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

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.

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 m², and CKD was defined as an eGFR <60 mL/min/1.73 m². Rapid eGFR decline was defined as a decrease ≥3 mL/min/1.73 m²/year.

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.

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.