ABSTRACT
PURPOSE: This study aimed to predict the outcome of urinary cadmium (Cd) excretion and renal tubular function by analyzing their evolution through 10 years after Cd exposure ceased. METHODS: Forty-one female, non-smoking workers were recruited from the year 2004 to 2009 when being removed from a nickel-cadmium battery factory, and they were asked to provide morning urine samples on three consecutive days at enrollment and in every follow-up year until 2014. Urinary Cd and renal tubular function biomarkers including urinary ß2-microglobulin (ß2-m) and retinol-binding protein (RBP) concentrations were determined with the graphite furnace atomic absorption spectrometry and the enzyme-linked immunosorbent assays, respectively. RESULTS: The medians of baseline Cd, ß2-m and RBP concentrations at enrollment were 6.19, 105.38 and 71.84 µg/g creatinine, respectively. Urinary ß2-m and RBP concentrations were both related to Cd concentrations over the years (ß absolute-ß2-m = 9.16, P = 0.008 and ß absolute-RBP = 6.42, P < 0.001, respectively). Cd, ß2-m and RBP concentrations in the follow-up years were all associated with their baseline concentrations (ß absolute-Cd = 0.61, P < 0.001; ß absolute-ß2-m = 0.64, P < 0.001; and ß absolute-RBP = 0.60, P < 0.001, respectively), and showed a decreasing tendency with the number of elapsed years relative to their baseline concentrations (ß relative-Cd = -0.20, P = 0.010; ß relative-ß2-m = -17.19, P = 0.002; and ß relative-RBP = -10.66, P < 0.001, respectively). CONCLUSIONS: Urinary Cd might eventually decrease to the general population level, and Cd-related tubular function would improve under the baseline conditions of this cohort.
