The Danish investigation on iodine intake and thyroid disease, DanThyr: status and perspectives. Prevention of iodine deficiency disorders by oral administration of lipiodol during pregnancy. Iodine supplementation improves cognition in mildly iodine-deficient children. Hypothyroid patients showing shortened responsiveness to oral iodized oil have paradoxically low serum thyroglobulin and low thyroid reserve. Thyroglobulin/thyrotropin ratio as a measure of thyroid damage. Iodine prophylaxis using iodized salt and risk of maternal thyroid failure in conditions of mild iodine deficiency. Goiter prevalence, urinary iodine excretion, thyroid function and anti-thyroid function and anti-thyroid antibodies after 12 years of salt iodization in Shahriar, Iran. Efficacy of low oral doses of iodized oil in the control of iodine deficiency in Zaire. Cognitive and motor functions of iodine-deficient but euthyroid children in Bangladesh do not benefit from iodized poppy seed oil (Lipiodol). The effect of varying doses of oral iodized oil in the prophylaxis of endemic goitre in elementary schools children. Iodine supplementation with oral or intramuscular iodized oil. A two-year follow-up of a comparative trial. Iodine supplementation in pregnancy and its effect on child cognition. Effect of voluntary intake of iodinated salt on prevalence of goitre in children. Earliest prevention of endemic goiter by iodine supplementation during pregnancy. Oral Iodine Supplementation Does Not Reduce Neutralizing-Antibody Responses to Oral Poliovirus Vaccine 919 Randomized clinical trial comparing different iodine interventions in school children. Persistence of goitre in children post-salt iodization in Islamic Republic of Iran: autoimmune status. Iodine supplementation: comparison of oral or intramuscular iodized oil with oral potassium iodide. A controlled trial in Zaire. Persistence of goiter despite oral iodine supplementation in goitrous children with iron deficiency anemia in Côte d'Ivoire. Serum thyroglobulin and urinary iodine concentration are the most appropriate indicators of iodine status and thyroid function under conditions of increasing iodine supply in schoolchildren in Benin. Mandatory fortification of bread with iodised salt modestly improves iodine status in schoolchildren. Effects of iodine supplementation during pregnancy on child growth and development at school age. Urinary iodine excretion as a predictor of the iodine content of breast milk. Improved iodine status is associated with improved mental performance of schoolchildren in Benin. Reappraisal of the risk of iodine-induced hyperthyroidism: An epidemiological population survey Prevalence of thyroid disorders in pregnant women with mild iodine deficiency Epidemiology of subtypes of hypothyroidism in Denmark. Mild iodine deficiency is associated with elevated hearing thresholds in children in Benin Postpartum thyroid dysfunction in pregnant thyroid peroxidase antibody-positive women living in an area with mild to moderate iodine deficiency: is iodine supplementation safe? Efficacy and safety of iodine in the postpartum period in an area of mild iodine deficiency. The nutritional status of a rural community in KwaZulu-Natal, South Africa: the Ndunakazi project. Iodine status as determined by urinary iodine excretion in Lesotho two years after introducing legislation on universal salt iodization.
OBJECTIVE Denmark was an area of iodine deficiency , and m and atory iodine fortification of table salt and salt in bread ( 13 p.p.m . iodine ) was initiated in 2000/2001 . The Danish investigation on iodine intake and thyroid disease ( DanThyr ) is the monitoring of the iodine fortification program . DESIGN AND METHODS DanThyr consists of three main parts : a study of population cohorts initialized before ( n=4649 ) and after ( n=3570 ) iodization of salt  , a prospect i ve identification of incident cases of overt hyper- and hypothyroidism in a population of around 550,000 people since 1997 , and compilation of data from the national registers on the use of thyroid medication , thyroid surgery , and radioiodine therapy . Studies were carried-out in parallel in subcohorts living in areas with differences in iodine content of ground water . RESULTS The study showed profound effects of even small differences in iodine intake level on the prevalence of goiter , nodules , and thyroid dysfunction . Mild and moderate iodine deficiency was associated with a decrease in serum TSH with age . Other environmental factors were also important for goiter development ( increase in risk , smoking and pregnancy ; decrease in risk , oral contraception and alcohol consumption ) , and the individual risk depended on the genetic background . Environmental factors had only a minor influence on the prevalence of thyroid autoantibodies in the population . There were more cases of overt hypothyroidism in mild than in moderate iodine deficiency caused by a 53 % higher incidence of spontaneous ( presumably autoimmune ) hypothyroidism . On the other h and , there were 49 % more cases of overt hyperthyroidism in the area with moderate iodine deficiency . The cautious iodine fortification program , aim ing at an average increase in iodine intake of 50 mug/day has been associated with a 50 % increase in incidence of hyperthyroidism in the area with the most severe iodine deficiency . The incidence is expected to decrease in the future , but there may be more cases of Graves ' hyperthyroidism in young people . CONCLUSION A number of environmental factors influence the epidemiology of thyroid disorders , and even relatively small abnormalities and differences in the level of iodine intake of a population have profound effects on the occurrence of thyroid abnormalities . Monitoring and adjustment of iodine intake in the population is an important part of preventive medicine The prevalence of iodine deficiency disorders and the thyroid status of the population were studied in an endemic goitre area in Algeria . After oral administration of lipiodol ( 0.5 ml ) , three treated groups of mother-newborn couples were compared to an untreated group : group A , mothers treated 1 - 3 months before conception ; group B , mothers treated during the first month of pregnancy ; group C , mothers treated during the third month of pregnancy . Untreated mothers were used as a control ( group D ) . After lipiodol treatment , all newborn babies and mothers were clinical ly euthyroid . All tested newborn babies were full term and no goitre was observed in the four groups . In the mothers , goitre prevalence and thyrotrophin levels decreased significantly , whereas maternal milk and urinary iodine and serum-free thyroxine levels were significantly higher after treatment . The rate of prematurity , stillbirths and abortions in the treated groups was reduced