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Medical practice involves a high number of radiological examinations using iodinated contrast media (ICM). Therefore, it is crucial for doctors of different specialties to be aware of possible adverse effects associated with ICM use. The most common and well characterized adverse effect is contrast-induced nephropathy, whereas thyroidal adverse reactions remain a diagnostic and therapeutic dilemma. ICM-induced thyroid dysfunction represents a highly heterogenous group of thyroid disorders. Due to supraphysiological iodine concentration, ICM can induce both hyper- and hypothyroidism. In most cases, the ICM-induced thyroid dysfunction is oligo- or asymptomatic, mild, and transient. In rare cases, however, the ICM-induced thyroid dysfunction may be severe and life threatening. Recently, the European Thyroid Association (ETA) Guidelines for the Management of Iodine-Based Contrast Media-Induced Thyroid Dysfunction were published. The authors advise an individualized approach to prevention and treatment of ICM-induced thyroid dysfunction, based on patient's age, clinical symptoms, pre-existing thyroid diseases, coexisting morbidities, and iodine intake. There is a geographic variation of ICM-induced thyroid dysfunction prevalence, which is linked to iodine intake. The prevalence of ICM-induced hyperthyroidism, which may pose a serious therapeutic challenge, is greater in countries with iodine deficiency. Poland is a region with a history of iodine deficiency, contributing to an increased prevalence of nodular thyroid disease, especially in the elderly. Therefore, the Polish Society of Endocrinology has proposed national, simplified principles of ICM-induced thyroid dysfunction prevention and treatment.

Background: Increasingly, patients are asking their physicians about the benefits of dietary and alternative approaches to manage their diseases, including thyroid disease. We seek to review the evidence behind several of the vitamins, minerals, complementary medicines, and elimination diets that patients are most commonly using for the treatment of thyroid disorders., Summary: Several trace elements are essential to normal thyroid function, and their supplementation has been studied in various capacities. Iodine supplementation has been implemented on national scales through universal salt iodization with great success in preventing severe thyroid disease, but can conversely cause thyroid disorders when given in excess. Selenium and zinc supplementation has been found to be beneficial in specific populations with otherwise limited generalizability. Other minerals, such as vitamin B12, low-dose naltrexone, and ashwagandha root extract, have little to no evidence of any impact on thyroid disorders. Avoidance of gluten and dairy has positive impacts only in patients with concomitant sensitivities to those substances, likely by improving absorption of levothyroxine. Avoidance of cruciferous vegetables and soy has little proven benefit in patients with thyroid disorders., Conclusion: While many patients are seeking to avoid conventional therapy and instead turn to alternative and dietary approaches to thyroid disease management, many of the most popular approaches have no proven benefit or have not been well studied. It is our responsibility to educate our patients about the evidence for or against benefit, potential harms, or dearth of knowledge behind these strategies., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The article presents current data on the prevalence of thyroid diseases associated with iodine deficiency in Russia, focuses on the features of the comorbidity of iodine deficiency and autoimmune thyroid pathologies, methods for assessing the iodine supply of the population. Information about the study and prevention of iodine deficiency diseases (IDD) in the USSR and the Russian Federation is given. The history of legislative initiatives aimed at eliminating dietary iodine deficiency and preventing IDD is illustrated in detail. The ways of solving the problem of iodine deficiency at the present stage, both at the federal and regional levels, are proposed.

The strategy for the elimination of diseases associated with iodine deficiency throughout the Russian Federation is based on the adoption of a federal law providing for the use of iodized salt as a means of mass (population) iodine prophylaxis. Chronic iodine deficiency that exists in Russia leads to dramatic consequences: the development of mental and physical retardation in children, cretinism, thyroid diseases, and infertility. Under conditions of iodine deficiency, the risk of radiation-induced thyroid cancer in children in the event of nuclear disasters increases hundreds of times. By definition, all iodine deficiency diseases (IDDs) can be prevented, while changes caused by iodine deficiency during fetal development and in early childhood are irreversible and practically defy treatment and rehabilitation. The actual average consumption of iodine by a resident of Russia is only 40-80 mcg per day, which is 3 times less than the established norm (150-250 mcg). Every year, more than 1.5 million adults and 650 thousand children with various thyroid diseases turn to medical institutions. The cause of 65% of cases of thyroid disease in adults and 95% in children is insufficient intake of iodine from the diet. At the stage of preparing the relevant legislative act, the development and implementation of regional programs for the prevention of IDD is of utmost importance. A typical draft of such a program is proposed in this article for its adaptation and use at the regional level.

Pre-emptive evacuation orders following the accident at the Fukushima Daiichi Nuclear Power Station (FDNPS) in March 2011 and subsequent regulatory limits regarding contaminated food, milk, and water minimized the external and internal radiation exposure doses of nearby residents. However, with regard to implementation of iodine thyroid blocking (ITB), residents were confused because no information on the matter was released by the central and/or local governments. Based on lessons learned from the FDNPS accident, many countries have revised their guidelines regarding ITB during nuclear disasters. To adequately revise such guidelines and ensure effective ITB implementation during a nuclear disaster, however, residents' perceptions of ITB must be clarified. In this study, the perception of risks associated with ITB was investigated in mothers residing near the Sendai Nuclear Power Plant (SNPP) in Kagoshima Prefecture, Japan. Of the 520 mothers surveyed, 467 (89.8%) expressed anxiety regarding the administration of potassium iodine (KI) to their children. Logistic regression analysis revealed that the mothers' anxiety regarding the administration of KI to their children was positively correlated with their wish to consult an expert about KI and their hesitation to let their children eat foods produced in Fukushima, and negatively correlated with having confidence about administering KI to their children. Careful communication of potential risks to mothers residing near nuclear power plants is thus critical for implementing effective ITB in children.

Autoimmune diseases, including autoimmune thyroid diseases (AITDs), may be associated with Crohn's disease (CD). Taking into consideration the role of tumor necrosis factor alpha (TNF-alpha) in the immune-mediated inflammation that underlies both diseases, we evaluated an ultrasound of thyroid gland in pediatric CD patients, naïve, and treated with infliximab (IFX), an anti-TNF-alpha antibody, to assess the risk for AITD and evaluated the usefulness of ultrasonography to diagnose AITD in patients with CD. Sixty-one patients with CD were enrolled in the study, including 36 patients (mean age 14.5 ± 3.5 years) treated with IFX (IFX group) for a mean of 13.9 ± 16.6 months and 25 patients (mean age 14.7 ± 2.3 years) who never received anti-TNF-alpha therapy (control group). An ultrasound examination of the thyroid gland was performed; thyroid function tests and thyroid antibodies were assessed. We found 10-times higher prevalence of decreased thyroid echogenicity in CD and IFX-naive patients compared to IFX-treated group [a significant reduction in thyroid echogenicity in 1/36 (2.8%) patients receiving IFX compared to 7/25 (28%) patients naive to biologic therapy]. The latter showed significantly lower thyroid-stimulating hormone (TSH) levels ( p = 0.034) and higher levels of thyroid antibodies ( p = 0.042) in comparison to control. Our data suggest the protective role of IFX therapy in the development of thyroid disorders and indicate the usefulness of thyroid ultrasound to identify the risk of probable AITD in pediatric patients with CD., (Copyright © 2020 Furtak, Wedrychowicz, Sladek, Wedrychowicz, Fyderek and Starzyk.)

