Weight‐Adjusted Waist Index Mediates the Association Between Cardiovascular Health (Life’s Crucial 9) and Stress Urinary Incontinence: A NHANES Study

Background Stress urinary incontinence (SUI) is a common and bothersome condition adversely affecting women’s well‐being. Although growing evidence links cardiometabolic health to pelvic floor disorders, the role of multidimensional cardiovascular health metrics—particularly Life’s Crucial 9 (LC9)—has not been adequately examined. This study aimed to evaluate the association between LC9 and SUI and to investigate whether the weight‐adjusted waist index (WWI), an indicator of central fat distribution, mediates this relationship. Methods We analyzed data from the 2005–2016 National Health and Nutrition Examination Survey (NHANES), including 8086 women with complete information. LC9 was constructed from nine components reflecting behavioral, biological, and psychological health. SUI was identified via a standardized questionnaire. Complex survey‐weighted multivariable logistic models were used to estimate odds ratios (ORs) with 95% confidence intervals (CIs). Nonlinear associations were explored with restricted cubic splines, and causal mediation analysis was conducted to quantify the indirect effect through WWI. Results After full adjustment for confounders, a 10‐point increase in LC9 score was associated with a significant reduction in SUI risk (OR = 0.82, 95% CI: 0.78–0.86). Women in the highest LC9 tertile had 45% lower odds of SUI compared to the lowest tertile (OR = 0.55, 95% CI: 0.47–0.64; p for trend < 0.001). Conversely, each unit increase in WWI was associated with elevated odds of SUI (OR = 1.22, 95% CI: 1.12–1.32), with the top tertile showing 37% higher odds (OR = 1.37, 95% CI: 1.16–1.62). Both exposures exhibited linear dose–response patterns ( p for overall < 0.001). Mediation analysis suggested that WWI may account for 13% of the observed association between LC9 and SUI ( p < 0.001). Conclusions Better cardiovascular health, as measured by LC9, is independently associated with a lower prevalence of SUI, and this relationship is partially mediated by central adiposity. These findings highlight the potential of composite health metrics in risk stratification and the development of integrated prevention strategies for SUI in women.