The renal handling of calcium and phosphorus in environmental cadmium-exposed subjects with renal dysfunction

Clearance methods were used to clarify the renal handling of calcium (Ca) and phosphorus (P) in a population with renal dysfunction induced by exposure to environmental cadmium (Cd). Seventy-six Cd-exposed subjects (32 men and 44 women) and 36 non-exposed subjects (18 men and 18 women) took part in this study. Fractional excretion of P was higher in the Cd-exposed subjects than in the non-exposed subjects, while that of Ca was equal to that of the non-exposed subjects. The urinary excretion rates of Ca and P tended to be lower in the Cd-exposed subjects than in the non-exposed subjects. The urinary excretion rate of Ca was closely related to creatinine clearance, while that of P was related to creatinine clearance and the percentage tubular reabsorption of phosphorus. It is thought that in Cd-induced renal dysfunction the urinary excretion of Ca depends on glomerular function, and no increased excretion of urinary Ca was observed by these clearance methods. It is also clarified that the parallelism in the urinary excretion of Ca and Na persists in Cd-exposed subjects with renal dysfunction.