For women experiencing, or who have experienced, menopause, few areas of medical research have seemed more confusing or frustrating than studies on the benefits and risks of hormone replacement therapy. The normal decrease in levels of the hormones estrogen and progesterone.

Which typically occurs between the ages of 45 and 55, triggers an array of unpleasant symptoms, such as hot flashes and mood swings, and has also long been known to put women at higher risk for osteoporosis and related bone injuries.

Research studies have demonstrated that medication that acts like estrogen and progesterone (or, in some instances, only estrogen) can lessen menopause-related symptoms, and protect women against colorectal cancer, osteoporosis, and fractures as well.

Because low estrogen levels in women are also known to be associated with a higher risk for heart disease, researchers thought hormone therapy would also reduce that risk in postmenopausal women, and indeed early studies seemed to confirm that conclusion.

Estrogen therapy can raise HDL (good) cholesterol levels by 7 to 8 percent and lower LDL (bad) cholesterol levels in the blood by as much as 10 to 14 percent. In addition, estrogen may also lower other undesirable cholesterol substances in the blood and improve the health of blood vessels in general.

On the other hand, estrogen has been shown to increase triglyceride levels as well as levels of certain blood-clotting factors. And while studies revealed that women had a 50 percent higher risk for heart problems and stroke immediately after beginning estrogen therapy, the risk appeared to lessen as time went on, and as a result women were encouraged to continue taking it.

Progesterone is typically prescribed along with estrogen because it protects against certain risks caused by using estrogen alone, including endometrial and ovarian cancer, but we know less about how progesterone may affect the heart than we do about estrogen’s effects.

A number of studies have sought to understand the benefits and risks of hormone therapy for women, but two merit special mention in the context of heart disease. The Heart and Estrogen/Progestin Replacement Study was a long-term examination of how hormone replacement affects women diagnosed with heart disease.

This study found that, when taken by women with heart disease, hormone therapy had no significant long-term benefit and carried significant risks, including a 48 percent increase in gallbladder disease requiring surgery and a doubling of the rate of blood clotting in the legs and lungs.

The results of a more recent study were more dramatic. The Women’s Health Initiative Study, sponsored by the National Institutes of Health, was to be a fifteen-year-long study of ways to prevent heart disease, cancer, and osteoporosis in postmenopausal women.

When the researchers involved in this study began examining the preliminary results, their findings were so strong and conclusive that they terminated the study of combination therapy early, so as not to prolong the risks to which it exposed the participants.

The study discovered that, rather than reducing heart disease risk, combination hormone-replacement therapy caused a 29 percent increase in heart attacks, a 41 percent increase in strokes, doubled the rates of blood clots in the legs and lungs, and increased the risk of breast cancer by 26 percent.

In short, not only does combination hormone therapy not protect women with heart disease from further heart problems, it also puts women who do not have heart disease at greater risk of having a heart attack. The study also found that hormone therapy had little effect on a postmenopausal woman’s quality of life.

The study did reveal some significant benefits of hormone therapy, however, including a 37 percent decline in the risk of colorectal cancer, a 34 percent reduction in hip fractures, and a 24 percent reduction in total fractures due to osteoporosis. Then, in what some people consider to be the knockout punch for hormone therapy, the study of estrogen alone was also stopped early.

After an average of seven years of follow-up, the estrogen therapy did not prevent heart disease and may have increased the risk of stroke. Even before the release of these new findings, the American Heart Association had announced that hormone therapy for women should not be used as protection against heart disease.

The new research underscores this conclusion. Should all women cease taking hormone medications? Not necessarily. Many women, especially those with a low risk for breast cancer or blood clots, can take these medications in the short term to counteract the most severe symptoms of menopause, including hot flashes, sleep problems, and mood swings.

Women who have a high risk of osteoporosis and its related injuries and who have found other treatments for these conditions ineffective may choose to continue with long-term hormone therapy for its proven benefits in this regard. One recent study suggests that women taking these medications for this reason may obtain some protection against heart problems by taking a statin medication at the same time.

But the research is clear that you should not take hormone therapy solely to protect against heart disease after menopause. Many postmenopausal women who are at risk of heart disease would be much better advised to use safer, more proven medications, including aspirin and beta-blockers.

What about the Orish Program?

You may have heard about the program that is promoted by Dr. Dean Ornish. The Ornish Program consists of a plant-based diet with no more than 10 percent of calories from fat, 180 minutes a week of moderate exercise, an hour daily of meditation and other stress-management practices, and biweekly, professionally supervised support group sessions. The approach is low-tech but requires a major commitment.

Ornish has demonstrated through imaging studies that this approach has promise. There are no long-term studies of health outcomes, and so it is not yet strongly recommended. A big challenge with this approach is whether people will find the time to make this dramatic change in their life. This program is currently being evaluated by Medicare in 1,800 patients. Preliminary finds are said to be promising.