Iodine deficiency during infancy and early childhood in Belgium: does it pose a risk to brain development?

Iodine deficiency is well documented in Belgium in adults including pregnan t women, adolescents, schoolchildren, and neonates, but no data are availab le in the age group 6 months-3 years. We investigated the status of iodine nutrition in 111 healthy subjects in this age group in an attempt to evalua te the risk of brain damage due to iodine deficiency in Belgium. In 244 cas ual urine samples collected in these subjects, the median concentration of iodine was 101 mug/l vs 180-220 mug/l under normal conditions. The daily su pplementation of the subjects with a physiological dose of 90 mug iodine wa s followed by a slow and progressive increase of urinary iodine, which reac hed a normal level only after a delay of about 30 weeks of therapy. This ob servation suggests that part of the supplement of iodine offered to the chi ldren was stored in their thyroid glands until the iodine content of the gl and had reverted to normal, reflecting the state of hyperavidity of the thy roid for iodide characteristic of iodine deficiency. In conclusion, infants and young children in Belgium are as iodine deficient as all other age gro ups of the population and, consequently, are at risk of brain damage. This works further illustrates the need for systematic iodine supplementation of the population in Belgium.