The effects of oral iodized oil on intelligence, thyroid status, and somatic growth in school-age children from an area of endemic goiter.

One hundred goitrous school children received 475 mg iodized oil by mouth, while 100 controls received mineral oil, on a double-blind basis. On follow-up 22 months later the urinary iodine had increased and goiter size had decreased in both groups, more strikingly in the iodine-treated children. There were no consistent differences between the two treatment groups in rate of somatic growth or performance on the Stanford-Binet and Bender tests. Because of the complexities introduced by increases in urinary iodine in the controls, we compared goiter reduction with improvement in IQ score in all children, regardless of group, and found a significant relationship (p = 0.014), particularly in girls (p = 0.029). We conclude that oral iodized oil is an attractive alternative to its injection but we recommend an approximate doubling of the dose used here for more effective control. Also, while our data are not conclusive, they support the possibility that correction of iodine deficiency may improve mental performance in school age children, particularly girls.