The first records of goiter and cretinism date back to ancient civilizations, the Chinese and Hindu cultures and then to Greece and Rome. In the Middle Ages, goitrous cretins appeared in the pictorial art, often as angels or demons. The first detailed descriptions of these subjects occurred in the Renaissance. The paintings of the madonnas in Italy so commonly showed goiter that the condition must have been regarded as virtually normal. In the seventeenth and eighteenth centuries, scientific studies multiplied and the first recorded mention of the word 'cretin' appeared in Diderot's Encyclopédie in 1754. The nineteenth century marked the beginning of serious attempts to control the problem; however, not until the latter half of the twentieth century was the necessary knowledge for effective prevention acquired.
Mass prophylaxis of goiter with iodized salt was first introduced in Switzerland and in Michigan in the United States. In Switzerland, the widespread occurrence of a severe form of mental deficiency and deaf mutism (endemic cretinism) was a heavy charge on public funds. However, following the introduction of iodized salt, goiter incidence declined rapidly and cretins were no longer born. Goiter also disappeared from army recruits.
A further major development was the administration of injections of iodized oil to correct iodine deficiency in Papua New Guinea for people living in inaccessible mountain villages. These long-lasting injections corrected iodine deficiency and prevented goiter for 3-5 years, depending on the dosage.
Subsequently, the prevention of cretinism and stillbirths was demonstrated by the administration of iodized oil before pregnancy in a controlled trial in the Highlands of Papua New Guinea. This proved the causal role of iodine deficiency.
To further establish the relation between iodine deficiency and fetal brain development, an animal model was developed in the pregnant sheep given an iodine-deficient diet. Subsequently, similar models were developed in the primate marmoset monkey and in the rat.
Studies with animal models confirmed the effect of iodine deficiency on fetal brain development (as already indicated by the results of the field trial with iodized oil in Papua New Guinea). The combination of the controlled human trials and the results of the studies in animal models clearly indicated that prevention was possible by correction of the iodine deficiency before pregnancy.
This work led Hetzel to propose the concept of the IDD resulting from all the effects of iodine deficiency on growth and development, particularly brain development, in an exposed population that can be prevented by correction of the iodine deficiency. Iodine deficiency is now recognized by the World Health Organization (WHO) as the most common form of preventable mental defect.
Although the major prevalence of iodine deficiency is in developing countries, the problem continues to be very significant in many European countries (France, Italy, Germany, Greece, Poland, Romania, Spain, and Turkey) because of the threat to brain development in the fetus and young infant.
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