Weight-adjusted-waist index is positively associated with urinary incontinence: results from the National Health and Nutrition Examination Survey (NHANES) 2001-2018.

Background: Urinary incontinence (UI) is closely related to obesity. The aim of this study is to evaluate the association of a novel anthropometric indicator weight-adjusted-waist index (WWI) with UI.

Methods: This cross-sectional study used the data from National Health and Nutrition Examination Survey (NHANES) 2001-2018. Weighted multivariable logistic regression was used to evaluate the relationship between WWI and three types of UI [stress UI (SUI), urgency UI (UUI), and mixed UI (MUI)]. The receiver operating characteristic (ROC) curve and Delong et al.'s test were utilized for comparison of the predictive capability for UI between WWI and body mass index (BMI), waist circumference (WC).

Results: A total of 41,614 participants were included in this study, of whom 23.57% had SUI, 19.24% had UUI, and 9.43% had MUI. In the fully adjusted model, WWI was positively associated with three types of UI [SUI: odds ratio (OR) = 1.19, 95%Confidence interval (CI) 1.13-1.25; UUI: OR = 1.18, 95%CI 1.13-1.24; MUI: OR = 1.19, 95%CI 1.11-1.27, all p < 0.001]. Compared to the lowest WWI interval, the positive correlation between WWI and UI still existed in the highest WWI group after converting WWI to a categorical variable by quartiles (SUI: OR = 1.52, 95%CI 1.35-1.71, p < 0.001; UUI: OR = 1.50, 95%CI 1.33-1.69, p < 0.001; MUI: OR = 1.55, 95%CI 1.32-1.83, p < 0.001). WWI had a stronger prediction for three types of UI than BMI and WC (all p < 0.001).

Conclusion: A higher WWI was linked with an increased likelihood of three types of UI (SUI, UUI, and MUI) in the United State population. Compared to BMI and WC, WWI had a stronger predictive power for UI. WWI may be a better adiposity parameter for evaluating UI.