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

Abstract

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.

Effect of oral iodized oil on thyroid size and thyroid hormone metabolism in children with concurrent selenium and iodine deficiency

“…Thyroid size was reduced by nearly half at 30 and 50 weeks and the goiter rate fell to near 10%. This reduction in goiter prevalence is more pronounced than those described by most previous authors (Bautista et al, 1982;Zitai, 1983;Eltom et al, 1985;Dunn, 1987;Benmiloud et al, 1994;Furne Âe et al, 1995), but because of varying conditions in these studies (age of subjects, severity of iodine de®ciency, geographic location, ultrasound vs palpation for goiter grading, follow-up intervals), it is dif®cult to compare results. In an area of endemic goiter in the Sudan, 200 mg of iodine as iodized oil reduced goiter prevalence as measured by palpation by 60% at 1 y (Elnager et al, 1995).…”

Iodine Deficiency and Schooling Attainment in Tanzania

“…Notably, in the only two of the above studies that analyzed results by gender, cognitive improvements were only found among girls, although in both cases the findings were merely suggestive given limited sample sizes (Bautista et al, 1982;Shrethsa, 1994). Consistent with this pattern, practitioners have noted that adolescent IDD, including rates of goiter and average severity among sufferers, is systematically higher among females (Allen and Gillespie, 2001;Simon et al, 1990).…”

“…As a result, even mild maternal iodine deficiency is now hypothesized to reduce intelligence quotients by a noticeable margin. 5 While there have been no experimental or large-scale observational studies of the cognitive effects of moderate iodine deficiency in humans, there is suggestive but mixed evidence from community-based assessments of iodine intervention trials that supplementation can improve performance on cognitive tests (Bleichrodt et al, 1994;Bautista et al, 1982). One oft-cited study in Ecuador found a 10-15 point difference in IQ between 50 offspring of women given iodine prophylaxis in early pregnancy compared with children in untreated communities (Shrethsa, 1994).…”

Effects of Micronutrients during Pregnancy and Early Infancy on Mental and Psychomotor Development

“…A number of intervention studies have been carried out in children ranging in age from 5 to 12 years. Two studies in Bolivia [68] and Bangladesh [99] did not show any effect, while two in Malawi [59] and Benin [100] Fig. 7.…”