Article

Selenium status, thyroid volume, and multiple nodule formation in an area with mild iodine deficiency

March 2011
European Journal of Endocrinology 164(4):585-90

March 2011
164(4):585-90

DOI:10.1530/EJE-10-1026

Source
PubMed

Authors:

Lutz Schomburg

Charité Universitätsmedizin Berlin

Josef Köhrle

Charité Universitätsmedizin Berlin

Inge Bülow Pedersen

Aalborg University

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The objective was to study the associations between serum selenium concentration and thyroid volume, as well as the association between serum selenium concentration and risk for an enlarged thyroid gland in an area with mild iodine deficiency before and after iodine fortification was introduced. Another objective was to examine the association between serum selenium concentration and prevalence of thyroid nodules. Cross-sectional study. We studied participants of two similar cross-sectional studies carried out before (1997-1998, n=405) and after (2004-2005, n=400) introduction of iodine fortification. Serum selenium concentration and urinary iodine were measured, and the thyroid gland was examined by ultrasonography in the same subjects. Associations between serum selenium concentration and thyroid parameters were examined in multiple linear regression models or logistic regression models. Serum selenium concentration was found to be significantly, negatively associated with thyroid volume (P=0.006), and a low selenium status significantly increased the risk for thyroid enlargement (P=0.007). Furthermore, low serum selenium status had a tendency to increase the risk for development of multiple nodules (P=0.087). Low serum selenium concentration was associated with a larger thyroid volume and a higher prevalence of thyroid enlargement.

Role of Selenium Intake for Risk and Development of Hyperthyroidism

Article

Full-text available

Feb 2019

Selenium, Zinc, and Copper Status in Euthyroid Nodular Goiter: A Cross-Sectional Study

Article

Full-text available

May 2021
Int J Prev Med

Background: It is known that some elements are needed for normal thyroid gland functions. Iodine and selenium are the most well-known trace elements necessary for thyroid metabolism. Selenium is involved in the formation of thyroid hormones and the structure of the deiodinases associated with the development of the thyroid gland. While the role of zinc in thyroid metabolism is at the T3 receptor level, the role of copper is yet not clear. Objective: To compare the levels of serum trace elements such as selenium, zinc, and copper between the patients with euthyroid nodular goiter and healthy participants. Methods: This cross-sectional study included 98 patients with euthyroid multinodular goiter and 83 healthy subjects without thyroid disease. The demographics, thyroid hormone levels, and thyroid ultrasonography of the participants were recorded. Venous blood samples were centrifuged and sera samples were stored at -80°C until analysis of selenium, zinc, and copper levels. The levels of trace elements were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Results: While serum, zinc, and selenium levels were significantly higher in the control group than the nodular goiter group, the copper levels were similar in the two groups. Trace elements were not correlated with thyroid hormone levels and thyroid volumes. Patients in the nodular goiter group were analyzed according to their solitary and multiple nodule status. The solitary and multiple nodular goiter groups were similar in terms of copper, zinc, and selenium levels. Conclusions: Deficiency of selenium and zinc may be associated with nodular goiter. Replacement of these trace elements may be useful for the prevention of nodular goiter, especially in deficient regions.

The Danish Investigation on Iodine Intake and Thyroid Disease (DanThyr): history and implications

Article

Full-text available

Apr 2024

Due to mild to moderate iodine deficiency in Denmark, health authorities initiated a voluntary iodine fortification (IF) program in 1998, which became mandatory in 2000. In line with recommendations from WHO, the Danish Investigation on Iodine Intake and Thyroid Disease (DanThyr) was established to monitor the effect on thyroid health and diseases. The program involved different study designs and followed two Danish sub-populations in the years before IF and up till 20 years after. Results showed that the IF was successfully implemented and increased the level of iodine intake from mild-moderate iodine deficiency to low-adequacy. The level of thyroglobulin and thyroid volume decreased following IF and there was an indication of fewer thyroid nodules. The incidence of hyperthyroidism increased transiently following IF but subsequently decreased below the pre-fortification level. Conversely, thyroid stimulating hormone levels and the prevalence of thyroid autoimmunity increased along with an increase in the incidence of hypothyroidism. These trends were mirrored in the trends in treatments for thyroid disease. Most differences in thyroid health and disease between regions with different iodine intake levels before IF attenuated. This review illustrates the importance of a monitoring program to detect both beneficial and adverse effects and exemplifies how a monitoring program can be conducted when a nationwide health promotion program – as IF - is initiated.

The role of selenium in autoimmune thyroiditis

Article

Full-text available

Mar 2024

Selenium (Se) is an essential trace element of fundamental importance for human health. Se is incorporated into selenoproteins (SPs) which are endowed with pleiotropic effects including antioxidant and anti-inflammatory effects and active production of thyroid hormones. It has also been suggested that Se plays a crucial role in the pathogenesis of various human diseases. The therapeutic effects of supplementation with Se have already been described in various thyroid diseases. However, there are still conflicting results regarding the optimal dose of Se to administer and the duration of treatment, efficacy, and safety. The highly beneficial effects of supplementation with Se have been observed in subjects with thyroid disease in the hyperthyroid phase. In line with these observations, clinical studies have shown that in patients with Basedow's disease (BD) and autoimmune thyroiditis (AT), treatment with a combination of antithyroid drugs and Se restores the euthyroid state faster than administration of antithyroid drugs alone. However, the efficacy of this therapeutic approach remains to be better evaluated.

IMPACT OF SELENIUM IN RESTORATION OF THYROID FUNCTION AND OUTCOMES OF ANTI-TUBERCULOSIS CHEMOTHERAPY IN THYROIDAL DYSFUNCTION

Article

Full-text available

Nov 2023

The effect of selenium on thyroid status and outcomes of chemotherapy was studied at examination of 180 tuberculosis patients with the pathological structural changes of thyroid. A subclinical hypothyroidism was diagnosed at this category of patients. Subclinical hypothyroidism progressed under antituberculosis chemotherapy. Prescribing of selenium nitric restored thyroid function with the increasing of blood level of free thyroxine and decreasing of thyroid stimulating hormone and also optimized the results of chemotherapy with increasing the percentage of tuberculosis patients stopped bacilli excretion and healing of the cavities in lungs. Thus sodium selenite was recommended like accompanying medicine if antituberculosis chemotherapy.

Ultrasonographic assessment of thyroidopathies in two intercontinental racial groups of pregnant women Can environment and birth policy (parity) modulate ultrasonographic features of goiter and thyroid nodules?

Thesis

Full-text available

May 2018

ABSTRACT Background: Thyroid diseases affect more women than men around the world. These pathologies constitute the second most common endocrinopathies, after diabetes mellitus. These diseases have universal distribution characteristics, with remarkable expression variation according across continents, races, countries, and within the same country depending on the iodine content distribution. In females, the physiological phenomena of puberty, pregnancy and postpartum period increase bodily iodine demand. These acute shifts in iodine requirement partly explain the greater frequency with which thyroid diseases develop in women (especially in the context of deficiency or excessive intake of iodine). In addition to the above-mentioned physiological shifts, racial, genetic and other environmental factors are recognized in many types of thyroid diseases. The impact of pregnancy on the thyroid gland is highly remarkable; hence, it is largely blamed for the occurrence of goiter and thyroid nodules (TN) especially against an iodinedeficient background. Thyroid disorders during pregnancy constitute a huge risk for the mother and pregnancy, as well as for the somatic and psychomotor development of the embryo/fetus and/or the infant. A further challenge is faced by clinicians in the presence of somatic or, behavioral changes (easily suggestive of psychic or psycho-affective disorders), as well as biochemical and immunological deviations that occur during pregnancy; these deviations often distort the clinical picture and delay the diagnosis and timely management of thyroid disorders. In addition to biochemical tests, morphological tests are of great importance in the diagnosis and follow-up of subjects with thyroid pathologies. Thyroid ultrasound (TUS) is the main morphological examination recommended in pregnant women because of its safety. It does not use ionizing radiation (as do radio-isotopic or radiological tests); it is widespread and very accessible to people. It is non-invasive and generally does not require prior preparation before its completion, and the cost is relatively affordable. Chinese women differ from their Congolese counterparts in terms of parity. This difference in obstetric history between the two populations is due to the variations in individual national birth control policies of the two countries. While a Chinese woman is limited to two children, their counterparts in the Democratic Republic of the Congo (DRC) have no limit to the number of children; hence, desire, health and wealth are the ruling considerations. We therefore found it useful to compare TUS results in the two populations; Chinese pregnant women and Congolese (DRC). Our cohort of two intercontinental groups not only offers racial and genetic predispositions disparities, but also highlights both environmental and birth policy (parity) variations and effects. Objective: This study first aimed to compare ultrasonographic features of goiter and thyroid nodules between the two populations (Chinese and Congolese pregnant women), and second to deduce a possible association between obstetric and environmental factors acting in synergy with race or genetic predispositions on the occurrence of goiter and thyroid nodules. Design and methods: A retrospective comparative study was performed for a cohort of ninety-two (92) pregnant women composed of 51 Chinese and 41 Congolese, who consulted for thyroid disorders at the Department of Endocrinology of Shandong Provincial Qianfoshan Hospital in the People Republic of China (PRC) and the University Clinics of Kinshasa in the D.R. Congo between February 2016 and July 2017. Thyroid ultrasound was performed using a 7.5-9 MHz frequency linear-array transducer with a Doppler device. We evaluated the thyroid ultrasonographic characteristics of the thyroid gland (especially those with goiter and nodules) as well as thyroid hormone levels. Ellipse formula [(height x width x thickness) x π/6] was used to calculate the volumes of thyroid lobes and those of TN. Thyroid gland appearance and TN characteristics (number (one nodule or multiple), echogenicity, internal contents, nodular vascularity, calcification, margin characteristics, and the maximum diameter of the single or dominant thyroid nodule) were recorded. Results The mean cohort age overall was 31.9±5.0 (22-48) years (30.7±4.4 (range 22-40) and 33.6±5.3 (range 23-48) among the Chinese and Congolese women, respectively (P>0.05)). Congolese women had more parity than Chinese. The mean thyroid volume was 12.9±1.1 and 68.2±7.7 mL for the Chinese and the Congolese women, respectively (P=0.000). Thirty-five of the 41 (85.4%) Congolese pregnant women had goiter, while only eight out of 51 (15.7%) Chinese had goiter. An influence of race and geographic location in the development of goiter was noted in this study; Congolese women were found to be 5.8 times more likely to develop a goiter than were Chinese women (odds ratio (OR)=5.8, P<0.001). However, parity seemed to be the main risk factor of goiter for women overall; the prevalence of goiter was higher among women having at least three births in the past (OR=8.3, P<0.001 vs nulliparous). Most goiters (62.5%) in the Chinese group were on the basis of Hashimoto’s thyroiditis (HT), while 88.6% of them were nodular in the Congolese group. The prevalence of TN was 10 times higher among Congolese women than among Chinese (OR=10.1, P<0.001) and correlated with parity in the two study populations (three times higher among women with at least three births in the past (OR=3.3, P<0.001 vs nulliparous)). Multiple thyroid nodules (MTN) were associated with parity among Congolese women (OR=4.5, P=0.04). The mean maximal diameter (32.8±3 mm vs 7.2±1 mm, P=0.001) and mean volume (29.1±4 mL vs 0.2±0.1 mL, P=0.003) of single/dominant nodules were greater among Congolese than among Chinese women. The Chinese group exhibited more cystic nodules (47.1%), while their comparative group had more mixed cystic-solid types (37.1%). Notably, the thyroid parenchyma was especially hypoechoic and heterogeneous on grayscale ultrasound, with hypervascularization on Doppler among Chinese pregnant women; while their counterparts in the Congolese group were similarly heterogeneous, the thyroids were nodular with normal vascularization and very minimal intraparenchymal calcification. Conclusion: Ultrasonography detected a higher prevalence of goiter and thyroid nodules in the Congolese than in the Chinese pregnant women. Our results showed that parity played a substantial role in the occurrence of these diseases, possibly varying according to regions (or environments). Possible interaction between many factors (such as parity and iodine deficiency) with genetic predispositions (possibly) could have a paramount role in the nodular phenotypic expression of thyroid nodules. Our data suggest that optimal iodine consumption and a good birth control policy (especially in the D.R. Congo) could play an essential role in reducing the prevalence of thyroid disorders among women. Keywords: Thyroid ultrasound; Aspects of goiter and thyroid nodules; Nodular phenotypic expression; Chinese and Congolese pregnant women; Birth control policy and parity.

