Coffee and caffeine intake and risk of urinary incontinence: a meta-analysis of observational studies

Background: Previous results from studies on the relationship between coffee/caffeine consumption and risk of urinary incontinence (UI) are inconclusive. We aim to assess this association using a meta-analysis of observational studies. Methods: Pertinent studies were identified by searching electronic database (Embase, PubMed and Web of Science) and carefully reviewing the reference lists of pertinent articles until July 2015. Random-effects models were used to derive the summary ORs and corresponding 95 % CIs. Results: Seven studies (one case-control, two cohort and four cross-sectional) were included in our meta-analysis. The summary ORs for any versus non-consumption were 0.75 (95 % CI 0.54-1.04) for coffee and 1.29 (95 % CI 0.94-1.76) for caffeine consumption. Compared with individuals who never drink coffee, the pooled OR of UI was 0.99 (95 % CI 0.83-1.18) for regular coffee/caffeine drinkers. Coffee/caffeine consumption was not associated with moderate to severe UI (OR 1.18, 95 % CI 0.88-1.58). In stratified analyses by gender, no significant association was found between UI risk and coffee/caffeine consumption in both men (OR 0.99, 95 % CI 0.42-2.32) and women (OR 0.92, 95 % CI 0.80-1.06). By subtype, the pooled ORs were 1.01 (95 % CI 0.86-1.19) for stress UI, 0.99 (95 % CI 0.84-1.16) for urge UI and 0.93 (95 % CI 0.79-1.10) for mixed UI. Conclusions: This meta-analysis found no evidence for an association between coffee/caffeine consumption and the risk of UI.