Despite long-standing supplementation of iodine in Iran, the prevalence of goitre among general people remains high in some regions. The study investigated the role of iron status in the aetiology of goitre in school children in Isfahan, Iran. Two thousand three hundred and thirty-one school children were selected by multi-stage random sampling. Thyroid size was estimated by inspection and palpation. Urinary iodine concentration (UIC) and serum ferritin (SF) were measured. Overall, 32.9% of the children had goitre. The median UIC was 195.5 μg/L. The mean±SD of SF in the goitrous and non-goitrous children was 47.65±42.51 and 44.55±37.07 μg/L respectively (p=0.52). The prevalence of iron deficiency in goitrous and non-goitrous children was 9.6% and 3.1% respectively (p=0.007). Goitre is still prevalent in school children of Isfahan. However, their median UIC was well in the accepted range. Iron deficiency is associated with goitre in a small group of goitrous children. The role of goitrogens should also be investigated in this region.
Cross-sectional studies; Goitre; Iodine; Iron deficiency; Serum ferritin; Iran
Iodine deficiency disorders (IDD) constitute significant public health problems in parts of the world with poor iodine nutrition, but have been eradicated in North America and other regions. We herein report three cases of iodine deficiency disorders (IDD) which occurred in women living in iodine-replete environments.
The clinical presentation, biochemical findings, and radiological features of the patients were analyzed and presented in three case reports. The radiological features are illustrated in sonographic and scintigraphic images. A literature review and discussion which highlight the risk factors, pathogenesis, ancillary investigations and rational treatment of iodine deficiency goiter and hypothyroidism are provided.
All of our three patients were young females, aged 24–38 years, who had goiter. Two of them presented with goitrous hypothyroidism. Radioactive iodine scintigraphy showed a characteristic finding of diffusely increased uptake (in the absence of clinical and biochemical evidence of hyperthyroidism). This scintigraphic pattern was found to be pathognomonic. Dietary iodine supplementation alone resulted in complete remission of IDD in the subjects, including the two patients with hypothyroidism.
IDD can occur in iodine replete-environments. A high index of suspicion is needed to recognize these cases. It is pertinent that the correct diagnosis be made to avoid unwarranted life-long thyroxine therapy in patients presenting with goiter and hypothyroidism, which is easily treatable with iodized salt. These cases underscore the need for considering iodine deficiency in the etiologic diagnosis of goiter and hypothyroidism, even in iodine sufficient regions.
Iodine deficiency; Goiter; Hypothyroidism; Urinary iodine
Pendred syndrome (PDS) is an autosomal recessive disorder characterized by sensorineural hearing impairment and variable degree of goitrous enlargement of the thyroid gland with a partial defect in iodine organification. The thyroid function phenotype can range from normal function to overt hypothyroidism. It is caused by loss-of-function mutations in the SLC26A4 (PDS) gene. The severity of the goiter has been postulated to depend on the amount of dietary iodine intake. However, direct evidence has not been shown to support this hypothesis. Because Slc26a4-null mice have deafness but do not develop goiter, we fed the mutant mice a control diet or an iodine-deficient diet to evaluate whether iodine deficiency is a causative environmental factor for goiter development in PDS.
We evaluated the thyroid volume in histological sections with the use of three-dimensional reconstitution software, we measured serum levels of total tri-iodothyronine (TT3) and total thyroxine (TT4) levels, and we studied the thyroid gland morphology by transmission electron microscopy.
TT4 levels became low but TT3 levels did not change significantly after eight weeks of an iodine-deficient diet compared to levels in the control diet animals. Even in Slc26a4-null mice fed an iodine-deficient diet, the volume of the thyroid gland did not increase although the size of each epithelial cell increased with a concomitant decrease of thyroid colloidal area.
An iodine-deficient diet did not induce goiter in Slc26a4-null mice, suggesting that other environmental, epigenetic or genetic factors are involved in goiter development in PDS.
The term iodine deficiency disorders (IDD) refers to all the effects of iodine deficiency on growth and development in human and animal populations that can be prevented by correction of the iodine deficiency. The objective of this paper was to determine the iodine nutrition status among schoolchildren in the Jazan Region of the Kingdom of Saudi Arabia (KSA), by measuring urinary iodine concentrations and by clinical assessments of goiter rate.
