Multiple metal exposure and renal tubular damage of residents in a metal-polluted region in Korea

This study investigates the correlations among urinary metals, the effects of co-exposure to multiple metals, and the relative importance of each metal in renal tubular damage (RTD) among residents of a metal-contaminated area. Urine sampling and health surveys were conducted for 120 participants living near a smelter for the Forensic Research via Omics Markers (FROM) study. Nine urinary metals (V, Cr, Mn, Ni, Mo, Cd, Sb, Pb, and Hg) and RTD markers such as beta-2-microglobulin (β2-MG) and N-acetyl-β-D-glucosaminidase (NAG) were analyzed. The effects of multiple metals on RTD and the relative importance of each metal were investigated using Bayesian kernel machine regression (BKMR). The nine metals were highly correlated with each other, suggesting co-exposure to multiple metals. In the results of BKMR, co-exposure to multiple metals significantly affected NAG levels across the entire urinary metal concentration range. Although β2-MG levels increased with rising urinary metal concentrations, the increase was not statistically significant. V and Cd were the highest contributors to β2-MG (posterior inclusion probability, PIP=0.853) and NAG (PIP=0.983), respectively. This study demonstrates co-exposure to metals among residents living in the metal-contaminated area and that co-exposure to multiple metals significantly increased NAG levels. Additionally, to the best of our knowledge, this is the first study to show that V is the highest contributor to the increase inβ2-MG. This study extends previous research by evaluating co-exposure to a more comprehensive array of metals, there by offering a broader perspective on the potential health impacts of RTD among residents in metal-contaminated areas.