Plasma Metallothionein Antibody, Urinary Cadmium, and Renal Dysfunction in a Chinese Type 2 Diabetic Population

Abstract

OBJECTIVE—It has been reported that diabetes may increase the risk of cadmium-induced kidney damage. The presence of metallothionein antibody (MT-Ab) increased the susceptibility for tubular damage among cadmium workers. This study focused on the relationships between levels of MT-Ab, urinary cadmium, and kidney function in a Chinese type 2 diabetic population. RESEARCH DESIGN AND METHODS—A cross-sectional study was performed on 229 type 2 diabetic patients (92 men and 137 women) who were recruited from two community centers in one district of Shanghai City in China. Information was obtained from interviews, health records, and blood and urine samples. RESULTS—Levels of the tubular biomarker β2-microglobulin increased significantly when the levels of MT-Ab and urinary cadmium were elevated in male and female subjects; in contrast, the levels of urinary albumin, a glomerular biomarker, did not display such a pattern. After adjusting for potential confounding covariates, logistic regression showed that the odds ratios (ORs) of tubular dysfunction increased upon 1) increasing the MT-Ab concentration from a low to high level (OR 5.56 [95% CI 2.25–13.73]) and 2) increasing the level of urinary cadmium from <1 to ≥1 μg/g creatinine (3.34 [1.17–9.53]); the OR of patients currently smoking was 3.51 (1.14–10.80) relative to that of those who had never smoked. CONCLUSIONS—This study proves that the presence of MT-Ab can potentiate tubular dysfunction among diabetic subjects and that patients with high MT-Ab levels are more prone to development of tubular damage.