Itai-Itai Disease

Abstract

Itai-Itai disease was first reported as a unique disease without any known cause in an academic conference in October 1955. Most of the patients affected by this new peculiar disease were middle-aged or older women who complained of severe pain and developed bone fractures with minimal force. In May 1968, the Ministry of Health and Welfare announced that chronic cadmium poisoning first caused renal impairment and then osteomalacia, and defined this entity as Itai-Itai (Ouch-Ouch) disease. It also announced that pregnancy, nursing, various hormonal disorders, aging, and inadequate calcium intake were additional factors associated with this disease. The Ministry also addressed the opinion that cadmium causing this chronic poisoning could be found only in the wastewater of Kamioka Mine operated by Mitsui Mining and Smelting Co., Ltd. The correlation coefficient between the prevalence of Itai-Itai disease patients according to hamlet and Cd concentrations in rice was 0.51. The correlation coefficient between the prevalence of Itai-Itai disease patients and urinary protein+urinary glucose positive rates was 0.74. Considering these close interrelationships between the development of Itai-Itai disease, Cd concentrations in rice, prevalence of renal injury, clinical course of Itai-Itai disease, and high prevalence of persons with renal impairment in these districts, it is reasonable to conclude that ingestion of Cd in rice induces renal injury, with Itai-Itai disease developing among those most severely affected. As of July 2018, 200 persons were officially designated as Itai-Itai disease patients and 343 residents were determined as being persons requiring further observation (suspected patients) in the cadmium-polluted Jinzu River basin.