HSCT (hematopoietic stem cell transplantation) is a widely applied method of treatment of pediatric patients with leukemia and other bone marrow-associated disorders. Metabolic disturbances can appear as procedure side effects. This study aimed to report incidence of lipid and thyroid disorders and time of their onset in pediatric patients after HSCT. There were 198 pediatric patients (123 males) aged 0.5-20 years who were subjected to HSCT. Patients were mostly diagnosed with Acute Leukemia ( n = 190). The analysis of lipids, thyroid hormones, and thyroid antibodies levels comprised one month before the HSCT to last follow up visit between 2016 and 2019 (median 3.8 ± 1.8 years after HSCT). In males, the triglycerides levels increased over two times in the course of HSCT in both patients with initially low and elevated HDL (high-density lipoprotein) levels. Most of the lipid disorders occurred in six months after HSCT. Patients treated with L-thyroxine exhibited decreased LDL (low-density lipoprotein) levels. HDL remained at a lower level in males. Thyroid hormone abnormalities were evenly distributed in time until 4 years after HSCT. Patients require long term follow up including lipid metabolism and thyroid function analysis. HSCT survivors demand introduction of polyunsaturated fatty acids into the diet to reduce risk of developing the lipid complications.

Background: Perchlorate-induced natrium-iodide symporter (NIS) interference is a well-recognized thyroid disrupting mechanism. It is unclear, however, whether a chronic low-dose exposure to perchlorate delivered by food and drinks may cause thyroid dysfunction in the long term. Thus, the aim of this review was to overview and summarize literature results in order to clarify this issue., Methods: Authors searched PubMed/MEDLINE, Scopus, Web of Science, institutional websites and Google until April 2020 for relevant information about the fundamental mechanism of the thyroid NIS interference induced by orally consumed perchlorate compounds and its clinical consequences., Results: Food and drinking water should be considered relevant sources of perchlorate. Despite some controversies, cross-sectional studies demonstrated that perchlorate exposure affects thyroid hormone synthesis in infants, adolescents and adults, particularly in the case of underlying thyroid diseases and iodine insufficiency. An exaggerated exposure to perchlorate during pregnancy leads to a worse neurocognitive and behavioral development outcome in infants, regardless of maternal thyroid hormone levels., Discussion and Conclusion: The effects of a chronic low-dose perchlorate exposure on thyroid homeostasis remain still unclear, leading to concerns especially for highly sensitive patients. Specific studies are needed to clarify this issue, aiming to better define strategies of detection and prevention.

Nutraceuticals are defined as a food, or parts of a food, that provide medical or health benefits, including the prevention of different pathological conditions, and thyroid diseases, or the treatment of them. Nutraceuticals have a place in complementary medicines, being positioned in an area among food, food supplements, and pharmaceuticals. The market of certain nutraceuticals such as thyroid supplements has been growing in the last years. In addition, iodine is a fundamental micronutrient for thyroid function, but also other dietary components can have a key role in clinical thyroidology. Here, we have summarized the in vitro, and in vivo animal studies present in literature, focusing on the commonest nutraceuticals generally encountered in the clinical practice (such as carnitine, flavonoids, melatonin, omega-3, resveratrol, selenium, vitamins, zinc, and inositol), highlighting conflicting results. These experimental studies are expected to improve clinicians' knowledge about the main supplements being used, in order to clarify the potential risks or side effects and support patients in their use.

The article presents the assumptions of a new specialist thyroid package (PS1) in outpatient specialist care in the field of endocrinology, which was introduced by the National Health Fund (NFZ - Narodowy Fundusz Zdrowia) from January 2020. It became an impulse to characterize the current problems affecting specialist care in the field of endocrinology, search for their potential causes and propose strategies that are intended to contribute to increasing the efficiency of the system.

In recent years, there has been a growing interest in nutraceuticals, which may be considered as an efficient, preventive, and therapeutic tool in facing different pathological conditions, including thyroid diseases. Although iodine remains the major nutrient required for the functioning of the thyroid gland, other dietary components play important roles in clinical thyroidology-these include selenium, l-carnitine, myo-inositol, melatonin, and resveratrol-some of which have antioxidant properties. The main concern regarding the appropriate and effective use of nutraceuticals in prevention and treatment is due to the lack of clinical data supporting their efficacy. Another limitation is the discrepancy between the concentration claimed by the label and the real concentration. This paper provides a detailed critical review on the health benefits, beyond basic nutrition, of some popular nutraceutical supplements, with a special focus on their effects on thyroid pathophysiology and aims to distinguish between the truths and myths surrounding the clinical use of such nutraceuticals.

Background and Objectives: In Australia, two public health measures were introduced between 2009 and 2010 to reduce iodine deficiency. However there has been a shortage of information regarding their effectiveness and the ongoing prevalence of iodine deficiency in Australia. The primary aim of this study was to assess the extent to which these public health measures have reduced rates of iodine deficiency among pregnant and lactating women., Methods and Study Design: A review was conducted to identify all studies published since January 2010 that quantitatively measured the iodine status of pregnant and/or lactating women in Australia., Results: We found 25 publications, of which seven were included in this review after our exclusion criteria were applied. Of the seven included publications, three demonstrated the pregnant and lactating women in their studies to be iodine replete (median urinary iodine concentrations (MUIC) greater than 150 μg/L, or a breast milk iodine concentration (BMIC) of greater than 100 μg/L). The remaining four publications found MUIC of pregnant and lactating women to be below the 150 μg/L threshold, in the mild-to-moderate iodine deficiency category. Only two studies, documented iodine sufficiency among pregnant and lactating women in the absence of iodine supplementation., Conclusions: Many pregnant and lactating women in Australia remain at least mildly iodine deficient. Antenatal iodine supplementation was the factor most consistently associated with an adequate iodine status. Larger, more representative studies or sentinel studies with a National coordination are needed to understand the differences in iodine status that exist across the country.

The knowledge about dietary habits and their influence in the development of autoimmune thyroid disease is insufficient. The aim of this study was to analyse the association of dietary factors and plasma thyroid peroxidase antibodies (TPO-Ab) and/or thyroglobulin antibodies (Tg-Ab). The study enrolled 1887 participants originating from the South Croatia. Participants with elevated plasma TPO-Ab and/or Tg-Ab were defined as cases ( n = 462) and those with TPO-Ab and/or Tg-Ab within referent values were defined as controls ( n = 1425). Dietary intake was evaluated according to a food frequency questionnaire containing 58 food items. Principal component analysis was used to group food items into dietary groups. We used logistic regression analysis to examine dietary groups associated with positive plasma TPO-Ab and/or Tg-Ab. The results indicate that the dietary group with frequent consumption of animal fats and butter is associated with positive plasma TPO-Ab and/or Tg-Ab ( p = 0.01). The dietary group with frequent consumption of vegetables as well as the dietary group with high consumption of dried fruit, nuts, and muesli are associated with negative findings of TPO-Ab and/or Tg-Ab ( p = 0.048 and p = 0.02, respectively). We showed that the anti-inflammatory dietary groups are associated with the negative findings of plasma TPO-Ab and/or Tg-Ab., Competing Interests: The authors declare no conflict of interest.

