THYROID VOLUME AND URINARY IODINE IN SCHOOL-CHILDREN AND ADOLESCENTS IN SLOVAKIA AFTER 40 YEARS OF IODINE PROPHYLAXIS

The thyroid volume (by ultrasonographic volumetry) was estimated in 4, 254 schoolchildren and adolescents 6-18 years of age from 12 districts of Slovakia and urinary iodine (by dry alkaline ashing followed by sp ectrophotometry) in 1,174 spot urine samples. No differences in thyroi d volume or in iodine excretion between individual districts were foun d. Similarly, no differences in thyroid volume between sexes were foun d up to the age of 14 years, however, thereafter, such volumes were co nsiderably higher in boys. When comparing our cummulated data with tho se reported by others for a population with optimal iodine intake, it was found: 1. the medians for most of the examined age groups were sli ghtly higher, 2. the percentage of values which were higher than 97 pe rcentiles of normal population was 3.01 for the age of 6-14 years, whi le that for the age of 15-18 years was 9.04. Only 35.9% of all values of urinary iodine were in the optimal range (i.e. 10-20 mu d/dl), whil e 56.1 were less than 10 mu g/dl and 15.9% less than 5 mu g/dl, the re maining 8.0% over 20 mu g/dl, In spite of long-term iodine prophylaxis (since 1949), the intake of iodine apparently is still not satisfacto ry, since a considerable amount of individuals appeared to be iodine d eficient on the day of examination. Iodine intake, however, may be mar ginally sufficient up to the age of about 13-14 years, while later a h igher number of enlarged thyroids was found which may be classified as goitre endemy grade I.