July 21, 2000 -- Do you live for latte? Crave cola? If you're a woman, take heed: Researchers say drinking too much caffeine may put some women at risk for a difficult and embarrassing bladder control problem as they age.
In a study of more than 250 women who were being evaluated for urinary incontinence, researchers from Rhode Island found that those who downed more than four cups of coffee per day were 2.5 times more likely than those who consumed little or no caffeine to have an unstable bladder condition called detrusor instability. Those who drank two to four cups of coffee per day (or the equivalent in other caffeinated beverages) were about 1.5 times more likely to have the condition.
Up to 40% of women over 65 may have the unstable bladder problem, as may nearly 30% of younger women. So, what is it exactly?
"[Detrusor instability] simply means that the bladder contracts involuntarily," explains urologist Jerry Blaivas, MD. The bladder is made of smooth muscle fibers, which can stretch as it fills and contract to empty it. Blaivas describes the bladder as being like a balloon with a knot tied at the bottom: The knot, or sphincter, opens and closes as needed to let urine out. "When you urinate, the bladder contracts, and the sphincter opens. In detrusor instability, the bladder contracts without your wanting it to -- sporadically during the day." Stress incontinence, another type of bladder control problem, involves a weakening of the sphincter.
Bladder instability often leads to the need to run for the bathroom, or to embarrassing accidents when urine leaks out without warning.
In an article published in the journal Obstetrics and Gynecology, Lily A. Arya, MD, and colleagues from Brown University School of Medicine in Providence saydrinking several cups of coffee, tea, or cola a day could increase the risk of bladder instability in women who already have bladder-control problems.
Age also increases the risk of bladder instability. In the study, those who were found to have bladder instability tended to be in their mid-50s, about 10 years older than those without the instability. The researchers also found that the women with bladder instability were more likely to be smokers.
Arya and colleagues say the link between caffeine and detrusor instability may have several explanations, including the possibility that caffeine stimulates the muscles of the bladder, causing them to contract involuntarily.
But there may actually be a simpler explanation, says Blaivas, a professor of urology at Weill Medical College of Cornell University and attending surgeon at New York Hospital Cornell Medical Center and Lenox Hill Hospital in New York. He points out that caffeine is a diuretic -- a substance that increases urine output. So women who drink lots of caffeine-containing drinks make more urine, and use their bladders more, than other women.
Blaivas, who was not involved in the study, tells WebMD that the authors' advice that women with symptoms of bladder instability cut back on caffeine is worth a try. But he says women with these symptoms typically require treatment that includes pelvic exercises, timed urination, and/or medications.
"The first thing to do is look for a reason why a person would have [bladder instability]," Blaivas says. Causes may include obstructions such as kidney stones or tumors, as well as age-related changes in muscle. "Many times we can use exercises to try to teach you to stop the bladder from contracting."