[The effects on bone of environmental cadmium exposure--summary of recent epidemiological studies]

In Itai-itai disease, which is the most severe manifestation of environmental cadmium exposure, the bone features are characteristic of osteomalacia induced by renal tubular dysfunction and osteoporosis. Lower bone mass and higher bone turnover have been observed in inhabitants of cadmium-exposed areas, compared with people in nonexposed areas in Japan. Decreased bone mass and increased bone fracture have been reported recently in large-scale epidemiological studies, conducted in Belgium and Sweden. An association between higher urinary cadmium and lower bone mass was also found in female Japanese. These studies suggest that environmental cadmium exposure could be a risk factor of osteoporosis even in the general population in Japan. The effect on bone could be caused indirectly through renal damage induced by cadmium exposure, or directly via an effect of cadmium on bone itself.