Microelementoses as predictors of immunological disorders in children with hypothyroidism living in the regions with different levels of technogenic pollution

Article

Jan 2023

Aim: to assess relationship between the humoral immunity status and the amounts of chemical elements (CE) in schoolchildren with hypothyroidism living in the regions with different levels and characteristics of technogenic environmental pollution. Patients and Methods: this study included 340 children 4–7 years old. The children underwent medical examination in the kindergartens located in a rural area of Rostov Region; industrial district of Rostov-on-Don (hereinafter referred to as Rostov); Shakhty, a city located in the coal mining area of the region; and in a dacha village in Rostov suburbs located distantly from the industrial facilities. In the rural area 105 children (group 1) were examined, in Rostov City — 125 children (group 2), in Shakhty — 90 (group 3). Group 4 (control) included 20 healthy children living in a dacha village of Rostov suburbs. The authors analyzed the Federal Service for Surveillance on Consumer Rights Protection and Human Well-being (Rospotrebnadzor) data characterizing the technogenic environmental pollution in the areas of residence of the studied children. Clinical laboratory tests were performed in all children. Results: such components of mineral fertilizers and pesticides as chlorides, nitrates, and phosphorus compounds prevailed among the technogenic contaminants in the rural regions. An intense xenogeneic burden was identified in the Rostov areas where kindergartens were located, while the highest xenogeneic burden was found in Shakhty. In groups 1, 2 and 3, free Т4 (fТ4) and free Т3 (fТ3) concentrations were lower than those in other groups. Moreover, the children of the first three groups had the highest thyrotropin (TSH) levels. In groups 1,2 and 3, serum IgM, IgG and total IgE levels were increased, and IgA level was decreased, while the most significant deviations from the normal values were found in the group 3 children who lived in the area with the highest adverse environmental impact. A positive statistically significant correlation was found between IgM and TSH levels (r=0,59, р=0,03) and between IgA и fТ4 levels (r=0.47, р=0.04). In addition, a negative statistically significant correlation was found between IgG и fТ4 levels (r=-0.49, р=0.04). In the group 1, 2 and 3 children, lead levels in the urine were higher than in the comparison group, and particularly high lead levels were detected in the group 3 children who lived in the area with the worst adverse environmental impact. In the same group, a positive statistically significant correlation was found between lead and TSH levels (r=0.62, р=0.02), between IgA and zinc (r=0.51, р=0.03), as well as between selenium and fТ4 (r=0.45, р=0.04). Also, a negative statistically significant correlation was determined between lead and fТ4 (r=-0.54, р=0.03) and between lead and IgA levels (r=-0.41, р=0.045). The ratio of selenium and lead in the group 3 children was significantly lower than in groups 1, 2 and 4. Conclusion: indicators demonstrating the intensity of humoral immunity were found in children with hypothyroidism, and the mostly pronounced pathological changes were reported in children living in the area with the highest technogenic environmental pollution. Reduced selenium and zinc levels along with increased lead concentrations in the morning sample of urine which correlated with decreased fТ4 and fТ3 levels in blood were found in children from the areas with adverse environmental conditions. KEYWORDS: thyroid, humoral immunity, chemical elements, microelementosis, iodine, iodine deficiency, xenogeneic burden. FOR CITATION: Popova V.A., Puzikova O.Z., Kozhin A.A. et al. Microelementoses as predictors of immunological disorders in children with hypothyroidism living in the regions with different levels of technogenic pollution. Russian Medical Inquiry. 2023;7(2):81–88 (in Russ.). DOI: 10.32364/2587-6821-2023-7-2-81-88.

Increased incidence of Hashimoto's thyroiditis in selenium deficiency: a prospective six-year cohort study

Article

Jul 2022
J CLIN ENDOCR METAB

Background: In 2015, we reported an increased prevalence of thyroid disease in a county of low habitual selenium (Se) intake in comparison to a neighbouring county with higher intake in a cross-sectional survey in Shaanxi Province, China. To explore longitudinal effects of low Se status, a prospective cohort study was conducted in the same area from 2013 to 2019, and TPO-autoantibodies (TPO-Ab) and disease incidence were compared. Methods: A total 1,254 subjects from 1,500 re-invited participants were successfully enrolled. Venous blood, fingernails, and urine samples were collected and analysed to evaluate thyroid status, TPO-Ab, serum Se, and urinary iodine. Diagnosis of Hashimoto's thyroiditis (HT) was based on elevated TSH, presence of TPO-Ab, and ultrasound characteristics. Se deficiency was categorized using a serum concentration of 80 µg/L as threshold, and tested by logistic regression for a relationship to TPO-Ab and HT. Results: Se deficiency was observed in 46.2% of participants from the adequate-Se county (Ziyang) and in 89.7% from the low-Se county (Ningshan). Se concentrations in fingernails differed strongly with residency (Ziyang vs. Ningshan; 678.7 vs. 364.3 μg/kg; Z=-9.552, P<0.001). Newly diagnosed HT in Ziyang was less frequent than in Ningshan (0.09% vs. 0.31%; χ2=4.350, P=0.037). The conversion rate to seropositive TPO-Ab was 10.2% in Ningshan vs. 5.6% in Ziyang. Excluding iodine as confounding factor, low-Se was confirmed as a risk factor for HT (relative risk(95%CI); 3.65(1.03-12.90), P<0.05). Conclusions: The data indicate an increased incidence of TPO-Ab seroconversion with low Se supply and support the hypothesis that Se deficiency contributes to HT as a modifiable risk factor.

Selenium Deficiency Due to Diet, Pregnancy, Severe Illness, or COVID-19—A Preventable Trigger for Autoimmune Disease

Article

Full-text available

Aug 2021
INT J MOL SCI

Lutz Schomburg

The trace element selenium (Se) is an essential part of the human diet; moreover, increased health risks have been observed with Se deficiency. A sufficiently high Se status is a prerequisite for adequate immune response, and preventable endemic diseases are known from areas with Se deficiency. Biomarkers of Se status decline strongly in pregnancy, severe illness, or COVID-19, reaching critically low concentrations. Notably, these conditions are associated with an increased risk for autoimmune disease (AID). Positive effects on the immune system are observed with Se supplementation in pregnancy, autoimmune thyroid disease, and recovery from severe illness. However, some studies reported null results; the database is small, and randomized trials are sparse. The current need for research on the link between AID and Se deficiency is particularly obvious for rheumatoid arthritis and type 1 diabetes mellitus. Despite these gaps in knowledge, it seems timely to realize that severe Se deficiency may trigger AID in susceptible subjects. Improved dietary choices or supplemental Se are efficient ways to avoid severe Se deficiency, thereby decreasing AID risk and improving disease course. A personalized approach is needed in clinics and during therapy, while population-wide measures should be considered for areas with habitual low Se intake. Finland has been adding Se to its food chain for more than 35 years—a wise and commendable decision, according to today’s knowledge. It is unfortunate that the health risks of Se deficiency are often neglected, while possible side effects of Se supplementation are exaggerated, leading to disregard for this safe and promising preventive and adjuvant treatment options. This is especially true in the follow-up situations of pregnancy, severe illness, or COVID-19, where massive Se deficiencies have developed and are associated with AID risk, long-lasting health impairments, and slow recovery.

