Long-term observation of serum creatinine and arterial blood pH in persons with cadmium-induced renal dysfunction

Twenty-one subjects who had cadmium (Cd)-induced renal dysfunction and who lived in a Cd-polluted area in Japan were investigated to determine changes in their renal function. Since 1974, serum creatinine and arterial blood pH were measured annually during the autumn months for 9-14 y. Mean serum creatinine was significantly increased during this period, i.e., from 1.19 +/- 1.28 mg/100 ml to 1.68 +/- 1.56 mg/100 ml. Even after cadmium exposure ceased, significant deterioration of glomerular filtration was found. Eleven subjects showed a greater than 20% serum creatinine increase during this period. The most severe case had a serum creatinine value of 4.4 mg/100 ml at the most recent examination and experienced generalized edema, which suggests a clinical diagnosis of renal failure. The mean arterial blood pH values decreased significantly in all subjects, i.e., from 7.400 +/- 0.023 to 7.361 +/- 0.034. The 11 subjects cited above also showed a significant decrease and progression of tubular dysfunction after Cd exposure ceased. Our findings suggest that Cd-induced renal tubular dysfunction and decreased glomerular filtration are aggravated even after cessation of environmental Cd exposure, and in some cases this renal dysfunction may progress to renal failure.