Although observational evidence suggests that concentrations of selenium , zinc , and iron are positively associated with iodine status , data from r and omized controlled trials fail to confirm this relationship .
Context The metabolism of thyroid hormones , which are essential for normal development , involves many proteins and enzymes .
It requires iodine as a key component but is also influenced by several other micronutrients , including selenium , zinc , iron , and vitamin A. Objective This systematic review was design ed to investigate the effect of micronutrient status and supplementation on  iodine status and thyroid hormone concentrations .
Thyroglobulin as a marker of iodine nutrition status in the general population.
OBJECTIVE The iodine status of a population is traditionally evaluated by either urinary iodine ( UI ) excretion or by some measure of thyroid volume and the prevalence of goitre . In this prospect i ve study of a m and atory iodization programme , we aim ed to evaluate serum thyroglobulin ( Tg ) as a marker of iodine status in the population . METHODS Two identical cross-sectional studies were performed before ( 1997 - 1998 , n=4649 ) and after ( 2004 - 2005 , n=3570 ) the initiation of the Danish iodization programme in two areas with mild and moderate iodine deficiency .  Serum Tg was measured from blood sample s. Thyroid volume was measured by ultrasonography . RESULTS Before iodization , the median serum Tg was considerably higher in moderate than in mild iodine deficiency . Iodization led to a lower serum Tg in all examined age groups . The marked pre-iodization difference in Tg level between the regions was eliminated . The prevalence of Tg above the suggested reference limit ( 40 microg/l ) decreased from 11.3 to 3.7 % ( P<0.0001 ) . Using bootstrapping , we demonstrated a higher efficacy of Tg than of thyroid volume to show a difference between pre- and post-iodization values . CONCLUSION We found serum Tg to be a suitable marker of iodine nutrition status in the population . The results may suggest that the Danish iodization programme has led to a sufficient iodine intake , even if the median UI excretion is still marginally low according to WHO criteria
Although observational evidence suggests that concentrations of selenium , zinc , and iron are positively associated with iodine status , data from r and omized controlled trials fail to confirm this relationship .
Context The metabolism of thyroid hormones , which are essential for normal development , involves many proteins and enzymes .
It requires iodine as a key component but is also influenced by several other micronutrients , including selenium , zinc , iron , and vitamin A. Objective This systematic review was design ed to investigate the effect of micronutrient status and supplementation on  iodine status and thyroid hormone concentrations .