Hard to hold

BPA exposure and hormone changes are a dangerous combo for aging men

Brian Bienkowski for Environmental Health News

    

It's an uncomfortable, often embarrassing problem—having to pee a lot, but not getting relief when you go.

For older men, this problem is increasingly common and can go beyond the awkward and cause real damage to the bladders or kidneys. In extreme cases it can be fatal.

New research out this month may have uncovered a dangerous combination of chemical exposure and hormone changes later in life as a culprit in obstructive voiding disorder, which refers to "urgency [and] increased frequency of urination, low urine flow pressure, and incomplete bladder emptying, which can lead to acute kidney injury," the authors wrote in the study published this month in the International Journal of Molecular SciencesInternational Journal of Molecular Sciences.

As men age they develop benign prostatic hyperplasia, which is enlargement of the prostate. 

Nearly all men, if they live long enough, will develop it and "if left unchecked they will have urinary retention" problems, William Ricke, professor, researcher and Director of the University of Wisconsin O'Brien Center of Research Excellence in Benign Urology and co-author of the new study, told EHN.

"Acute urinary retention if left unchecked by a urologist, urine can back up into kidneys and, in mouse models, those kidneys start to look like another bladder," Ricke said. "You don't have kidneys, you die."

In the new study of lab mice, Ricke and colleagues have linked the combination of exposure to the ubiquitous chemical bisphenol-A (BPA) around the time of birth and elevated estrogen levels as an adult to urinary disorders, kidney problems and enlarged prostates and bladders.

The study in mice is the first to show that BPA—a chemical that mimics the hormone estrogen—along with the elevated natural estrogen levels men experience as they age can collectively combine to induce prostate, bladder and kidney problems. 

This one-two punch of exposure during genital development and hormone changes with age can leave men with urinary issues and prostate enlargement, which can wreak havoc on their health.

BPA is a key ingredient in polycarbonate plastic, making the plastic much more durable and stronger. It is pervasive in food and beverage containers, canned goods and store receipts—and us. 

More than 90 percent of people in the U.S. have BPA in their bodies. And that may be an underestimate, as recent research has found that tests used by federal scientists "dramatically" undercount BPA and other chemical exposures.

BPA has been linked to a range of health problems including cancer, diabetes, obesity, infertility and behavioral problems. Previous research has also shown BPA can disrupt proper development of male genitals. Health professionals have long known that as men age, levels of the hormone testosterone decrease and levels of estrogen increase.

Elevated levels of estrogen can spur enlarged prostates in men, which is a major cause of urinary issues. But not all men experiencing urinary issues have an enlarged prostate, Fredrick vom Saal, senior author of the new study and a professor of biology at the University of Missouri-Columbia, told EHN.

But it does seem that excess estrogen—whether it's the natural hormone increasing with age or the synthetic estrogen mimic BPA—feeds into urinary issues.

Vom Saal and colleagues exposed some mice to BPA during fetal development, and then checked for bladder, kidney, prostate and urinary issues in the mice as they aged later and hormone balances changed.

"Animals exposed to BPA … during perinatal development were more likely than negative controls to have urine flow/kidney problems and enlarged bladders, as well as enlarged prostates," vom Saal and co-authors wrote.

Vom Saal said BPA exposure during development "hypersensitized the whole system for subsequent exposure to those hormones." So, when estrogen levels naturally start increasing as the male mice age, those exposed to BPA as fetuses and babies were more susceptible to experience the urinary and health issues.

"These critical periods of exposure [during development] are setting up those individuals for sensitivity to those hormones for the rest of their life," vom Saal said.

"All of the estrogens you're exposed to combine to impact the severity of this disease as you age," vom Saal said. "And the most abundant external source of estrogenic activity is BPA."

Ricke said "time will tell" how much the new study will inform us about humans' development of prostate and urinary issues. However, previous studies in humans confirm that additional estrogen exposure can be associated with prostate issues later in life, he said.

"We've seen that higher estrogen levels often occur in African American boys developing in pregnant woman—the estrogen levels are higher in circulation—and in those men prostate cancer is much more aggressive, and incidences are higher," Ricke said, adding that next research steps would include trying to further understand what the mouse model they used would mean for humans.

He added that, while most men in the U.S. have access to medical care that can address the problems identified in the study, these are still potentially fatal issues in most of the world.

"We're fortunate to live in the Western world, for many men throughout the world, particularly in developing countries, they still don't have access to urologists."