Tohoku J. Exp. Med., 2002, 196 (1)

Review

Perspectives on Cadmium Toxicity Research

MASAHIKO SATOH, HIROSHI KOYAMA,¹ TOSHIYUKI KAJI,² HIDEAKI KITO³
and CHIHARU TOHYAMA

Environmental Health Sciences Division, National Institute for Environmental Studies, Tsukuba 305-8506, ¹Community Health Care, Gunma University School of Health Sciences, Maebashi 371-8514, ²Department of Environmental Health, Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa 920-1181, and ³Department of Hygienics, Gifu Pharmaceutical University, Gifu 502-8585

Since there are a plethora of studies on cadmium toxicity and poisoning in laboratory animals and humans, we have limited this review to studies that are relevant to human health issues by focusing on carcinogenicity, genotoxicity, circulatory disease, nephrotoxicity and life expectancy. Cadmium exposure has been established to induce cancer in various tissues of laboratory animals. Contrary to early findings of the lack of genotoxicity by cadmium, recent findings of mammalian cell culture studies have revealed genotoxic effects. Furthermore, cadmium exposure at relatively low doses induces circulatory diseases in laboratory animals. Despite such results of various cadmium toxicities in animal studies, data from human studies are lacking and insufficient to support the cause-effect relationship. Although cadmium is currently considered to be a human carcinogen by the International Agency for Research and Cancer, it is inappropriate to conclude that sufficient evidence on the carcinogenicity of cadmium in humans exists. It is also thought that epidemiological studies so far reported do not support the occurrence of cadmium-induced circulatory disease in humans. Since there are inconsistent reports on the relationship of cadmium exposure with the life expectancy of people living in cadmium-polluted areas, further studies are needed for clarification. It is also necessary to examine apparent discrepancies in result between humans and experimental animals. It has been established that long-term exposure to cadmium causes renal dysfunction in both humans and experimental animals, and whether there are any differences in the inducibility of metallothionein in the kidney warrants further study.

Keywords —— cadmium; chronic toxicity; metallothionein; low dose effects

© 2002 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2002, 196, 23-32

Address for reprints: Masahiko Satoh, Ph.D., Environmental Health Sciences Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan.

e-mail: masahiko@nies.go.jp.

This paper was presented at the Sendai Symposium: Paradigm Shift in Heavy Metal Toxicology held on November 21-22, 2001.