How Estrogen May Help Prevent Urinary Tract Infections After Menopause

Laboratory study suggests vaginal supplementation would benefit some women

By Serena Gordon

HealthDay Reporter

THURSDAY, June 20 (HealthDay News) -- Estrogen treatment delivered vaginally may help prevent repeat urinary tract infections in postmenopausal women, new laboratory research suggests.

Urinary tract infections are common among women, with one-quarter experiencing recurring infections. And age-related changes increase the likelihood of these infections developing after menopause, when estrogen production plummets.

Until now, taking antibiotics prophylactically -- to ward off recurrent urinary tract infections -- has been the gold standard for these women, said Thomas Hannan, a research instructor in pathology and immunology at Washington University School of Medicine in St. Louis. "But antibiotic resistance is increasing, and some women are resistant to everything we have," Hannan said. "We need other options. We need non-antibiotic options."

This study, published in the June 19 issue of the journal Science Translational Medicine, "suggests a more holistic approach by changing the way women respond to bacteria," said Hannan, co-author of an editorial accompanying the study in the journal.

The results support the use of vaginal estrogen as a preventive measure for postmenopausal women with recurrent urinary tract infections, he wrote in the editorial.

Working in the laboratory and with animal models, the researchers identified a number of ways that estrogen -- the female sex hormone -- helps keep recurrent urinary tract infections at bay.

"This study presents some underlying mechanisms for the beneficial effect of [topical estrogen formulations] after menopause and supports the application of estrogen in postmenopausal women suffering from recurrent UTIs," wrote the study's authors, from the Karolinska Institute in Stockholm, Sweden.

About half of all women will experience at least one urinary tract infection in their lifetime, according to the study. For about 25 percent of these women, the infection will come back again within six months.

Low estrogen levels have previously been linked to recurrent infections, and the new study sought to identify exactly how estrogen might affect a woman's risk of recurrent urinary tract infections.

For the study, the researchers used human cells from postmenopausal women who had used supplemental vaginal estrogen for two weeks. They also worked with mice that were given bacteria that would cause urinary tract infections like those in humans.

They found that estrogen encourages production of natural antimicrobial substances in the bladder. The hormone also makes the urinary tract tissue stronger by closing the gaps between cells that line the bladder. By gluing these gaps together, estrogen makes it harder for bacteria to penetrate the deeper layers of the bladder wall, the study authors said.

Estrogen also helps prevent too many cells from shedding from the top layers of the bladder wall.

"Normally, there's an innate response to infection and some cells die -- sort of taking one for the team -- and then these cells shed," Hannan said. "But shedding too much could allow bacteria to get into the deeper tissue, so this exfoliation is a double-edged sword."

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Did Men's Yen for Younger Women Cause Menopause?

Study found bias may have sidelined older women sexually, prompted changes that led to infertility

By Barbara Bronson Gray

HealthDay Reporter

THURSDAY, June 13 (HealthDay News) -- Can women blame men for menopause?

They may have a case, according to new research that suggests it was men's interest in mating with younger females that gave evolutionary rise to menopause by sidelining older women from reproduction.

Menopause -- when a woman stops getting menstrual periods and can't become pregnant -- is unique to humans and its cause is still unknown, explained study author and evolutionary biologist Rama Singh. "We accept as a given the idea that older women tend to be unable to reproduce," but Singh said this is actually an "evolutionary puzzle."

It has long been thought that menopause is what causes women, primarily in their early 50s, to stop being able to get pregnant, but the researchers found evidence that things could actually have occurred the other way around. In other words, infertility may have been the cause, not the effect, of menopause in early humans.

There are at least 10 theories of why menopause occurs, according to the researchers, including ideas based on the fact that women are living longer and depleting the number of eggs in their ovaries, to what is called the "grandmother hypothesis." That idea holds that menopause allows older women to provide childcare that contributes to the survival of their grandchildren, making them more fit or valuable to the human tribe.

But Singh's research, published online June 13 in the journal PLOS Computational Biology, suggests something altogether new.

"This paper is saying that men have played the major or dominant part in choosing mates," said Singh, who is a professor of population genetics and evolution at McMaster University, in Canada. "Somewhere along the line in our evolutionary history, males did not mate randomly but preferred young women because they are more attractive."

Going way back in human history, people reproduced all their lives, explained Singh. While it's possible that some women may have experienced menopause 30,000 years ago, now 100 percent of women experience it. "Menopause is an evolutionary phenomenon," he said.

The scientists found that the development of menopause seems to have done nothing to improve the chances of human survival over time, but rather occurred because women of a certain age weren't finding mates, and thus reproductive ability was unnecessary for them.

Yet Singh pointed out that if women long ago had been the ones choosing younger mates, older men would have been the ones losing their fertility, not women.

The process of natural selection favors the most fit, so women who are most likely to reproduce are protected, explained Singh. Natural selection is the gradual, non-random process through which biological traits become either more or less common, due to the way reproduction occurs, Singh explained.

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Survey Tallies Menopause Symptoms' Toll

Title: Survey Tallies Menopause Symptoms' Toll
Category: Health News
Created: 3/1/2013 2:36:00 PM
Last Editorial Review: 3/4/2013 12:00:00 AM

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