Urinary incontinence symptoms and knowledge across activity levels in young women (UI-SKY Project): a mixed-methods comparative study

Urinary incontinence (UI) in young women is increasingly recognized but remains under-reported and insufficiently addressed. While physical activity has been implicated in pelvic floor dysfunction, evidence regarding its relationship with urinary incontinence remains heterogeneous and context-dependent. This study aimed to evaluate UI prevalence, symptom burden, and knowledge, and to explore perceptions and care-seeking behaviors among young women. A nationwide mixed-methods comparative study was conducted among 461 women aged 18–40 years in Thailand. Participants were categorized into three groups based on physical activity levels: athletes ( n = 141), recreationally active ( n = 152), and sedentary ( n = 168). Quantitative data were collected using validated questionnaires including ICIQ-UI SF, IIQ-7, and PIKQ-UI which assessed UI severity, impact on quality of life, and knowledge of urinary incontinence, respectively. Multivariable regression analyses were performed to assess associations between activity level and outcomes. In-depth interviews were conducted with 30 participants and analyzed using reflexive thematic analysis. Findings were integrated using an explanatory sequential approach. Overall, 30.8% of participants reported UI, with prevalence decreasing across activity levels (39% sedentary, 30% recreationally active, 22% athletes; p = 0.004). Athletes had significantly lower odds of UI compared with sedentary women (adjusted OR 0.45, 95% CI 0.25–0.80; p = 0.007). Physical activity was not associated with symptom severity among symptomatic individuals. Both athletes and recreationally active women reported lower quality-of-life impact compared with sedentary participants (adjusted OR 0.55 and 0.52, respectively). Despite these favorable outcomes, athletes demonstrated significantly lower pelvic floor knowledge (adjusted OR 0.17, 95% CI 0.08–0.34; p < 0.001), indicating a knowledge–behavior gap. Qualitative findings revealed consistent themes of age-related misperception, symptom normalization, stigma, and delayed care-seeking. Participants commonly relied on self-management and informal information sources, and a substantial gap between PFMT awareness and practice was identified. UI in young women in this study population represents an under-recognized public health issue, with prevalence highest among sedentary individuals. While physical activity is associated with lower UI prevalence and better quality-of-life outcomes, significant gaps in pelvic floor knowledge and health-seeking behavior persist, particularly among athletes. Integrated, behaviorally informed interventions are needed to improve awareness, promote preventive practices, and address system-level barriers in this population.