Biological half-life of cadmium in the urine of inhabitants after cessation of cadmium exposure

Abstract

We investigated the biological half-life of the urinary cadmium concentration (U-Cd) based on a 24-year follow-up study after cessation of cadmium exposure in a cadmium-polluted area. Spot urine samples were obtained from all inhabitants in this area in 1979, 1986, 1991, 1999 and 2003. Biological half-life was calculated in the inhabitants whose U-Cd was more than 5 μg l⁻¹ (9 men and 12 women) or 5 μg g⁻¹ creatinine (9 men and 19 women) using a one-compartment model. The estimated half-life and 95% confidence intervals were 13.6 years (9.0–28.2 years) and 13.9 years (9.6–25.6 years) for unadjusted U-Cd in men and women, respectively. For creatinine-adjusted U-Cd, they were 14.2 years (11.2–19.4 years) and 23.5 years (17.7–35.0 years) in men and women, respectively. The biological half-lives of U-Cd obtained in this study were identical with the values of total body burden determined by a different method.

Keywords::

• Urinary cadmium
• biological half-life
• long-term follow-up study
• risk assessment
• human

Acknowledgment

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.