Background: Low-iodine intake has historically been an issue in China, causing widespread iodine deficiency diseases (IDD). China started to introduce universal salt iodization in 1995, but reports of increased thyroid disease are a concern and appropriate levels of iodine intake must be considered., Objective: To assess the prevalence of thyroid disease with different urinary iodine concentrations (UICs) in the general population of those residing in mainland China. Furthermore, we aimed to analyze the relationship between thyroid disease and UIC, to provide guidance in establishing effective health policies regarding iodine intake., Methods: PubMed, Cochrane, Embase, CNKI, Wan fang, and CQVIP databases were searched for random community-based relevant studies with UIC published before January 2016 in mainland China. Two independent reviewers extracted data from eligible citations, and obtained prevalence of thyroid disease for different UICs, as well as the intergroup interaction P values., Results: Forty-three articles were included. The prevalence of thyroid nodules was 22.3% (95% confidence interval [CI]: 20.6%-24.1%) for the low-iodine group, 25.4% (95% CI: 20.8%-28.8%) for the medium-iodine group, and 6.8% (95% CI: 2.8%-11.5%) for the high-iodine group. In the high-iodine group, the prevalence of thyroid nodules was lower than the other groups. The prevalence of 8.3% (95% CI: 3.8%-17.3%) for subclinical hypothyroidism in the high-iodine group was significantly higher than the low- and medium-iodine groups (P < .01). The prevalence of hypothyroidism in the medium-iodine group was 0.2% (95% CI: 0.1%-0.4%), and was lower than the prevalence of the other 2 groups (P < .01). There was no difference in prevalence of hyperthyroidism in each group., Conclusions: Thyroid nodules are the most easily detectable thyroid disease. These have a lower prevalence in the high-iodine group. The prevalence of most thyroid diseases is lowest for a UIC ranging from 100 to 299 μg/L. This serves as a reference for health policy-making with respect to iodine levels. Further studies on this topic should be carried out according to sufficient thyroid cancer data.

Introduction: Italy is still characterized by a mild iodine deficiency and is among the most intensive users of chemical products for agriculture in Europe. The aim of this study was i) to evaluate thyroid effects of exposure to mancozeb, a fungicide widely used in agriculture, in a sample of Italian grapevine workers, and ii) to verify whether the iodine intake may modulate the risk of thyroid disruption due to the mancozeb metabolite ethylenthiourea (ETU)., Methods: One hundred seventy-seven occupationally exposed male workers (29 from Chianti, a mild iodine deficient area, and 148 from Bolzano an iodine sufficient province) and 74 non-occupationally exposed male controls (34 from Chianti and 40 from Bolzano) were enrolled in the study. Serum biomarkers of thyroid function, as well as urinary iodine and ETU concentrations were assessed. Moreover all the recruited subjects underwent clinical examination and thyroid ultrasound., Results: Multivariate comparisons showed lower mean serum levels of FT4 in Chianti-workers as compared to Bolzano-workers. Moreover, an increased urinary iodine excretion (>250µg/L) was more frequently found among more exposed workers (ETU>20µg/L) than among less exposed ones and this effect was more pronounced in Chianti- than in Bolzano-workers. Chianti-workers also showed a significantly higher frequency of very low thyroid volume (≤6.0ml) as compared to controls., Conclusions: These findings showed a mild thyroid disrupting effect due to occupational exposure to mancozeb, more pronounced in workers residing in an area characterized by a mild to moderate iodine deficiency as compared to workers residing in an area covered by a long-lasting iodine prophylaxis program., (Copyright © 2017 Elsevier Inc. All rights reserved.)

I prophylaxis is the most effective strategy to eradicate I deficiency disorders, but it has been shown to affect the thyroid disease pattern. In this study, we assessed the frequency of thyroid disorders in an adult population living in two areas of southern Italy after implementing I prophylaxis. To this aim, a cross-sectional, population-based study including 489 subjects from an I-deficient rural and an I-sufficient urban area of southern Italy was conducted. Thyroid ultrasound was performed on all participants, and urine and blood samples were collected from each subject. The levels of thyroid-stimulating hormone (TSH), thyroglobulin (TgAb) and thyroperoxidase antibodies (TPOAb), urinary I excretion (UIE), and thyroid volume and echogenicity were evaluated. We found that the median UIE was higher in the urban than in the rural area (P=0·004), whereas the prevalence of subjects affected by goitre was higher in the rural compared with the urban area (P=0·003). Positive TgAb rather than TPOAb were more frequent in subjects from the urban area compared with the rural area (P=0·009). The hypoechoic pattern at thyroid ultrasound (HT-US) was similar between the two areas, but TgAb were significantly higher (P=0·01) in HT-US subjects from the urban area. The frequency of elevated TSH did not differ between the two screened populations, and no changes were found for TgAb positivity in subjects with high TSH in the urban compared with the rural area. Our findings support that the small risks of I supplementation are far outweighed by the substantial benefits of correcting I deficiency, although continued monitoring of populations is necessary.

Objective: Thyroid-stimulating hormone (TSH) level in neonates is recommended as an indicator for presence of iodine deficiency (ID) at a population level and as a monitoring tool in programs of iodine supplementation. The purpose of this study, based on data from the National Newborn Screening Program (NNSP) for congenital hypothyroidism (CH) in 2014, was to analyze neonatal TSH levels to predict the current status of iodine nutrition in Turkey., Methods: According to screening methodology, heel-prick blood samples of newborns were collected on filter paper cards usually on day 3-5 after birth (or shortly before discharge). Results of samples collected >48 h after birth were analyzed. The degree of severity of ID was assessed by using the epidemiologic criteria of the World Health Organization (WHO). Elevated TSH levels (>5 mIU/L) were processed and classified according to province, region, birth season, and sampling time., Results: A total of 1,298531 newborns were registered in the NNSP for the CH database. Of those, 1,270311 newborns had screening results collected >48 h after birth and were included in the statistical analyses. The national prevalence of elevated TSH was 7.2%. While the Gaziantep sub-region had the highest TSH elevation rate (15.9%), the Tekirdağ sub-region had the lowest rate (4.0%; p<0.001). Seasonal variations were also significant, and the elevated TSH prevalence rate was highest in winter (7.4%; p<0.001)., Conclusion: National CH screening results suggest that Turkey may still be mildly iodine deficient. Nationwide studies should be performed for direct assessment and monitoring of iodine status in vulnerable populations to confirm accuracy of our results.

The epidemiology of thyroid disorders is significantly associated with iodine supply. In 1999, Slovenia increased iodine content in kitchen salt from 10 mg to 25 mg of potassium iodide per kg of salt. According to the WHO criteria, Slovenia shifted from a mildly iodine-deficient country to a country with adequate iodine intake. Ten years after the increase in iodine intake, the incidence of diffuse goitre and thyroid autonomy decreased. Now patients with diffuse goitre and thyroid autonomy reach older age than the patients before the increase in iodine intake. In addition, patients with thyroid autonomy are less frequently hyperthyroid than ten years ago and iodine-induced hyperthyroidism is less severe. The incidence of highly malignant thyroid carcinoma has also dropped. However, the incidence of Hashimoto's thyroiditis increased, most probably in genetically predisposed individuals. Over the last ten years, many animal and in vitro studies evaluated the effects of endocrine disrupting chemicals (EDC) on various aspects of the thyroid function. They mostly studied the effects of polychlorinated biphenyls (PCBs) and dioxins, brominated flame retardants, phthalates, bisphenol A, perfluorinated chemicals, and perchlorate. However, human studies on the effects of EDCs on the thyroid function are very scarce, especially the long-term ones. What they do suggest is that PCBs and dioxins interfere with the transport of thyroid hormones and adversely affect the thyroid function. Many authors agree that iodine deficiency predisposes the thyroid gland to harmful effects of EDCs. Therefore the effects of EDCs in iodine-deficient areas could be more severe than in areas with adequate iodine intake.

