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 .
Mild iodine deficiency is associated with elevated hearing thresholds in children in Benin
Objective : Elevated hearing thresholds have been demonstrated in population s afflicted by endemic cretinism as a result of severe iodine deficiency . However , data on the effects of less severe iodine deficiency on hearing thresholds in apparently normal children are scant . This study addresses the question whether there is a relationship among iodine variables , hearing and mental performance in a mildly iodine-deficient population . Design : A r and omized , placebo-controlled intervention trial with an observation period of 11 months . Setting : An iodine-deficient area in northern Benin . Subjects : A total of 197 school children , aged 7–11 y. Interventions : A total of 97 children received an oral dose of iodized oil , containing 540 mg I , while 100 children received a placebo . About 3–4 months after supplementation , the whole population began to have access to iodized salt .  Non-verbal mental tests were administered and biochemical indicators ( thyrotropin , free thyroxine , thyroglobulin and urinary iodine ) were measured at the beginning and the end of the study . Hearing was measured at the end of the study in both ears by pure-tone audiometry at seven frequencies . Results : In this mildly iodine-deficient child population children with higher serum thyroglobulin concentrations had significantly higher hearing thresholds in the higher frequency range ( ≥2000 Hz ) than children with lower serum thyroglobulin concentration . Moreover children with lower hearing thresholds performed significantly better on the mental tests used . Conclusions : Even when iodine deficiency is ‘ mild ’ , promotion of adequate iodine intake through salt iodization programs and other means remains crucial . Sponsorship : Nestlé Foundation , Lausanne , Switzerl and ; Wageningen University , Wageningen , The Netherl and s . European Journal of Clinical Nutrition ( 2001 ) 55 ,
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 .