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19-05-2011 | Internal medicine | Article

High caffeine intake linked to frequent urinary incontinence


Free abstract

MedWire News: High caffeine intake - equivalent to 4 or more cups of coffee per day - increases the incidence of frequent urgency incontinence, US study results show.

The findings illustrate that by reducing daily caffeine consumption to the lowest amount observed in the study (0-149 mg), those who consumed the most (450 mg or more) could avoid 16% of daily frequent urinary incontinence and 25% of urgency urinary incontinence.

"Caffeine may promote incontinence through its diuretic effect, especially in individuals with underlying detrusor overactivity," say Mary Townsend (Channing Laboratory, Boston, Massachusetts, USA) and colleagues.

The team investigated the association between caffeine intake and incident urinary incontinence in 65,176 women from the Nurses' Health Study cohorts 2000 and 2001. Participants completed food frequency questionnaires approximately every 4 years that detailed caffeine intake (coffee, tea, chocolate, soda drinks), and urinary incontinence experiences were recorded at least once during three follow-up survey mailouts between 2000 and 2005.

Incident cases were defined as women who reported urinary incontinence (including a few drops, enough to wet the underwear, enough to wet the outer clothing, and enough to wet the floor) at least once monthly, and frequent incontinence was defined as urinary incontinence at least once weekly.

The greatest contributor to caffeine intake was coffee, at 76%. Almost half (49%) of the women were in the lowest category of caffeine intake, while 9% reported consuming 450 mg or greater per day.

The incidence rate of frequent urinary incontinence was 1.9, 1.6, 2.5, and 2.7 cases per 100 person-years in women who consumed 0-149, 150-299, 300-449, and 450 mg caffeine or above per day, respectively.

After adjusting for potentially confounding factors, women in the highest caffeine intake group were a significant 1.2 times more likely to experience frequent urinary incontinence than those in the lowest intake category.

Women in the highest intake group also had a borderline significant 1.3-fold increased risk for urgency urinary incontinence (defined as primarily leaking with an urge to urinate or sudden feeling of bladder fullness), compared with those in the lowest intake group.

No significant associations were noted between urinary incontinence and decaffeinated coffee, indicating that observations made regarding caffeinated coffee "are likely due to caffeine rather than to other components of coffee or to lifestyle factors related to coffee drinking," write the researchers in the Journal of Urology.

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Sarah Guy

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