Thyroglobulin (Tg) is the major glycoprotein produced by the thyroid gland, where it serves as a template for thyroid hormone synthesis and as an intraglandular store of iodine. Measurement of Tg levels in serum is of great practical importance in the follow-up of differentiated thyroid carcinoma (DTC), a setting in which elevated levels after total thyroidectomy are indicative of residual or recurrent disease. The most recent methods for serum Tg measurement are monoclonal antibody-based and are highly sensitive. However, major challenges remain regarding the interpretation of the results obtained with these immunometric methods, particularly in patients with endogenous antithyroglobulin antibodies or in the presence of heterophile antibodies, which may produce falsely low or high Tg values, respectively. The increased prevalence of antithyroglobulin antibodies in patients with DTC, as compared with the general population, raises the very pertinent possibility that tumor Tg may be more immunogenic. This inference makes sense, as the tumor microenvironment (tumor cells plus normal host cells) is characterized by several changes that could induce posttranslational modification of many proteins, including Tg. Attempts to understand the structure of Tg have been made for several decades, but findings have generally been incomplete due to technical hindrances to analysis of such a large protein (660 kDa). This review article will explore the complex structure of Tg and the potential role of its marked heterogeneity in our understanding of normal thyroid biology and neoplastic processes.

Background: Although in the last decade several studies have addressed the protective role of black and green tea on several diseases, including cancer, there are only few and controversial studies on the effect of tea on benign and malignant thyroid diseases., Methods: An age and gender group matched case-control study conducted in Athens, Greece, was designed. 113 Greek patients with histologically confirmed thyroid cancer and 286 patients with benign thyroid diseases along with 138 healthy controls were interviewed with a pre-structured questionnaire in person by trained interviewers., Results: An inverse association between chamomile tea consumption and benign/malignant thyroid diseases was found (P < 0.001). The odds of chamomile tea consumption, two to six times a week, after controlling for age, gender and BMI, were 0.30 (95% CI: 0.10-0.89) and 0.26 (95% CI: 0.12-0.5) for developing thyroid cancer and benign thyroid diseases, respectively when compared with not consumption. The duration of consumption was also inversely associated with the diseases. Thirty years of consumption significantly reduced the risk of thyroid cancer and benign thyroid diseases development by almost 80%. Similar, although weaker protective association, was found for sage and mountain tea. Adjustment for smoking, alcohol and coffee consumption did not alter the results., Conclusions: Our findings suggest for the first time that drinking herbal teas, especially chamomile, protects from thyroid cancer as well as other benign thyroid diseases., (© The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.)

Background: One of the most efficient radiation protection methods to reduce the risk of adverse health outcomes in case of accidental radioactive iodine release is the administration of potassium iodine (KI). Although KI administration is recommended by WHO's guidelines for iodine prophylaxis following nuclear accidents and is also widely implemented in most national guidelines, the scientific evidence for the guidelines lacks as the guidelines are mostly based on expert opinions and recommendations. Therefore, this study will provide evidence by systematically reviewing the effects of KI administration in case of accidental radioactive iodine release on thyroid cancer, hypothyroidism, and benign nodules., Methods: We will apply standard systematic review methodology for the identification of eligible studies, data extraction, assessment of risk of biases, heterogeneity, and data synthesis. The electronic database search will be conducted in MEDLINE (via PubMed) and EMBASE, and covers three search blocks with terms related to the health condition, intervention, and occurrence/location. We have no date or language restrictions, but restrictions to humans only. We will include studies comparing the effects of KI administration on thyroid cancer, hypothyroidism, and benign thyroid nodules in a population exposed to radioactive iodine release. The quality of the studies will be graded. If feasible, a meta-analysis will be conducted., Discussion: This proposed systematic review will update the existing WHO guideline from 1999. New evidence on the efficacy of KI administration to reduce thyroid cancer, hypothyroidism, and benign thyroid nodules in the event of an accidental release of radioactive iodine to the environment will provide the basis for an update of the WHO guideline for iodine prophylaxis following nuclear accidents., Systematic Review Registration: PROSPERO CRD42015024340.

Background: Iodine deficiencies were prevalent in China until the introduction of universal salt iodization (USI) in 1995. In 2012, the standard salt iodine concentration was adjusted to 20-30 mg/kg. The success of USI for the control of iodine deficiency disorders requires monitoring its effect at a population level., Methods: Two cross sectional surveys of a representative sample of children aged 8-10 years in Zhejiang Province were carried out in 2011 and 2013. Data on participants' socio-demographic characteristics were collected from the children using a structured questionnaire. Spot urine samples were collected and delivered to local Center for Disease Control and Prevention laboratory for measuring urinary iodine concentration. In 2011, out of 420 selected children aged 8-10 years, 391 were recorded and provided urine samples. In 2013, out of 1560 selected children aged 8-10 years, 1556 were recorded and provided urine samples., Results: The median urinary iodine concentration of subjects in the 2013 survey was 174.3 μg/L, significantly lower than that of 2011(p = 0.000). The median urinary iodine concentration of subjects living in urban and rural areas in the 2013 survey was 169.0 μg/L, and 186.1 μg/L respectively, significantly lower than that of 2011 only for subjects living in urban areas (p = 0.000). There were no significant differences for subjects living in rural areas in the survey in 2011 and in 2013 (p = 0.086)., Conclusions: At the time the new local iodization policy put forward, iodine nutrition was generally adequate in both urban and rural areas, suggesting that the new policy for adjusting the standard salt iodine concentration is effective. Our data also indicate that the reason people living in urban areas had a lower urinary iodine concentration than people in rural areas may be due to their preference for using non-iodized salt in the last 2 or 3 years. Maintaining USI at an appropriate level is an important part of preventing iodine deficiency disorders and should always be based on regular monitoring and comparison of urinary iodine concentration by province.

Background: Iodine deficiency is the result of insufficient intake of dietary iodine and as a consequence causes multiple adverse effects. About 2 billion individuals in the world are affected by iodine deficiency. It has been found that the most effective way to control iodine deficiency is through the universal salt iodization. However, salt iodization alone may not be sufficient to assure adequate iodine nutrition. In most industrialized countries, excess consumption of salt has become recognized as a health risk. Therefore, biofortification of vegetables with iodine offers an excellent opportunity to increase iodine intake., Aim and Methods: The aim of this study was to test the efficiency of a new model of iodine prophylaxis in a group of 50 healthy volunteers through the intake of vegetables (potatoes, cherry tomatoes, carrots, and green salad) fortified with iodine. Each serving of vegetables consisted of 100 g of potatoes, carrots, tomatoes, or salad containing 45 mg of iodine (30% of the Recommended Daily Allowance), and the volunteers consumed a single serving of vegetables, as preferred, each day for 2 weeks. Urinary iodine (UI) excretion was measured before and after intake of vegetables., Results: The UI concentration measured in volunteers before the intake of vegetables was 98.3 mg/L (basal value), increasing to 117.5 mg/L during the intake of vegetables. Seven days after the discontinuation of vegetable intake, UI was 85 mg/L. UI concentration increment was 19.6% compared with the basal value; therefore, the difference was statistically significant (P = .035)., Conclusions: Biofortification of vegetables with iodine provides a mild but significative increase in UI concentration and, together with the habitual use of iodized salt, may contribute to improve the iodine nutritional status of the population without risks of iodine excess.