A school-based cross-sectional survey was conducted in the Jazan region of southwestern KSA from May to November 2010. A total of 311 children, aged 6–13 years, drawn from 12 schools, were selected by a three-stage cluster random sampling method. Data on sociodemographic characteristics were collected using a structured questionnaire. Urine samples were collected and physical examinations were conducted to determine the presence or absence of goiter. Data were analyzed using SPSS version 17.0. Chi square and independent t-tests were used for proportions and mean comparisons between groups.
Out of 360 selected children, 311 were examined. There were 131 males (42%) and 180 females (58%). The median urinary iodine concentration (UIC) of the study group was 421 μg/L. The study population proportion with UIC > 300 μg/L was 74% with a higher proportion among males and urban populations. The proportion of children with UIC of 100–300 μg/L was only 21% and was significantly higher among females compared with males (p < 0.001). Only about 3% of the children had a median UIC less than 50 μg/L. The prevalence of total goiter rate (TGR) among the sample of schoolchildren in Jazan was 11%, with significant variations between rural and urban populations and by gender.
The present study demonstrates a remarkable achievement in Universal Salt Iodization (USI) and IDD elimination goals in the Jazan area. However, UIC levels reflect excessive iodine intake and may put the population at risk of adverse health consequences like iodine-induced hyperthyroidism and autoimmune thyroid diseases.
Iodine nutrition; Saudi Arabia; Jazan; USI
Butanol-insoluble iodinated compounds in the urine of patients with congenital goiters have been generally regarded as iodopeptides. Monoiodohistidine (MIH) and diiodohistidine (DIH) were identified from the urine of four patients with congenital goitrous hypothyroidism. From radioiodine studies, 40-70% of the urinary radioactivity was in the iodide-free fraction from which about 40% was identified as MIH and DIH by crystallizations to a constant specific activity.
Iodotyrosines were simultaneously identified in the urine. However the presence of an iodotyrosine-deiodinase activity was demonstrated in the two removed goiters with a normal Km for MIT. In vivo iodotyrosine deiodination was normal for hypothyroid subjects.
No thyroglobulin was identified in the thyroids from these patients. The major iodoprotein was iodoalbumin which, after in vivo labeling, contained 84-89% of the total soluble protein radioactivity. The thyroxine content of the goiter iodoalbumins and other iodoproteins was extremely low.
Iodohistidines were identified in comparable proportions in the iodoalbumin and in the other iodoproteins isolated from each goiter. The average iodohistidine content of these proteins as crystallizable MIH and DIH was in the individual cases 15 and 4% of the in vivo incorporated radioiodine. DIH was identified in all iodoprotein fractions. The mean DIH/MIH ratios from the individual cases were 1.16 and 0.35. The corresponding DIT/MIT ratios were 3.19 and 1.45, respectively.
The major consequence of this thyroglobulin defect is the iodination of inappropriate proteins (mainly albumin) resulting in low yields of thyroxine and high yields of iodohistidines. Iodohistidines from the goiter iodoproteins were not deiodinated and, at least for MIH, were quantitatively excreted in the urine of these patients. From the MIH iodoalbumin content and the MIH urinary excretion, goiter iodoalbumin turnover estimates were made and, although elevated, could not maintain a normal thyroxine secretion.
The urinary excretion of iodohistidines easily demonstrated by column chromatography is offered as a test for detecting this variety of congenital goiter.
What is the current status of Iodine Deficiency Disorders (IDD) in the state of Jharkhand?
(1) To determine the status of iodine deficiency in the state. (2) To determine the availability and cost of adequately iodized salt at the retail shops. (3) To study the perceptions of the community regarding iodine deficiency, salt and iodized salt.
A cross-sectional community-based survey.
Thirty clusters selected through the probability proportion to size (PPS) sampling in the state of Jharkhand.
Children aged 6-12 years, households, retail shopkeepers and opinion leaders.
Quantitative and qualitative methodology using a pretested questionnaire and focus group discussion used to carry out the community-based survey.
Total goiter rate (TGR) was 0.9%. Median urinary iodine level was 173.2 µg/L. The proportion of individuals with urinary iodine levels less than 100 and 50 µg/L were 26.4% and 10%, respectively. Slightly less than two-thirds (64.2%) of the households were found to be consuming adequately iodized salt as measured by titration (greater than 15 ppm). Iodized salt was available across the state and the cost varied between Re. 1 and Rs. 8 per kilogram. A common belief among the community was that iodized salt is equivalent to refined packet salt that is further equivalent to expensive salt.