Iodine Biofortification of Vegetables Could Improve Iodine Supplementation Status

Article

Full-text available

Oct 2020

Iodine is an essential trace element for both humans and animals. It is essential to produce important hormones by the thyroid gland. In most inland areas, the soils are iodine deficient and its amount is insufficient to produce agricultural crops with adequate iodine content to cover the recommended daily intake. In connection with the occurrence of iodine deficiency disorders (IDDs), it has been the subject of intensive research in the past. However, following the introduction of iodized table salt in the food industry, problems related to IDD were not solved and studies on iodine mobility and bioavailability from soils are rare even today and have remained insufficiently investigated. In many countries, mainly in Europe, the prescription rate of medicaments used to treat goiter is still high. Thus, there are a considerable amount of studies looking for alternative methods for iodine supplementation in foodstuffs among the use of iodized table salt. In most cases, the subject of these studies are agricultural crops. This mini review presents the consequences of inadequate and excess iodine intake, the current status of iodine supplementation and the most recent alternative methods of the application of iodine in agriculture and its effect on the quality of used plant species.

The effect of additive containing an organic form of iodine on the physiological-biochemical parameters of the body of cows

Article

Full-text available

Feb 2020

Iodine deficiency in soil and water in many countries leads to its low content in plants and animal feed produced from them. The limited intake of this element in animals can lead to endemic diseases. The lack of iodine in animal feeding is most often compensated for by the use of additives with an inorganic form of iodine, which can be poorly absorbed by the body. Feed products with an organic form of iodine have a great biological effect. A study on the effect of iodine-containing additives on the physiological and biochemical parameters of the animal organism was carried out on two groups of 15 cows. The experimental group was fed an organic form of iodine as part of the additive, the control group received an inorganic form of iodine. For all animals during the experiment the biochemical parameters of blood, milk productivity and reproductive ability were studied. During the experiment, an increase in metabolic and redox processes in the body was noted in the experimental group. An increase in mineral metabolism, including iodine content, was found. Due to the sufficient intake of organic iodine in the animals of the experimental group, there was an increase in the activity of the main hepatic enzymes AST and ALT. An increase in the process of gluconeogenesis due to an increase in the glucose content in the blood of experimental cows was revealed. An increase in milk production and reproductive function of animals of the experimental group was established. Within 30 days after the termination of feeding the supplement with the organic form of iodine in the experimental group, a prolonging effect was observed, consisting in higher values of blood biochemical parameters, improved reproductive function and milk productivity relative to equivalent animals in the control. As a result, it was concluded that the use of an additive with an organic form of iodine in the amount of 1.5 g in feeding cows for 60 days increases the iodine content in the blood serum of animals and increases the performance of all types of metabolism, which may indicate the best stimulating effect of the organic form of iodine on thyroid activity glands. This in turn helps to improve the productive and reproductive qualities of animals. To recommend the studied drug as a means to replenish iodine deficiency in animals and to more accurately analyze its effect on the hormone-forming function of the thyroid gland, it is necessary to study the level of thyroid hormones in the blood.

Histoloical and Biochemichal Study on the Toxic Effects of Bisphenol A on the Thyroid Gland of Adult Male Albino Rats and the Possible Protection by Selenium

Article

Sep 2019

50 years of the ETA: “the selenium connection”

Article

Jul 2019

The recent celebration of the 50 years of the ETA closely coincided with that of the 200 years since the discovery and description of selenium, an essential trace element for normal thyroid gland function and thus an adjuvant in the treatment of thyroid diseases. The aim of this commentary is to briefly outline the half centennial of the ETA while also signaling important moments in the history of selenium, developments in its availability round the world, details of its connection with thyroid function and, finally, its current and projected modes of application.

Effect of selenium on anti-Tg antibody in patients with autoimmune hypothyroidism: A randomized controlled trial

Article

Full-text available

Apr 2024

Background The current study intends to assess the impact of oral selenium intake on anti-Tg antibody in individuals with autoimmune hypothyroidism. Methods In this double-blinded randomized controlled trial, two groups of 72 autoimmune hypothyroid patients were randomly assigned; one group received levothyroxine (LT4) and oral selenium and the other group was given placebo with LT4. Anti-Tg antibody, free T4, anti-TPO antibody, and TSH were identified in both groups before the treatment and also 3 months after treatment and analysis of data was done by SPSS software. Results After the intervention, the average amount of anti-Tg antibody decreased in both of the groups, and this decrease was noticeably greater in the intervention group (P = 0.03). In the intervention group, the TSH level decreased after the intervention (p < 0.05), and the free T4 level increased after the intervention (p < 0.05); the changes in these two variables were statistically significant. Conclusion Consumption of selenium, compared to placebo, in patients with autoimmune hypothyroidism drastically reduces the level of anti-Tg antibody, and it significantly increases the free T4 level. Also, there is a greater decrease in the level of TSH compared to the control group.

Дослідження ефективності препаратів селену в профілактиці та комплексному лікуванні дифузного зоба

Article

Full-text available

Aug 2014

Досліджено ефективність комбінованої профілактики та лікування дифузного зоба препаратами селену і йоду у 54 хворих – чоловіків віком 41–50 років з діагнозом дифузного зоба І та ІІ ступеня. Діагноз дифузного зоба встановлювали на підставі пальпаторного та ультразвукового дослідження щитоподібної залози (ЩЗ), об’єм якої зіставляли з площею поверхні тіла. Всіх обстежених розподілено на три групи. Хворі І групи протягом 3 міс отримували препарати селену та йоду, ІІ – препарати йоду, ІІІ (контрольна) групі проводили лише динамічне спостереження. Для контролю вимірювали також об’ем ЩЗ у чоловіків, які постійно споживали йодовану сіль і у яких не було пальпаторних ознак зоба. У 11,8 % хворих І групи виявлено зменшення розмірів ЩЗ до нормальних об’ємів та більш виражене зменшення об’єму ЩЗ – (на 2,15 см³/м² ± 0,07 см³/м²), ніж при монотерапії препаратами йоду (на 0,92 см³/м² ± 0,17 см³/м²). Ми дійшли висновку, що препарати селену в дозі 100 мкг/доба можна рекомендувати у поєднанні з препаратами йоду для профілактики та лікування дифузного зоба у разі комбінованої недостатності споживання селену та слабкого йодного дефіциту.

Nutrient synergy: definition, evidence, and future directions

Article

Full-text available

Oct 2023

Nutrient synergy refers to the concept that the combined effects of two or more nutrients working together have a greater physiological impact on the body than when each nutrient is consumed individually. While nutrition science traditionally focuses on isolating single nutrients to study their effects, it is recognized that nutrients interact in complex ways, and their combined consumption can lead to additive effects. Additionally, the Dietary Reference Intakes (DRIs) provide guidelines to prevent nutrient deficiencies and excessive intake but are not designed to assess the potential synergistic effects of consuming nutrients together. Even the term synergy is often applied in different manners depending on the scientific discipline. Considering these issues, the aim of this narrative review is to investigate the potential health benefits of consuming different nutrients and nutrient supplements in combination, a concept we define as nutrient synergy, which has gained considerable attention for its impact on overall well-being. We will examine how nutrient synergy affects major bodily systems, influencing systemic health. Additionally, we will address the challenges associated with promoting and conducting research on this topic, while proposing potential solutions to enhance the quality and quantity of scientific literature on nutrient synergy.

Influencing Factors and New Reference Intervals of Adult Thyroid Volume in Iodine-Sufficient Areas of China

Article

Full-text available

May 2023
BIOL TRACE ELEM RES

The diagnosis of goiter is based on the thyroid volume measured by ultrasound in which iodine plays an important role. The purpose of this study was to evaluate the factors that affect thyroid volume and update the reference range of thyroid volume to provide a new basis for the diagnosis and treatment of goiter. A study population from mainland China was evaluated in the Thyroid disorders, Iodine status and Diabetes Epidemiological (TIDE) study. Thyroid size was measured by ultrasound, and thyroid volume was calculated. A quantile regression model was used to analyze the influence of related factors on the thyroid volume at each percentile. The median urinary iodine concentration (UIC) was 185.54 μg/l. The quantile regression model suggested that body surface area (BSA) and thyroid-stimulating hormone (TSH) were positive and negative factors for thyroid volume, respectively (p < 0.01). Excess iodine reduces the median and lower limits of thyroid volume. In iodine-sufficient areas, smoking is no longer a risk factor. The reference value range of thyroid volume stratified by sex was 3.92-19.06 ml for males and 3.1-16.17 ml for females. The maximum reference ranges for stratification by sex and BSA were 4.25-20.98 ml for men and 3.44-18.31 ml for women. The iodine nutrition level of the population in mainland China is sufficient. Iodine has the potential to alter the effect of certain factors on thyroid volume and effect is not regional. The new reference interval of adult thyroid volume based on sex and BSA has been updated, which can be used as a reliable reference for updating the diagnostic criteria of endemic goiter.

Goiter size changes as an indicator of response to treatment following selenium intake, and its correlation with goiter type

Article

Full-text available

Jan 2023

Introduction: Goiter is a common problem in the world; however, it is more prevalent in countries with iodine deficiency. Goiter has different etiologies while one of them is Hashimoto's thyroiditis. Selenium is a trace element that has different important effects in the body. It has also some effects in the thyroid. Objectives: This study aimed to evaluate the effect of selenium intake on goiter size and the correlation with goiter type. Patients and Methods: In prospective observational study, 20 patients with Hashimoto's goiter and 40 patients with non-Hashimoto's goiter were evaluated for thyroid sizes. The nodule sizes were else evaluated. After the first evaluation, daily selenium supplement (200 mg) was prescribed for all patients for six months. After this time, the sizes of goiter and nodules were measured again. Results: Results showed that the size of both goiter lobes in both Hashimoto's and non-Hashimoto's groups was significantly reduced before and after selenium intake (P < 0.001). The reduction rate in left lobe size in patients with Hashimoto's goiter was 50.73% and in non-Hashimoto's goiter patients was 20.89% (P < 0.001). The reduction rate in right lobe size in patients with Hashimoto's goiter was 53.37% and in non-Hashimoto's goiter was 20.46 (P < 0.001). Conclusion: We conclude that administration of selenium is effective in reducing the size of the goiter.

