Interaction between Pelvic Bone Mineral Density and Sex Steroid Hormone on the Risk of Urinary Incontinence from National Health and Nutrition Examination Survey 2013–2014

Introduction: The correlation between sex hormone levels and pelvic bone mineral density in people with urinary incontinence (UI) has not been evaluated. This study explored the association between sex hormones, pelvic bone mineral density, and UI, and analyzed the association between pelvic bone mineral density-combined sex hormones and UI in women. Method: The data of the National Health and Nutrition Examination Survey (NHANES) 2013–2014 were used in this cross-sectional study. Women aged 20 years and older with complete sex steroid hormone and pelvic bone mineral density data were included. Outcomes were stress UI (SUI), urgency UI (UUI), and mixed UI (MUI). Sex steroid hormone included testosterone, estradiol, and sex hormone binding globulin (SHBG). Multivariate logistic regression analyses with the odds ratios (ORs) and 95% confidence intervals (CIs) were used. Results: Of 2,442 women, 579 had SUI, 202 had UUI, and 344 had MUI. The estimated multiplicative interactions were significantly between testosterone and pelvic bone mineral density, between SHBG and pelvic bone mineral density on UI (p = 0.002, p = 0.003), MUI (p = 0.036, p < 0.001), and SUI (p = 0.008, p = 0.044), respectively. High pelvic bone mineral density was associated with UI (p = 0.022) and MUI (p = 0.028) in the age <45-year-old subgroup. Multiplicative interactions were between testosterone and pelvic bone mineral density on all types of UI in the age <45-year-old subgroup, on SUI in women who did not have vaginal deliveries, and on UI in women who had more than one-time vaginal delivery. Conclusion: Our study found negatively multiplicative interactions between testosterone, SHBG, and pelvic bone mineral density on UI, MUI, and SUI. Similar results were found in women aged <45 years old and in women who had more than one-time vaginal delivery. Clinicians may consider testosterone or SHBG supplementation and pelvic density enhancement in women with SUI, MUI, and low endogenous testosterone levels.