Biological Aging Exhibits an Inverted J-Shaped Relationship with Stress Urinary Incontinence in Women.

BACKGROUND

Biological aging is a systemic driver of chronic disease, yet its relationship with female urinary incontinence (UI) remains unexamined. We leveraged three conceptually distinct metrics-PhenoAge (PA), Klemera-Doubal Method (KDM), and Homeostatic Dysregulation (HD)-to quantify biological age and assessed their associations with stress UI (SUI), urgency UI (UUI), and mixed UI (MUI) in a nationally representative cohort.

METHODS

This cross-sectional study included 8,561 women ≥20 years from NHANES 2005-2010 and 2015-2018. After outlier exclusion and covariate selection via LASSO regression, multivariable logistic regression and restricted cubic splines (RCS) were used to estimate ORs and dose-response shapes. Subgroup analyses, mediation analyses, and sensitivity analyses were performed.

RESULTS

PA and KDM were positively associated with UI. The third quartile of PA and KDM conferred the highest risk for SUI (PA: Q3 OR = 1.58, 95% CI 1.33-1.88; KDM: Q3 OR = 1.39, 95% CI 1.20-1.62). Higher quartiles were also linked to greater UI severity. Fully adjusted RCS models revealed inverted J-shaped relationships for SUI (PA inflection: 43.6; KDM: 34.7) and inverted U-shaped relationships for UUI and MUI with KDM (UUI inflections: 40.7 and MUI inflections: 40.5). Associations were robust across most subgroups but attenuated with increasing reproductive risk factors. No significant mediation by sex steroids or α-Klotho was observed.

CONCLUSION

Biological aging is significantly positively associated with UI, and its relationship with SUI follows an inverted J-shaped curve. Interventions that slow biological aging may offer a novel strategy for UI prevention; however, longitudinal studies are required to establish causality.