The results of the present survey show that the iodine nutrition in the state of Jharkhand is optimal. Considering that the consumption of adequately iodized salt should increase from 64.2% to the goal of more than 90%, sustained efforts are required in this place to consolidate the current coverage of adequately iodized salt and increase it to greater than 90%.
Goiter; iodine deficiency disorders; Jharkhand
Iodine deficiency disorder (IDD) creates major public health problems in India, including Gujarat. The Bharuch district is a known iodine deficiency endemic area. This study was conducted to estimate the prevalence of goiter in primary school children; to determine the median urinary iodine concentration; to assess the level of iodine in salt samples at the household and retail shop levels; and to study the profile of salt sold at retail shops.
This study was carried out by using the 30-cluster survey method in the primary schools of the rural areas in Bharuch district. A total of 70 students, including five boys and five girls from the first to seventh classes, who were present in class on the day of the visit were selected randomly for goiter examination from each village. Urine samples were collected from one boy and one girl from each class in each cluster. From each community, a maximum of two boys and two girls from each standard in the same age group were examined and also salt samples were tested from their households. From each village, one retail shop was visited and the salt purchased from those shops was immediately tested for iodine with spot kits.
We found a goiter prevalence of 23.2% (grade 1 – 17.4% and grade 2 – 5.8%). As the age increased, the goiter prevalence decreased except in nine-year-olds. The median urinary iodine excretion level was 110 μg/L. An Iodine level > 15 ppm was found in 93% of the salt samples tested at the household level.
The present study showed moderate goiter prevalence in primary school children in the Bharuch district of Gujarat and an inadequate iodine content of salt at some household levels.
Goitre survey; IDD; prevalence; primary school children; household level
Five to 10 per cent of cretinism in the United States is due to some congenital enzymatic defect in thyroid hormone synthesis. The clinical signs of hypothyroidism appear in early infancy. Differentiation from athyreotic cretinism is important because the metabolic defect tends to be familial and its presence in the patient's infant relatives should be diagnosed as early as possible. The differentiation is easily made if a goiter is discernible, but if it is not, radioiodine uptake should be measured, for in this condition the uptake is normal or greater. Thyroid replacement is the treatment in either the athyreotic state or the metabolic deficiency.
The three known defects in thyroid hormone synthesis are (1) failure to oxidize iodine to elemental iodine resulting in failure of all subsequent processes; (2) failure to deiodinate free iodotyrosine, and (3) failure to form iodothyronine although the previous steps are accomplished.
Lithium carbonate, a widely used treatment for bipolar disorders, is associated with goiter, hypothyroidism and thyrotoxicosis. However, the effect of lithium to increase radioactive iodine uptake has received little attention, thus, making Lithium a confounding factor in the interpretation of thyroid radionuclide studies. We herein report a case of misinterpreted high radioactive iodine uptake in a euthyroid, lithium-treated goitrous patient. We conclude that lithium therapy should be considered in the etiologic diagnoses of patients with goiter and homogenously elevated radioiodine uptake. It is pertinent to recognize this phenomenon in order to prevent unwarranted treatment with radioactive iodine or thionamides.
What is the situation of iodine deficiency disorder (IDD) and salt consumption in Jammu region?
The prevalence of IDD has decreased markedly as a result of medical as well as socio-economic factors.
To assess the magnitude of IDD in Jammu region and also assess the salt consumption patterns in the region.
Primary schools in both urban and rural areas.
Clinical examination of study population for goiter, laboratory assessment of casual urine sample for urinary iodine estimation of I2 content of salt samples collected from sub-samples of study population.
School children in the age group of 6-12 years were selected for study using WHO 30-cluster methodology, urine samples were collected from 15% of selected children and salt samples from 5% of sub-sample.
No ethical issues were involved.
An overall goiter prevalence of 11.98% was observed in the region. Females had a prevalence of 16.1% and males 10.1%. The median urinary iodine excretion in the region was 96.5 μg/l (range: 29.0-190.0 μg/l). Forty-nine percent of subjects had biochemical iodine deficiency with 6.7% having moderate and 42.53% mild iodine deficiency. In Jammu region, 74.47% of households consume powdered salt with 98.17% powdered salt samples having an I2 content of greater than 15 ppm.