Micronutrient Deficiencies in Systemic Sclerosis: A Scoping Review

Article

Full-text available

Dec 2022

Purpose: The primary aim is to identify the micronutrient deficiencies commonly reported in SSc. The exploratory aim is to evaluate associations between micronutrient deficiencies and SSc clinical manifestations. Patient and methods: We conducted a scoping review of all published reports on SSc and nutrition in PubMed from its inception to August 2020. Clinical trials, observational studies, meta-analyses, and case series (with ≥20 cases) containing data on nutritional deficiency and SSc were included. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) for reporting our findings. Two reviewers (ADN and ERV) studied the titles and abstracts of all search results with pre-specified inclusion and exclusion criteria. Results: Among 790 retrieved publications, 35 full-length articles and 3 abstracts met the inclusion/exclusion criteria. Included studies took place across multiple geographic locations and included patients with both diffuse and limited cutaneous SSc. Vitamin D deficiency was the most commonly reported deficiency described in SSc, followed by vitamin B12, vitamin B9, selenium, zinc, and iron. In addition, some small studies found deficiencies in vitamins B1, B6, C, E, and A. While some studies reported associations between specific micronutrient deficiencies and SSc disease features (eg, interstitial lung disease was commonly associated with vitamin D deficiency and elevated homocysteine [Hcy]), the evidence to support these associations was not robust. Conclusion: Micronutrient deficiencies are common in SSc and are associated with specific SSc features. Routine screening for micronutrient deficiencies may lead to early detection of malnutrition. Future studies are needed to understand how interventions to replete micronutrient deficiencies affect patient outcomes in SSc.

Current Strategies for Selenium and Iodine Biofortification in Crop Plants

Article

Full-text available

Nov 2022

Selenium and iodine are essential trace elements for both humans and animals. Among other things, they have an essential role in thyroid function and the production of important hormones by the thyroid gland. Unfortunately, in many areas, soils are deficient in selenium and iodine, and their amount is insufficient to produce crops with adequate contents to cover the recommended daily intake; thus, deficiencies have an endemic character. With the introduction of iodized table salt in the food industry, the thyroid status of the population has improved, but several areas remain iodine deficient. Furthermore, due to the strong relationship between iodine and selenium in metabolic processes, selenium deficiency often compromises the desired positive impact of salt iodization efforts. Therefore, a considerable number of studies have looked for alternative methods for the simultaneous supplementation of selenium and iodine in foodstuff. In most cases, the subject of these studies is crops; recently, meat has also been a subject of interest. This paper reviews the most recent strategies in agriculture to fortify selenium and iodine in crop plants, their effect on the quality of the plant species used, and the potential impact of food processing on their stability in fortified crops.

Oxidative stress in Hashimoto’s thyroiditis: possible adjuvant therapies to attenuate deleterious effects

Article

Full-text available

Sep 2022
MOL CELL BIOCHEM

A number of studies have shown that oxidative stress is related to the pathogenesis of several immunological diseases, such as Hashimoto’s thyroiditis (HT), although there is no plausible mechanism to explain it. Thus, we aimed at hypothesizing and providing some possible mechanisms linking oxidative stress to autoimmunity aspects and its implications for HT, as well as adjuvant therapeutic proposals to mitigate the deleterious effects. Our hypothesis is that deficient eating habits, autoimmune regulator gene predisposing gene, dysbiosis and molecular mimicry, unfolded proteins and stress in the endoplasmic reticulum, and thymus involution appear to be the main potential factors leading to HT oxidative stress. Likewise, we show that the use of minerals selenium and zinc, vitamins D and C, as well as probiotics, can be interesting adjuvant therapies for the control of oxidative damage and poor prognosis of HT. Further clinical trials are needed to understand the real beneficial and side effects of these supplements. Graphical abstract

Study on the association between trace elements and thyroid nodule in Guangxi, China

Preprint

Full-text available

Jul 2022

In addition to genetic factors, environmental exposures are considered to be one of the most important factors affecting thyroid dysfunction in humans. And some trace elements and metal elements in patients often interact with related proteins and hormones, leading to thyroid dysfunction. This study investigated the relationship of selected elements on thyroid nodule in a population from Guangxi. Blood and urine collected from 96 participants (48 patients with thyroid nodules and 48 controls) were analyzed to determine the hormones in serum as well as the elements in urine using kits as well as inductively coupled mass spectrometry, respectively. The relationship between demographics, clinical characteristics and urinary levels of characteristic thyroid trace elements (T3, T4 and TSH) was investigated using Chi-square test, Pearson correlation analysis, independent sample T-test and Kruskal-Wallis test (K-W test). In the serum, T3/T4 and TSH were lower in the nodule group than in the control group, but there was a correlation between T3 and T4 and the elements in the nodule group. In urine, the concentrations of Cd and Sr were higher and the values of Se, Fe and V were lower in the urine of patients with thyroid nodules compared to controls, and there was a correlation between the various elements. This study showed a correlation between thyroid nodules and exposure to environmental elements, particularly among the various elements in the organism of patients with thyroid nodules.

Serum selenium concentration in patients with autoimmune thyroid disease

Article

Full-text available

Jun 2022
Folia Med

Introduction : Selenium (Se) is one of the environmental factors with an essential role in the pathogenesis of autoimmune thyroid disease (ATD). Scarce data is available for the selenium status of the Bulgarian population especially for patients with thyroid disorders. Aim : To compare the serum selenium (s-Se) concentrations in patients with ATD and healthy controls from Bulgarian population. Materials and methods : The s-Se concentrations were measured in 105 patients newly diagnosed or untreated for the previous 6 months with ATD (mean age 44±13 years). The patients were divided into three groups: euthyroid autoimmune thyroiditis (AIT) (n=31), hypothyroid AIT (n=33), and hyperthyroid patients with AIT or Graves’ disease (GD) (n=41). The results were compared to s-Se concentrations in 40 age- and sex-matched healthy controls. Determination of s-Se was carried out by inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted acid mineralization of the serum samples. Results : The s-Se concentrations in patients with hyperthyroidism were significantly lower than those in the control group (hyperthyroidism: 69±15.0 µg/L vs. controls: 84±13 µg/L, p <0.001). There was no significant difference in the s-Se concentrations between euthyroid and hypothyroid participants with AIT and healthy controls. The s-Se concentrations in our control individuals were within the range of 53-137 µg/L, reported in literature data on mean serum and plasma levels of European healthy adults. Conclusions : The mean s-Se concentrations observed in all groups were below or close to the cutoff value of 80 µg/L, considered optimal for the activity of the Se-dependent antioxidant systems.

2 COVID ijms-23-02360

Article

Full-text available

Feb 2022
INT J MOL SCI

The review presents the latest data on the role of selenium-containing agents in the regulation of diseases of the immune system. We mainly considered the contributions of selenium-containing compounds such as sodium selenite, methylseleninic acid, selenomethionine, and methylse-lenocysteine, as well as selenoproteins and selenium nanoparticles in the regulation of defense mechanisms against various viral infections, including coronavirus infection (COVID-19). A complete description of the available data for each of the above selenium compounds and the mechanisms underlying the regulation of immune processes with the active participation of these selenium agents, as well as their therapeutic and pharmacological potential, is presented. The main purpose of this review is to systematize the available information, supplemented by data obtained in our laboratory, on the important role of selenium compounds in all of these processes. In addition, the presented information makes it possible to understand the key differences in the mechanisms of action of these compounds, depending on their chemical and physical properties, which is important for obtaining a holistic picture and prospects for creating drugs based on them.

The Role of Selenium in Pathologies: An Updated Review

Article

Full-text available

Jan 2022

Selenium is an essential microelement required for a number of biological functions. Selenium—and more specifically the amino acid selenocysteine—is present in at least 25 human selenoproteins involved in a wide variety of essential biological functions, ranging from the regulation of reactive oxygen species (ROS) concentration to the biosynthesis of hormones. These processes also play a central role in preventing and modulating the clinical outcome of several diseases, including cancer, diabetes, Alzheimer’s disease, mental disorders, cardiovascular disorders, fertility impairments, inflammation, and infections (including SARS-CoV-2). Over the past years, a number of studies focusing on the relationship between selenium and such pathologies have been reported. Generally, an adequate selenium nutritional state—and in some cases selenium supplementation—have been related to improved prognostic outcome and reduced risk of developing several diseases. On the other hand, supra-nutritional levels might have adverse effects. The results of recent studies focusing on these topics are summarized and discussed in this review, with particular emphasis on advances achieved in the last decade.

Effects of Selenium Mineral on Health

Article

Full-text available

Jan 2022

Selenium (Se), discovered by Brezilius and Gahn in 1817, is a trace element that is known as a cofactor of many enzymes in our body and has an antioxidant function. It is found in nature and organisms in organic and/or inorganic forms. Se is an important component of selenoproteins that play a role in many biological functions such as antioxidant defense, formation of thyroid hormones, DNA synthesis, fertility, and reproduction. The most important sources of Se are brazil nuts, offal, and fish. Adults should consume 55 micrograms per day. Se toxicity can occur if Se has taken into the body more than necessary. The most common clinical symptoms of Se toxicity are hair loss and split nails. Adults should consume no more than 400 micrograms of Se per day. Se shortage is more common in areas where the soil contains little Se. As a result of deficiency, Keshan and Kashin-Beck diseases occur in people. Se is a mineral that has been linked to chronic illnesses like cancer and cardiovascular disease. There is also a relationship between seleni-um and gut microbiata. This review aims to discuss the Se mineral from a clinical and metabolic point of view.

