Hormone Replacement Therapy

Continued

In one recent study, Salpeter and her colleagues found that HRT reduced the number of heart attacks and cardiac deaths by 32% in women who were 60 or younger (or women who had been through menopause less than 10 years ago). In older women, hormone replacement therapy seemed to increase cardiac events in the first year, and then began to reduce them after two years.

The 32% drop is significant, but perhaps not as dramatic as it sounds. In hard numbers, Salpeter estimates that of women aged 50 to 59 who don't get hormone replacement therapy, about 7 out of 4,800 will have a cardiac event in one year. With HRT, 3 out of 4,800 will have a cardiac event.

Salpeter's study indicates something crucial: The age at which a woman starts HRT may make a big difference.

Salpeter argues that when a person first starts hormone replacement therapy, her risk of blood clots increases slightly. In healthy women who are in their 50s -- and close to the age of menopause -- this increase is very unlikely to cause problems. The higher risk subsides after a couple of years, she says, although other experts disagree.

But women in their 60s may be more likely to already have early heart disease or hardening of the arteries (arteriosclerosis). In these cases, the risk of blood clots becomes more serious. So if a woman first starts hormone replacement therapy in her 60s, the initial risks are more dangerous, Salpeter says.

This is what Salpeter says affected the results of the Women's Health Initiative trial. The average age of a woman in that trial was 63, with a range of ages between 50 and 79. She and other critics argue that the researchers were looking at many women who might already have been sick.

"I was surprised when I first heard the [WHI] results," says Lynne T. Shuster, MD, director of the Women's Health Clinic at the Mayo Clinic in Rochester, Minn. "But, once I saw the details, I wasn't surprised anymore. They gave women who were older and possibly had underlying arteriosclerosis a pill that increased the risk of blood clotting. Of course it increased the risk of heart problems."

Shuster and Salpeter argue that those results have no bearing on whether younger, healthy women in their 50s would benefit from HRT.

"Basically, [the WHI researchers] were looking at the wrong group of people," Salpeter tells WebMD.

Rossouw defends the WHI study design. "We were specifically testing the hypothesis that hormone therapy would help protect older women against disease," Rossouw tells WebMD, "The results were absolutely clear: They do not."