I have read with the greatest interest the convincing study on the dose-response of cadmium ions in kidneys (1). Cadmium compounds also harm the proteoglycan metabolism (2), and by using the urinary proteoglycan excretion as an indicator of cadmium effects the threshold would be at 5 microg/g creatinine (3). This agrees very well with the threshold found in
the current investigation.

Heikki Savolainen

1 Chaumont A, De Winter F, Dumont X, et al. The threshold level of urinary cadmium associated with increased urinary excretion of retinol-binding protein and beta-2-microglobulin: a reassessment in a large cohort of nickel cadmium battery workers. Occup Environ Med 2011; 68:257-264.

2 Savolainen H. Cadmium-associated renal disease. Renal Failure 1995;17:483-487.

3 Savolainen H. Studies on urinary proteoglycan excretion in occupational cadmium exposure. Pharmacol Toxicol 1994; 75:113-114.