Context: Iodine deficiency disorders are a major public health problem, and programs have been implemented to improve iodine nutrition., Objective: The objective of the study was to verify the effects of voluntary iodine prophylaxis in a small rural community (Pescopagano, Italy)., Design: The design of the study was the evaluation of the prevalence of thyroid disorders 15 years after a previous survey conducted before iodine prophylaxis., Setting: The setting for this study was a general community survey., Participants: One thousand one hundred forty-eight residents were examined in 2010 and 1411 in 1995., Results: In 2010, 757 of 1148 subjects (65.9%) routinely used iodized salt, urinary iodine excretion being significantly higher than in 1955 (median 98.0 μg/L, vs 55.0 μg/L, P < .0001). The prevalence of goiter was lower in 2010 than in 1995 (25.8% vs 46.1%, P < .0001), mainly due to the reduction of diffuse goiter (10.3% vs 34.0%, P < .0001). In 2010 vs 1995, thyroid autonomy in subjects younger than 45 years old (3 of 579, 0.5% vs 25 of 1010, 2.5% P = .004) and nonautoimmune hyperthyroidism in subjects older than 45 years old (8 of 569, 1.4% vs 18 of 401, 4.5%, P = .03) were less frequent. The prevalence of hypothyroidism was higher in 2010 vs 1995 (5.0% vs 2.8%, P = .005), mainly because of an increased frequency of subclinical hypothyroidism in subjects younger than 15 years old (7 of 83, 8.4% vs 0 of 419, 0.0%, P < .0001). Accordingly, serum thyroid autoantibodies (19.5% vs 12.6%; P < .0001) and Hashimoto's thyroiditis (14.5% vs 3.5%; P < .0001) were more frequent in 2010 than in 1995., Conclusions: In the present work, the role of voluntary iodine prophylaxis was assessed in a small rural community relatively segregated, in which genetic and other environmental factors have not substantially changed between the 2 surveys. Iodine intake strongly affected the pattern of thyroid diseases, but the benefits of correcting iodine deficiency (decreased prevalence of goiter and thyroid autonomy in younger subjects and reduced frequency of nonautoimmune hyperthyroidism in older subjects) far outweighs the risk of development of thyroid autoimmunity and mild hypothyroidism in youngsters.

Background: 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., Methods: 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., Results: 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., Conclusions: 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.

Radioactive iodide ((131)I-) protection studies have focused primarily on the thyroid gland and disturbances in the hypothalamic-pituitary-thyroid axis. The objective of the current study was to establish (131)I- urinary excretion profiles for saline, and the thyroid protectants, potassium iodide (KI) and ammonium perchlorate over a 75 hour time-course. Rats were administered (131)I- and 3 hours later dosed with either saline, 30 mg/kg of NH(4)ClO(4) or 30 mg/kg of KI. Urinalysis of the first 36 hours of the time-course revealed that NH(4)ClO(4) treated animals excreted significantly more (131)I- compared with KI and saline treatments. A second study followed the same protocol, but thyroxine (T(4)) was administered daily over a 3 day period. During the first 6-12 hour after (131)I- dosing, rats administered NH(4)ClO(4) excreted significantly more (131)I- than the other treatment groups. T(4) treatment resulted in increased retention of radioiodide in the thyroid gland 75 hour after (131)I- administration. We speculate that the T(4) treatment related reduction in serum TSH caused a decrease synthesis and secretion of thyroid hormones resulting in greater residual radioiodide in the thyroid gland. Our findings suggest that ammonium perchlorate treatment accelerates the elimination rate of radioiodide within the first 24 to 36 hours and thus may be more effective at reducing harmful exposure to (131)I- compared to KI treatment for repeated dosing situations. Repeated dosing studies are needed to compare the effectiveness of these treatments to reduce the radioactive iodide burden of the thyroid gland.

The World Health Organization considers iodine deficiency as a major worldwide cause of mental and development diseases, estimating that about 13% of the world population is affected by diseases caused by iodine deficiency. Iodine is a trace element necessary for the synthesis of thyroid hormones which, since it cannot be formed by the organism, must be taken regularly with food. Fish and shellfish are generally a good source, because the ocean contains a considerable amount of iodine. On the contrary, plants which grow in iodine-deficient soils are poor in this element, as well as meat and other animal products fed in plants low in iodine. Salt is the best way for iodine supplementation. Cooking the food with iodized salt is a desirable practice because it guarantees the presence of this element. There are also other methods to provide iodine to the general population, such as adding iodine to drinking water or taking supplements of iodine. In pregnancy is recommended iodine supplementation, except in patients with known thyroid disorders. Iodine is an essential component of thyroid hormones (T4 and T3). Inadequate iodine intake leads to inadequate thyroid hormone production. The most important consequences of iodine deficiency, in the general population are goiter and hypothyroidism, and in the severe cases, mental retardation, cretinism and increased neo-natal and infant mortality. The International Council for the Control of Iodine Deficiency Disorders (ICCIDD) formed in 1985, with the only aim of achieving optimal iodine nutrition in the world, in cooperation with UNICEF and WHO. In Portugal, recent studies show significant deficiencies in pregnancy and The Portuguese Society of Endocrinology Diabetes and Metabolism, in partnership with General Directorate of Health, proposed an iodine supplementation during pregnancy with 150-200µg/day.

Objectives: Iodine deficiency is still a notable health-care problem in several regions of Europe and can be responsible for maternal and fetal goiter, miscarriages, stillbirths, reduced fetal growth, congenital hypothyroidisms, damaged reproduction in adult life, and inadequate development and maturation of the fetal brain, which is the major preventable cause of mental defects. The aim of this study was to assess the medical students' knowledge and practices regarding the program of iodized-salt-use and active iodine prophylaxis program launched by the Italian Ministry of Health., Materials and Methods: A self-administered, anonymous, 19 single-item questionnaire was developed. We have collected 294 filled forms: 86 from first-year, 118 from fourth-year and 90 from sixth-year medical students at the First Medical School of 'Sapienza' University of Rome, Italy, in May 2009., Results: Two hundred eighty four students (96.6%) affirm that they know of the existence iodized salt, even though only 199 (67.7%) report personal consumption. This level is quite far from the target (consumption by almost 80% of the general population) suggested by the international literature. No statistically relevant difference was observed between the answers of male and female students., Conclusions: Our study proves that clinical students have a more detailed knowledge on iodized salt if compared with pre-clinical students, but such knowledge remains overall defective and in some cases absolutely incorrect. Additional education is probably needed to prepare physicians to play a critical role in counseling about iodine prophylaxis.

