Urinary incontinence, ethnicity, and breast cancer among Colorado women

Prevalent urinary incontinence (UI), operationally defined as weekly leakage of a few drops of urine or greater leakage at least monthly, was studied in relation to ethnicity, breast cancer, and adjuvant breast cancer therapies. Participants were consenting Colorado residents in the Southwest Study of Hormones, Insulin, Nutrition, and Exercise (SHINE), a multi-state population-based breast cancer case-control study. The 741 participants in our SHINE/Women's Pelvic Health Study (SHINE/WPH) included 379 breast cancer cases, 362 controls, 250 Hispanic, and 491 non-Hispanic White women. Hispanic women reported more stress UI (OR=1.7, p=.005) and mixed UI (OR=1.8, p=.005) than non-Hispanic White women. However, these elevated risks among Hispanics were largely accounted for by their higher prevalences of known UI risk factors, including parity, adiposity, and diabetes. Although several breast cancer risk factors are protective against UI, UI prevalence among SHINE/WPH breast cancer cases was similar to that of population controls, and modestly though non-significantly higher after adjustment for risk factors (adjusted OR = 1.29, 95% CI 0.90 – 1.85). UI prevalences among breast cancer patients receiving adjuvant chemotherapy or anti-hormonal therapy were compared respectively to breast cancer cases not receiving the corresponding therapy, and to population controls. Overall, prevalence of stress UI was elevated among breast cancer cases who had previously been treated by chemotherapy (OR=1.7, P=.02), and among breast cancer cases who had received anti-hormonal therapies. (OR=1.6, P=.02). In models incorporating both therapies, chemotherapy retained significance (OR=1.7, p=.05). More research is needed on variations in UI according to both ethnicity and prior cancer therapies.