Iodine deficiency remains a public health problem in the region, though the region seems to be in a state of nutritional transition from iodine deficiency to iodine sufficiency.
Crystalline salt; excretion; goiter; powdered salt; prevalence; urinary iodine
This cross-sectional study investigated the prevalence of goitre in Isfahan, a centrally-located city in Iran, 15 years after the initiation of universal salt iodization. In total, 2,523 Isfahani adults (1,275 males, 1,248 females) aged >20 years were selected by multi-stage cluster-sampling method. Goitre rate, serum thyroid-stimulating hormone (TSH), thyroxine (T4), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), and urinary iodine concentration (UIC) were measured and compared between the goitrous (n=478) and the non-goitrous (n=2,045) participants. The total goitre rate was 19% (n=478) of the 2,523 adults. The rate of Grade I and II goitre was 12.4% (n=312) and 6.6% (n=166) respectively. The total goitre rate, Grade I and II goitre were more prevalent among women than among men. Hypothyroidism was observed in 6.4% (130/2,045) and 18.6% (89/478) of the non-goitrous and goitrous participants respectively [odds ratio (OR)=3.6, 95% confidence interval (CI) 2.7-4.9, p=0.001]. Hyperthyroidism was present in 0.8% (17/2,045) and 5.2% (29/478) of the non-goitrous and goitrous adults respectively (OR=9.0, 95% CI 4.9-16.6, p=0.001). Hypothyroidism was more prevalent in Grade II than in Grade I goitre and among those without goitre (31.3%, 14.1%, and 6.4% respectively) (p=0.001). Positive TPOAb was observed in 24% (n=50) of the non-goitrous and 33.5% (n=84) of the goitrous subjects (p=0.03). Positive TPOAb was observed in 24.6% (35 of 142) of the Grade I and 45% (49 of 109) of the Grade II goitrous adults (p=0.001). Positive TgAb was observed in 21.6% (n=45) of the non-goitrous and 35.9% (n=90) of the goitrous adults (p=0.001). Positive TgAb was observed in 30.3% (43 of 142) of the Grade I and 43.1% (47 of 109) of the Grade II goitrous adults (p=0.04). The median UIC was 18 μg/dL (range 1-80 μg/dL). It was 17.9 μg/dL and 19 μg/dL in the non-goitrous and goitrous adults respectively. After 15 years of successful universal salt iodization in Isfahan, goitre is still endemic, which may be due to thyroid autoimmunity. However, other environmental or genetic factors may have a role.
Autoimmunity; Cross-sectional studies; Goitre; Hypothyroidism; Hyperthyroidism; Impact studies; Iodine; Iodine deficiency; Iran
The most severe brain damage associated with thyroid dysfunction during development is observed in neurological cretins from areas with marked iodine deficiency. The damage is irreversible by birth and related to maternal hypothyroxinemia before mid gestation. However, direct evidence of this etiopathogenic mechanism is lacking. Rats were fed diets with a very low iodine content (LID), or LID supplemented with KI. Other rats were fed the breeding diet with a normal iodine content plus a goitrogen, methimazole (MMI). The concentrations of -thyroxine (T4) and 3,5,3'triiodo--thyronine (T3) were determined in the brain of 21-d-old fetuses. The proportion of radial glial cell fibers expressing nestin and glial fibrillary acidic protein was determined in the CA1 region of the hippocampus. T4 and T3 were decreased in the brain of the LID and MMI fetuses, as compared to their respective controls. The number of immature glial cell fibers, expressing nestin, was not affected, but the proportion of mature glial cell fibers, expressing glial fibrillary acidic protein, was significantly decreased by both LID and MMI treatment of the dams. These results show impaired maturation of cells involved in neuronal migration in the hippocampus, a region known to be affected in cretinism, at a stage of development equivalent to mid gestation in humans. The impairment is related to fetal cerebral thyroid hormone deficiency during a period of development when maternal thyroxinemia is believed to play an important role.
Often patients in whom there is little to suggest myxedema or cretinism have subclinical hypothyroidism. Once the condition is suspected, it can be diagnosed by determination of protein-bound iodine and, if the PBI is low, by response to therapy with thyroid hormone.
