Conditions Of Iodine Deficiency Research Articles

Usefulness of low iodine diet in managing patients with differentiated thyroid cancer - initial results

BackgroundLow iodine diet (LID) is recommended in patients with differentiated thyroid cancer before radioiodine administration. Patients with increased thyroglobulin (Tg) level, but negative 131I whole body scan present diagnostic and therapeutic dilemma. This study was designed to evaluate the benefit of a two-week LID in patients with elevated serum Tg levels and negative 131I whole body scans.Patients and methods.For the impact assessment of two-week LID on radioiodine tissue avidity, radioiodine scans before and after LID were compared. Sixteen patients with serum Tg > 2 μg/L, negative Tg-antibodies, and negative radioiodine scans underwent two-week LID before the 131I administration. Fourteen patients underwent diagnostic scanning and two patients received radioiodine therapy. Iodine concentration in the morning urine specimens were measured in each patient, a day before and 15th day after starting LID.ResultsFollowing self-managed LID, patients were able to significantly reduce their iodine body content by 50% (range 28–65%, p<0,001). 13 patients (82%) accomplished mild iodine deficiency (50-99 μg/L) and one patient (6%) achieved targeted moderate iodine deficient state (<50 μg/L). All diagnostic post-LID scans were negative. Both post-therapy 131I scans showed radioiodine accumulation outside of normal 131I distribution (neck region and diffuse hepatic uptake). This study demonstrated that two-week LID is effective way to decrease total body iodine content, although without a visible effect on post-LID diagnostic 131I scans.ConclusionsA more stringent dietary protocol and longer iodine restriction period are probably needed to achieve targeted moderate iodine deficiency in patients preparing for 131I administration. This might result in higher radioiodine avidity of thyroid remnant/metastases.

The first results of pilot project on combined preventive suplementation of iodine- and iron deficiency conditions in Tyumen region

In 2008–2010 pilot project were realized in Tyumen region on combined preventive maintenance iodine deficiency and iron deficiency conditions, within the framework of which children from pilot of the territory got feeding, enriched premixes of the iodine and ferric while checking group has formed the children, getting monoprevention iodized salt. In study were examined 467 children. Frequency of the goiter on ultrasonography in pilot territory fell from 19.8 to 6.4%, in checking from 12.5 to 10.1%. In group teenager on background combined micronutrient preventive maintenance frequency tests ferritin less 15 mcg/l fell for 76 weeks in four times (p = 0.000), herewith average factors in 2010 above, than in 2008 (p = 0.114). In group teenager checking territory on background monoprevention frequency of the lowered tests ferritin more, than in group on background of the combined preventive maintenance in 2 times (p = 0.004), improvements for period of the study is not revealed.Dynamics indices of iodine deficiency conditions on background of the combined preventive maintenance and monoprevention confirms greater efficiency of the simultaneous using the products fortifications iodine and iron. Shown efficiency micronutrient preventive maintenances of the latent deficit ferric fortifications bread.

Iodine intake is still inadequate among pregnant women eight years after mandatory iodination of salt in Turkey

A recent study showed first sign of reduction in goiter prevalence and elimination of iodine deficiency state among school-age children in Turkey after a decade of mandatory iodination of table salt. However, iodine status among pregnant women is a still debated issue in our country. To investigate iodine status, iodized salt consumption rate, and goiter prevalence in 1st trimester pregnant women 8 yr after the mandatory iodination. MATERIAL/ SUBJECTS AND METHODS: One hundred and forty-one 1sttrimester pregnant women who had been followed-up between January and October 2006 in the obstetric outpatient clinics in Turkey were included. Besides a physical examination, subjects underwent laboratory investigations for free T(3), free T(4), and urinary iodine concentration (UIC). All subjects completed a questionnaire regarding sociodemographic parameters, use of iodized salt, and pregnancy history. Goiter status was revealed by a palpation method according to World Health Organization (WHO) guidelines. In this study, we found that the median UIC of pregnant women was 149.7 microg/l (range 20.9-275.1 microg/l). Almost half of the subjects were below the WHO, United Nations Children's Fund, and International Council for the Control of Iodine Deficiency Disorders lower median reference limits of 150 microg/l. Total goiter prevalence was 24.8%, of which 9.2% were visible goiters. Among the study patients, 2.1% had subclinical hypothyroidism, and 0.7% had overt hypothyroidism. The rate for iodized salt use among the pregnant women was 95%. Our study revealed that iodine deficiency still remains a serious problem for pregnant women. Based on our results, antenatal follow-up protocols in the primary care setting in Turkey must include iodine supplementation.