when compared to the untreated group , whereas placental and birth weights were significantly higher . In group D two cases of neonatal hypothyroidism were detected . Their re-evaluation confirmed that hypothyroidism was transient . Groups A , B and C were statistically different from group D with regard to neonatal thyrotrophin and thyroxine . Positive correlations were found between neonatal thyroxine and birth weights and placental weights on the one h and , and maternal urinary iodine and free thyroxine on the other . Consequently , these data indicate that oral administration of lipiodol before or during the first trimester of pregnancy normalizes thyroid function in newborn babies and mothers , increases placental and birth weight and reduces the frequency of iodine deficiency disorders . ( ABSTRACT TRUNCATED AT 250 WORDS BACKGROUND The effects of severe iodine deficiency during critical periods of brain development are well documented . There is little known about the consequences of milder forms of iodine deficiency on neurodevelopment . OBJECTIVE The objective was to determine whether supplementing mildly iodine-deficient children with iodine improves cognition . DESIGN A r and omized , placebo-controlled , double-blind trial was conducted in 184 children aged 10 - 13 y in Dunedin , New Zeal and . Children were r and omly assigned to receive a daily tablet containing either 150 microg I or placebo for 28 wk .  Biochemical , anthropometric , and dietary data were collected from each child at baseline and after 28 wk . Cognitive performance was assessed through 4 subtests from the Wechsler Intelligence Scale for Children . RESULTS At baseline , children were mildly iodine deficient [ median urinary iodine concentration ( UIC ) : 63 microg/L ; thyroglobulin concentration : 16.4 microg/L ] . After 28 wk , iodine status improved in the supplemented group ( UIC : 145 microg/L ; thyroglobulin : 8.5 microg/L ) , whereas the placebo group remained iodine deficient ( UIC : 81 microg/L ; thyroglobulin : 11.6 microg/L ) . Iodine supplementation significantly improved scores for 2 of the 4 cognitive subtests [ picture concepts ( P = 0.023 ) and matrix reasoning ( P = 0.040 ) ] but not for letter-number sequencing ( P = 0.480 ) or symbol search ( P = 0.608 ) . The overall cognitive score of the iodine-supplemented group was 0.19 SDs higher than that of the placebo group ( P = 0.011 ) . CONCLUSIONS Iodine supplementation improved perceptual reasoning in mildly iodine-deficient children and suggests that mild iodine deficiency could prevent children from attaining their full intellectual potential . The trial was registered with the Australia New Zeal and Clinical Trials Register as ACTRN12608000222347 In Central Africa , all of northern Zaire is very severely deficient in iodine . A peculiar feature of this endemia is that iodine deficiency and the ensuing thyroid gl and stimulation not only leads to goitre formation but also to progressive thyroid involution and to myxoedematous cretinism . An iodine supplementation trial based on oral administration of small doses of iodine was made in 81 schoolchildren . All of them received a small dose of iodine ( 0.1 ml containing 48 mg ) per os and the thyroid status was followed during 4 months . Blood and urine sample s were collected at the start of the study , then 2 weeks , 2 months and 4 months after iodine administration . Before iodine supplementation the mean urinary iodine level was 0.18 + /- 0.02 micromol/l , and 10 % of the subjects had a urinary iodine level below 0.08 micromol/l . Fifty-two percent of the subjects had a serum thyrotropin ( TSH ) level above 10 mU/l . All the subjects responded to the administration of iodine . and all of them recovered a euthyroid status . Most of them were still euthyroid at the end of the study . However . within 4 or even 2 months , some subjects ( 15 % of the total ) reverted to hypothyroidism . At the entry of the study these subjects were all hypothyroid and had elevated TSH and paradoxically low serum thyroglobulin ( TG ) values . In myxoedematous cretins living in the same area , even lower serum TG levels were found . Together with the absence of goitre , a paradoxically low serum TG Suggests a low thyroid reserve , and in the present case a reduced amount of functional thyroid tissue . We show that the serum TG/TSH ratio may be used as a predictive index of thyroid reserve and of positive response to iodine administration . These data further suggest that thyroid damage is not confined to myxoedematous cretins . but is widely distributed in the phenotypically normal population . Widely distributed thyroid damage may render iodine prophylaxis based on oral administration unpredictable CONTEXT Mild to moderate iodine deficiency during pregnancy can cause transient maternal hypothyroidism and impaired mental development of the progeny . These unfavorable effects are preventable by iodine supplementation . In Europe , however , less than 50 % pregnant women receive iodine-containing supplements , thus representing dietary iodized salt the only carrier of iodine for most women in this life stage . OBJECTIVE / DESIGN This longitudinal study is aim ed to investigate the effects of long-term iodized salt consumption on maternal thyroid function during gestation . PARTICIPANTS / OUTCOME MEASURES : We prospect ively evaluated thyroid function in 100 consecutive thyroperoxidase antibody-negative pregnant women from a mildly iodine-deficient area . Sixty-two women who had regularly used iodized salt for at least 2 yr prior to becoming pregnant and 38 who commenced iodized salt consumption upon becoming pregnant were classified as long-term ( LT ) and short-term ( ST ) iodine supplemented , respectively . RESULTS Long-term iodized salt consumption result ed in a very low prevalence of maternal thyroid failure ( MTF ) in LT women . Conversely , short-term iodine prophylaxis does not seem to protect against the risk of MTF , the prevalence of which was almost 6-fold higher in ST than LT women ( 36.8 % vs. 6.4 % ; chi(2 ) 14.7 , P < 0.0005 ; relative risk 5.7 , 95 % confidence interval 2.03 - 16.08 , P < 0.001 ) . The relative risk reduction amounted to 82.5 % , this measure indicating the extent to which long-term iodine prophylaxis using iodized salt would reduce the risk of MTF in ST women . CONCLUSIONS Prolonged iodized salt significantly improves maternal thyroid economy and reduces the risk of maternal thyroid insufficiency during gestation , probably because of a nearly restoring intrathyroidal iodine stores OBJECTIVE In a previous study in 1983 , goiter was found to be endemic in Shahriar , Iran .  