Natural Autoimmunity to Selenoprotein P Impairs Selenium Transport in Hashimoto’s Thyroiditis

Article

Full-text available

Dec 2021
INT J MOL SCI

The essential trace element selenium (Se) is needed for the biosynthesis of selenocysteine-containing selenoproteins, including the secreted enzyme glutathione peroxidase 3 (GPX3) and the Se-transporter selenoprotein P (SELENOP). Both are found in blood and thyroid colloid, where they serve protective functions. Serum SELENOP derives mainly from hepatocytes, whereas the kidney contributes most serum GPX3. Studies using transgenic mice indicated that renal GPX3 biosynthesis depends on Se supply by hepatic SELENOP, which is produced in protein variants with varying Se contents. Low Se status is an established risk factor for autoimmune thyroid disease, and thyroid autoimmunity generates novel autoantigens. We hypothesized that natural autoantibodies to SELENOP are prevalent in thyroid patients, impair Se transport, and negatively affect GPX3 biosynthesis. Using a newly established quantitative immunoassay, SELENOP autoantibodies were particularly prevalent in Hashimoto’s thyroiditis as compared with healthy control subjects (6.6% versus 0.3%). Serum samples rich in SELENOP autoantibodies displayed relatively high total Se and SELENOP concentrations in comparison with autoantibody-negative samples ([Se]; 85.3 vs. 77.1 µg/L, p = 0.0178, and [SELENOP]; 5.1 vs. 3.5 mg/L, p = 0.001), while GPX3 activity was low and correlated inversely to SELENOP autoantibody concentrations. In renal cells in culture, antibodies to SELENOP inhibited Se uptake. Our results indicate an impairment of SELENOP-dependent Se transport by natural SELENOP autoantibodies, suggesting that the characterization of health risk from Se deficiency may need to include autoimmunity to SELENOP as additional biomarker of Se status.

Selenium: An Element of Life Essential for Thyroid Function

Article

Full-text available

Nov 2021
MOLECULES

Selenium (Se), a microelement essential for life, is critical for homeostasis of several critical functions, such as those related to immune–endocrine function and signaling transduction pathways. In particular, Se is critical for the function of the thyroid, and it is particularly abundant in this gland. Unfortunately, Se deficiency is a very common condition worldwide. Supplementation is possible, but as Se has a narrow safety level, toxic levels are close to those normally required for a correct need. Thus, whether the obtaining of optimal selenium concentration is desirable, the risk of dangerous concentrations must be equally excluded. This review addressed the contribution by environment and food intake on Se circulating levels (e.g., geographical factors, such as soil concentration and climate, and different quantities in food, such as nuts, cereals, eggs, meat and fish) and effects related to its deficiency or excess, together with the role of selenium and selenoproteins in the thyroid pathophysiology (e.g., Hashimoto’s thyroiditis and Graves’ disease).

Exploring physicians and patients’ perspectives for current interventions on thyroid nodules using a MCDA method

Article

Full-text available

May 2021

Background The detection of thyroid cancer has rapidly increased over last few decades without an increase in disease specific mortality. Several studies claim that the diagnose of thyroid nodules through routine ultrasound imaging is often the trigger for cascade effects leading to unnecessary follow-up over many years or to invasive treatment. The objective of this study was to explore physicians’ and patients’ insights and preferences regarding the current interventions on thyroid nodules. Methods An online survey was developed using a comprehensive multi-criteria decision analysis (MCDA) framework, the EVIdence based Decision-Making (EVIDEM). The EVIDEM core model used in this study encompassed 13 quantitative criteria and four qualitative criteria. Participants were asked to provide weights referring to what matters most important in general for each criterion, performance scores for appraising the interventions on thyroid nodules and their consideration of impact of contextual criteria. Normalized weights and standardized scores were combined to calculate a value contribution across all participants, additionally differences across physicians and patients’ group were explored. Results 48 patients and 31 physicians were included in the analysis. The value estimate of the interventions on thyroid nodules reached 0.549 for patients’ group and 0.5 was reported by the physicians’ group, compared to 0.543 for all participants. The highest value contributor was ‘Comparative effectiveness’ (0.073 ± 0.020). For the physicians’ group, ‘Comparative safety’ (0.050 ± 0.023) was given with higher value. And for the patients’ group, ‘Type of preventive benefits’ (0.059 ± 0.022) contributed more positively to the value estimation. 51% participants considered ‘Population priorities and access’ having a negative impact on the interventions of nodules.66% participants thought that the ‘system capacity’ had a negative impact. Conclusion Our study shows participants’ preferences on each criterion, i.e., physician indicated keeping the interventions safe and effective more important, patients indicated quality of life after receiving interventions more important. Through comparison among participants, differences have been highlighted, which can make better communication between physicians and patients. This study provides a supportive decision-making for healthcare providers when they explored the interventions on thyroid nodules.

Effect of selenium on thyroid autoimmunity and regulatory T cells in patients with thyroiditis: A randomized‐controlled trial

Article

Full-text available

Apr 2021
CTS-CLIN TRANSL SCI

Selenium is an essential trace element in human. Recent studies of selenium (Se) supplementation on the effect of Hashimoto thyroiditis (HT) have been reported, but the exact benefit is unclear as well as the underlying immunologic mechanism. We aimed to evaluate the clinical effect of selenium (Se) treatment in HT patients, and explore the potential mechanism against thyroid autoimmunity. A prospective, randomized‑controlled study was performed in HT patients assigned to two groups. Se‐treated group (n=43) received Se‐yeast for 6 months, while no treatment in control group (n=47). The primary outcome is the changement of thyroid antibody (TPOAb or TGAb). Secondly, thyroid function, urinary iodine (UI), Se, Glutathione peroxidase3 (GPx3) and Selenoprotein P1 (SePP1) levels were measured during the treatment. Meanwhile, regulatory T cells (Tregs) and their subsets activated Tregs (aTregs), resting Tregs (rTregs) and secreting Tregs (sTregs), as well as Helios and PD‐1 expression on these cells were also detected. The results showed that Se supplementation significantly decreased thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TGAb), and thyroid stimulating hormone (TSH) levels, accompanied with the increased Se, GPx3 and SePP1, compared with control group. Subgroup analysis revealed that subclinical HT may benefit more from this treatment in the decrease of TSH levels by interaction test. Moreover, the percentage of aTregs, Helios/Tregs, and Helios/aTregs were significantly higher in Se group than control. In conclusion, Se supplementation may have a beneficial effect on thyroid autoantibodies and thyroid function by increasing the antioxidant activity and upregulating the activated Treg cells.

Йодо- та селенодефіцит у патогенезі зобної трансформації щитоподібної залози та автоімунних тиреопатій (огляд літератури та результати власних досліджень)

Article

Dec 2020

У статті описано сучасний погляд на роль дефіциту йоду та селену в патогенезі захворювань щитоподібної залози (ЩЗ), зокрема її зобної трансформації та автоімунних тиреопатій. Відмічена кореляція вираженості патологічних змін зі ступенем йододефіциту. У зонах зниженого споживання йоду (<50 мкг на добу) 25-30% населення мають ту чи іншу патологію ЩЗ, серед яких найчастішою є ендемічний зоб. Другою за частотоювиникнення патологією ЩЗ є вузловий зоб, частота якого в ендемічних по зобу регіонах досягає 50-70% від усіх захворювань ЩЗ. Поєднаний дефіцит йоду і селену посилює проблему йодної недостатності, призводить до зростання частоти гіпертрофічних і гіперпластичних процесів у ЩЗ і автоімунних тиреопатій. Метою роботи було визначення вмісту йоду та селену в пацієнтів із доброякісною патологією ЩЗ. Матеріал і методи.Обстежено 81 пацієнта, віком від 19 до 69 років, яким проводили ультразвукове обстеження ЩЗ, визначали рівень екскреції йоду зі сечею церій-арсенітним методом у модифікації J.T. Dunn та ін. і рівень селену в сироватці крові спектрофлуориметричним методом. Результати. У 43,6% пацієнтів при різних видах зобної трансформації, колоїдному проліферуючому зобі, автоімунних тиреопатіях та їх поєднанні відзначено низький рівень йодної екскреції (<100 мкг/л); у 38,5% пацієнтів виявлено стабільно оптимальне йодне забезпечення (100-150 мкг/л) і в 17,9% пацієнтів — стабільно високе (>150 мкг/л). У 76,5% пацієнтів виявлено значно знижений рівень селену в крові (<80 мкг/л), у 13,6% пацієнтів — субоптимальний (81-100 мкг/л) і лише в 9,9% пацієнтів — оптимальний (101-120 мкг/л). Також відзначено, що в пацієнтів із вузловою патологією ЩЗ, автоімунними тиреопатіями та при їх поєднанні зафіксовано дефіцит селену в порівнянні з контрольною групою (ехографічно незмінена ЩЗ). Висновок. Терапія препаратами йоду та селену під контролем їх вмісту виправдана в процесі тривалого спостереження за пацієнтами із зобною трансформацією ЩЗ і автоімунними тиреопатіями.

Selenium deficit and metabolism

Article

Oct 2016

Long term effect of nutrition on thyroid disease

Article

Full-text available

Jan 2021

Many forms of thyroid diseases have been classified under autoimmune thyroid disease. These include hyperthyroidism or commonly known as Grave’s disease, and hypothyroidism commonly identified as Hashimoto’s thyroiditis. Many nutritional elements have been linked to the function of the thyroid gland as any disturbance in these elements can lead to the development of relevant thyroid diseases. The most important elements include iodine, iron, selenium, zinc, and soy. In this current manuscript, we aimed to discuss the effect of these nutritional elements on the development of thyroid diseases by reviewing relevant studies in the literature. Although it is widely known that iodine is an essential component for the synthesis and release of these hormones, exaggerated intake of iodine can also lead to the development of hypothyroidism by negative feedback mechanisms. Besides, it can also trigger abnormal autoimmune reactions which can lead to the development of AITD. Selenium is another important factor and evidence shows that it has been associated with Grave’s thyroiditis, however, further evidence is needed as recommended by previous investigations. Clinicians should also take care of iron, zinc, and soy levels during management to obtain a better prognosis.