Present study investigated the protective role of melatonin (MLT, 5mg/kg body wt., ip) against the long term effects of mercuric chloride (MC; 2 and 4 mg/kg body wt., po) in the thyroid gland of the rats through certain antioxidative indices like superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione (GSH), catalase (CAT) and lipid peroxidation (LPO), other biochemical parameters such as succinate dehydrogenase (SDH), adenosine triphosphatase (ATPase), acid phosphatase (ACPase) and alkaline phosphatase (ALPase) were also measured. Antioxidative enzymes and other parameters showed a significant reduction while LPO and mercury levels increased significantly in a dose dependent manner in MC treated animals as compared to control groups. Co-treatment with MLT revealed no significant effect on antioxidative and metabolic indices in the thyroid gland of rats. The results of present study thus strongly suggest that mercury affected antioxidant defense system and other metabolic enzymes of thyroid. Co-administration of melatonin exerted a protective effect against mercury induced endocrine toxicity., (Copyright 2009. Published by Elsevier Ltd.)

Background & Objective: Universal salt iodization (USI) was implemented in all counties of China in 1995. This study was undertaken to assess the status of iodine deficiency disorders control and prevention after 10 years of implementation of USI in a severe iodine deficiency region in China., Methods: Thirty primary school were selected in Gansu province utilizing cluster sampling methodology for the years 1995 and 2005. In each selected school, 40 children aged 8-10 yr were randomly selected for thyroid and IQ examination, and urinary samples were collected from 12. On the spot casual urine samples and salt samples were collected from a subset of children included in the study. In 2005, casual urine samples were also collected from 50 pregnant and lactating women in each cluster. Effect of health education was studied by a combination method of giving questionnaires to and observing students and families., Results: The total goiter rates (TGR) were found to be 13.5 and 38.7 per cent in 2005 and 1995 respectively. The medians urinary iodine excretion levels of children were 191.8 and 119.9 mICROg/l in 2005 and 1995. The median urinary iodine excretion level of women was 161.9 mICROg/l. The mean intelligence quotient (IQ) was 96.9 in 2005 significantly more than that in 1997 (P<0.05). The health education pass rate of children and women were 21.1 and 51.1 per cent respectively., Interpretation & Conclusion: After ten years of universal salt iodization (USI), iodine nutrition of people improved and the current iodine nutrition status of population was adequate. Decrease in TGR and increase in IQ showed that IDD control and prevention had made great progress through ten years USI, salt iodization played the key role in IDD control and prevention for sustained elimination of IDD, the programme of USI and other measures like health education should be persisted and enforced.

Iodine deficiency has multiple adverse effects in humans, termed iodine deficiency disorders, due to inadequate thyroid hormone production. Globally, it is estimated that 2 billion individuals have an insufficient iodine intake, and South Asia and sub-Saharan Africa are particularly affected. However, about 50% of Europe remains mildly iodine deficient, and iodine intakes in other industrialized countries, including the United States and Australia, have fallen in recent years. Iodine deficiency during pregnancy and infancy may impair growth and neurodevelopment of the offspring and increase infant mortality. Deficiency during childhood reduces somatic growth and cognitive and motor function. Assessment methods include urinary iodine concentration, goiter, newborn TSH, and blood thyroglobulin. But assessment of iodine status in pregnancy is difficult, and it remains unclear whether iodine intakes are sufficient in this group, leading to calls for iodine supplementation during pregnancy in several industrialized countries. In most countries, the best strategy to control iodine deficiency in populations is carefully monitored universal salt iodization, one of the most cost-effective ways to contribute to economic and social development. Achieving optimal iodine intakes from iodized salt (in the range of 150-250 microg/d for adults) may minimize the amount of thyroid dysfunction in populations. Ensuring adequate iodine status during parenteral nutrition has become important, particularly in preterm infants, as the use of povidone-iodine disinfectants has declined. Introduction of iodized salt to regions of chronic iodine deficiency may transiently increase the incidence of thyroid disorders, but overall, the relatively small risks of iodine excess are far outweighed by the substantial risks of iodine deficiency.

Background: Infants born at extreme prematurity are at high risk of developmental disability. A major risk factor for disability is having a low level of thyroid hormone described as hypothyroxinaemia, which is recognised to be a frequent phenomenon in these infants. Derangements of critical thyroid function during the sensitive window in prematurity when early development occurs, may have a range of long term effects for brain development. Further research in preterm infants using neuroimaging techniques will increase our understanding of the specificity of the effects of hypothyroxinaemia on the developing foetal brain. This is an explanatory double blinded randomised controlled trial which is aimed to assess the effect of thyroid hormone supplementation on brain size, key brain structures, extent of myelination, white matter integrity and vessel morphology, somatic growth and the hypothalamic-pituitary-adrenal axis., Methods: The study is a multi-centred double blinded randomised controlled trial of thyroid hormone supplementation in babies born below 28 weeks' gestation. All infants will receive either levothyroxine or placebo until 32 weeks corrected gestational age. The primary outcomes will be width of the sub-arachnoid space measured using cranial ultrasound and head circumference at 36 weeks corrected gestational age. The secondary outcomes will be thyroid hormone concentrations, the hypothalamic pituitary axis status and auxological data between birth and expected date of delivery; thyroid gland volume, brain size, volumes of key brain structures, extent of myelination and brain vessel morphology at expected date of delivery and markers of morbidity which include duration of mechanical ventilation and/or oxygen requirement and chronic lung disease. Trial registration Current Controlled Trials ISRCTN89493983.

(131)I radiation therapy of differentiated thyroid cancer may be compromised by thyroid stunning (i.e., a paradoxical inhibition of radioiodine uptake caused by radiation from a pretherapeutic diagnostic examination). The stunning mechanism is yet uncharacterized at the molecular level. We therefore investigated whether the expression of the sodium/iodide symporter (NIS) gene is changed by irradiation using (131)I. Confluent porcine thyroid cells on filter were stimulated with thyroid-stimulating hormone (TSH; 1 milliunit/mL) or insulin-like growth factor-I (IGF-I; 10 ng/mL) and simultaneously exposed to (131)I in the culture medium for 48 h, porcine NIS mRNA was quantified by real-time reverse transcription-PCR using 18S as reference, and transepithelial iodide transport was monitored using (125)I(-) as tracer. TSH increased the NIS expression >100-fold after 48 h and 5- to 20-fold after prolonged stimulation. IGF-I enhanced the NIS transcription at most 15-fold but not until 5 to 7 days. (131)I irradiation (7.5 Gy) decreased both TSH-stimulated and IGF-I-stimulated NIS transcription by 60% to 90% at all investigated time points. TSH and IGF-I stimulated NIS synergistically 15- to 60-fold after 5 days. NIS expression was reduced by (131)I also in costimulated cells, but the transcription level remained higher than in nonirradiated cells stimulated with TSH alone. Changes in NIS mRNA always correlated with altered (125)I(-) transport in cultures with corresponding treatments. It is concluded that down-regulation of NIS is the likely explanation of (131)I-induced thyroid stunning. Enhanced NIS expression by synergistically acting agents (TSH and IGF-I) partly prevents the loss of iodide transport expected from a given absorbed dose, suggesting that thyroid stunning might be pharmacologically treatable.

