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Department of Public Health, University of Liverpool, PO Box 147, Liverpool L69 3BX, UK
The iodine deficiency disorders, endemic goitre, stillbirths, abortions, congenital abnormalities, endemic cretinism, and impaired mental function, are found worldwide. Known for millenia, they currently put 29% of the world’s population at risk. The most important is cretinism, found in two forms. Neurological cretinism possibly develops due to an insult in early pregnancy, hypothyroid cretinism to an insult late in pregnancy or in early life.
The classical medical causes of environmental iodine deficiency, glaciation and leaching, do not adequately explain the prevalence and distribution of iodine deficiency disorders, nor have the new insights into the environmental chemistry of iodine been assimilated properly with medical knowledge. Joint studies would be of help.
The presence of various factors other than iodine deficiency in the causation of the disorders is recognized. These are often thought to be geologically related. Recent work suggests plate tectonics as the unifying factor, since iodine deficiency disorders are found along many plate collision zones. Concentration of major and trace elements as a result of plate subduction provides a possible source of goitrogens. A systematic search is needed.
The iodine goitrogen ratio could provide the link between environmental iodine and differing intensities of the iodine deficiency disorders found in affected communities.
