Association between urinary heavy metal/trace element concentrations and kidney function: a prospective study.

Background: Chronic kidney disease (CKD) is an important public health problem. Although cross-sectional studies have identified many heavy metals/trace elements associated with reduced kidney function, prospective studies are needed to determine the pathogenic role of these elements in the development and progression of CKD. Methods: To explore the association between baseline urinary heavy metal/trace element concentrations and long-term impaired kidney function (IKF)/CKD, as well as the incidence of rapid decline in kidney function in a population-based exploratory prospective study, with mean age 51.9 years at baseline whose urinary trace elements concentrations have been determined by inductively coupled plasma mass spectrometry. IKF was defined by a reduced estimated glomerular filtration rate (eGFR) between 60 and 90 mL/min/1.73 m Results: Over a mean follow-up of 12.5 years, 123 participants (2.6%) experienced rapid decline in kidney function, and 1455 (31.7%) developed IKF or CKD. After adjusting for covariates including baseline eGFR, we found that urinary vanadium [hazard ratio (HR) = 1.07, 1.03-1.12], cobalt (HR = 1.69, 1.21-2.37), nickel (HR = 1.19, 1.08-1.3), copper (HR = 1.03, 1.01-1.06), selenium (HR = 1.33, 1.02-1.73), molybdenum (HR = 1.48, 1.2-1.82) and iodine (HR = 1.1, 1.02-1.2) were associated with an increased risk of new incident IKF or CKD cases during the follow-up. Also, urinary copper [odds ratio (OR) = 1.12, 1.04-1.21], silver (OR = 1.83, 1-3.35), molybdenum (OR = 1.02, 1.01-1.04) and cadmium (OR = 1.05, 1.01-1.09) were associated with an increased risk of rapid eGFR decline. Conclusion: In the general population, several urinary heavy metals/trace elements are associated with a rapid decline in kidney function or new cases of IKF/CKD.