Objective: To establish a method of ion chromatography for urine iodide determination and evaluate its application in epidemiological studies., Methods: Urinary iodine was determined using ICS-2500 ion chromatography coupled with IonPac AS7 analytical column (4 mm x 250 mm), silver electrode and direct current amperometry for 467 elderly subjects (above 50 years) with their urinary Tsh and FT4 also determined. The history of thyroid diseases was examined among these subjects., Results: The peak area of the ion chromatography was linearly correlated with urinary iodine concentration, with the correlation coefficient of 0.9999. The detection limit of iodide was around 3.5 microg/L (S/N=3), with coefficients of variation ranging from 3.16% to 3.45% and mean recovery rate of 95%. The urinary iodine level in the 467 elderly subjects showed a positively skewed distribution with the median level of 224.7 microg/L., Conclusion: Ion chromatography for urinary iodine determination has excellent selectivity, sensitivity, reliability, accuracy and stability, and may ensure satisfactory effect for application in epidemiological studies.

Unlabelled: When thyroid tissues exhibited concentrations of therapeutic (131)I that appeared to be less than that predicted by data from the preceding diagnostic (131)I, the phenomenon was called stunning. We hypothesized that stunning arose from the early effects of the therapeutic dose of (131)I and that the initial uptake of (131)I, observed within the first day, was not impaired by the diagnostic dose., Methods: The hypothesis was tested by 2 types of studies. In each type, the fractional concentrations of (131)I in residual neck thyroid tissues of patients with papillary thyroid carcinoma were quantified. In the first study, fractional concentrations of diagnostic and therapeutic (131)I were measured at 2 d, a time when stunning has been observed, and expressed as ratios of radioactivity: therapeutic/diagnostic (Rx/Dx). Three different doses of diagnostic (131)I were prescribed to assess a dose response. In the second study, patients were prospectively recruited and tested to record disappearances of radioactivity from thyroid tissues. Diagnostic doses were 1.0 mCi (37 MBq) in all; therapeutic doses were 150 and 30 mCi (5,550 and 1,110 MBq), each to half of the patients. The disappearance curves were extrapolated to the period between 0 and 1 d, an interval when maximum uptake of ingested (131)I would be expected. The fractional concentrations of (131)I at 2 d and at 0-1 d were compared in terms of Rx/Dx ratios to assess changes at each time point., Results: In the first study, after diagnostic doses of 2, 1, and 0.5 mCi (74, 37, and 18.5 MBq), mean 2-d Rx/Dx values in 24, 29, and 17 patients were 0.35, 0.50, and 0.46 (P = 0.087). Of all patients, 74% exhibited Rx/Dx <0.6. In the second study, 6 of 10 patients exhibited disappearance curves of (131)I in which Rx/Dx was <0.6 at 2 d; 5 of the 6 had Rx/Dx values >0.97 at the 0- to 1-d point. In 1 patient the Rx/Dx was 0.54 at 2 d and 0.66 at the earlier time point. The other 4 patients had disappearance curves in which Rx/Dx values were >1.0 throughout or were above 0.6 and did not greatly change., Conclusion: Two days after the administration of (131)I, the mean fractional concentration of radioactivity in thyroid tissues after a therapeutic dose is <60% of the diagnostic dose in most patients, but no correlation of Rx/Dx with the mCi in the diagnostic dose was seen. In 5 of 6 patients in whom the Rx/Dx at 2 d was <0.6, the maximum fractional concentrations of therapeutic and diagnostic (131)I (i.e., the tissue uptakes during the first day) were similar; this pattern was most apparent after therapies with 150 mCi. These results support the hypothesis that "stunning" of thyroid tissues, often observable by 2 d, is primarily the consequence of early destructive effects from therapeutic (131)I.

Background: The Chernobyl accident in 1986 caused widespread radioactive contamination and enormous concern. Twenty years later, the World Health Organization and the International Atomic Energy Authority issued a generally reassuring statement about the consequences. Accurate assessment of the consequences is important to the current debate on nuclear power., Objectives: Our objectives in this study were to evaluate the health impact of the Chernobyl accident, assess the international response to the accident, and consider how to improve responses to future accidents., Discussion: So far, radiation to the thyroid from radioisotopes of iodine has caused several thousand cases of thyroid cancer but very few deaths ; exposed children were most susceptible. The focus on thyroid cancer has diverted attention from possible nonthyroid effects, such as mini-satellite instability, which is potentially important. The international response to the accident was inadequate and uncoordinated, and has been unjustifiably reassuring. Accurate assessment of Chernobyl's future health effects is not currently possible in the light of dose uncertainties, current debates over radiation actions, and the lessons from the late consequences of atomic bomb exposure., Conclusions: Because of the uncertainties over the dose from and the consequences of the Chernobyl accident, it is essential that investigations of its effects should be broadened and supported for the long term. Because of the problems with the international response to Chernobyl, the United Nations should initiate an independent review of the actions and assignments of the agencies concerned, with recommendations for dealing with future international-scale accidents. These should involve independent scientists and ensure cooperation rather than rivalry.

Many animals, man included, live in areas providing insufficient iodine (I) for optimal health. Degrees of I deficiency (ID) vary from mild-moderate to very severe, with quali- and quantitatively different negative consequences. To understand the mechanisms involved in adaptation to different grades of ID, we fed rats a low-iodine diet, plus additions resulting in a 250-fold range of I daily available to the thyroid, ranging from 5 mug (adequate) down to 0.02 microg I. We measured thyroid weight, total I, T(4), T(3), and type I 5' iodothyronine deiodinase (D1) activity, TSH, T(4), free T(4), and T(3) in plasma, T(4) and T(3) in 11 tissues, and two 5' deiodinase isoenzymes in four. TSH-independent thyroid autoregulation plays an important role in addition to TSH-dependent mechanisms in the adaptation to ID, avoiding a decrease of T(3) in plasma and most tissues, despite a marked decrease of plasma T(4), whereas extrathyroidal responses of D2 mitigate T(3) deficiency in tissues in which T(3) is mostly generated from T(4). We focused on mild and moderate ID, the least investigated experimentally, despite its current frequency in industrialized countries. The novel and important finding of our study is that thyroid status cannot be defined for the animal as a whole: at all grades of ID, T(3) is simultaneously elevated, normal, and low in different tissues. Present findings in mild-moderate ID draw attention to the importance, for man, of the resulting hypothyroxinemia that may affect mental functions and neurodevelopment of the inhabitants, even when they do not have the increased TSH or clinical hypothyroidism, often wrongly attributed to them.

In order to examine whether iodine supplements may have caused a global decline in sperm concentrations during the past several decades, the synchronicity of the decline in mean sperm counts and the introduction of iodine supplements was analyzed statistically. A positive correlation between the incidence of thyroid disease and sperm counts has been detected in Europe. In addition, it has been shown that sperm counts began falling around 1965 in the United States, 40 years after iodine supplements were introduced. Mean sperm counts before and after 1965 were 111 x 10(6)/ml and 70 x 10(6)/ml, respectively, in calculations weighted by the number of subjects included in each individual publication. The timing of the declines coincided with the introduction of iodine supplements in the United States, France, and the United Kingdom. The implications are that the global decline in sperm concentrations may be caused by iodine intake. Geographical variation in the types of sperm count decline also appears to be present.

