[Disorders due to iodine deficiency].

1. An insufficient dietary supply of iodine results in the development of a variety of disorders of thyroid function and development of the fetus and young infants, grouped under the general heading of Iodine Deficiency Disorders, IDD. Endemic goiter constitutes the most spectacular disorder from the clinical and epidemiological point of view. However, the most serious consequence of iodine deficiency is the impact on neuro-intellectual development at a population level, varying from endemic mental retardation to the complete picture of endemic cretinism. 2. Considering that mental retardation due to iodine deficiency represents the longterm consequence of hypothyroidism occurring during the perinatal period, it is presently recognized that the target groups to the effects of iodine deficiency at a population level are, by order of priority, the fetus, the newborn, the pregnant woman, the child and, finally, the adult. 3. The newborn is more susceptible than the adult to the effects of iodine deficiency. Consequently, systematic screening for congenital hypothyroidism in endemic areas is a particularly sensitive index for detecting the presence and action of goitrogens in the environment and for monitoring the effects of programs of iodine prophylaxis. 4. IDD are particularly prevalent in developing countries. However, large areas or even countries in Europe are still obviously iodine deficient. For example, the iodine intake in adults in Belgium is 50 to 70 micrograms/day which is lower than the recommended dietary allowance for iodine (at least 100 micrograms/day). 5. IDD should be corrected on a world scale, including in Europe. Special attention should be devoted to the protection of mother and child. Within this framework, the iodine content of formula milk should be increased in Europe. 6. Finally, correction of iodine deficiency in Europe would decrease the avidity of the thyroid for iodide and, consequently, would constitute the most efficient preventive measure in case of nuclear fallout.