Iodine nutritional status of children on the island of Tanna, Republic of Vanuatu

To evaluate the iodine nutritional status of children living on the island of Tanna, Republic of Vanuatu. Cross-sectional study. Urine and household salt samples were collected for iodine measurement. Thyroid volumes were measured by ultrasound. A food consumption frequency survey was carried out, particularly in relation to salt, iodine-rich foods and foods that containing thiocyanate, a potentially goitrogenic substance. Urinary thiocyanate levels were also measured. Island rural communities in Tanna, Vanuatu. One hundred and fifty-three schoolchildren between 8 and 10 years of age from four locations on the island participated. The median urinary iodine excretion (UIE) among the children was 49 mg/l, indicating moderate iodine deficiency. This was corroborated by 27% of boys and 33% of girls having thyroid glands greater than the international standard for their age, and 36% of boys and 45% of girls having thyroid glands greater than the international standard for their body surface area based on ultrasonography. There was a highly statistically significant inverse correlation between thyroid volume and UIE for boys and girls (r = -0.444, P = 0.001 and r = -0.319, P = 0.005, respectively). There was no correlation between thiocyanate and UIE or thyroid volume. Only 34% of children reported to consume fish (tinned or fresh) on a weekly basis. Against the common perception, the study has demonstrated that the children on the island of Tanna were in a state of moderate iodine deficiency. More data need to be collected from other Pacific Island countries in order to provide evidence for formulating public policy in prevention and control of iodine deficiency disorders in these nations.

Efficiency of iodine prophylaxis in Russia: ways of optimization

The paper deals with one of the most topical problems of modern thyroidology - prophylaxis of iodine deficiency and iodine-deficiency states resulting in mental disorders in children living in the natural mild iodine deficiency regions. It also discusses the causes and degree of mental disorders in the children and gives recommendations on the optimization of the currently existing iodine prophylaxis system in Russia.

The goitre rate, its association with reproductive failure, and the knowledge of iodine deficiency disorders (IDD) among women in Ethiopia: Cross-section community based study

BackgroundIodine deficiency is severe public health problem in Ethiopia. Although urinary iodine excretion level (UIE) is a better indicator for IDD the goitre rate is commonly used to mark the public health significance. The range of ill effect of IDD is however beyond goitre in Ethiopia. In this study the prevalence of goitre and its association with reproductive failure, and the knowledge of women on Iodine Deficiency were investigated.MethodsA cross-section community based study was conducted during February to May 2005 in 10998 women in child bearing age of 15 to 49 years. To assess the state of iodine deficiency in Ethiopia, a multistage "Proportional to Population Size" (PPS) sampling methods was used, and WHO/UNICEF/ICCIDD recommended method for goitre classification.ResultsTotal goitre prevalence (weighted) was 35.8% (95% CI 34.5–37.1), 24.3% palpable and 11.5% visible goitre. This demonstrates that more than 6 million women were affected by goitre.Goitre prevalence in four regional states namely Southern Nation Nationalities and People (SNNP), Oromia, Bebshandul-Gumuz and Tigray was greater than 30%, an indication of severe iodine deficiency. In the rest of the regions except Gambella, the IDD situation was mild to moderate. According to WHO/UNICEF/ICCIDD this is a lucid indication that IDD is a major public health problem in Ethiopia. Women with goitre experience more pregnancy failure (X2 = 16.5, p < 0.001; OR = 1.26, 1.12 < OR < 1.41) than non goitrous women. Similarly reproductive failure in high goitre endemic areas was significantly higher (X2 = 67.52; p < 0.001) than in low. More than 90% of child bearing age women didn't know the cause of iodine deficiency and the importance of iodated salt.ConclusionEthiopia is at risk of iodine deficiency disorders. The findings presented in this report emphasis on a sustainable iodine intervention program targeted at population particularly reproductive age women. Nutrition education along with Universal Salt Iodization program and iodized oil capsule distribution in some peripheries where iodine deficiency is severe is urgently required.

