk of dying as men with average levels of the hormone.
"Among men with chronic heart failure and reduced left-ventricular ejection fraction, high and low concentrations of estradiol [estrogen] compared with the middle quintile of estradiol are related to an increased mortality," the researchers wrote.
However, Dr. Stephen Siegel, a cardiologist at the New York University Langone Medical Center, said that though the study "raises certain issues on how hormones may be affected or may affect cardiac function and mortality, it doesn't necessarily link cause and effect."
Heart failure occurs when the heart muscle weakens and can't pump blood as efficiently to the rest of the body as it should. As many as 5 million people in the United States currently have heart failure, according to the U.S. National Heart, Lung, and Blood Institute. Each year, about 300,000 Americans die as a result of heart failure, the institute reports.
The study, which was done in Poland, included 501 men with an average age of 58 years. All of the men had heart failure and a left ventricular ejection fraction of 28 percent. Ejection fraction is a measure of how well the heart is pumping, and the left ventricle is the heart's main pumping chamber. A normal left ventricular ejection fraction would be between 55 percent and 70 percent, according to the American Heart Association.
During the three-year follow-up period, 171 of the men died. When the researchers separated the men into groups based on their estrogen levels, they found that those with the lowest and highest levels of estrogen were more likely to have died.
The group with the lowest estrogen levels had a 44.6 percent survival rate, and those with the second-lowest scores had a 65.8 percent survival rate. The middle group had the highest survival rate, at 82.4 percent. The fourth group, which had elevated estrogen levels, had a 79 percent survival rate, and the group with the highest estrogen levels had a 63.6 percent survival rate.
"This is an interesting observation," said Dr. David Haines, chairman of cardiovascular medicine at Beaumont Hospital in Royal Oak, Mich. "But, it seems just as likely that it could be an epidemiological phenomenon."
Haines said that, based on the data from the study, he would not recommend supplementing heart failure patients with low estrogen, nor would he use medication to block the effects of estrogen on men with high levels.
"For something to be deadly at both ends is unlikely," said Dr. Stuart Katz, director of the heart failure program at the New York University Langone Medical Center in New York City. "Whenever you see this type of U-shaped relationship, it means there has to be two different explanations for what you've seen."
He said it's possible that estrogen may be a marker for worsening heart disease, but said it's probably not a more useful marker than those currently used. "I doubt this study will change what clinicians do," said Katz.
The three heart specialists agreed that though the study's observations raise interesting questions, much more research needs to be done before any changes in clinical practice might occur.
More information
Learn more about heart failure at HeartFailure.org.