Iodized salt has been distributed in the region for the past 12 years , and the present study was performed to examine the effect of iodide supplementation on indicators of iodine deficiency ( IDD ) and thyroid antibodies . DESIGN & METHODS A total of 3164 people , 58 % women and 42 % men , were selected by r and om sampling from the Shahriar area . Goiter was staged according to World Health Organization guidelines . Urinary iodine was measured by a digestion method , and thyroid hormone measurements were done by radioimmunoassay . The results were compared with those of 1983 . RESULTS Goiter prevalence before and after iodine supplementation was 50 and 40 % in men , 70 and 51 % in women , and 60 and 47 % in the whole community , respectively ( p < 0.001 ) . A decrease in the prevalence of goiter was observed especially in younger individuals . The mean urinary iodine excretion was 7.6 and 18.5 micrograms/dL , before and after iodine supplementation . In 1983 , the urinary iodine in 47.5 % of the population studied was between 2 to 5 micrograms/dL , while in 1995 , 65 % of the population studied had urinary iodine between 10 to 25 micrograms/dL , 12 years after iodine supplementation . Mean serum T4 , T3 , and thyroid-stimulating hormone ( TSH ) were normal before and after intervention . There was no significant change in occurrence of positive antibodies , or of hypo- and hyperthyroidism , following iodine supplementation . CONCLUSION The result of this study shows that the use of iodized salt causes an increase in excreted urinary iodine and a decrease in the prevalence of thyroid goiter , especially in younger age groups . Consumption of iodized salt with 40 parts per million ( ppm ) iodine has not caused increased prevalence of thyroid dysfunction in this area BACKGROUND About one billion people worldwide are at risk for iodine deficiency . Despite existing programs of prophylaxis , the prevention of iodine deficiency is still a challenge throughout the developing world . We studied the efficacy of low doses of iodized oil in an area of severe iodine deficiency in Zaire . METHODS Seventy-five subjects with visible goiter were r and omly assigned to receive a single oral dose of placebo or either 0.1 or 0.25 ml of iodized oil , corresponding to 0 , 47 , and 118 mg of iodine , respectively . The mean ages of the subjects in the three groups were 23 , 22 , and 22 years , respectively , and the ratios of males to females were 0.25 , 0.32 , and 0.19 .  Efficacy was assessed by evaluating goiter size and measuring urinary iodine and serum thyroid hormone concentrations for 12 months . RESULTS Goiter size decreased in most of the subjects who received either dose of iodized oil . Their urinary iodine concentrations were normal for six to nine months and their serum thyroxine and thyrotropin concentrations were nearly all normal throughout the study period . There were no side effects , even in subjects whose serum thyroxine concentrations had initially been low . In the placebo group , neither goiter size nor any of the biochemical values changed . CONCLUSIONS The oral administration of a single small dose of iodized oil is capable of correcting iodine deficiency for about a year . This method of supplementation is likely to be more effective , efficient , and acceptable than the administration of either intramuscular or large oral doses of iodized oil Iodine supplementation before pregnancy in iodine-deficient women prevents cretinism and neuromotor deficits in their offspring . It is unclear whether iodine supplementation benefits cognitive function in iodine-deficient school-aged children . We therefore conducted a double-blind , r and omized , controlled trial of the effects of iodized poppy seed oil ( Lipiodol ) on cognitive and motor function and weight gain of iodine-deficient school children . The study was conducted with 305 children in grade s 1 and 2 from 10 primary schools in two iodine-deficient areas in Bangladesh . The children were stratified by school and grade and r and omly assigned to receive 400 mg of oral Lipiodol or a placebo . All children were given a battery of cognitive and motor function tests and had their weights , serum thyroxine ( T4 ) and thyroid-stimulating hormone ( TSH ) and urinary iodine levels measured before and 4 mo after the intervention . On enrollment , both groups were moderately iodine deficient ( median urinary iodine values : placebo group = 3.3 micromol/L , n = 148 ; iodine group = 3.1 micromol/L , n = 152 ; goiter prevalence in both groups > 95 % ) . However , their T4 and TSH levels were within the normal range . After 4 mo , there was a significant treatment effect on urinary iodine levels ( P < 0.0001 ) , but the levels of the treated group were still below normal ( median = 7.9 micromol/L ) . No significant differences were found in T4 and TSH levels , weight gain , cognitive or motor function . The findings suggest that Lipiodol supplementation in moderately iodine-deficient children with normal T4 levels is unlikely to benefit their cognitive function . However , it remains possible that other iodine preparations may have benefits The effect of oral iodine supplementation on total goitre rate ( % TGR ) and urinary iodine excretion among school children 4 to 16 years of age was studied . In the first group ( n = 57 ) 200 mg oral iodized oil reduced % TGR from 31.6 % to 17.5 % and 33.3 % to 24.6 % in males and females respectively , while in the second group ( n = 53 ) , 400 mg iodine reduced the % TGR from 34.0 % to 20.8 % in males and 35.9 % to 24.5 % in females after 13 months of intervention . This gave a relative indication that the 200 mg is as effective as the 400 mg in goitre reduction . In subsequent tests , the maximum urinary iodine excretion was obtained from the groups which received two doses of iodized oil 24 hours after the intervention . A significant ( p = 0.003 ) greater increase in urinary iodine excretion was noted at 24 hours among both male and female children administered 400 mg than among those who received 200 mg . Measurements after 24 hours showed no significant difference between urinary iodine excretion of the two dose groups . These results suggest that : ( i ) 200 mg is likely equally effective as 400 mg for iodine deficiency disorders control and prevention among children and ( ii ) iodine could be administered annually rather than biannually A controlled trial of iodine supplementation comparing oral with intramuscular iodized oil has been carried out in an iodine deficient area of Zaire . Two years after the administration of 2 ml of oral iodized oil to the population of four villages the overall goitre prevalence had fallen from 64 to 54 % . In a further two villages given 2 ml of intramuscular oil the prevalence fell from 65 to 50 % . The effectiveness of supplementation was also assessed by measuring changes in thyroid function in women of reproductive age . Among women in the villages given oral iodized oil , the geometric mean thyroxine concentration , measured in dried bloodspots , rose from 27.2 to 52.6 nmol/L at the two-year follow-up . This was similar to the response of the intramuscularly treated villages in which thyroxine levels rose from 32.1 to 65.4 nmol/L. There was no change in goitre prevalence or thyroid function in two control villages . Oral iodized oil is a cheaper and simpler alternative to the injected form providing effective iodine prophylaxis for up to two years after a single dose Maternal hypothyroidism and hypothyroxenemia due to iodine deficiency have been shown to affect development of the newborn negatively . Maternal iodine supplementation may therefore improve cognitive performance of the offspring , even in areas of mild-to-moderate iodine deficiency ( ID ) . Several iodine supplementation studies have been performed in mildly ID pregnant women in Europe . These studies have shown that iodine supplementation increases maternal urinary iodine ( UI ) excretion and reduces thyroid volume , as well as prevents increases in infant thyroid volume and thyroglobuline . However , r and omized controlled studies with long-term outcomes are lacking . Therefore , two trials were started in 2008 in areas of low iodine status ; one in Bangalore , India ( n=325 ) , and another in Bangkok , Thail and ( n=514 ) . Pregnant women were recruited < 14 weeks gestational age and r and omized to either receive a daily dose of 200 μg I ( as KI ) or an identical placebo throughout pregnancy . Both trials are ongoing , and women are followed up during pregnancy and at delivery . UI , thyroid hormones , and thyroid size are measured . Birth outcomes are recorded , such as gestational age at delivery , height , weight , and APGAR scores , and cord blood and heel stick blood ( < 72 h ) is collected from the child . Child development is assessed at 6 weeks of age using the Neonatal Behavioral Assessment Scale ( NBAS ) , and at 12 and 24 months of age using the Bayley Scales of Infant Development . The outcomes of these trials will contribute importantly to the evidence base for iodine supplementation of pregnant women living in areas of mild iodine deficiency The availability of iodinated salt containing 20 mg of iodine as io date /kg salt consumed on a voluntary basis enabled us to investigate its effect on goitre prevalence and iodine excretion in urine in a longitudinal , prospect i ve , r and omized study over 4 years . With this salt , under the assumption of a consumption of 5 g salt per day and person , an additional intake of 100 micrograms of iodine can be achieved . The study was performed on initially 334 children ( 168 boys , 166 girls ) at the age of 10 years living in an area of iodine deficiency . After 4 years , 286 children still participated in the study . Initially , goitre prevalence as assessed by palpation was found to be 30.5 % ( 37.4 % in girls and 23.8 % in boys ) . Neck circumference was found to be significantly higher in children with goitre compared with those without ( 30.2 + /- 1.4 vs 29.4 + /- 1.4 cm ; P less than 0.001 ) . Iodine excretion in the urine was significantly lower in children with goitre compared with those without ( 40.4 + /- 16.7 micrograms/g creatinine vs 46.1 + /- 24.9 micrograms/g creatinine ; x + /- SD ; P less than 0.05 ) . The children were r and omly assigned to two different groups : group A ( N = 146 ) was asked to use iodinated salt , group B ( N = 188 ) non-iodinated salt . Over the 4 years , a continuous increase in iodine excretion in urine could be demonstrated in group A. ( ABSTRACT TRUNCATED AT 250 WORDS During pregnancy complex changes of maternal thyroid function occur and they are influenced by the maternal iodine supply . It has been demonstrated that with decreasing iodine supply maternal goiter and hypothyroxinemia as well as fetal and neonatal hypothyroidism become more prevalent . Therefore iodine supplementation during pregnancy is now strongly recommended also in areas of moderate iodine deficiency . To monitor the success of iodine supplementation and its theoretical risk of increasing the frequency of thyroid autoantibodies , we have investigated the thyroid volume , thyroid function , urinary iodine excretion and antibodies to thyroid peroxidase at 10 - 12 weeks of gestation and postpartum in 38 mothers receiving 300 micrograms potassium iodide/day and in 70 mothers without iodine supplementation .  In all of their newborns thyroid volume was determined by ultrasound . The thyrotropin ( TSH ) levels and antibodies to thyroid peroxidase ( TPO-ab ) in the neonates were measured in dried blood spots on filter paper from their newborn screening . Urinary iodine excretion was increased significantly after iodine supplementation in mothers ( p < 0.001 ) and their newborns ( < 0.05 ) . No hypo- or hyperthyroidism was observed in the mothers or newborns . Interestingly , no difference of maternal thyroid volumes was observed between the two groups after pregnancy , but the volumes of the thyroid gl and s in newborns of mothers who received iodine were significantly ( p < 0.004 ) lower ( 0.7 + /- 0.4 ml ) than in the control group ( 1.5 + /- 1.1 ml ) . There was no change in the frequency of TPO-ab in either group after pregnancy . In four mothers transplacental passage of these antibodies was documented by positive measurement in the blood sample of the newborn . This study documents that iodine supplementation during pregnancy in an area of moderate iodine deficiency results in a lower size of neonatal thyroid volume and that this supplementation was not accompanied by an increase in the frequency of TPO-ab Iodine deficiency is a major cause of impaired mental development , goitre , and cretinism in many parts of the world . Because existing immunization programmes can be used to deliver oral iodized oil ( OIO ) to infants at risk , it was important to know whether OIO could adversely affect the antibody response to vaccines , such as trivalent oral poliovirus vaccine ( OPV ) . A r and omized , double-blind , placebo-controlled clinical trial was conducted in Subang , West Java , Indonesia , in which 617 eight-week-old infants received either OIO or a placebo ( poppy-seed oil ) during a routine visit for their first dose of OPV as part of the Exp and ed Programme on Immunization ( EPI ) . The infants received two boosters of OPV at 4-week intervals after the first dose , and were followed up when 6 months old . Neutralizing antibody titres to poliovirus serotypes 1 , 2 , and 3 were compared in serum sample s that were taken from 478 of these infants just before the first dose of OPV and at 6 months . It was found that oral iodized oil did not reduce the antibody responses to any of the three serotypes of OPV . These results indicate that oral iodine may safely be delivered