(RxWiki News) Estrogen — a hormone used to treat symptoms of menopause — has been shown to increase the risk for certain cancers. But other questions about the safety of estrogen therapy remain. For example, is it safe for the heart?
A recent study compared the relationship between the use of two common oral estrogen therapies — estradiol and conjugated equine estrogen (CEE) — and heart-related events (blood clots, stroke and heart attack).
This study found that CEE users had a significantly greater risk of blood clots than estradiol users.
However, CEE users were not found to have an increased risk for a heart attack or stroke when compared to estradiol users. The study authors noted that more studies are needed, however, to confirm their findings.
"Speak with your doctor about treatment for menopause symptoms."
This study was led by Nicholas L. Smith, PhD, in the Department of Epidemiology at the University of Washington in Seattle. The research team compared the heart-related safety of estradiol and CEE in a group of post-menopausal women.
CEE is made from the urine of pregnant female horses and includes 10 estrogen compounds. Estradiol is a natural estrogen compound that contains only one type of estrogen. Estradiol is sold under various brand names, including Estrace and Femtrace.
For their study, the researchers analyzed data from 384 women between the ages of 30 and 79 years in the Heart and Vascular Health Study between 2003 and 2009. Of these women, 201 served as the controls — women who used estradiol or CEE but had no history of heart-related events.
The researchers looked at new cases of myocardial infarction (heart attack), ischemic stroke (blocked blood vessel to the brain) and venous thrombosis (blood clot) that occurred in the participants during the study period. A pharmacy database was used to determine participants' use of either oral estrogen drug.
Several factors were taken into account that could have influenced the occurrence of heart-related events including birth date, height, weight, race/ethnicity, smoking status, general health, hypertension (high blood pressure), diabetes, cholesterol level, history of cardiovascular conditions and procedures, cancer (all cancers except non-melanoma skin cancers) and hospitalizations or inpatient surgical procedures in the last 30 days.
The researchers found that CEE users had more than twice the risk of venous thrombosis compared to estradiol users.
They did not find a statistically significant increase in risk for ischemic stroke or myocardial infarction for CEE users when compared to estradiol users.
Since the risk for myocardial infarction was close to being significant, the researchers noted that an increased risk for this type of heart event may still be possible.
The authors concluded that different estrogen drugs may carry different risks for heart-related events, so women should speak with their doctors about the best treatment options.
This study was published on September 30 in JAMA Internal Medicine.
Some of the study authors reported potential conflicts of interest with companies and agencies including the Swiss National Science Foundation and Medtronic, Inc.