ABSTRACT
In Switzerland the previous severe iodine deficiency has been corrected by iodization of salt. Changing food habits make it mandatory to periodically monitor iodine intake. In 1994 we therefore measured thyroid volume by sonography in 217 schoolchildren, and iodine, creatinine and sodium in casual urine samples of 214 schoolchildren, 40 pregnant women and 30 breast-fed newborns. Iodine was also measured in 30 breast milk samples. In schoolchildren, goiters of WHO grades Ia/Ib/II were found by palpation in 10.6/2.3/ 0.9%. By contrast, only two of the children had a sonographic thyroid volume exceeding the 97 percentile of the WHO, which underlines the difficulty of estimating the size of small goiters by palpation. Mean thyroid volume at 6/7/9/ 10/11 years of age was 2.1/2.2/3.3/3.3/3.1 ml, which is well within the normal range suggested by the WHO. Mean urinary iodine in schoolchildren (118 +/- 49 micrograms per gram creatinine) and in pregnant women (193 +/- 113 micrograms per gram creatinine) is within required limits, albeit with a decrease since 1988. In breast milk (7.8 +/- 5.9 micrograms/dl) and in urine of newborns (6.6 +/- 3.3 micrograms/dl) iodine values are below the Swedish reference values but well above values found in iodine deficient areas. We conclude that the iodine supply in schoolchildren and pregnant women is just sufficient and in newborns slightly below recently recommended limits. Compared to 1988 the iodine supply to schoolchildren is diminishing. The discrepancy between the rather low iodine content in breast milk despite a normal iodine supply during pregnancy remains to be explained.