Patients in the following categories should have protein-bound iodine determination: Those having (1) a history of previous treatment for hypothyroidism; (2) suboptimal development in children; (3) ovarian dysfunction, infertility, habitual abortion or unusual menopausal disorders; (4) symptoms of malaise and debility, such as undue fatigue, somnolence, mental asthenia and anxiety; (5) unexplained anemia; (6) colloid goiter, adenomatous goiter and cancer of the thyroid gland.
If hypothyroidism is diagnosed, administration of thyroid hormone in increasing amounts, as determined by serial serum PBI tests, should be carried out indefinitely. Instruction of the patient is essential.
Thyroid disorders are common endocrine disorders encountered in the African continent. Environmental and nutritional factors are often implicated in the occurrence of some thyroid disorders that occur in this part of the world. This is a narrative review that seeks to document the pattern, prevalence, and management of thyroid disorders in the continent.
Materials and Methods:
The search engine used for this review were PubMed and Google scholar. All available articles on thyroid disorders from the sub-African continent, published until May 2011, were included.
Iodine deficiency disorders (IDD) which top the list of thyroid disorders and remain the commonest cause of thyroid disorders in the continent is often affected not only by the iodine status in the region but sometimes also by selenium deficiency and thiocyanate toxicity. The reported prevalence rates of endemic goiter range from 1% to 90% depending on the area of study with myxedematous cretinism still a prominent feature of IDD in only a few regions of the continent. The extent of autoimmune thyroid disorders remains unknown because of underdiagnosis and underreporting but the few available studies note a prevalence rate of 1.2% to 9.9% of which Graves diseases is the commonest of these groups of disorders. Rarer causes of thyroid dysfunction such as thyroid tuberculosis and amiodarone related causes are also documented in this review. The onset of new thyroid diseases following amiodarone usage was documented in 27.6% of persons treated for arrhythmia. Reports on thyroid malignancies (CA) in Africa abound and differentiated thyroid malignancies are noted to occur more commonly than the other forms of thyroid CA. The documented prevalence rates of thyroid CA in the African continent are as follows (papillary: 6.7–72.1%, follicular: 4.9–68%, anaplastic: 5–21.4%, and medullary: 2.6%–13.8%). For the differentiated thyroid CA, there is a changing trend toward the more frequent occurrence of papillary CA compared to follicular CA and this may be attributable to widespread iodization programs. Our review shows that diagnosis and evaluation of thyroid disorders are reliant in most regions of the continent on clinical acumen and suboptimal diagnostic facilities and expertise are what obtain in many practices. The frequently employed management options of thyroid disorders in the continent are pharmacological and surgical treatment modalities.
Diagnosis and management of thyroid disorders in the African continent remain suboptimal. Thyroid registries may be helpful to determine the scope of the burden of thyroid disorders since this knowledge may help change policies on the approach to the management of these disorders.
Africa; epidemiology; thyroid
Because iodine deficiency can influence background rates of thyroid disease or modify radiation dose–response relationships, we compiled descriptive data on iodine status among participants in a Belarusian–American screening study who were exposed in childhood to radioiodine fallout from the Chornobyl nuclear accident. We have used the data from two consecutive screening cycles to examine whether indicators of iodine status changed before and after documented government initiatives to improve iodine intake.
Urinary iodine concentrations in spot samples and prevalence of diffuse goiter by palpation were assessed in 11,676 exposed subjects who were 18 years or younger at the time of the accident on April 26, 1986, and were screened beginning 11 years later in connection with the Belarus–American Thyroid Study. Data for the first (January 1997–March 2001) and second (April 2001–December 2004) screening cycles, which largely correspond to time periods before and after official iodination efforts in 2000/2001, were compared for the cohort overall as well as by oblast of residence (i.e., state) and type of residency (urban/rural).
Median urine iodine levels among cohort members increased significantly in the later period (111.5 μg/L) compared to the earlier (65.3 μg/L), with the cycle 2 level in the range defined as adequate iodine intake by the World Health Organization. During the same period, a significant decline in diffuse goiter prevalence was also observed. In both cycles, urinary iodine levels were lower in rural than in urban residents. Urinary iodine levels, but not rates of goiter, varied by oblast of residence. In both periods, adjusted median urine iodine concentrations were similar in Gomel and Minsk oblasts, where ∼89% of cohort members resided, and were lowest in Mogilev oblast. Yet Mogilev oblast and rural areas showed the most marked increases over time.
