Prevalence of symptoms related to interstitial cystitis in women: A population based study in Finland

Purpose: Interstitial cystitis is a chronic inflammatory bladder disease. Despite intensive research its prevalence, etiology, diagnosis and appropriate treatment remain elusive. We estimated the prevalence of urinary symptoms related to interstitial cystitis in women in Finland. Materials and Methods: We randomly selected 2,000 study participants 18 to 71 years old from the Finnish population register. The prevalence of urinary symptoms was evaluated using the validated O'Leary-Sant interstitial cystitis symptom and problem index questionnaire, which was mailed to subjects. Women with high (12 or greater) symptom and problem scores, including nocturia 2 or greater, pain 2 or greater, and excluding urinary infection and pregnancy, were considered most likely to have interstitial cystitis. Results: The response rate after 2 mailings was 67.2% (1,343 respondents). After further exclusions 1,331 women (66.6%) comprised the final study group. Of these 1,331 respondents 11 (0.8%) reported severe symptoms and problems (12 or greater), including 6 (0.45%) who fulfilled the criteria for probable interstitial cystitis. Conclusions: The prevalence of urinary symptoms corresponding to probable interstitial cystitis is 450/100.000 (95% confidence interval 100 to 800), which is an order of magnitude higher than previously reported.