Cadmium and health: the Belgian experience.

Studies in the 1970s on chronic cadmium poisoning in man in Belgium showed that the earliest effect was renal dysfunction with proteinuria. Subsequent studies were focused on the characterization of cadmium proteinuria, the diagnosis and prognosis of cadmium nephropathy and the assessment of the concentrations in urine and renal cortex leading to its occurrence. Chronic exposure to cadmium in industry gives rise to a proteinuria which may be tubular, glomerular or mixed in character. This proteinuria may be accompanied or preceded by a variety of other renal effects. In active male workers, three main groups of thresholds for urinary cadmium have been identified for the induction of these effects with corresponding thresholds in the renal cortex. However, these estimates probably cannot be extrapolated to the general population exposed to cadmium mainly by the oral route. The results of a large-scale cross-sectional study (Cadmibel) suggest that subclinical changes in tubular function may occur in the general population above a threshold of urinary cadmium as low as 2 micrograms/24h.