Urine iodine level and multiple risks are associated with thyroid structural abnormalities among adults in Heilongjiang Province, China

Article

Jan 2020
ASIA PAC J CLIN NUTR

Background and objectives: The prevalence of adult thyroid structural abnormalities has increased significantly worldwide. However, no study has examined the thyroid structure and urine iodine levels of adults in Heilongjiang Province in the last decade. Therefore, this study aims to investigate the rate and risk factors of thyroid structural abnormalities among the residents of this province. Methods and study design: A probability proportional sampling method was used, and a total of 3,645 individuals in Heilongjiang Province were included. The subjects was asked to complete a thyroid ultrasound and fill out a questionnaire. Furthermore, urine iodine levels and salt iodine content were determined, and multivariate logistic regression was used to identify the independent risk factors for thyroid diseases. Results: The prevalence of thyroid structural abnormalities in Heilongjiang Province was 56.0%. Univariate analysis showed that there were significant differences between the structural abnormalities group and the normal thyroid group in terms of sex, age, body mass index, hypertension, diabetes, smoking, alcohol consumption, frequency of seafood consumption and pickled food consumption, employment status, and urine iodine level (p<0.05). Multivariate analysis showed that the following were independent risk factors of thyroid disease: female, increased age, hypertension, diabetes, cigarette smoking frequent seafood consumption, employment, and urine iodine levels. Conclusions: The prevalence of thyroid structural abnormalities in adults in Heilongjiang Province was relatively high. Therefore, to help prevent the occurrence of thyroid disease in adults in Heilongjiang Province, the risk factors of thyroid structural abnormalities should be better understood.

Selenium Deficiency-From Soil to Thyroid Cancer

Article

Full-text available

Aug 2020

Featured Application: The paper underlines the link between soil, food and human health, with a particular emphasis on thyroid cancer in case of Se deficiency, in order to provide a scientific basis to Public Health Recommendations. Abstract: Selenium (Se) is an essential micronutrient present in human diet, entering in the composition of selenoproteins as selenocysteine (Se-Cys) amino acid. At the thyroid level, these proteins play an important role as antioxidant and in hormone metabolism. Selenoproteins are essential for the balance of redox homeostasis and antioxidant defense of mammalian organisms, while the corresponding imbalance is now recognized as the cause of many diseases including cancer. The food chain is the main source of Se in human body. Dietary intake is strongly correlated with Se content in soil and varies according to several factors such as geology and atmospheric input. Both Se deficiency and toxicity have been associated with adverse health effects. This review synthesizes recent data on the transfer of Se from soil to humans, Se U-shaped deficiency and toxicity uptake effects and particularly the impact of Se deficiency on thyroid cancer.

Selenium in Hyperthyroidism

Article

Full-text available

Feb 2020

Introduction: Thyroid gland has the highest selenium content compare with other endocrine organs. Enzyme that catalyzing thyroid hormone activation, iodothyronine deiodinases, were identified as selenocysteine-containing proteins. Selenium levels in soil and rice consumed in Indonesia were lower than in several other countries, which can increase the risk of selenium deficiency.Methods: This is an article review of the current literatures published up to November 2018 about the role of selenium in hyperthyroid.Result: Several studies have shown that selenium supplementation can be beneficial in patients with Graves disease and autoimmune thyroiditis. Selenium has an important immunomodulatory effect, but the effects of selenium supplementation in hyperthyroid has not been conclude. Data regarding selenium intake, prevalence of deficiency, and the relationship between selenium and thyroid disease in Indonesia are limited. Various studies of selenium supplementation in thyroid disease provide controversial results, so there are no guidelines that include selenium as standard therapy hyperthyroid. Selenium supplementation can enhance the restoration of biochemical euthyroidism in Graves disease and was associated with a significant decrease in the levels of thyroid peroxidase antibodies in autoimmune thyroiditis.Conclusions: Micronutrients that play a role in thyroid hormone synthesis and maintain thyroid function in addition to selenium are iodine, iron, zinc, and vitamin A. By correcting the deficit of selenium, and meeting other micronutrient requirements may provide health benefits in patient with hyperthyroid.

Selenium in thyroid disorders — essential knowledge for clinicians

Article

Jan 2020

In the 1990s, selenium was identified as a component of an enzyme that activates thyroid hormone; since this discovery, the relevance of selenium to thyroid health has been widely studied. Selenium, known primarily for the antioxidant properties of selenoenzymes, is obtained mainly from meat, seafood and grains. Intake levels vary across the world owing largely to differences in soil content and factors affecting its bioavailability to plants. Adverse health effects have been observed at both extremes of intake, with a narrow optimum range. Epidemiological studies have linked an increased risk of autoimmune thyroiditis, Graves disease and goitre to low selenium status. Trials of selenium supplementation in patients with chronic autoimmune thyroiditis have generally resulted in reduced thyroid autoantibody titre without apparent improvements in the clinical course of the disease. In Graves disease, selenium supplementation might lead to faster remission of hyperthyroidism and improved quality of life and eye involvement in patients with mild thyroid eye disease. Despite recommendations only extending to patients with Graves ophthalmopathy, selenium supplementation is widely used by clinicians for other thyroid phenotypes. Ongoing and future trials might help identify individuals who can benefit from selenium supplementation, based, for instance, on individual selenium status or genetic profile.

Selenium exerts protective effects against oxidative stress and cell damage in human thyrocytes and fibroblasts

Article

Full-text available

Apr 2020
ENDOCRINE

Purpose Selenium, incorporated into specific seleno-enzymes, is essential to proper thyroid function and protect cells from oxidative damage induced by H2O2 during thyroid hormone synthesis. Several studies indicated that low selenium levels are associated with thyroid autoimmunity and related disorders, but real effectiveness of selenium supplementation in such diseases is still controversial. We evaluated the effect of selenium on oxidative damage in human thyrocytes and thyroid fibroblasts in vitro. Methods To induce oxidative stress, primary cultures were exposed to H2O2, in the presence or the absence of selenium, as either selenomethionine or selenite. We performed the following assays: cell viability, caspase-3 activity, BCL-2/BAX gene expression, DNA fragmentation, malondialdehyde levels, and glutathione peroxidase (GPx) activity measurements. Results Thyrocytes and thyroid fibroblasts exposed to H2O2 and preincubated with both selenocompounds displayed a significant dose-dependent increase in cell viability compared to cells incubated with H2O2 alone. Pretreatment with selenomethionine and selenite significantly reduced caspase-3 activity and BAX mRNA levels and increased BCL-2 mRNA levels in a dose-dependent manner. Accordingly, H2O2 induced a diffuse pattern of DNA degradation and an increase in malondialdehyde levels, which was prevented by the pretreatment with both selenomethionine and selenite. Both selenocompounds induced an increase in GPx activity, suggesting that these protective effects may be, almost in part, mediated by these selenoproteins. Conclusion In human thyrocytes and fibroblasts in vitro, selenium exerts protective effects against H2O2 in a dose-dependent manner, being selenite effective at lower doses than selenomethionine.

Cross-sectional analysis of trace element status in thyroid disease

Article

Mar 2020
J TRACE ELEM MED BIO

Background: The synthesis of thyroid hormone depends on a set of trace elements, most importantly selenium and iodine. The dietary supply with certain micronutrients is limited in many areas of the world, including central Europe and large parts of Asia and Africa. Moreover, both thyroid disease risk and therapy effects are modulated by trace element supply and status. Objective: Assessment of trace element status in thyroid patients in a European metropolis. Material and methods: Adult patients visiting a medical praxis in Berlin, Germany, were enrolled into a cross-sectional analysis, and serum samples were obtained from thyroid patients (n = 323) with different conditions including goitre, hypothyroidism, malignancy or autoimmune thyroid disease. Trace elements (iodine, selenium, copper and zinc) were assessed by ICP-MS/MS or total reflection X-ray analysis, along with two protein biomarkers of selenium status (selenoprotein P, glutathione peroxidase), and compared to the clinical phenotype. Results: The patients displayed relatively low serum zinc and selenium concentrations as compared to a set (n = 200) of healthy subjects (zinc; 1025+/-233 vs. 1068+/-230 μg/L, p < 0.01, selenium; 76.9+/18.8 vs. 85.1+/-17.4 μg/L, p < 0.0001). A high fraction of patients (37.5%) was classified as selenium-deficient (serum selenium concentrations <70 μg/L), in particular the patients with thyroid malignancy (59%). Serum copper was not different between the groups, and total serum iodine concentrations were unrelated to thyroid disease. Explorative statistical analyses yielded no significant interactions between the trace elements and disease parameters, except for free thyroxine inversely correlating to the copper/selenium ratio. Conclusions: In adult thyroid patients, there is no relation of circulating copper, iodine, selenium or zinc concentrations to thyroid hormone. However, a large fraction of German thyroid patients displays a considerable selenium deficit, known to constitute a disease risk potentially impairing convalescence and aggravating autoimmune disease processes. It appears advisable to testing thyroid patients for selenium deficiency, and once diagnosed, an increased supply via dietary counselling or active supplementation should be considered.

Nutraceutical Supplements in the Thyroid Setting: Health Benefits beyond Basic Nutrition

Article

Full-text available

Sep 2019

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.

Selenium supplementation in thyroid eye disease: an updated review from a clinical ophthalmic perspective

Article

Nov 2023
Orbit

Thyroid eye disease (TED) consists of a spectrum of autoimmune orbital pathology that threatens patients' quality of life and vision. Research suggests that oxidative stress plays a role in both the thyroid gland and orbit. Selenium has been proposed as a potential therapeutic adjunct given its role in thyroid physiology and antioxidant metabolism. Furthermore, selenium status has been linked to multiple pathological thyroid states. Despite the preponderance of evidence demonstrating a role for selenium in thyroid disease, limited research exists highlighting its role in TED specifically. This review summarizes the pathophysiology and role of selenium in thyroid eye disease (TED) and the current body of evidence including in vitro and in vivo studies highlighting the role for supplementation in clinical ophthalmic practice. Notably, relatively lower selenium levels have been shown to have a modest correlation with severity of thyroid eye disease. Selenium supplementation has shown some benefit in patients with mild Graves' Orbitopathy in European populations presumed deficient. Despite the preponderance of evidence demonstrating a role for selenium in thyroid disease, limited data is available to conclusively expand its role in TED outside of a 6-month course of supplementation in selenium deficient or relatively deficient populations. Data subject to geographic and population differences in selenium levels limits the generalizability of supplementation in TED. Despite mechanistic evidence of its antioxidant effects in TED beyond the advantages of thyroid disease in general, the benefits of selenium supplementation should be interrogated further and contextually tailored in both clinical and research formats for ophthalmic practice.

