October 17, 2011

Researchers link estrogen use and urinary incontinence

Gina Northington

Researchers have found that postmenopausal women who reported taking postmenopausal hormone therapy with estrogen for five years or more were more likely to develop urinary incontinence than were women who took estrogen for less than five years or not at all.

"The incidence of urinary incontinence increases as a woman ages and after menopause," says Gina Northington, assistant professor in the School of Medicine's Department of Gynecology and Obstetrics. "Results from the Women's Health Initiative [WHI] and other observational studies have shown a relationship between the use of postmenopausal HRT and incident urinary incontinence during follow-up. However, many of these studies were conducted in largely homogeneous populations without looking at patients' other health conditions."

The article was published online in Menopause: The Journal of the North American Menopause Society on Oct. 13, and will published in print in the March 2012 edition of the journal.

Northington, who is also director of the Division of Female Pelvic Medicine and Reconstructive Surgery, is the first author on the paper. A new faculty member at Emory,  she completed the research while on the faculty at the University of Pennsylvania.

Hormone replacement therapy is used to supplement the body with either estrogen alone or estrogen and progesterone during and after menopause.

Northington's study involved interviewing postmenopausal women in an ethnically diverse community in Baltimore who initially reported no symptoms of urinary incontinence. The women were already a part of an ongoing prospective observational study conducted by the National Institute of Mental Health and were followed for 10 years.

The women were surveyed in 1993 about self-reported estrogen use and signs of urinary incontinence (UI) and then again in 2004. They were also asked about condition-specific functional loss associated with UI, meaning how a woman is functioning with urinary incontinence and if they are avoiding certain social and physical activities because of the problem.

Among the 167 postmenopausal women surveyed who did not report UI in 1993, 47  or 28.1 percent reported new incidences of UI. Of the 167 postmenopausal women, 46  or 27.5 percent reported using hormone therapy containing estrogen, and 14  or 8.3 percent women reported using hormone therapy containing estrogen for five years or more in 1993.

"Our findings join a growing body of literature that suggests that postmenopausal hormone therapy increases the risk of developing urinary incontinence," explains Northington. "Many patients are no longer taking HRT because of the 2002 WHI findings that showed risks of breast cancer, heart disease and stroke. But for those who still need estrogen to help with postmenopausal symptoms such as hot flashes, they are given the lowest dose possible for the shortest amount of time."

Northington and her co-investigators at the University of Pennsylvania confined their analysis to self-reported use of estrogen only. The researchers were not able to determine the specific risk associated with the combined use of estrogen and progesterone. Because this was a small study, few definitive conclusions can be made. However, the study was strengthened because the participants were followed for 10 years.

More research is also needed to understand how HRT affects the bladder and urethral function to promote UI, and to identify other therapies that will treat menopausal symptoms without the adverse effects of UI.

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