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 .
Efficacy of oral iodised oil is associated with anthropometric status in severely iodine-deficient schoolchildren in rural Malawi.
The effect of anthropometric status on the efficacy of an oral supplement of iodised oil ( 1 ml Lipiodol Ultrafluide , 490 mg I ; Laboratoire Guerbet , Aulnay-sous-Bois , France ) was examined in 8 - 10-year-old schoolchildren ( n 197 ) of Ntcheu , a severely I-deficient district of Malawi . The study was a controlled trial using the I concentration of casual urine sample s to monitor the I status . The median urinary I concentration increased from 0.15 micromol/l at baseline ( 51.3 % of children < 0.16 micromol/l , 89.7 % < 0.40 micromol/l , 95.7 % 0.79 micromol/l ) to 0.32 micromol/l at 40 weeks ( 29.1 % of the children < 0.16 micromol/l , 71.0 % < 0.40 micromol/l , 96.1 % < 0.79 micromol/l ) while the total goitre prevalence fell from 63 % to 21 % . Variables of efficacy were estimated from a hyperbolic function describing the longitudinal pattern of urinary I excretion after the dose . The I retention and I elimination rate , and the periods of protection from mild ( < 0.79 micromol/l ) or moderate ( < 0.40 micromol/l ) I deficiency were obtained for groups of children with differing anthropometric status at baseline . Initial height-for-age and mid upper-arm circumference were not significantly related to efficacy . However , both the I retention and I elimination rate were reduced in children with lower initial weight-for-height . Children with lower skinfold thickness at baseline also had reduced I retention , which result ed in shorter protection periods from recurrent moderate and mild I deficiency . The efficacy of the oral iodised-oil supplement was not related to changes in anthropometric status during follow-up , nor was it related to the consumption of a food supplement of 1610 kJ immediately before the iodised-oil dose . Very low ( < 0.16 micromol/l ) urinary I concentration , and the presence of goitre at baseline were both associated with higher I retention and elimination rate .  Children with goitre at baseline were found to have a prolonged duration of protection against recurrent moderate I deficiency . We conclude that in apparently healthy schoolchildren in I-deficient areas , general anthropometric status has a little influence on the efficacy of oral iodised oil for correcting I deficiency
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 .