A complex association with cadmium

Cadmium is a heavy metal that is often found in water systems and soil owing to its release from industrial processes. Occupational exposure is seen in those who work in production and use of nickel–cadmium batteries, phosphate fertilizers, copper and nickel smelting, and waste incineration and disposal. Furthermore, exposure in the general population can occur via cigarette smoke, water and consumption of foods that accumulate cadmium. The long half-life of this metal means that it can accumulate in human tissue, leading to a variety of health concerns. The mechanisms and causes of overactive bladder (OAB) remain unclear, but the known neurotoxic and pro-inflammatory properties of cadmium mean it is considered a possible contributing factor.

Data were analysed from the 2007–2020 National Health and Nutrition Examination Survey (NHANES), and the relationship between blood cadmium levels and OAB and its components were assessed using weighted multivariate logistic regression. Prevalence of OAB in this database was 26.2% of the 15,467 respondents. Blood cadmium levels were associated with overall OAB, but this association was small and not significant after adjusting for other variables, although blood cadmium levels in the OAB group were statistically higher than in the non-OAB group. Cadmium was inversely associated with severity of nocturia (OR 0.85, 95% CI 0.74–0.98, P < 0.05) and was also linked to more severe incontinence in adults aged 50–59 years and in non-Hispanic Black patients.