to infants at the same time as oral poliovirus vaccine according to current EPI immunization schedules OBJECTIVE The purpose of this trial was to compare three different iodine interventions . DESIGN School children aged 8 - 10 years were r and omized into one of three groups : group A was provided with iodized salt by research ers with an iodine concentration of 25 ppm ; group B purchased iodized salt from the market ; and group C was similar to group B with the exception that they were given iodized oil capsules containing 400 mg iodine at the beginning of the study . Salt iodine content was measured bimonthly for 18 months and indicators of iodine deficiency were measured at baseline and 6 , 9 , 12 and 18 months after r and omization . RESULTS The prevalence of abnormal thyroid volumes , based on the World Health Organization ( WHO ) body surface area reference > 97th percentile , was 18 % at baseline and declined to less than 5 % by 12 months in groups A and C , and to 9 % after 18 months in group B. Results for goitre by palpation were similar . The median urinary iodine was 94 microg l(-1 ) at baseline and increased in all groups to > 200 microg l(-1 ) at the 6-month follow-up . CONCLUSIONS In this population of school children with initially a low to moderate level of iodine deficiency , the group receiving salt with 25 ppm ( group A ) was not iodine deficient on all indicators after 18 months of study . When the iodine content of the salt varied , such as in group B , by 18 months thyroid sizes had not yet achieved normal status We evaluated the prevalence of autoimmune thyroiditis in a r and om sample of 1188 schoolchildren aged 8 - 13 years with normalized iodine intake in the Islamic Republic of Iran . The prevalence of goitre was 39.6 % ; the majority had palpable but non-visible goitre . Of a sub sample of 500 children , median urinary iodine excretion ( 18/8 microg/dL ) indicated normal iodine intake . Thyroid peroxidase ( TPO ) antibody was positive in 3.7 % of children and was significantly correlated with the prevalence of goitre and hypothyroidism . No correlation was seen between urinary iodine excretion and positive TPO antibody , mean TPO antibody , hypothyroidism or prevalence of goitre . Autoimmune thyroiditis explains some cases of goitre but other goitrogenic factors need to be evaluated A community-based controlled trial of iodine supplementation comparing oral or intramuscular iodized oil with oral potassium iodide has been carried out in 23 severely iodine-deficient villages in Eastern Zaire . The overall goitre prevalence in the population ( n = 5999 ) was 61 % and mean urinary iodine excretion in sample of 57 women 10.9 ( SD 6.8 ) micrograms/g creatinine . All adults in three groups of four villages were given single doses of potassium iodide of 0.5 g , 1.0 g , and 2.0 g respectively . A fourth group was given oral iodized oil ( 2 ml ) and a fifth placebo-treated . A further three villages were given intramuscular iodized oil ( 2 ml ) . The effectiveness of supplementation was assessed by measurements of bloodspot thyroxine ( T4 ) concentration in women of reproductive age in the villages . The effects of iodide were small and inconsistent . Eight months after supplementation with oral iodized oil the distribution of T4 concentrations was similar to that seen with intramuscular oil . We conclude that oral iodized oil is an effective alternative to injected oil and would be feasible for iodine supplementation in remote areas with untrained people BACKGROUND In developing countries , many children are at high risk of goiter and iron deficiency anemia . Because iron deficiency can have adverse effects on thyroid metabolism , iron deficiency may influence the response to supplemental iodine in areas of endemic goiter . OBJECTIVE The aim of this study was to determine whether goitrous children with iron deficiency anemia would respond to oral iodine supplementation . DESIGN A trial of oral iodine supplementation was carried out in an area of endemic goiter in western Côte d'Ivoire in goitrous children ( n = 109 ) aged 6 - 12 y. Group 1 ( n = 53 ) consisted of goitrous children who were not anemic . Group 2 ( n = 56 ) consisted of goitrous children who had iron deficiency anemia . At baseline , thyroid gl and volume and urinary iodine , thyrotropin , and thyroxine were measured by using ultrasound . Each child received 200 mg I orally and was observed for 30 wk , during which urinary iodine , thyrotropin , thyroxine , hemoglobin , and thyroid gl and volume were measured . RESULTS The prevalence of goiter at 30 wk was 12 % in group 1 and 64 % in group 2 . The mean percentage change from baseline in thyroid volume 30 wk after administration of oral iodine was -45.1 % in group 1 and -21.8 % in group 2 ( P < 0.001 ) . Among the anemic children , there was a strong correlation between the percentage decrease in thyroid volume and hemoglobin concentration ( r(2 ) = 0.65 ) . CONCLUSION The therapeutic response to oral iodine was impaired in goitrous children with iron deficiency anemia , suggesting that the presence of iron deficiency anemia in children limits the effectiveness of iodine intervention programs Iodine deficiency control programs have greatly reduced iodine deficiency disorders worldwide . For monitoring changes in iodine status , different indicators may be used . The aim of this study was to evaluate the suitability of indicators of iodine status and thyroid function , thyroglobulin ( Tg ) , thyroid-stimulating hormone ( TSH ) and free thyroxine ( FT4 ) in serum , thyroid volume and urinary iodine concentration , in iodine-deficient schoolchildren under conditions of increasing iodine supply . The study was established as a double-blind , placebo-controlled oral administration of a single dose of iodized oil to schoolchildren ( 7 - 10 y old ) , living in an iodine-deficient area of Benin , with an observation period of 10 mo . However , 3 - 4 mo after supplementation , iodized salt became available in the area . The study population therefore comprised an iodized oil-supplemented group  and a nonsupplemented group  , both of which had variable , uncontrolled intakes of iodized salt during the last 6 mo of the study . Initial mean serum concentrations of TSH and FT4 were within the normal range , whereas serum Tg concentration , urinary iodine concentration and thyroid volume were indicative of moderate-to-severe iodine deficiency . At the end of the study , all indicators had improved significantly , except thyroid volume , which had decreased only in the supplemented group . The supplemented group also still had significantly lower serum Tg and higher urinary iodine concentrations than the nonsupplemented group . Serum Tg and urinary iodine concentrations are the indicators most influenced by a changing iodine