You may remember the Women's Health Initiative (WHI), a large trial of over 16,000 post-menopausal women, which was designed to examine the effects of hormone replacement therapy on cardiovascular disease and bone health. In 2002, the WHI was stopped prematurely when it was found that estrogen plus progestin therapy increased the risk of breast cancer, as well as stroke, heart attack, and blood clots. This increased risk outweighed the benefits of decreased risk of bone fractures and colorectal cancer.

Physicians at the University of North Carolina analyzed data from participants in the WHI from after the trial was stopped in July 2002 until March 2005. In a recent article in the Journal of the American Medical Association, they reported that, even three years after stopping the trial, the women who were given hormone replacement therapy continued to be at a higher risk for cancer, particularly breast cancer.

Although the risk of cardiovascular events such as heart attack and blood clots decreased within this same three year time period, the researchers also found that the beneficial effects of hormone replacement therapy on bone strength decreased as well. These findings confirm that combination hormone replacement therapy should not be used to prevent disease in healthy, post-menopausal women. However, with appropriate physician guidance, hormone replacement may still be used for short periods of time to treat the uncomfortable symptoms of menopause.