Exploring the relationship between appendicular skeletal muscle index and urge urinary incontinence risk in adult women: a cross-sectional analysis of the National Health and Nutrition Examination Survey

Front Nutr. 2025 Jun 18:12:1606089. doi: 10.3389/fnut.2025.1606089. eCollection 2025.

Abstract

Objective: This study aimed to investigate the relationship between the appendicular skeletal muscle index (ASMI) and Urge urinary incontinence (UUI) in a large cohort of adult women.

Methods: This study utilized data from the National Health and Nutrition Examination Survey during the periods of 2001-2006 and 2011-2018. ASMI was identified as the exposure factor. UUI was the outcome variable. We first compared the baseline characteristics of individuals with and without UUI. The effect of ASMI on UUI was assessed using weighted multivariate logistic regression models. Additionally, the relationship between the two was illustrated using restricted cubic splines.

Results: A total of 19,009 women aged 20 and above participated in this study, with 5,960 diagnosed with UUI and 13,049 not affected. The results of the adjusted multivariate logistic regression analysis showed a significant inverse relationship between ASMI and the probability of UUI. Specifically, with every one-unit rise in ASMI, the likelihood of UUI diminished by 69% in the fully adjusted model (OR = 0.31; 95% CI: 0.12-0.82; p = 0.02). Furthermore, participants falling within the highest ASMI quartile showed a 28% reduction in UUI risk relative to those in the lowest quartile (OR = 0.72; 95% CI: 0.55-0.94; p = 0.02). A restricted cubic spline analysis demonstrated a nonlinear relationship between ASMI and UUI (p for nonlinearity = 0.02). Subgroup analyses suggested that various demographic and health factors did not significantly alter this association.

Conclusion: The ASMI was significantly negatively correlated with the risk of UUI, suggesting that an increase in ASMI may have been associated with a lower risk of UUI.

Keywords: NHANES; appendicular skeletal muscle; appendicular skeletal muscle index; sarcopenia; urge urinary incontinence; urinary incontinence.