Estrogen Update

Beverly Vaughn, MD

In January 2006, the safety of estrogen use was in the news again. The Journal of Women's Health published a study examining the risk of heart disease in women on hormone therapy. This article looked at data from the Nurses' Health Study which started 30 yrs ago and ended in the year 2000. Its participants were 121,000 healthy volunteers who answered questions about various life health events every two years by completing a questionnaire.

Authors observed women who used estrogen or estrogen with progestin (synthetic progesterone) close to the start of their menopause, had fewer incidences of coronary heart disease than those who did not. This observation held true even after accounting for risk factors such as weight, smoking, high blood pressure and differences in physical activity: Factors which are known to influence the risk of heart disease.

When they evaluated the participants who began hormones at age 60 and above; the women who took estrogen alone showed no effect on heart disease. The women on estrogen and progestin showed an inconsequential decrease. Their conclusion, women who begin hormone therapy close to the age of menopause have a lesser risk of heart disease.

How can this be explained in light of the results of the WHI study in 2002? One answer is the women in the WHI study were an average age of 62. Many of these women were far past the beginning of their menopause. This is relevant for 2 reasons 1) the younger women in the Nurses Study may have been healthier to start and 2) the vessels in the heart do not respond to estrogens potential beneficial effects as people age. Another possibility is that the women in the Nurses' study who used hormones were healthier than ones who did not. They would therefore, have a lower risk of heart disease based on their overall health.

This article does not challenge the recommendations that hormone therapy should only be used for hot flashes and only for a short period of time. It does keep the debate open as to what exactly are the effects of hormone therapy on various parts of the body. The questions raised by hormones are complex and not likely to have definitive answers for years to come. Another study, the KEEPS trial, which looks at women in their fifties and hormone therapy, is due to be completed in the next year or two. It will be interesting to learn their findings.

Beverly Vaughn, MD