[Thyroid weight and iodized salt prevention. Comparative study of autopsy material from the Institute for Pathology].

In spring 1980 the amount of iodine in Swiss salt for human consumption was increased from 10 to 20 mg KI per kg, a dose producing a daily intake of iodine assumed to be sufficient to prevent goiter due to iodine deficiency. To study the influence of this higher level of iodine in table salt, thyroid weights and goiter incidence were determined in different age groups of both sexes in all autopsy cases seen in the Institute of Pathology, University of Zürich in 1984 and 1985. The findings were compared with the results of a similar investigation performed for the years 1978 and 1979 by Gerber shortly before doubling of the iodine content in Swiss table salt. The mean thyroid weights of adults aged up to 40 years were practically identical in both periods. In 1984/85, however, the mean thyroid weights of adults aged over 40 years were definitely lower than those of 1978/79 and did not exceed 25 g up to the age of 50. As regards goiter incidence, there were practically no differences between the two periods, viz. 30% in 1978/79 and 31% in 1984/85 for both sexes. The high incidence of goiter in older patients is probably due to insufficient iodine intake in youth. However, other factors such as inborn errors of iodine metabolism have also to be considered.