Biological aging partly mediates the association between physical activity and overactive bladder: evidence from NHANES 2007–2020

BACKGROUND: Overactive bladder (OAB) impairs quality of life and may increase mortality risk. Physical activity (PA) is a modifiable behavior that could protect against OAB, but the role of biological aging as a potential mechanistic link remains unclear. We examined associations among PA, biological aging, OAB, and all-cause mortality and tested mediation by biological aging. METHODS: Data from the National Health and Nutrition Examination Survey (2007-2020) were used. Weighted Cox regression assessed OAB and all-cause mortality associations. Weighted logistic regression examined associations among PA, biological aging (PhenoAge and KDMAge acceleration), and OAB. Finally, Mediation analysis explored the mediating effect of biological aging on the PA-OAB relationship. RESULTS: This study included 18,664 participants, of whom 3,989 (21.37%) reported OAB symptoms. In the mortality-linked cohort (2,553 participants with OAB), 539 (21.11%) deaths were observed. Cox regression showed OAB significantly increased all-cause mortality risk (HR 1.430 [95% CI 1.275-1.604]; P < 0.001), while PA reduced mortality risk in OAB patients (HR 0.572 [95% CI 0.468-0.698]; P < 0.001). Fully adjusted models showed PA reduced OAB risk (OR 0.856 [95% CI 0.775-0.946]; P = 0.003), while each 1-unit increase in PhenoAge and KDMAge acceleration raised OAB risk by 2.7% (P < 0.001) and 2.9% (P = 0.018). Mediation analysis revealed PA delayed PhenoAge and KDMAge acceleration (mediation proportions: 13.47% and 2.71%, respectively), reducing OAB risk. CONCLUSIONS: PA could reduce the risk of developing OAB partly by slowing biological aging and decrease all-cause mortality in patients with OAB. This study emphasizes the role of PA in preventing and managing OAB and encourages further evaluation of the mechanisms and effects of behavioral interventions for OAB.