Objective: This study aimed to clarify the iodine deficiency status in the Semipalatinsk region that has been contaminated by radioactive fallout from nuclear testing during the period of the former USSR., Design: Based on the Japan-Kazakstan joint project of adult cancer screening around the Semipalatinsk Nuclear Testing Site (SNTS), from May to October 2002 spot urine specimens were collected at random in each village. Separately, children aged 5-15 years from around the SNTS were chosen at random and spot urine specimens were collected from them., Setting: Area contaminated by radioactive fallout around the SNTS, Republic of Kazakstan., Subjects: A total of 2609 adults aged >40 years from 16 settlements in three regions and one city, and 298 children aged 5-15 years from two regions and one city., Results: Median urinary iodine concentrations of adults and children in all regions were in the range of 116.0-381.7 and 127.7-183.0 microg l(-1), respectively. The highest prevalence of values <50 microg l(-1) (14.1%) did not exceed 20%. Distributions within each group, adults and children, showed almost the same pattern, except for one region where more than 50% of adults had urinary iodine concentration >100 microg l(-1)., Conclusions: In agreement with our previous studies, the urinary iodine concentration data showed no clear evidence of iodine deficiency around the SNTS. Kazakstan is geographically and nutritionally at moderate risk of iodine deficiency disorders without fortification or iodine replacement by iodised salt. The socio-medical prophylaxis against iodine deficiency has been successfully maintained in East Kazakstan.

The paper summarizes the updated information published in peer review journals on the status of iodine deficiency in Western and Central Europe. Nationwide evaluations of the prevalence of goiter and of the concentrations of urinary iodine were conducted during recent years in 17 of the 31 countries of Western and Central Europe, mostly in school-aged children. Fourteen of the 31 countries had reached a normal status of iodine nutrition, three countries were close to iodine sufficiency, iodine deficiency persisted in 13 other countries and data are missing for Albania. The most important alterations of thyroid function due to iodine deficiency in Europe occur in neonates and very young infants. The major measure for the prevention of iodine deficiency is the fortification of all salt for human and animal consumption and for the food industry. The recommended daily intake of iodine for all ages in all inhabitants in Europe are as follows: 90 microg/day from 0 to 59 month, 120 microg/day between 6 and 12 years, 100 microg/day in adolescents and adults and 200 microg/day in pregnant and lactating women. The main guidelines for the correction of iodine deficiency in Europe are included.

Screening for vitamin B12 deficiency and thyroid disease is cheap and enables early diagnosis to be made and treatment to be started while it is still simple and can prevent the development of such serious conditions as dementia, depression, or irreversible tissue damage. In 1995-6, 83% (126/151) of all 75-year-olds in Härryda, a district (population 28,500) to the east of Gothenburg, agreed to undergo a health control designed to detect hypo- or hyper-thyroidism or vitamin B12 deficiency among elderly residents without symptoms (or with atypical symptoms not easily recognised). Of the 126 participants, four (3%) had low plasma cobalamin (vitamin B12) levels (a figure similar to or lower than those reported by others), and were treated with vitamin B12 after further examination; eight (6%) had serum thyroid stimulating hormone (TSH) levels below the lower normal limit, though further examination showed all eight to be euthyroid; and two (1.6%) were diagnosed as being hypothyroid (a lower prevalence than figures reported elsewhere), and were treated with laevothyroxine. The findings suggest that such screening might be useful in primary care. However, the clinical diagnosis of vitamin B12 deficiency, and of hypo- or hyperthyroidism, is often difficult, especially in the elderly; and although a low serum TSH level is also considered to be a reliable marker of hyperthyroidism, like others this study showed that it may occur even in the absence of disease. Thus, serum TSH and plasma B12 levels are useful screening variables, but need to be complemented by other tests before diagnosis is set.

The consequences of iodine deficiency occurring still in Poland include serious health disorders in the population, such as psycho- somatic retardation, hypothyroidism, endemic goitre, even cretinism. Administration of iodized edible salt with daily diet is an effective method for prevention of iodine deficiency. The condition of success is the proper level of potassium iodide in this salt and adequate distribution of iodized salt in various regions of the country. Successful iodine prophylaxis should be based on iodination of edible salt in amounts of 30 +/- 10 mg of KJ/kg. The permission given in the period from February to May 1994 by the General Sanitary Inspector for the production and marketing of edible salt iodized in proportions of 30 +/- 10 mg KJ/kg opened the possibility of starting its production in salt mines. The purpose of the presently reported work was to assess, in cooperation with the Province Sanitary Epidemiological Stations, the adequacy of iodination of the Polish edible salt produced in the years 1994-1995. The study was carried out according to the Polish Standard "Salt (Sodium Chloride) /PN-80/C-84081.35. Potassium iodide determination by photo colorimetric method." In 1995 the number of edible salt samples analyzed was 2484, and this number included 2129 samples of iodized salt. Potassium iodide content agreeing with the above permission was found in 122 samples, that is in 57.4% of iodized salt samples. In 603 samples (28.3%) of iodized salt this content was below that given in the permissions. In 1994 this study was carried out taking 2172 samples of edible salt, including 1586 samples of iodized salt. The content of potassium iodide agreeing with the permissions (30 +/- 10 mg/kg) was found in 342 samples (28, 1%), but 272 (22.4%) samples of iodized salt produced by salt mines contained lower amounts of potassium iodide than the amount indicated in the permissions, but still within the limits set down in the Polish Standard (20 +/- 5 mg/kg). The obtained results (57.4%) indicate an improvement of the process of salt iodination as compared with the results obtained in 1992 and 1993 (38.3%) and 1994 (28.1%). However, varying amounts of potassium iodide differing from the accepted values were found in salt declared as iodized.

1. An insufficient dietary supply of iodine results in the development of a variety of disorders of thyroid function and development of the fetus and young infants, grouped under the general heading of Iodine Deficiency Disorders, IDD. Endemic goiter constitutes the most spectacular disorder from the clinical and epidemiological point of view. However, the most serious consequence of iodine deficiency is the impact on neuro-intellectual development at a population level, varying from endemic mental retardation to the complete picture of endemic cretinism. 2. Considering that mental retardation due to iodine deficiency represents the longterm consequence of hypothyroidism occurring during the perinatal period, it is presently recognized that the target groups to the effects of iodine deficiency at a population level are, by order of priority, the fetus, the newborn, the pregnant woman, the child and, finally, the adult. 3. The newborn is more susceptible than the adult to the effects of iodine deficiency. Consequently, systematic screening for congenital hypothyroidism in endemic areas is a particularly sensitive index for detecting the presence and action of goitrogens in the environment and for monitoring the effects of programs of iodine prophylaxis. 4. IDD are particularly prevalent in developing countries. However, large areas or even countries in Europe are still obviously iodine deficient. For example, the iodine intake in adults in Belgium is 50 to 70 micrograms/day which is lower than the recommended dietary allowance for iodine (at least 100 micrograms/day). 5. IDD should be corrected on a world scale, including in Europe. Special attention should be devoted to the protection of mother and child. Within this framework, the iodine content of formula milk should be increased in Europe. 6. Finally, correction of iodine deficiency in Europe would decrease the avidity of the thyroid for iodide and, consequently, would constitute the most efficient preventive measure in case of nuclear fallout.