Iodine supply in newborns and infants - a comparative study of iodine intake and iodine excretion of children and their mothers

Background: Since 1989 the use of iodized salt has been allowed in Germany, additional supplementation with iodide tablets has been recommended during pregnancy and lactation. This study was undertaken to clarify whether the iodine intake of neonates and young infants improved since then. Patients and methods: In the first part of the study the urinary iodine exc retion of 52 newborns and their mothers in 1998 was compared to data of sim ilar studies 1983 in the area of Gottingen and 1982 in the areas of Heidelb erg and Rothenburg, Germany. All these are geographically low-iodine areas. In the second part the iodine supply of infants in 1998-1999 under feeding with mother's milk or formulas in 1998 and 1999 was obtained by measuring iodide concentrations in urine and milk using a high pressure liquid chroma tography (HPLC) method. Results: 45% of pregnant women were without iodide supplementation in 1998. In 1998 the median urinary iodide concentration during the first week of l ife was 4,3 mug/dl, which was more than twice that found in 1983 (1,75 mug/ dl). Infants feeded by mother's milk without maternal iodine supplentation or by semi-elementary diet had the lowest urinary iodine excretion, whereas significantly higher values were measured when feeding formulas for term o r preterm infants. Conclusions: The iodine intake of newborns has markedly improved during 15 years. The WHO criterias for adequate iodine supply (TSH < 5 <mu>U/ml and u rinary iodine >/ = 1 mug/dl) were only partly fulfilled in Gottingen indica ting that a mild iodine deficiency still exists with the risk of iodine def iciency disorders.