Association between body fat distribution and female stress urinary incontinence: a cross-sectional study with the NHANES 2011-2018.

Background: The android to gynoid ratio (A/G ratio) reflects the distribution of abdominal fat relative to gluteofemoral fat and may affect stress urinary incontinence (SUI) by increasing pelvic floor load due to elevated intra-abdominal pressure. However, its direct relationship with SUI remains uncertain. The aim of this study was to explore whether a higher A/G ratio is linked to increased SUI prevalence in American women aged ≥20 years. Methods: This cross-sectional analysis used data from 5,309 women aged ≥20 years in the 2011-2018 National Health and Nutrition Examination Survey (NHANES). The A/G ratio was assessed using dual-energy X-ray absorptiometry (DXA). Weighted multivariable logistic regression was applied to examine the association between the A/G ratio and SUI in women. Subgroup analyses based on smoking status, hypertension, diabetes, hypercholesterolemia, vigorous physical activity, moderate physical activity, vaginal delivery, cesarean section, menopausal status, and body mass index (BMI) were conducted to assess effect modification. Restricted cubic splines (RCS) and receiver operating characteristic (ROC) curve were employed to analyze nonlinear relationships and predictive accuracy, respectively. Results: Among the 5,309 participants, 1,958 reported experiencing SUI. After adjusting for covariates, a higher A/G ratio was independently associated with increased SUI risk [odds ratio (OR) =3.640, 95% confidence interval (CI): 2.150-6.162]. The number of vaginal deliveries, cesarean deliveries, and BMI subgroups may interact with the A/G ratio (P<0.05). In the smoking status subgroup, significant positive associations between the A/G ratio and SUI were observed in both never-smokers (OR =3.611, 95% CI: 1.739-7.497) and current-smokers (OR =4.720, 95% CI: 1.311-16.997), indicating that a higher A/G ratios correlates with increased SUI risk in these two subgroups. In the vigorous activity subgroup, a significant positive association between the A/G ratio and SUI prevalence in the on-vigorous activity group (OR =4.752, 95% CI: 2.386-9.506). RCS analysis showed a linear association between the A/G ratio and SUI (P for nonlinearity =0.25). ROC curve analysis yielded an area under the curve (AUC) of 0.758 for the A/G ratio in predicting SUI. Conclusions: The A/G ratio is a risk factor for SUI in women aged ≥20 years, suggesting its potential utility in clinical risk stratification.