Assessment of the Protective Effects of Selenium and Zinc against Potassium Dichromate Induced Thyrotoxicity in Preimplanted Wistar albinos Rats

Article

Mar 2023

Hexavalent chromium is an environmental pollutant considered to be an endocrine-disrupting metal. Selenium and zinc are essential trace elements, known to play a crucial role in thyroid homeostasis. The purpose of the current work is to investigate the effects of potassium dichromate (K₂Cr₂O7) administrated subcutaneously (s.c) on the 3rd day of pregnancy in preimplanted rats by using graded doses (10, 50, 100 mg/kg, s.c) or K₂Cr₂O7 (10 mg/kg, s.c) in association with Selenium (0.3 mg/kg, s.c) and Zinc chloride (20 mg/kg, s.c). The hormonal profile, apoptosis induction and histological changes in thyroids were evaluated. Our main findings showed that K₂Cr₂O7 promoted hypothyroidism with a significant decrease in plasma T3 and T4 levels (P<0.001), while plasma TSH level increased significantly (P<0.001), in addition, a hypertrophy of the thyroid was noted (P<0.01). Moreover, K2Cr2O7 (10 mg/kg, s.c) induced apoptosis via the caspase 3 pathway (P<0.001) and altered the gland histoarchitecture. The co-treatment with Se or ZnCl₂ has ameliorated the hormonal status and restored partially the thyroid histoarchitecture. We concluded that the administration of Selenium and Zinc can prevent the hazardous effects of potassium dichromate on the hormonal and histological status of the thyroid gland in preimplanted Wistar albino rats.

Antimicrobial and anti-viral effects of selenium nanoparticles and selenoprotein based strategies: COVID-19 and beyond

Article

Jun 2023
J DRUG DELIV SCI TEC

Deficiency of selenium (Se) has been described in a significant number of COVID-19 patients having a higher incidence of mortality, which makes it a pertinent issue to be addressed clinically for effective management of the COVID-19 pandemic. Se nanoparticles (SeNPs) provide a unique option for managing the havoc caused by the COVID-19 pandemic. SeNPs possess promising anti-inflammatory and anti-fibrotic effects by virtue of their nuclear factor kappa-light-chain-stimulator of activated B cells (NFκB), mitogen-activated protein kinase (MAPKs), and transforming growth factor-beta (TGF-β) modulatory activity. In addition, SeNPs possess remarkable immunomodulatory effects, making them a suitable option for supplementation with a much lower risk of toxicity compared to their elemental counterpart. Further, SeNPs have been shown to curtail viral and microbial infections, thus, making it a novel means to halt viral growth. In addition, it can be administered in the form of aerosol spray, direct injection, or infused thin-film transdermal patches to reduce the spread of this highly contagious viral infection. Moreover, a considerable decrease in the expression of selenoprotein along with enhanced expression of IL-6 in COVID-19 suggests a potential association among selenoprotein expression and COVID-19. In this review, we highlight the unique antimicrobial and antiviral properties of SeNPs and the immunomodulatory potential of selenoproteins. We provide the rationale behind their potentially interesting properties and further exploration in the context of microbial and viral infections. Further, the importance of selenoproteins and their role in maintaining a successful immune response along with their association to Se status is summarized.

The protective role of nutritional antioxidants against oxidative stress in thyroid disorders

Article

Full-text available

Jan 2023

An imbalance between pro-oxidative and antioxidative cellular mechanisms is oxidative stress (OxS) which may be systemic or organ-specific. Although OxS is a consequence of normal body and organ physiology, severely impaired oxidative homeostasis results in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells’ function and viability. The thyroid gland is an organ that exhibits both oxidative and antioxidative processes. In terms of OxS severity, the thyroid gland’s response could be physiological (i.e. hormone production and secretion) or pathological (i.e. development of diseases, such as goitre, thyroid cancer, or thyroiditis). Protective nutritional antioxidants may benefit defensive antioxidative systems in resolving pro-oxidative dominance and redox imbalance, preventing or delaying chronic thyroid diseases. This review provides information on nutritional antioxidants and their protective roles against impaired redox homeostasis in various thyroid pathologies. We also review novel findings related to the connection between the thyroid gland and gut microbiome and analyze the effects of probiotics with antioxidant properties on thyroid diseases.

The Effect of Oral Selenium on the Size of Thyroid Nodules in Patients with Benign Thyroid nodules: A Brief Study

Article

Full-text available

Nov 2022

Objective: The thyroid gland is susceptible to the formation of nodules. Therefore, due to the critical role of selenium in the function of the thyroid gland, the impact of this element on the size and volume of this organ and its nodules were examined. Materials and Methods: During three months, two groups consisting of 30 patients with benign thyroid nodules who were referred to Baghaeipour Endocrinology Clinic were given daily doses of 100 and 200 micrograms of selenium, and a control group of 30 people without selenium consumption were assessed. Results: The results of intergroup analysis detected that the mean (±SD) of nodules length in the 100 µg selenium consumer group was 17.13 (±7.9) and 14.93 (±6.01) before and after intervention respectively (P= 0.008). About the nodules height in the 200 µg selenium consumer group, the mean (±SD) was 9.3 (±2.8) and 8.93 (±2.71) before and after intervention in that order (P= 0.001). Conclusion: Our findings suggest that selenium has been effective in the size and volume of the nodule and thyroid gland, as well as the TSH hormone, and further studies are needed to determine its therapeutic approach and efficacy.

Relationship between dietary selenium intake and serum thyroid function measures in U.S. adults: Data from NHANES 2007–2012

Article

Full-text available

Oct 2022

Although numerous studies have explored the relationship between selenium intake and thyroid diseases, few epidemiological studies have investigated the association between selenium intake and thyroid hormones. Therefore, we conducted this analysis to investigate the association between dietary selenium intake and thyroid hormones. Our sample included 5,575 adults (age ≥ 20) years from the National Health and Nutrition Examination Survey (NHANES) 2007–2012. Thyroid hormones, including total triiodothyronine (T3), total thyroxine (T4), free T3 (FT3), free T4 (FT4), and thyroid-stimulating hormone (TSH), were detected. Multivariable linear regression models showed that log10-transformed selenium intake (LogSe) was negatively correlated with TT4 (β = −0.383, 95% CI: −0.695, −0.070) and TT4/TT3 (β = −0.003, 95% CI: −0.006, −0.0004) in U.S. adults. Besides, additional stratified analyses by sex demonstrated that LogSe was negatively associated with TT4 (β = −0.007, 95% CI: −0.013, −0.001) and TT4/TT3 (β = −0.664, 95% CI: −1.182, −0.146) and positively associated with FT4/TT4 (β = 0.031, 95% CI: 0.004, 0.059) in male adults. Meanwhile, subgroup analysis by iodine status showed that LogSe was negatively associated with TT4 (β = −0.006, 95% CI: −0.011, −0.002), FT4/FT3 (β = −0.011, 95% CI: −0.023, −0.00002) and TT4/TT3 (β = −0.456, 95% CI: −0.886, −0.026) in iodine sufficiency but not in iodine deficiency adults. Our results demonstrated that the increased dietary selenium intake was negatively correlated with TT4 and TT4/TT3 in U.S. adults. Furthermore, the association between dietary selenium intake and thyroid hormones was more pronounced in males and iodine sufficiency adults.

Wpływ suplementacji diety selenem na przebieg autoimmunologicznego zapalenia tarczycy – przegląd badań klinicznych przeprowadzonych w populacji europejskiej

Article

Full-text available

Oct 2021
PHMD/ Postepy Hig Med Dosw

Wiele obserwacji wskazuje na zależność między zmniejszonymi zasobami selenowymi organizmu a różnymi schorzeniami tarczycy, w tym także autoimmunologicznym zapaleniem tarczycy (AZT). W większości prac poświęconych temu zagadnieniu zmiana stężenia przeciwciał anty-TPO była główną miarą oceny skuteczności suplementacji selenem (Se) diety pacjentów z AZT. Stężenie przeciwciał anty-TPO ma wpływ na intensywność nacieków limfocytarnych w gruczole tarczowym i stopień jego uszkodzenia, dlatego zmniejszenie ich stężenia w wyniku zwiększonego spożycia Se może się przyczynić do skuteczniejszego leczenia AZT. W części prac omówionych w artykule ewaluacja immunoregulacyjnego działania Se w przebiegu AZT została rozpatrzona w odniesieniu do szerszego zakresu parametrów biochemicznych i immunologicznych (głównie dotyczy to zmian w wytwarzaniu cytokin i chemokin). Wielu autorów potwierdziło wpływ Se na zmniejszanie stężenia przeciwciał anty-TPO, jednak wyniki wszystkich prac nie są jednoznaczne. Przyczyną rozbieżności może być odmienny stopień wysycenia tarczycy Se i jodem w różnych grupach pacjentów, różny stopień zaawansowania choroby, różne dawki Se podawanego pacjentom, stosowanie lub niestosowanie jednoczesnej terapii L-tyroksyną oraz polimorfizmy pojedynczych nukleotydów (SNP) występujące w genach kodujących poszczególne selenobiałka. Na podstawie dostępnej literatury można wnioskować, iż zagadnienie dotyczące roli Se w AZT jest nadal słabo poznane. Istnieje potrzeba kontynuowania badań oceniających wpływ suplementacji diety Se na przebieg tej choroby, które powinny obejmować poza anty-TPO inne parametry kliniczne. Dopiero wyniki tak szeroko ujętych badań mogą być pomocne w formułowaniu nowych wytycznych dotyczących wspomagania leczenia przez odpowiednią modyfikację diety z uwzględnieniem suplementacji Se.

