Long-Term Observation of Serum Creatinine and Arterial Blood pH in Persons with Cadmium-Induced Renal Dysfunction

Abstract

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 > 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.