REVIEW ERS ' CONCLUSIONS Despite most of the included studies being of low quality , the results suggest that iodine supplementation , especially iodised oil , is an effective means of decreasing goitre rates and improving iodine status in children .
Indications of positive effects on physical and mental development and mortality were seen , although results were not always significant .
Adverse effects were generally minor and transient .
BACKGROUND Iodine deficiency is the main cause of potentially preventable mental retardation in childhood , as well as causing goitre and hypothyroidism in people of all ages .
It is still prevalent in large parts of the world .
OBJECTIVES To assess the effects of iodine supplementation overall , and of different forms and dosages of iodine supplementation separately , in the prevention of iodine deficiency disorders in children .
Reversibility of severe hypothyroidism with supplementary iodine in patients with endemic cretinism.
The reversibility of thyroid dysfunction in children with endemic cretinism treated with supplemental iodine  is unknown . To study this question we conducted a five-month follow-up of 51 patients with cretinism ( age 14 and below ) , who were r and omly assigned to treatment ( 0.5 ml of intramuscular iodized oil ) and control groups . The geometric mean initial serum level of thyrotropin ( 223 microU per milliliter ; SD , 97 to 513 ) and the mean ( + /- SD ) initial serum level of thyroxine ( 1.0 + /- 1.2 micrograms per deciliter ) indicated that all patients had severe hypothyroidism . Within one month after receiving the iodized oil , 13 of 14 of the younger patients ( less than 4 years ) and 1 of 9 of the older patients ( 4 to 14 years ; P less than 0.001 ) had thyrotropin values below 20 microU per milliliter . Five months after treatment , the levels of thyrotropin had decreased and those of thyroxine had increased in all children , but greater changes occurred in the 13 younger patients than in the 14 older patients . The mean levels of thyrotropin were 2 microU per milliliter ( SD , 0.6 to 6 ) vs. 38 microU per milliliter ( SD , 11 to 132 ; P less than 0.001 ) , and the mean ( + /- SD ) levels of thyroxine were 13.1 + /- 2.8 vs. 8.1 + /- 4.6 micrograms per deciliter ( P less than 0.001 ) . In the untreated group , 3 of the 9 younger patients and none of the 15 older patients recovered normal thyroid function within five months . We conclude that iodine supplementation restored a biochemically euthyroid state in all younger children with cretinism but only some of the older children . In addition , some younger patients became euthyroid without iodine supplementation
REVIEW ERS ' CONCLUSIONS Despite most of the included studies being of low quality , the results suggest that iodine supplementation , especially iodised oil , is an effective means of decreasing goitre rates and improving iodine status in children .
Indications of positive effects on physical and mental development and mortality were seen , although results were not always significant .
Adverse effects were generally minor and transient .
BACKGROUND Iodine deficiency is the main cause of potentially preventable mental retardation in childhood , as well as causing goitre and hypothyroidism in people of all ages .
It is still prevalent in large parts of the world .
OBJECTIVES To assess the effects of iodine supplementation overall , and of different forms and dosages of iodine supplementation separately , in the prevention of iodine deficiency disorders in children .