The Potential Mediating Role of Depressive Symptoms in the Inverse Association Between Dietary Index of Gut Microbiota and Overactive Bladder: A Cross‐Sectional Study

Overactive bladder (OAB) is a prevalent urinary dysfunction with a substantial burden. Diet, gut microbiota, and psychological factors such as depression are increasingly implicated in disease pathways, yet evidence from large‐scale studies remains limited. This study investigates the association between the dietary index of gut microbiota (DI‐GM) and OAB using weighted regression and examines whether depressive symptoms serve as a potential mediator through mediation analysis. Data from 30 014 adults in the 2007–2020 National Health and Nutrition Examination Survey (NHANES) were analyzed. DI‐GM scores were derived from dietary recalls; OAB was defined by standardized symptom criteria; depressive symptoms were measured using the Patient Health Questionnaire‐9 (PHQ‐9). Logistic regression, sensitivity, and mediation effect analysis were conducted. Among participants, 6320 had OAB (weighted prevalence 21.0%). Higher DI‐GM scores were associated with lower odds of OAB (fully adjusted odds ratio [OR] = 0.956, p < 0.001), mainly driven by beneficial dietary components. Depressive symptoms mediated 25.8% of the association, rising to 35.4% for beneficial components. A gut microbiota‐supportive dietary pattern is inversely associated with OAB prevalence, underscoring the importance of diet quality in bladder health. Depressive symptoms potentially mediated this link, suggesting dietary interventions may be complemented by psychological support.