Relationship between exposure to cadmium, lead, and mercury and the occurrence of urinary incontinence in women

Cadmium, lead, and mercury are nephrotoxic metals that are commonly found as hazardous pollutants in many areas of the USA. We examined the relationship between exposure to cadmium, lead, and mercury with the occurrence of urgency urinary incontinence (UUI) and stress urinary incontinence (SUI) in women. This study was conducted using data on women > 20 years of age, collected between 2005 and 2016, who reported experiencing urinary incontinence in the National Health and Nutrition Examination Survey (NHANES). Restricted cubic spline analysis was used to characterize a dose–response relationship between continuous exposure to different nephrotoxic metals and the occurrence of UUI and SUI. A total of 4406 women were included in this study, with 2624 (59.6%) suffering from SUI and 3177 (72.1%) suffering from UUI in the weighted population. The results of our multivariate analysis indicated that age, race, marital status, body mass index (BMI), and exposure to nephrotoxic metals were risk factors for developing UI. The odds ratio (OR; 95% confidence interval) for developing UI was positively correlated with the exposure to cadmium and lead in women. The OR of SUI occurrence increased with increasing levels of cadmium in blood, with a peak at 4 µg/L. The OR of UUI occurrence increased with increasing levels of blood and urinary lead, with peaks at 7 µg/dL and 5 µg/L, respectively. The presence of mercury was not significantly correlated with the occurrence of SUI or UUI. Exposure to high levels of cadmium and lead, which are nephrotoxic metals, is associated with the occurrence of UI in women.