supply . Current normal reference ranges of serum concentrations of TSH and FT4 are too wide for detecting iodine deficiency in this age group Iodine deficiency has re-emerged in many parts of the world including the UK , Australia and New Zeal and ( NZ ) . In 2009 , the NZ government introduced the m and atory fortification of bread with iodised salt as a strategy to improve iodine intakes . The aim of the present study was to assess the impact of fortification on the iodine status of NZ schoolchildren . A school-based cluster survey was used to r and omly select schools from two NZ cities . Children aged 8 - 10 years were administered a general question naire , and asked to provide a casual urine and finger-prick blood sample . The median urinary iodine concentration ( UIC ) of the children ( n 147 ) was 113 μg/l , which falls between 100 and 199 μg/l indicating adequate iodine status ; 12 % of children had a UIC < 50 μg/l and 39 % had a UIC < 100 μg/l . The median serum thyroxine concentration was 115 nmol/l . The median serum thyroglobulin ( Tg ) concentration was 10.8 μg/l and falls in the 10.0 - 19.9 μg/l range indicative of mild iodine deficiency , suggesting that these children still had enlarged thyroid gl and s. When compared with the median UIC of 68 μg/l reported in the 2002 NZ Children 's Nutrition Survey , the UIC of children in the present study had increased , which is probably caused by the addition of iodised salt to bread . However , the elevated concentration of Tg in these children suggests that the increase in UIC is not sufficient to ensure that thyroid volume has normalised . The fortification of other staple foods , in addition to bread , should be considered to ensure good iodine status in NZ children Growth and development of 207 children ( 49 % males ; mean age 5.4 years [ SD 0.2 ] , range 4 to 7.3 years whose mothers received iodine during pregnancy , and children who received iodine first in their 2nd year , were examined in 1996 ; 192 children ( 49 % males ; mean age 6.5 years [ SD 0.2 ] , range 5.8 to 6.9 years ) whose mothers received iodine while pregnant were seen in 1998 . Children were from the southern part of China 's Xinjiang Province which has the lowest levels of iodine in water and soil ever recorded .  Head circumference but not height was improved for those who received iodine during pregnancy ( compared with those receiving iodine at age 2 ) and for those supplemented before the end of the 2nd trimester ( relative to those supplemented during the 3rd trimester ) . Iodine before the 3rd trimester predicted higher psychomotor test scores for children relative to those provided iodine later in pregnancy or at 2 years . Results from the test for cognitive development result ed in trend only differences between those children supplemented during pregnancy versus later . The results address the question of when maternal iodine supplements should begin in public health programs world wide . Findings may be relevant to the treatment of maternal and newborn thyroid deficiency in industrialized countries , particularly for those infants delivered before the end of the second trimester Endemic goitre has re-emerged in Thail and . This is particularly dangerous for children since iodine deficiency disorders ( IDDs ) might negatively influence their intellectual and mental development . In order to assess the situation , the iodine content of breast milk was determined and a method is proposed on how to monitor IDDs in lactating mothers later on . Seventy-five lactating women aged from 15 to 45 years , from 12 villages of 3 districts , namely Chumpae . Srichompu and Pupaman within the mountainous areas of Khon Kaen province , Northeast of Thail and were investigated . The breast milk from 46.7 per cent of mothers was found to be below recommended st and ards . In addition , 52.0 per cent of the women investigated had low urinary iodine excretion . The risk of women with low iodine excretion was 15 fold higher in comparison to women with sufficient iodine excretion to provide breast milk for their babies with insufficient iodine content . It is concluded that urinary iodine excretion can be used to monitor the IDDs in lactating mothers BACKGROUND An adequate iodine supply in utero and shortly after birth is known to be crucial to an individual 's physical and mental development . The question of whether iodine supplementation later in life can exert a favorable influence on the mental performance of iodine-deficient population s was addressed in various studies , but with contradictory results . OBJECTIVE The aim of this study was to examine the effect of an improvement in iodine status on mental and psychomotor performance of schoolchildren ( 7 - 11 y ) who were moderately to severely iodine deficient . DESIGN The study , which was originally planned as a double-blind , r and omized , placebo-controlled intervention , was carried out in an iodine-deficient population of schoolchildren ( n = 196 ) in northern Benin . As the population began to have access to iodized salt during the 1-y intervention period , the study population was split post hoc-on the basis of urinary iodine concentrations-into a group with improved iodine status and a group with unchanged iodine status . Changes in mental and psychomotor performance over the intervention period were compared . RESULTS Children with increased urinary iodine concentrations had a significantly greater increase in performance on the combination of mental tests than did the group with no change in urinary iodine concentrations . CONCLUSIONS An improvement in iodine status , rather than iodine status itself , determined mental performance in this population , which was initially iodine deficient . These findings suggest a " catch-up " effect in terms of mental performance The occurrence of iodine-induced hyperthyroidism ( IIH ) has been reported after iodine supplementation from clinics and hospitals , but not following an epidemiologic survey . We studied the prevalence of thyroid derangement in a population following iodine supplementation . One yr after more than 75 % of the population had been consuming 40 ppm iodized salt ; information regarding history of endemic goiter and iodized salt production , distribution , consumption and monitoring were collected in four cities of the Islamic Republic of Iran . A total of 6048 subjects were r and omly selected . All subjects were assessed for size of goiter , and urinary iodine and serum T4 , T3 , TSH , anti-thyroglobulin and antithyroperoxide were measured . Before iodine supplementation , all four cities were areas of endemic goiter . The rate of household consumption of iodized salt was 50 , 75 and 90 % in 1994 , 1995 and 1996 , respectively . Ninety-one percent of the salt sample s contained 15–55 ppm iodide . Total goiter rate was 57 , 62 and 68 % ; median urinary iodine was 188 , 197 and 190 μg/l in the age groups of 6–18 , 19–40 and > 40 yr , respectively . Prevalence of clinical and sub clinical hyperthyroidism was 0.34 and 0.41 and those of clinical and sub clinical hypothyroidism were 0.51 and 1.07 % , respectively . Nine point eight and 18 % in the 19–40 yr age group and 17.6 and 25.6 % in > 40 yr old subjects had positive anti-thyroperoxidase and antithyroglobulin , respectively . This systemic epidemiologic study in an iodine deficient population showed that , following a well-executed iodine supplementation program , the occurrence of IIH is rare To assess the prevalence of thyroid disorders in a region with mild iodine deficiency , this study was undertaken in a r and omized sample of pregnant women during different gestational periods . Evaluations were performed in 215 women : thyroid ultrasound scanning , thyroid stimulating hormone ( TSH ) , free thyroxine ( T4 ) and thyroid peroxidase ( TPO ) antibodies .  At the time of participation in the study , some women ( 90/215 ) had been receiving 150–200 µg iodine .  Hypothyroidism was found in four women ( 1.86 % ) . Positive TPO antibodies were seen in 34 of 215 women ( 15.8 % ) , and TPO antibody level over 150 mU/l was found in 9.8 % ( 21/215 ) . There was no significant difference between TSH levels in women with positive or negative TPO antibodies . There were no differences in TSH level between the women receiving and those not receiving iodine prophylaxis .  The prevalence of goiter in 211 euthyroid women was found to be 24.2 % ( 51/211 ) . In the group with iodine prophylaxis , thyroid volume was found to be significantly lower ( t = 2.5 ; p = 0.02 ) than in women who had not received it , or had started it during the second trimester . By comparison of history data on the prevalence of aborted pregnancy between the group with positive ( 26.5 % ; 9/34 ) and the group with negative TPO antibodies ( 14.3 % ; 26/181 ) , no significant differences were found . We conclude that , in mild iodine deficiency , pregnancy is related to a high risk of goiter , which can be prevented by iodine prophylaxis . TPO antibody carrier status in pregnant women is probably not associated with a significant risk of thyroid dysfunction or spontaneous abortion OBJECTIVE Studies of hypothyroidism are often based on referred patients , and limited information is available on the incidence rates of subtypes of hypothyroidism in the general population . We therefore studied incidences of subtypes of primary , overt hypothyroidism in a Danish population cohort and compared incidences in two subcohorts with different levels of iodine intake . DESIGN A prospect i ve population -based study , monitoring a well-defined cohort representative of the Danish population . METHODS The Danish Investigation of Iodine Intake and Thyroid Diseases registry of hyper- and hypothyroidism was established as part of the monitoring of the iodine fortification of salt in Denmark . A computer-based system linked to laboratory data bases identified all patients diagnosed with new , biochemically overt hypothyroidism in population s living in Aalborg ( moderate iodine deficiency , n = 311,102 ) and Copenhagen ( mild iodine deficiency , n = 227,632 ) . We subsequently evaluated all identified patients to verify incident thyroid disease , and subclassified hypothyroidism into nosological types . RESULTS During a 4-year period ( 2,027,208 person-years ) 685 new cases of overt hypothyroidism  were diagnosed in the cohort ; the incidence rate was 32.8 per 100,000 person-years ( st and ardised to the Danish population ) . Nosological types of hypothyroidism were : spontaneous ( presumably autoimmune ) 84.4 % , post-partum 4.7 % , amiodarone-associated 4.0 % , subacute thyroiditis 1.8 % , previous radiation or surgery 1.8 % , congenital 1.6 % and lithium-associated 1.6 % . Crude incidence rates were 29.0 around Aalborg and 40.6 in an area of Copenhagen . The higher incidence rate of hypothyroidism in the area with higher iodine intake was caused solely by more cases of spontaneous ( presumably autoimmune ) hypothyroidism , whereas the incidence of non-spontaneous hypothyroidism ( all types combined ) was significantly lower in the area with higher iodine intake . CONCLUSION In a population -based study we observed a higher incidence of hypothyroidism with higher iodine intake . This was due solely to the entity of spontaneous hypothyroidism . The occurrence of overt hypothyroidism was relatively low in Denmark 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 , In moderately iodine-deficient , pregnant , thyroid peroxidase antibody (TPO-Ab)-positive women the role of iodine supplementation in the development of postpartum thyroid dysfunction ( PPTD ) was studied in a placebo-controlled , r and omized , double blind trial . Screening for TPO-Ab was performed in early pregnancy in a population of healthy pregnant Danish women with no previous diagnosed thyroid disease ( prevalence , 117 of 1,284 ; 9.1 % ) . The participants were r and omized , stratified according to TPO-Ab level , to three groups . All participants received a daily vitamin and mineral tablet with 150 microg iodine or no iodine . The + /+ group received iodine during pregnancy and the postpartum period , the + /- group received iodine during pregnancy only , and the -/- group received no iodine supplementation . A total of 66 TPO-Ab positive women were followed , and in the postpartum period sera were collected at 8-week interval for biochemical evaluation of thyroid function and antibody level . Compliance was evaluated by 24-h urinary iodine measurements . PPTD developed in 55 % of the participants . In 67 % of the cases abnormal TSH was accompanied by abnormalities in thyroid hormones , whereas 33 % had abnormal serum TSH only . There was no statistically significant difference in the frequency of PPTD in the three groups : + /+ group , 59 % ( 95 % confidence interval , 36 - 79 % ) ; + /- group , 60 % ( 36 - 81 % ) ; and -/- group , 46 % ( 26 - 67 % ) . There were also no differences in the severity of the PPTD , as evaluated by duration and grade of deviation of TSH and thyroid hormones from normality . The occurrence , severity , and type of PPTD predominantly depended on the TPO-Ab level : TPO-Ab below 200 U/L at screening , 35 % developed PPTD ; TPO-Ab of 200 - 900 U/L , 54 % ; and TPO-Ab above 900 U/L , 75 % developed PPTD . Women with low levels of antibodies predominantly remained euthyroid or had hyperthyroidism only , whereas women with high antibody levels had hyperthyroidism followed by hypothyroidism or hypothyroidism only . We conclude that iodine supplementation ( 150 microg ) during pregnancy and the postpartum period to TPO-Ab-positive women living