Local blood flow in the dorsal hippocampus and cerebellar cortex in the offspring of iodine-deficient rats

Experimental studies demonstrated that hypothyroidism can lead to depressive behavior and that thyroid hormones can have antidepressant effects. Postnatal changes in local blood flow in the dorsal hippocampus and cerebellar cortex were studied in the offspring of rats kept in conditions of iodine deficiency at conception and throughout gestation. The data obtained from these studies showed that severe limitation of iodine intake before and during gestation leads to marked deficiency in the blood supply to both of these brain structures, though the decrease in local blood flow in the dorsal hippocampus was more marked. Addition of iodine to the diet of females prevented this deficit of blood flow in both structures.

Assessment of Iodine Deficiency Disorders in Purulia District, West Bengal, India

Iodine deficiency disorders IDD are major public health problems in India, including West Bengal. Existing programme to control IDD needs to be continuously monitored through recommended methods and indicators. The objective of this study was to assess the prevalence of goitre, status of urinary iodine excretion UIE level and to estimate iodine content of salts at the household level in Purulia district, West Bengal. A school-based, cross-sectional study was conducted during June-September 2005; among 2,400 school children, aged 8-10 years. The "30 cluster" sampling methodology and indicators for assessment of IDD, as recommended by the joint WHO/UNICEF/ICCIDD consultation, were utilized for the study. Goitre was assessed by standard palpation technique, urinary iodine excretion was analyzed by wet digestion method and salt samples were tested by spot iodine testing kit. The total goitre rate TGR was 25.9% (95% Cl=24.1-27.1%) with grade I and grade II (visible goitre) being 19.5% and 6.4% respectively. Goitre prevalence did not differ by sex but significant difference was observed in respect of age. Median urinary iodine excretion level was 9.25 microg/dl and 31.6% children had value less than 5 microg/dl. Only 33.4% of the salt samples tested had adequate iodine content of > or = 15 ppm, High goitre prevalence (25.9%) and median urinary iodine (9.25 microg/dl) below normal range indicate existence of current iodine deficiency in Purulia district. The district is still in the iodine-deficient state. Moreover, salt iodisation level far below the recommended goal highlights IDD as major public health problems in the district. Intensified information, education and communication activities along with sustained monitoring are urgently required.

Iodine Uptake and Loss - Can Frequent Strenuous Exercise Induce Iodine Deficiency?

Most of the daily dietary iodine intake (approximately 90 %) will be excreted in the urine; measurement of urinary iodine excretion is thus routinely used as an index of dietary iodine intake. However, urinary excretion is not the only means of iodine loss. Subjects such as athletes or those participating in vigorous exercise can lose a considerable amount of iodine in sweat, depending on environmental factors such as temperature and humidity. In areas of lower to moderate dietary iodine intake, loss in sweat can equal that in urine. Although electrolyte loss in sweat is well-recognized and replacement strategies are adopted, there is less recognition of potential iodine loss. Crude calculations reveal that if sweat iodide losses are not replaced, dietary stores could be depleted in an athlete undergoing a regular training regime. The significance of these losses could be increased in areas where dietary iodine intake is lower in the summer months. Although there is little doubt that excessive sweating can induce a relative iodine deficiency state, there is no case as yet for iodine supplementation in those that take vigorous exercise. However, sustained iodine loss may have implications for thyroid status and possibly consequences for athletic performance.

Histopathologic pattern of thyroid disease.

