Influence of Consumption of Cadmium-Polluted Rice or Jinzu River Water on Occurrence of Renal Tubular Dysfunction and/or Itai-itai Disease

The aim of this study was to clarify whether consumption of cadmium (Cd)-polluted rice or Jinzu River water exerted any influence on the occurrence of renal tubular dysfunction and/or Itai-itai disease. From the participants of health examinations conducted in 1967 and 1968, 3,078 subjects who had resided for > 30 years in the present hamlet and were aged > 50 years were selected as the target population and were divided according to their residence in 55 hamlets. In a multiple regression analysis, the regression coefficients between rice-Cd concentration and prevalence of abnormal urinary findings (proteinuria, glucosuria, or proteinuria with glucosuria) or patients with Itai-itai disease were statistically significant between both sexes. The correlation between the prevalence of users of Jinzu River water and the occurrence of glucosuria in men as well as abnormal urinary findings in women was not statistically significant. We surmise that eating Cd-polluted rice and drinking and/or cooking with Jinzu River water influenced the occurrence of Itai-itai disease. The occurrence of renal tubular dysfunction is likely to have also been influenced by both factors, with eating Cd-polluted rice having a greater impact on the occurrence of renal tubular dysfunction as compared to drinking and/or cooking with Jinzu River water.