in an area with mild to moderate iodine deficiency did not induce or worsen PPTD . The study confirmed that screening for TPO-Ab in early pregnancy can predict women at high risk for development of PPTD BACKGROUND Iodine deficiency ( even moderate ) plays a major role in pregnancy associated goiter development , which is only party reversible after pregnancy . The prevalence of post partum thyroiditis is reported to be slightly lower in areas of iodine deficiency . Thus iodine supplementation may be effective in decreasing pregnancy associated increase in thyroid volume , but enhances the risk of increasing the prevalence of thyroid dysfunction in the post partum period . Therefore , we evaluated the effect of iodine supplementation ( with two different doses : 50 microg and 250 microg ) on the prevalence of post partum thyroiditis and the decrease in thyroid volume up to 8 months post partum in an area of mild iodine deficiency . PATIENTS AND METHODS Thyroid volume of 56 women was evaluated 5 days and 3 months after delivery ( study I ) . In an intervention study ( Study II ) 70 women were r and omized to receive 50 or 250 microg of potassium iodide for a period of 8 months post partum beginning five days after delivery . Thyroid volume , the echogenecity of the thyroid gl and , thyroid hormone parameters ( T4 , T3 , fT4 , TSH ) and thyroid antibodies ( TPO and Tg-Ab ) were measured 5 days , 3 and 8 months after delivery . RESULTS A total number of 11 women developed postpartum thyroid dysfunction : 4 women developed manifest thyroid dysfunction ( 3 hyperthyroidism and 1 hypothyroidism ) 3 months post partum . The remaining seven had sub clinical hypo- or hyperthyroidism . All changes were clinical ly mild and transient as evidence d by normalization of thyroid hormone parameters on reexamination at 8 months . Among the eleven , 6 women in the 50 microg iodine group and 5 women of the 250 microg iodine group developed thyroid dysfunction , suggesting that the iodine dose did not affect post partum thyroiditis . The administration of only 50 microg iodine was associated with a significant fall of thyroid size already 3 months after delivery ( 25.4 + /- 1.5 ml ( mean + /- sem ) to 18.2 + /- 1.25 p < 0.001 ) . The application of 250 microg iodine was equally effective . 8 months post partum a slight but further decrease could be demonstrated . On the other h and , in study I no significant reduction in thyroid volume was observed in women receiving no supplementary iodine ( thyroid volume at delivery 29 + /- 2.2 ml ; at 3 months 27.5 + /- 3.0 ml . CONCLUSION The administration of supplementary iodine ( up to 250 microg ) to an unselected population , residing in an area of mild iodine deficiency , in the post partum period is save as indicated by a prevalence of 5.7 % manifest thyroid dysfunction . These changes are clinical ly mild and transient . Even the amount of 50 microg of iodine supplementation seems to by very efficient in reducing pregnancy associated increments in thyroid volume OBJECTIVES To assess the nutritional status of six month to 11 year old rural Black children and their mothers as a first phase in a nutrition intervention project . DESIGN Cross sectional study . SETTING A rural African community + /- 60 km northwest of Durban , KwaZulu-Natal , South Africa . SUBJECTS A r and om sample of 127 mothers and 105 pre-school and 131 primary school children were selected from this community . MAIN OUTCOME MEASURES Anthropometric ( height and weight ) , biochemical and dietary and socio-demographic information was collected . RESULTS Among the pre-schoolers anaemia was present in 23.8 % , iron deficiency in 19.8 % , while marginal vitamin A deficiency was observed in 44.9 % . Urinary iodine levels indicated moderate iodine deficiency in 31.8 % and severe iodine deficiency in 9.1 % . In primary school children the prevalence of anaemia was 22 % , while marginal vitamin A deficiency was observed in 50.8 % . Moderate iodine deficiency was observed in 37.9 % of primary school children while 13.6 % presented with severe iodine deficiency . The prevalence of goitre in this group was 22.1 % . Almost 22 % of mothers were anaemic and 18.9 % were iron deficient . Only 1.6 % of mothers were marginally vitamin A deficient . An enlarged thyroid was observed in 26.7 % of mothers of which 17.3 % were palpable and 9.4 % visible . Of mothers 43.4 % were overweight while 33.8 % were obese . CONCLUSION The rural community in KwaZulu-Natal , showed a high prevalence of anaemia , marginal vitamin A deficiency and iodine deficiency . The information gathered during this cross sectional study served as a basis to plan and implement an intervention study aim ed at addressing the nutritional deficiencies OBJECTIVE Mild to severe iodine deficiency has been documented in Lesotho since 1960 . To eliminate the persisting iodine deficiency , legislation on universal salt iodization was introduced in 2000 as a long-term public health intervention strategy . We assessed the urinary iodine status of school children and women of child-bearing age in Lesotho 2 y after the introduction of legislation on universal salt iodization . METHODS A 31-cluster national survey was conducted in 2002 by using the proportion to population size method . In each cluster , 30 women ages 15 to 30 y and 30 primary school children ages 8 to 12 y were r and omly selected to provide urine sample s for urinary iodine analysis . Data were interpreted according to criteria of the World Health Organization , United Nations Children 's Fund , and International Council for Control of Iodine Deficiency Disorders ( 2001 ) . Statistical analysis was performed using SAS . RESULTS We analyzed 912 urine sample s from children and 924 from women . The median urinary iodine concentrations were 214.7 microg/L for children and 280.1 microg/L for women , indicating more than adequate iodine intake . Median iodine concentration was higher in the lowl and s ( 256.0 microg/L in children and 329.9 microg/L in women ) than in the mountains ( 99.30 microg/L in children and 182.6 microg/L in women ) . Analysis of the distribution of the data showed values below 50 microg/L in 10.1 % of children and in 9.8 % of women . In addition , 21.5 % of children and 17.9 % of women had urinary iodine excretion values below 100 microg/L. In contrast , 36 % of children and 47.2 % of women had urinary iodine concentrations in excess of 300 microg/L. CONCLUSION Results of urinary iodine excretion measurements indicated that iodine deficiency has been eliminated as a public health problem in Lesotho . However , the high median urinary iodine concentration of women in the lowl and s indicated the possibility of a risk of iodine-induced hyperthyroidism in vulnerable people
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 .