Diseases of the thyroid are manifested by alteration in hormone secretion, enlargement of the thyroid gland (goiter), or both. The principal diseases of the thyroid gland are goiter (diffuse or nodular), hypo or hyperthyroidism, thyroiditis and neoplasms. The incidence and prevalence of these thyroid diseases in a given community are variable depending on various factors. Simple (non-toxic) goiter is extremely common throughout the world and is most prevalent in mountainous areas. The reported prevalance of goiter in Ethiopia varies between 18% and 30%. To review the histopathologic patterns of thyroid disease and their relationship with age and sex over a five year period. Tikur Anbessa teaching and referral hospital, Department of Pathology, Faculty of Medicine, Addis Ababa University. Retrospective analysis of five years biopsy material from patients with thyroid disease. Seven hundred and eighty consecutive patients with thyroid disease were included in the study. Six hundred and sixty (79%) were found to be non-neoplastic and 164 (21%) were neoplastic. Nodular colloid goiter (NCG) were found in 600 (76.9%) cases. Adenoma, carcinoma and thyroiditis accounted for 100 (12.8%), 64 (8.2%) and 16 (2.1%) cases respectively. Female to male ratio was 4.5:1. Eighty five point seven per cent of the thyroid diseases were found in the age group 20-59 years. Nodular colloid goiter is the most prevalent thyroid disease. Papillary carcinoma is the most frequent cancer seen in this series. Appropriate measures should be taken to reduce the iodine deficiency states in the diet to alleviate the social and medical consequences of the NCG. Similary clinical evaluation of goiter should be thorough, and use all means especially histopathologic study of the specimens to arrive at a definitive diagnosis as thyroid carcinoma is not uncommon.

Two-week low iodine diet is necessary for adequate outpatient preparation for radioiodine rhTSH scanning in patients taking levothyroxine.

We evaluated a self-managed, outpatient, low iodine diet (LID) (<50 microg/day) designed to decrease total body iodine (TBI) in preparation for radioiodine (131I) scans. However, levothyroxine (LT4) ingestion is a significant source of dietary iodine in recombinant human TSH (rhTSH)-stimulated studies. Measuring urine iodine to creatinine ratios (I/Cr), a reflection of TBI, we evaluated the LID for 7-day and 14-day periods to determine the efficacy of our LID to deplete TBI, with and without LT4. Patients following the LID for 14 days (n = 28) without LT4 attained the goal of an iodine deficient state (I/Cr <50 microg/g) in 78% of cases, establishing the diet's efficacy in significantly reducing TBI. In patients taking LT4, 7 days of the LID was insufficient to attain this goal of true iodine deficiency. However, a 14 day LID while taking LT4 resulted in 21% of patients being iodine deficient. For diagnostic purposes, a 7 day LID period (n = 21) suboptimally but adequately (I/Cr <100 microg/g) prepared 41% of the patients, whereas 14 days on the diet (n = 24) adequately prepared 71% of the patients taking LT4. Our simple, self-managed, outpatient, LID effectively makes patients iodine deficient. Though less efficacious when taking LT4, this LID adequately reduces TBI for rhTSH-stimulated 131I uptake scans when followed for 14 days.

Goiter prevalence in Kermanshahian primary school children, 9 years after Iodine salt consumption (2001)

Background & Objectives: Iodine Deficiency Disorder (IDD) is the most common endocrine disorder in the world. It is estimated that about 1.5 billion people are in iodine deficiency state. Many studies have shown the high prevalence of endemic goiter and iodine deficiency in Iran. For control of this health problem salt iodinization is the best accepted strategy in the world. The main objective of this study is to determine the efficacy of iodide salt after 9 years of iodide salt consumption. Materials and methods: In a quasi-experimental study 637 primary school children were examined clinically for goiter based on WHO classification, and their urine was evaluated for iodine per gram creatinine. Results: 94 students (14.7%) including 50 males (15.38%) and 44 females (14.1%) had goiter, with no significant difference between two sexes. The most common grade of goiter was 1a. Compared with a previous report in 1992, there was no significant increase in goiter prevalence but increase in urine iodine was statistically significant (P<0001). Discussion : Despite increase in urine iodine concentration, the rate of goiter is not decreased. It seems that salt iodinization and iodine consumption should be increased.

Iodine deficiency conditions in the Tukayevsky District of Tatarstan

Iodine is a micronutrient: the daily requirement is 100-200 mcg. The most obvious manifestation of iodine deficiency is endemic goiter. Iodine deficiency increases the frequency of congenital hypothyroidism and leads to irreversible brain damage in the fetus and newborn. In addition to pronounced forms of mental retardation, iodine deficiency causes a decrease in the intellectual potential of the entire population living in an area of iodine deficiency.

