Benchmark Dose of Urinary cadmium For Renal Effects by Hybrid Approach in a Cadmium Nonpolluted Area in Japan

Abstract

PP-31-165 Background/Aims: To apply an updated hybrid approach to estimate benchmark doses (BMD) and their 95% lower confidence limits (BMDL) for cadmium-induced renal effects in humans. Using this method, the BMD and BMDL were estimated based on a continuous exposure and a continuous effect marker, thereby avoiding categorization of the subjects which was inevitable in previously used approach. Methods: The target subjects were 547 men and 723 women aged 50 years or older in a cadmium non-polluted area in Japan. We measured urinary cadmium (U-Cd) as a marker of long-term exposure, urinary protein, β2-microglobulin (β2-MG), and N-acetyl-β-d-glucosaminidase (NAG) as renal effect markers. BMD and BMDL corresponding to an additional risk (BMR) of 5% were calculated and with the background risk at zero exposure set at 5%. Results: The BMDL of U-Cd for renal effect markers were 2.1 (urinary protein), 2.6 (β2-MG), and 4.1 (NAG) μg/g creatinine in men and 1.5 (urinary protein), 1.4 (β2-MG), and 3.1 (NAG) μg/g creatinine in women. Conclusion: The BMDLs in the present study may contribute further to the discussion for the health risk assessment of cadmium exposure, compared to BMDLs by previously used approach.