Body Mass Index and Depressive Symptoms as Risk Factors for Urinary Incontinence in Women: A Nationally Representative Study.

INTRODUCTION AND HYPOTHESIS

Urinary incontinence (UI) is associated with body mass index (BMI) and may be influenced by depressive symptoms. This study was aimed at assessing the relationship between BMI and UI risk and frequency in adult women, with a focus on depressive symptoms, measured by Patient Health Questionnaire-9 (PHQ-9) score, as a potential mediator.

METHODS

Data from 6107 adult women in the National Health and Nutrition Examination Survey from 2005 to 2018 were analyzed. Weighted multivariable-adjusted regression analysis determined odds ratios (ORs) and 95% confidence intervals (CIs) for BMI-UI associations. Restricted cubic spline (RCS) analysis evaluated nonlinear relationships, and causal mediation analysis examined the mediating role of depressive symptoms. Subgroup analyses were stratified by PHQ-9 score.

RESULTS

Higher BMI was associated with increased UI risk and frequency. When BMI was categorized into quartiles, UI risk progressively increased from Q2 to Q4. In the fully adjusted model, OR for UI risk in Q4 vs Q1 was 2.53 (95% CI 1.83, 3.52; p < 0.001), with a significant trend across quartiles. RCS analysis indicated a nonlinear relationship, with increased UI risk, particularly at BMI levels above 30. Depressive symptoms were independently associated with higher UI risk and frequency, with significant mediation effects. Mediation analysis revealed that PHQ-9 score accounted for approximately 6.8% of the effect of the BMI on UI risk and 6.5% on UI frequency (both p < 0.001).

CONCLUSIONS

Elevated BMI and depressive symptoms are independently associated with increased UI risk and frequency among adult women. The mediation effect of depressive symptoms underscores the importance of addressing mental health and weight management to reduce UI risk. These findings advocate a holistic approach to UI prevention and treatment, integrating physical and mental health strategies.