High bromide intake affects the accumulation of iodide in the rat thyroid and skin.

The effect of a high bromide intake on the kinetics of iodide uptake and elimination in the thyroid and skin of adult male rats was studied. In rats fed a diet with sufficient iodine supply (> 25 microg I/d), the iodide accumulation in the skin predominated during the first hours after 131I iodide application. From this organ, radioiodide was gradually transferred into the thyroid. A high bromide intake (> 150 mg Br-/d) in these animals led to a marked decrease in iodide accumulation, especially by the thyroid, because of an increase in iodide elimination both from the thyroid and from the skin. In rats kept under the conditions of iodine deficiency (< 1 micro I/d), the iodide accumulation in the thyroid, but not in the skin, was markedly increased as a result of a thyrotropic stimulation. The effect of a high bromide intake (> 100 mg Br-/d) in these animals was particularly pronounced because the rates of iodide elimination were most accelerated both from their thyroid and from their skin.

Age-dependent exposure to radioactive iodine (131I) in the thyroid and total body of newborn, pubertal and adult fischer 344 rats.

Female rats of the Fischer 344 strain at ages of 1, 4 and 9 weeks were exposed to 131I intraperitoneally with activities of 0.38, 1.03 and 3.42 kBq per gram of body weight under the condition of iodine deficiency. The absorbed doses in the thyroid increased linearly depending on the injected activities. Irradiation at 1 week old caused heavier exposure than those at 4 and 9 weeks old by 7.5 and 7.7 times, respectively; however, damage of the thyroid tissue was more obvious in the 4-week-old groups than in the 1-week-old groups. The absorbed doses in the total body were proportional to the square root of the injected activities. The one-week-old groups were exposed more heavily than the 4- and 9-week-old groups by 3.6 and 4.7 times, respectively, shown by the slow excretion of 131I with the values of effective half-life of 131I activity (Teff). An IDD-treatment was not so effective to enhance the 131I absorption in the total body, as in the thyroid. No matter how the iodine concentration in the blood changed, the 1-week-old groups could not react to normalize the level. We drew standard curves, which enabled us to estimate the absorbed doses in the thyroid and the total body in the case of the injected activities of 131I for the newborn, pubertal and adult rats.

Environmental Agents, Endocrine Disrupting Chemicals and Rat Thyroid Carcinogenesis

Thyroid cell proliferation caused by environmental compounds is well known to be associated promotion of carcinogenesis. For example, kojic acid, a secondary fungal metabolite, induces cell proliferation in rat thyroid follicular epithelium, and promotes thyroid carcinogenesis after initiation with N-bis(2-hydroxypropyl)nitrosamine (DHPN). This was due to negative feedback through the pituitary-thyroid axis caused by inhibition of iodide uptake and iodine organification. Subcutaneous cholesterol pellets containing 17β-estradiol 3-benzoate also enhance rat thyroid carcinogenesis in ovariectomized female rats initiated with DHPN, although this was not the case with weak endocrine disrupting chemicals such as methoxychlor, atrazine and bisphenol A, which rather caused inhibition, possibly due to decrease in body weight gain. A high soybean diet enhances thyroid cell proliferation with increase in serum TSH level in synergism with a low iodine diet, presumably soybean diet primarily stimulate serum TSH release from the pituitary specifically under iodine deficiency conditions.

Determinants of thyroid volume in healthy French adults participating in the SU.VI.MAX cohort.

To study the relative importance of determinants of thyroid volume. Cross-sectional study on a sample of subjects issued from the SU.VI.MAX cohort. 2987 French subjects (1713 women aged 35-60 years and 1274 men aged 45-60 years). None of them had previous or present thyroid disease. Thyroid volume was determined by ultrasound. Serum TSH and free thyroxine (fT4) were measured in duplicate. Urinary iodine and urinary thiocyanate were assayed in random morning urine samples. For both sexes, thyroid volume (ml) was positively correlated with weight, height, body mass index and body surface area (P = 0.0001) and negatively with age for females (P = 0.0009). When the urinary iodine concentration was adjusted for urinary thiocyanate concentration and their interaction, the thyroid volume was negatively correlated with urinary iodine (males P = 0.02, females P = 0.006) and positively correlated with urinary thiocyanate (males P = 0.0001, females P = 0.004). Mean thyroid volume was greater among active smokers than non-smokers (males P < 0.0001, females P = 0.0004) and was greater among former smokers than among non-smokers (males P = 0.0001, females = 0.004). Free T4 and thyroid volume were positively correlated for both sexes (P = 0. 0001). TSH was negatively correlated with thyroid volume for both groups (P = 0.0001). Female users of oral contraception (aged 35-45 years) had a smaller thyroid volume than non-users (P = 0.0009). The state of borderline iodine deficiency observed in France, in association with a slightly goitrogenic environment, may result in sustained stimulation of the thyroid, independently of TSH level, and is of paramount importance in the formation of goitre. Smoking may affect the thyroid, inducing marked long-lasting thyroid enlargement.