Trends in urinary iodine concentrations and prevalence of diffuse goiter by palpation suggest that iodination efforts in Belarus were successful, with benefits extending to the most iodine-deficient populations. Iodine status should be considered when evaluating thyroid disease risk in radioiodine-exposed populations since it can change over time and may influence rates of disease and, possibly, dose–response relationships.
We aimed to evaluate thyroid functions and volumes and detect abnormalities in 80 neonates with Down syndrome.
Data about free triiodothyronine, free thyroxine, thyroid stimulating hormone, thyroglobulin and urinary iodine levels, and ultrasonographic thyroid volume were collected.
Abnormal thyroid function tests were detected in 53.8% of the patients (n = 50) and these were hyperthyrotropinemia, hypothyroidism, iodine deficiency and iodine overload in 32, 2, 12 and 4 patients, respectively. Thyroid volumes were assessed in 36 patients and a total of 17 abnormalities were detected (7 hypoplasia, 3 agenesis and 7 goiter). In patients with hyperthyrotropinemia mean thyroid volume was significantly greater and mean TSH was significantly higher when compared to the patients without hyperthyrotropinemia.
Neonatal screening by thyroid function tests in Down syndrome should be performed to prevent further intellectual deterioration and improve overall development. In the neonatal period, the risk of hyperthyrotropinemia should be kept in mind.
Down syndrome; Hyperthyrotropinemia; Newborn
Several studies pertaining to current status of Iodine Deficiency Disorder Control Programme in India have revealed goiter prevalence in the range of 1.5–44.5%, mean urinary iodine excretion level ranging from 92.5–160 mcg/L and iodized salt coverage ranging from 37–62.3%. Most of these studies were based on school children. However, very few studies have focused on pregnant women. This population is very sensitive to marginalized iodine deficiency throughout their gestational period.
This 40 cluster cross sectional study was done in Raipur district. Iodine content of salt was estimated by using “Rapid Salt Testing Kits” along with observing salt storage practices, at household and in shops. Pregnant women were interviewed by using semi structured comprehensive questionnaire, which was based on knowledge attitude, and practices about salt use pattern and awareness about IDDCP, UIE level were also estimated.
Prevalence of goiter was 0.17%. Many (41.12%) pregnant women had <15ppm iodine content in the salt sample and 51.58% of women had subnormal iodine uptake. Wrong salt storage practice was observed in 36.3% of households.
There were lacunae in Iodine deficiency control program in Chhattisgarh. Implementation and monitoring of program was weak. Thus for monitoring purpose IDD Cell & IDD Laboratory should be established at district level. This will lead to periodic assessment of Iodine Deficiency Disorders, by monitoring of Iodine intake and all other preventive, promotive as well as curative measures in the state.
Iodine Deficiency Disorder Control Program (IDDCP); Monitoring; Evaluation; Goiter; Universal Salt Iodization (USI); Median Urinary Iodine Excretion (MUIE)
Possible interactions between selenium and iodine metabolism were investigated in 7- to 16-year-old children with goiter (n = 136) living in southeastern Poland in iodine-deficient areas influenced by a sulfur industry. The Se-iodine interactions in these children were compared to the interactions in children from outside of that region (n = 38). Blood selenium (BSe) concentration and plasma glutathione peroxidase activity were much lower in the study group (64.1 +/- 15.7 microg/L; 111.0 +/- 27.6 U/L) than in the control group (85.3 +/- 19.6 microg/L; 182.4 +/- 35.6 U/L). Almost all of the data [plasma thyroid-stimulating hormone (TSH) concentration, plasma free thyroxine (fT(4)) concentration] fell within the reference limits. There was no statistically significant difference between the control and the study groups with respect to fT(4) and TSH. However, statistically significant differences of fT(4) and TSH in the study group were revealed between females belonging to the lower (n = 21; fT(4), 16.1 +/- 3.3 pmol/L; TSH, 1.83 +/- 1.05 mU/L) and upper Se quartiles (n = 24; fT(4), 14.5 +/- 2.2 pmol/L; TSH, 1. 26 +/- 0.90 mU/L), p < 0.05. Neither group differed in iodine in urine concentration, age, and body mass index. The difference in fT(4) concentrations can be attributed to an Se deficiency. The relationship exists only for females, which suggests a sex-linked hormonal response to concomitant Se and iodine deficiencies.
