Serum Copper and Zinc Levels and Urinary Incontinence in Adult Women

Recent findings show that oxidative damage may contribute to lower urinary tract symptoms. Copper can induce oxidative stress while zinc is involved in the defense against oxidative stress. We examined the associations between serum copper and zinc levels and urinary incontinence (UI) in adult women. Data were retrieved from the 2011–2016 National Health and Nutrition Examination Surveys. Outcomes for multivariate logistic regression were any UI (AUI), urge UI (UUI), stress UI (SUI), mixed UI (MUI), and moderate/severe UI. Questions on urinary incontinence were asked by trained interviewers. The weighted UI prevalences were 44.89% for AUI, 28.12% for UUI, 41.64% for SUI, 17.27% for MUI, and 20.79% for moderate/severe UI in adult women. After adjusting for multiple factors, serum copper levels in the highest quartile were associated with UUI [odds ratios (95% confidence intervals): 1.74 (1.11–2.74)]. In women older than 50 years, serum copper levels in the highest quartile were associated with UUI [2.94 (1.57–5.49)], AUI [1.97 (1.19–3.27)], MUI [2.43 (1.19–4.97)], and moderate/severe UI [2.37 (1.06–5.31)]. Serum copper levels in the second quartile were also associated with MUI overall [1.75 (1.03–2.97)] and in young women (20–49 years) [2.29 (1.02–5.17)]. Positive associations were also found between serum copper levels and UUI in non-obese women. There were no associations between serum zinc levels and UI outcomes. Serum copper levels were associated with UUI, MUI, AUI, and moderate/severe UI in adult women, especially women older than 50 years. Causality deserves to be confirmed further.