Neonatal thyroid screening as a monitoring tool for the control of iodine deficiency.

In conditions of iodine deficiency, the frequency distribution of neonatal thyroid-stimulating hormone (TSH) is shifted towards elevated values. Elevated serum TSH in the neonate indicates insufficient supply of thyroid hormones to the developing brain, and therefore constitutes the only indicator that allows prediction of brain damage, which is the main complication of iodine deficiency. This paper reviews studies on neonatal thyroid function in iodine deficiency and confirms the former statement by WHO/UNICEF/ICCIDD that the frequency of neonatal TSH above 5 mU/L blood is below 3% in conditions of normal iodine supply, that a frequency of 3-19.9% indicates mild iodine deficiency and that frequencies of 20-39.9% and above 40% indicate moderate to severe iodine deficiency, respectively. Neonatal thyroid screening appears as a particularly sensitive index in the monitoring of iodine supply at a population level.

Analysis of current recommendations and criteria of the world health organization for the assessment of iodine deficiency conditions

The incidence of endemic goiter in the Orel district of Russia has been studied in order to assess the informative value of the new WHO classification for identification of iodine deficiencies (1994). A total of 2103 children living in three rural regions, two of which were polluted with low-dose radiation after the Chernobyl accident, have been examined in 1992-1996. The incidence of goiter and thyroid dysfunction in the newborns corresponded to grave endemia, and the median of blood thyroglobulin was moderately increased in the region with the highest pollution (5 to 15 Ci/km2 for 127Cs), characterized by a slight iodine deficiency. In a less contaminated region (1 to 5 Ci/km2) with a similar level of iodine deficiency, incidence of goiter, and median of blood thyroglobulin the incidence of thyroid dysfunction in the newborns was moderate. In a pure region, despite a more evident iodine deficit and a compatible increase of the median of blood thyroglobulin, the incidence of endemic goiter and thyroid dysfunction of the newborns was the minimal. Hence, the values of the analyzed iodine deficit indicators did not correlate with the actual iodine deficiency in all the regions examined. These differences suggest a possible contribution of strumogenic factors other than iodine deficit to the formation of goiter endemia in the examined district. The detection of these factors in the environment is needed for objective evaluation of the causes and severity of the endemic process and for the development of differentiated approaches to the prevention and treatment of thyroid abnormalities in the population exposed to radiation.

Evolution of hypothyroidism in familial goitre due to deiodinase deficiency: report of a family and review of the literature

We studied two sisters who developed large non-toxic goitres in adolescence. Deiodinase deficiency was diagnosed by a rapid thyroid uptake of radioactive iodine (RAI) at 2 hours associated with a marked fall in thyroidal 131I by 24 hours. Serial RAI scans in the second patient documented evolution of the iodine-deficient state. Conservation of intra-thyroidal iodine stores was maintained by avid iodine uptake and failure to release organified 131I. With progressive loss of inorganic iodine, hypothyroidism developed, associated with a rise in serum TSH which further exacerbated the loss of iodine. Treatment with L-thyroxine resulted in an improvement of thyroid function, but normalization was achieved only after small doses of Lugol's iodine were administered. These studies illustrate the variable nature and late onset of an inborn error of thyroid metabolism. This family supports an autosomal recessive mode of inheritance for deiodinase deficiency. We have documented progression from a euthyroid to hypothyroid state resulting from decompensation of iodine conservation mechanisms.