Contrary to earlier reports that estrogen replacement therapy increased the risk of heart attack and stroke, researchers are now saying that it may actually be beneficial for some women.
Here's a little back-story (taken from this LA Times article).
Long-term use of hormone replacement therapy was popularized in 1966 by Dr. Robert A. Wilson's book "Feminine Forever," which touted the treatment as a panacea for menopausal ills. Subsequent animal and small human studies suggested the hormones could help ward off heart attacks and increase bone density. By the end of the century, an estimated 40% of menopausal women were taking the drugs. It came as a shock in 2002 when researchers from the Women's Health Initiative reported that the drugs actually increased risks of heart attack and stroke.
According to the LA Times the initial negative findings in the Women's Health Initiative resulted because the investigators included a substantial number of older women in the study in the hopes of observing enough heart attacks to be able to draw conclusions. Researchers now know that when estrogen therapy is administered to women who are10 years or more post-menopause there is a higher risk of heart attack associated with the therapy.
The new study, [published in the June 2007 issue of the New England Journal of Medicine,] involved a subset of 1,064 women in the Women's Health Initiative study who were ages 50 to 59 and had undergone surgically induced menopause through a hysterectomy. Half were randomized to receive a Wyeth-produced estrogen called Premarin and half a placebo.
The women were on the drugs for an average of 7 1/2 years. About a year after the study was stopped, physicians used CT scans to measure the buildup of calcium deposits, or atherosclerotic plaque, in their blood vessels. Overall, they found, women taking estrogen had 42% less calcification of their arteries. Women who had taken at least 80% of their daily doses of the drug had 61% less calcification.
Essentially, estrogen therapy appears to have different effects depending on the stage of menopause at which it is administered. This is called the "timing hypothesis".
Researchers believe the benefits of estrogen replacement occur only if it is started before atherosclerosis begins to develop. Once the hardening of the arteries has set in, estrogen is known to produce damaging effects.
Here's my two cents:
There are usually always risks and benefits associated with any therapy (hormones, in particular, have very complex effects). The patient must decide if the benefits outweigh the risks.
It is always disturbing when medical recommendations (made by organizations we should be able to trust) are changed or reversed because in some cases they may be a matter of life and death for the patient.
As research advances and scientists learn more about how particular therapies and diseases affect the body it is not surprising that from time to time an old recommendation will be replaced by a new one, which may likewise one day be replaced by an even newer one.
Image taken from here.