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 .
A cross-sectional survey of urinary iodine status in Latvia.
BACKGROUND AND OBJECTIVE A nationwide survey of schoolchildren was conducted to detect regional differences in urinary iodine excretion in Latvia and to compare the results with data from the newborn thyroid-stimulating hormone ( TSH ) screening data base as well with the results of a similar study performed in Latvia 10 years ago . MATERIAL S AND METHODS We conducted a cross-sectional school-based cluster survey of 915 children aged 9 - 12 years in 46 r and omly selected schools in all regions of Latvia .  Urine sample s , question naires on the consumption of iodized salt and information on socioeconomic status were collected . TSH levels in newborns were also measured . RESULTS The median creatinine-st and ardized urinary iodine concentration ( UIC ) in our study was 107.3μg/g Cr . UIC measurements indicative of mild iodine deficiency were present in 31.6 % , moderate deficiency in 11.9 % and severe deficiency in 2.8 % of the participants . The prevalence of iodine deficiency was the highest in the southeastern region of Latgale and the northeastern region of Vidzeme . The prevalence of TSH values > 5mIU/L followed a similar pattern . The self-reported prevalence of regular iodized salt consumption was 10.2 % . Children from urban schools had a significantly lower UIC than children from rural schools . CONCLUSIONS Our findings suggest that although the overall median UIC in Latvian schoolchildren falls within the lower normal range , almost 50 % of the schoolchildren are iodine deficient , especially in urban schools and in the eastern part of Latvia . The absence of a m and atory salt iodization program puts a significant number of children and pregnant women at risk
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 .