The function of the adult thyroid is regulated by thyroid-stimulating hormone (TSH), which acts through a G protein–coupled receptor. Overactivation of the TSH receptor results in hyperthyroidism and goiter. The Gs-mediated stimulation of adenylyl cyclase–dependent cAMP formation has been regarded as the principal intracellular signaling mechanism mediating the action of TSH. Here we show that the Gq/G11-mediated signaling pathway plays an unexpected and essential role in the regulation of thyroid function. Mice lacking the α subunits of Gq and G11 specifically in thyroid epithelial cells showed severely reduced iodine organification and thyroid hormone secretion in response to TSH, and many developed hypothyroidism within months after birth. In addition, thyrocyte-specific Gαq/Gα11-deficient mice lacked the normal proliferative thyroid response to TSH or goitrogenic diet, indicating an essential role of this pathway in the adaptive growth of the thyroid gland. Our data suggest that Gq/G11 and their downstream effectors are promising targets to interfere with increased thyroid function and growth.
Iodine deficiency disorder is a major problem worldwide, especially during pregnancy and childhood. The magnitude of the problem is quite big in Ethiopia. The main aim of the present study was to determine the prevalence and severity of iodine deficiency disorders.
A cross-sectional survey was conducted in Shebe Senbo District on January 2011. Three elementary schools were selected by lottery method from 20 schools. From each school, students were selected by simple random sampling. Spot urine sample (5 ml) was taken to measure urine iodine level; physical exam was made to palpate goiter and salt samples were collected to estimate iodine content.
Out of 389 participants, 179 (46%) were males. The total goiter rate was 59.1% (Grade 1: 35.2%; Grade 2:23.9%). The median urinary iodine level was 56 4g/L that indicates iodine deficiency. Out of 389 households in the study area, 277 (71.2%) were using non-iodinated salt, 102 (26.2%) of the households were using iodinated salt. Cabbage usage was significantly associated with goiter.
Endemic goiter is quite prevalent in the study area. Median urinary iodine value of the study samples was found to be far lower than standards. Quality of the salt used by the study population was found to be poor in its iodine content. The use of cabbage (goitrogen) has shown remarkable influence on the development of goiter. Therefore, awareness creation and distribution of iodized salt are highly recommended.
Iodine deficiency disorders; goiter; median urinary iodine; severity; prevalence
Ten years after the Chernobyl nuclear plant catastrophe more than 500 children in Belarus are suffering from thyroid cancer. The major cause of the high incidence of thyroid cancer in children under 15 years of age appears to be contamination resulting from that catastrophe, mainly with isotopes of radioactive iodine. Another important factor may be iodine deficiency in the environment. A countrywide program for investigation of goiter prevalence and iodine deficiency has been established in the Republic of Belarus with the assistance of the European World Health Organization office. The program will oversee the examination of 11,000 children and adolescents 6 to 18 years of age from 30 schools in urban and rural areas. The results obtained in a group of 824 children and adolescents (the pilot phase) are typical for significant iodine deficiency and moderate goiter endemism. It is clear that the present situation does not completely reflect the situation that existed at the time of the Chernobyl catastrophe. However, data from epidemiologic studies conducted many years before the accident showed high goiter prevalence in the contaminated areas, indicating that the prevalence of iodine deficiency at the time of the catastrophe was similar to the present one or even greater. Such an assumption could lead to a better understanding of the thyroid pathologies that have been observed.
