Depression and anxiety as causes and consequences of urinary incontinence in women: a population-based study

Objective To examine the bidirectional relationships between depression, anxiety, neuroticism, and urinary incontinence in women. Design A prospective time-to-event and two-sample Mendelian randomisation (MR) study. Setting Individual participant data from the UK Biobank and summary genome-wide association (GWAS) study data from international consortia. Participants Up to 118 526 UK Biobank women with linked health records and up to 1.6 million participants with GWAS summary data. Main outcome measures Urinary incontinence (UI) and its subtypes (stress, urge, mixed), urinary urgency (irrespective of leakage), depression, anxiety, and neuroticism. Results We triangulated evidence to demonstrate bidirectional relationships between depression/anxiety and UI. In prospective analyses adjusted for confounders, depression was associated with a higher rate of new onset UI (any UI: Hazard Ratio (HR) 1.67; 95% Confidence Intervals (CI) 1.55 to 1.81) and its subtypes, with the strongest associations observed for mixed UI (HR 1.91; 95%CI 1.59 to 2.31). Similarly, anxiety and higher neuroticism scores were prospectively associated with UI and its subtypes. In the reverse direction, all UI subtypes were associated with a higher rate of new onset depression (e.g. any UI: HR 1.40; 95%CI 1.27 to 1.54) and anxiety (e.g. any UI: HR 1.28; 95%CI 1.17 to 1.39). Two-sample MR provided evidence for a causal effect of genetic liability to depression and neuroticism on UI and its subtypes (e.g. depression on any UI: OR ivw ; 1.25 95%CI 1.16 to 1.35). Evidence for a causal effect in the reverse direction was weaker, with modest effects of genetic liability to any UI on depression. Little evidence was found for causal effects of anxiety with UI subtypes in either direction. Results were largely robust to sensitivity analyses. Conclusion We find evidence of bidirectional relationships between depression/anxiety and UI. Evidence that depression, anxiety and neuroticism are predictors of UI onset has implications for treatment. Research is needed to examine if treatments for depression/anxiety could be effective in alleviating UI. KEY MESSAGE What is already known on this topic Urinary incontinence (UI) co-occurs with depression and anxiety, but the exact nature of the relationship is poorly understood because much of the existing evidence comes from cross-sectional studies. Amongst the existing prospective studies, only one used a clinically validated questionnaire to assess UI, few distinguished between UI subtypes (stress, urgency and mixed UI), and some did not adjust for important confounders. It is commonly believed that depression and anxiety are consequences of UI; if they are also causes of UI this has important implications for clinical care. What the study adds Our study demonstrates that the relationship between UI and depression/anxiety is bidirectional; We found that depression, anxiety and neuroticism (a personality trait characterised by a disposition to experience depression and anxiety) are predictors of UI onset and that UI is associated with new onset depression and anxiety. Depression and anxiety are not routinely assessed in urology clinics, and a continued failure to recognise their contribution to the onset and persistence of UI could be a cause of low success rates of existing treatments for UI.