Dietary caffeine intake and the risk for detrusor instability: A case-control study

Objective: To determine whether there is an association in women between ca ffeine intake and risk for detrusor instability. Methods: Women were included if they had symptoms of urinary incontinence, completed a 48-hour voiding diary detailing fluid and caffeine intake, and had undergone standardized multichannel urodynamics. The study group had 13 1 women with detrusor instability on provocative cystometry and maximum ure thral closure pressure greater than 20 cm of water. The control group had 1 28 women without detrusor instability on provocative cystometry and maximum urethral closure pressure greater than 20 cm of water. For statistical com parison, women were divided into the following three groups on the basis of caffeine intake: minimal (< 100 mg/day), moderate (100-400 mg/day), and hi gh (> 400 mg/day). Results: The mean caffeine intake of women with detrusor instability (484 /- 123 mg/day) was significantly higher than that of controls (194 +/- 84 m g/day, P =.002). On univariate analysis, significant risk factors for detru sor instability were age, smoking status, and caffeine intake. On multivari ate analysis, the statistically significant association between high caffei ne intake and detrusor instability persisted after controlling for age and smoking (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.1, 6.5, P =.01 8). When women with moderate caffeine intake were compared with those with minimal caffeine intake, the risk for detrusor instability was lower and di d not reach significant levels (OR 1.5, 95% CI 0.1, 7.2, P=.093). Conclusion: An association between high caffeine intake and detrusor instab ility was seen in this population. Larger studies are required to determine whether the association is causal. (Obstet Gynecol 2000;96:85-9. (C) 2000 by The American College of Obstetricians and Gynecologists.).