Women who have gone through menopause and who have been using a vaginal form of estrogen therapy do not have a higher risk of cardiovascular disease and cancer than women who have not been using any type of estrogen.
Among women with an intact uterus, the risks of stroke, invasive breast cancer, colorectal cancer, endometrial cancer and pulmonary embolism/deep vein thrombosis were not significantly different between vaginal estrogen users and nonusers. The risks of coronary heart disease, fracture and premature death were lower in users than non-users. The risks of coronary heart disease, stroke, cancer and pulmonary embolism/deep vein thrombosis for women who had undergone hysterectomies were not significantly different in users of vaginal estrogen compared to nonusers.
Randomized trials and other studies have shown that women who take estrogen therapy in the form of a pill may have an increased risk of blood clots, stroke and if the estrogen is used together with progestogen pills, invasive breast cancer. Some women take a vaginal form of estrogen, and it has not been known whether that treatment carries risks similar to the tablet form.
The researchers examined data from participants in the Women's Health Initiative Observational Study who were recruited at 40 U.S. clinical centers and were ages 50 to 79 when they began the study.
This study, the first to examine potential adverse health effects in users of vaginal estrogen compared with non-users, suggests that vaginal estrogen therapy is a safe treatment for genitourinary symptoms such as burning, discomfort, and pain during intercourse associated with menopause.
The paper's authors are Dr. Carolyn Crandall of UCLA; Kathleen Hovey of the State University of New York at Buffalo; Christopher Andrews of the University of Michigan; Dr. Rowan Chlebowski of City of Hope; Marcia Stefanick of Stanford University; Dr. Dorothy Lane of the State University of New York at Stony Brook; Dr. Jan Shifren and Dr. JoAnn Manson of Harvard University; Chu Chen of the Fred Hutchinson Cancer Research Center; Andrew Kaunitz of the University of Florida; and Jane Cauley of the University of Pittsburgh.
The study was published in the peer-reviewed journal Menopause.
The research was supported by the Women's Health Initiative, which is funded by the National Heart, Lung, and Blood Institute, the National Institutes of Health and the U.S. Department of Health and Human Services.
Kaunitz serves as a consultant for: Allergan, AMAG, Pfizer and Shionogi. He receives research grants from TherapeuticsMD, with funds paid to the University of Florida. He also receives royalties from UpToDate.
Chlebowski serves as consultant for Amgen, Genentech, Novartis, Astra-Zeneca and Pfizer. He also is on speaker's panel for Genentech and Novartis.
Shifren serves as a research consultant to the New England Research Institutes.