Cadmium overload and toxicity.

Abstract

Studies suggest that cadmium is associated with several clinical complications, primarily renal dysfunction and bone disease, but also some cancers. Cadmium toxicity has been associated with clinical manifestations at exposure levels that are well below the limits set by the World Health Organization. Here I review the OSCAR study, which demonstrates an association between environmental and occupational cadmium exposure and renal tubular damage, as well as the Cadmibel study, a cross-sectional population study demonstrating an association of cadmium exposure with renal dysfunction. The paper also reviews the association of end-stage renal disease prevalence with occupational and environmental exposure to cadmium in the Swedish population of Kalmar County. Renal tubular damage was shown to develop at levels of exposure much lower than previously thought. Cadmium-induced tubular proteinuria is irreversible, and continued exposure may lead to glomerular damage with decreased glomerular filtration rate. Itai-itai disease in the Jinzu river basin is discussed, as are the implications of low-level cadmium exposure in the PheeCad project. Cadmium accumulates in bone and is associated with osteomalacia and osteoporosis. Other bone-seeking trace elements, such as chromium, lanthanum, strontium and zinc, are of concern because of low level environmental, occupational or clinical exposure. As techniques are perfected for detecting smaller amounts of trace elements in various tissues in the body, investigators are finding that the threshold for toxicity from trace elements is much lower than expected. Further research on cadmium is necessary to reveal the mechanisms of toxicity and true environmental and occupational exposure limits.