Plasma calcitonin (CT) was measured in the basal state and/or during provocative tests of hormone secretion in 11 children with congenital non-goitrous cretinism (CNC), in 1 girl with a lingual thyroid, and in 11 normal children. Basal and stimulated CT concentrations were significantly lower in the patients with CNC than in the normal subjects. Mean basal CT (+/- SE) was 41 +/- 4 pg/ml in the normal children, 24 +/- 3 pg/ml in the children with CNC, and 20 +/- 2 pg/ml in the patient with the lingual thyroid. The mean incremental CT responses to calcium infusion were 7.0 +/- 2 pg/ml in the children with CNC, 6.0 pg/ml in the patient with the lingual thyroid, and 146 +/- 47 pg/ml in the normal children. The children with CNC also demonstrated a significant delay in the return of the total serum calcium to basal level after the calcium infusion. The mean incremental CT response after infusion of pentagastrin was 7.6 +/- 2 pg/ml in the children with CNC, 10.0 pg/ml in the child with the lingual thyroid, and 34.4 +/- 11 pg/ml in the normal children. These data indicate that CT deficiency is present in children with CNC and suggest that the deficiency is a consequence of the defective embryologic development of the thyroid gland.
After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1) a non-fortified bread, (2) a high-zinc bread, and (3) a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p < 0.001) except in the control (p > 0.05). Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p < 0.01). It was concluded that fortification of flour with 50–100 ppm zinc was an effective way to achieve adequate zinc intake and absorption in zinc-deficient people. It also appeared that consuming zinc-fortified bread improved iron absorption.
Bread fortification; Serum iron; Serum zinc; Zinc deficiency; Zinc sulfate
To assess iodine supply and follow thyroid epidemiology for ten years after an iodine increase from 10 to 25 mg of potassium iodide per kilogram of salt in 1999.
In 2002 and 2003, we determined the thyroid size by palpation and ultrasound and measured urinary iodine concentration (UIC) in 676 schoolchildren from 34 schools throughout Slovenia. From 1999 to 2009, we followed the incidence of diffuse and nodular goiter, thyroid autonomy, Graves’ disease, and Hashimoto’s thyroiditis among adults in the stable catchment area of the University Medical Centre Ljubljana with 1 000 000 inhabitants.
In children, only 1% had a goiter grade 2 (visible and palpable thyroid gland), median thyroid volume was 5.8 mL, and median UIC was 148 µg/L. In adults, the incidence of diffuse goiter and thyroid autonomy decreased significantly (2009 vs 1999, rate ratio [RR], 0.16; 95% confidence interval [CI], 0.12-0.21 and RR, 0.73; 95% CI, 0.62-0.86, respectively), with a lower incidence in younger participants in 2009 (P < 0.001). The incidence of multinodular goiter and solitary nodule increased (2009 vs 1999, RR, 1.55; 95% CI, 1.35-1.79 and RR, 1.72; 95% CI, 1.49-1.99, respectively). No long-term changes were observed for Graves’ disease (2009 vs 1999, RR, 0.95; 95% CI, 0.81-1.13), while the incidence of Hashimoto’s thyroiditis increased strongly (2009 vs 1999, RR, 1.86; 95% CI, 1.64-2.12).
The change from mildly deficient to sufficient iodine supply was associated with a marked change in the incidence of thyroid epidemiology – a significant decline in the incidence of diffuse goiter and thyroid autonomy and a marked increase in the incidence of Hashimoto’s thyroiditis.
A method has been devised which is free of many of the shortcomings of serial epithyroid counting techniques as an index of the rate of thyroid hormone secretion. By means of this method, the effect of treatment with Lugol's iodine on the rate of thyroidal secretion of thyroxine (T4) has been assessed in eight patients with thyrotoxicosis due to diffuse or multinodular goiter. The technique involves administration of a tracer dose of inorganic 125I followed several days later by an intravenous tracer dose of 131I-labeled T4. Serial observations of serum protein-bound (PB) 125I and 131I are accompanied by frequent measurements of endogenous serum T4 (T4-127I) concentration. Regardless of whether or not its administration was anteceded and accompanied by the administration of large doses of methimazole, iodine induced a rapid decrease in serum T4-127I concentration which could not be explained by an increase in the peripheral turnover of T4, as judged from the metabolism of the 131I-labeled hormone. Hence, the decreased serum T4 concentration could only have resulted from decreased secretion of the hormone by the gland. Analyses of specific activity relationships between PB125I or T4-127I and PB131I made possible estimations of the extent to which iodine had decreased the rate of secretion of T4. From such analysis, and in view of other considerations, it is concluded that the rapid decrease in T4 secretion induced by iodine is not the result of an acute, sustained inhibition of T4 synthesis, but rather results from an abrupt decrease in the fractional rate of thyroidal T4 release.