Caffeine Does Not Worsen Urinary Incontinence in Women

Contrary to common belief, the intake of caffeine does not appear to cause a worsening or a progression of urinary incontinence (UI), according to a new study.

Researchers at Brigham and Women's Hospital (Boston, MA, USA), Harvard Medical School (Boston, MA, USA), and other institutions conducted a prospective cohort study in 21,564 women with moderate UI enrolled in the Nurses' Health Study and Nurses' Health Study II, to estimate the association between long-term caffeine intake and risk of UI progression; UI progression was identified from questionnaires during two years of follow-up.

Baseline caffeine intake and change in caffeine intake during the four years before baseline were measured using food frequency questionnaires. Odds ratios (ORs) for incontinence progression were then calculated.

The results showed that the percentage of women with UI progression was similar across categories of baseline level of caffeine intake and change in caffeine intake before baseline. For example, percentages were 21% compared with 22%, comparing 450 mg or more to less than 150 mg of caffeine per day.

Comparing women with increased caffeine intake to those with stable caffeine intake, percentages with progression were 22% compared with 20%. The results were similar in separate analyses of urge and stress UI. The authors stressed that the study did not address the short-term effects of caffeine on the bladder. The study was published in the May 2012 issue of Obstetrics and Gynecology.

“If a woman feels she wants to abstain from caffeine that’s completely fine, but based on our results, women with moderate incontinence shouldn’t be concerned,” said lead author epidemiologist Mary Townsend, ScD, of Brigham and Women’s Hospital. “But the results need to be confirmed with more research because there's a possibility that caffeine could make urinary symptoms worse over longer than a few years.”

Urinary incontinence is about twice as common in women than men, and its likelihood rises with age. One large US study found that almost one-quarter of women in their 60s and 70s said they had urine leakage at least once a month; the rate rose to one-third among women in their 80s. Caffeine might promote UI because it is a diuretic, and people who already have an overactive bladder may be more susceptible to those effects, since even low doses of caffeine can speed muscle contractions in the bladder. Risk factors for UI include obesity and past pregnancies with vaginal births.

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Brigham and Women's Hospital
Harvard Medical School