Positive effects of selenium supplementation in women with newly diagnosed Hashimoto's thyroiditis in an area with low selenium status

Article

Jun 2021

Objective Autoimmune thyroid diseases, including Hashimoto's thyroiditis, are the most common ones among autoimmune diseases. The reported effects of selenium supplementation on the course of Hashimoto's thyroiditis are not consistent. It is therefore important to continue this line of research. Design The participants received selenium in the form of sodium selenite(IV) at a dose of 100 µg/day for 6 months. Patients Newly diagnosed and previously untreated Hashimoto's thyroiditis with euthyroidism or subclinical hypothyroidism. A total of 36 patients (aged 20 to 52 years) qualified for this study, of whom 29 women were successfully enrolled and completed the intervention. Measurements Both before and after supplementation the following parameters in serum were tested: anti-thyroid peroxidase antibodies, thyroid function indicators, selenium as well as antioxidant status parameters and other biochemical parameters (lipid profile, glucose). Iodine supply and subjective assessment of physical and psychological health were also monitored. Results Selenium supplementation decreased significantly level of anti-thyroid peroxidase antibodies what might have had a stabilizing effect on thyroid function, as values of thyroid parameters were within normal range before and at the end of the study. Mean level of selenium among patients was not different to healthy people in Poland. Median of ioduria was within normal range. Conclusions The study shows a potential way of protective effect of selenium in limiting development of overt hypothyroidism. The increase in the concentrations of Se and SELENOP in the serum of patients verifies successful supplementation and good compliance, but did not affect the antioxidant status parameters measured.

From the secrets of longevity... nutraceutics. Thyroid disorders – part III

Article

Jan 2020

Gabriela Vlăsceanu

Selenium and selenoproteins: it’s role in regulation of inflammation

Article

Full-text available

Jun 2020
InflammoPharmacology

Selenium is an essential immunonutrient which holds the human’s metabolic activity with its chemical bonds. The organic forms of selenium naturally present in human body are selenocysteine and selenoproteins. These forms have a unique way of synthesis and translational coding. Selenoproteins act as antioxidant warriors for thyroid regulation, male-fertility enhancement, and anti-inflammatory actions. They also participate indirectly in the mechanism of wound healing as oxidative stress reducers. Glutathione peroxidase (GPX) is the major selenoprotein present in the human body, which assists in the control of excessive production of free radical at the site of inflammation. Other than GPX, other selenoproteins include selenoprotein-S that regulates the inflammatory cytokines and selenoprotein-P that serves as an inducer of homeostasis. Previously, reports were mainly focused on the cellular and molecular mechanism of wound healing with reference to various animal models and cell lines. In this review, the role of selenium and its possible routes in translational decoding of selenocysteine, synthesis of selenoproteins, systemic action of selenoproteins and their indirect assimilation in the process of wound healing are explained in detail. Some of the selenium containing compounds which can acts as cancer preventive and therapeutics are also discussed. These compounds directly or indirectly exhibit antioxidant properties which can sustain the intracellular redox status and these activities protect the healthy cells from reactive oxygen species induced oxidative damage. Although the review covers the importance of selenium/selenoproteins in wound healing process, still some unresolved mystery persists which may be resolved in near future. Graphic abstract

The Link between Selenium and Chemoprevention: A Case for Selenoproteins

Article

Full-text available

Nov 2004

Selenium is effective in reducing cancer incidence in animal models, and epidemiologic data, as well as supplementation trials, have indicated that selenium is likely to be effective in humans. The mechanism by which selenium prevents cancer remains unknown. The mammalian genome encodes 25 selenoprotein genes, each containing one or more molecules of selenium in the form of the amino acid selenocysteine, translationally inserted into the growing peptide in response to the UGA codon. There is evidence that several of these proteins may be involved with the mechanism by which selenium provides its anticancer effects. Data are reviewed indicating that genetic variants of the cytosolic glutathione peroxidase are associated with increased cancer risk, and that loss of one of the copies of this same gene may be involved with malignant progression. Similarly, allelic differences in the gene for a second selenoprotein, Sep15, may be relevant to the protection provided by selenium, and allelic loss at this locus have been reported as well. These data, along with the differential expression patterns reported for other selenoproteins in tumor vs. normal tissues, support the role of selenoproteins in the chemoprotection by selenium.

Selenium deficiency as a possible factor in the pathogenesis of myxoedematous endemic cretinism

Article

Full-text available

May 1987
Acta Endocrinol

Myxoedematous endemic cretinism is prevalent in African goitre endemies. It has been related to a thyroid 'exhaustion' atrophy occurring near birth. It is proposed that this might result from the low resistance of a fragile tissue to enhanced H2O2 generation under intense thyroid stimulation by thyrotropin. In support of this hypothesis, low selenium and glutathione peroxidase serum levels have been found in the African endemic area of the Idjwi Island (Kivu, Zaire). Serum selenium and plasma glutathione peroxidase were lower in the area of high endemicity of goitre and cretinism (Northern part of the Island). However, only the former difference is statistically significant. These data thus suggest a role of oligoelements and oxygen toxicity in the pathogenesis of endemic cretinism.

Effects of combined iodine and selenium deficiency on thyroid hormone metabolism in rats

Article

Full-text available

Mar 1993

This paper compares the effects of combined iodine and selenium deficiency, of single deficiencies of these trace elements, and of no deficiency on thyroid hormone metabolism in rats. In rats deficient in both trace elements, thyroidal triiodothyronine (T3), thyroidal thyroxin (T4), thyroidal total iodine, hepatic T4, and plasma T4 were significantly lower, and plasma thyroid-stimulating hormone (TSH) and thyroid weight were significantly higher than in rats deficient in iodine alone. Plasma and hepatic T3 concentrations were similar in the dietary groups. Hepatic type I iodothyronine deiodinase (ID-I) activity was inhibited by selenium deficiency irrespective of the iodine status. Type II deiodinase (ID-II) activity in the brain was significantly higher and in pituitary, significantly lower in combined deficiency than in iodine deficiency alone. These data show that selenium can play an important role in determining the severity of the hypothyroidism associated with iodine deficiency.

Day-to-day and within-day variation in urinary iodine excretion

Article

Full-text available

Jun 1999
EUR J CLIN NUTR

To examine the day-to-day and within-day variation in urinary iodine excretion and the day-to-day variation in iodine intake. Collection of consecutive 24-h urine samples and casual urine samples over 24h. The study population consisted of highly motivated subjects from our Institute. Study 1: Ten healthy subjects (seven females and three males) aged 30-46 y. Study 2: Twenty-two healthy subjects (9 males and 13 females) aged 30-55 y. Study 1: 24-h urine samples were collected for four consecutive days. Study 2: Each urine voided over 24 h was collected into separate containers. In both studies dietary records were kept. Twenty-four-hour urinary iodine excretion, 24-h urinary iodine excretion estimated as I/Cr*24 h Cr and as a concentration in casual urine samples. Study 1: Both iodine excreted in 24-h urine and iodine intake varied from day-to-day. Iodine excretion correlated with iodine intake (=-0.46, P=0.01). Iodine intake (mean 89 +/- 6.5 microg/d) was not significantly different from iodine excretion (mean 95 +/- 5.3 microg/d). Study 2: Twenty-four hour iodine excretion estimated as I/Cr*24 h Cr from the morning urine sample was significantly lower than actual 24-h iodine excretion, whereas 24-h iodine excretion estimated as I/Cr*24 h Cr from the first sample after the morning sample and the last sample before the subjects went to bed was not significantly different from actual 24-h iodine excretion. Twenty-four-hour urine excretion estimated as a concentration was lower than actual 24-h iodine excretion in casual urine taken at any time of the day. For determination of iodine status in an individual, more than one 24-h urine sample must be used. The use of the I/Cr ratio in casual urine samples is a usable measure of iodine status if corrected for the age- and sex-adjusted 24-h creatinine excretion. Further, the study suggests that fasting morning urine samples would underestimate iodine status in this population.

Effect of oral iodized oil on thyroid size and thyroid hormone metabolism in children with concurrent selenium and iodine deficiency

Article

Full-text available

Mar 2000
EUR J CLIN NUTR

To determine the efficacy of oral iodized oil in goitrous children who are both selenium (Se) and iodine deficient; to investigate if Se status modifies the response of iodine deficient, goitrous children to oral supplementation with iodized oil. A longitudinal intervention trial. Two rural villages in the western Côte d'Ivoire. 51 goitrous non-anemic schoolchildren with both iodine and Se deficiency. Each child received an oral dose of 0.4 ml iodized poppyseed oil containing 200 mg of iodine. They were followed for 1 y with measurements of urinary iodine (UI), thyrotropin (TSH), thyroxine (T4), and thyroid volume by ultrasound. At baseline all children were goitrous and Se deficient; median UI was 29 microg/l and mean serum Se (s.d.) was 14.8 (10.7) microg/l. After receiving iodized oil, thyroid volume decreased significantly vs baseline at 10, 15, 30 and 50 weeks (P<0.001). At 50 weeks mean percentage change in thyroid volume from baseline was-46.6% and only five children remained goitrous. Median TSH values at 5, 10, 15, 30 and 50 weeks were reduced significantly (P<0.001) compared to baseline. Among individual children the severity of Se deficiency predicted the degree of response to iodized oil. Baseline serum Se and percentage change in thyroid volume from baseline at 50 weeks were strongly correlated (r2=0.554). Baseline Se and percentage decrease in TSH from baseline at 30 weeks were also well-correlated (r2=0.467). Although more severe Se deficiency partially blunts the thyroid response to iodine supplementation, oral iodized oil is an effective method for iodine repletion in goitrous children who are Se deficient. The Swiss Federal Institute of Technology, Zürich, the Foundation for Micronutrients in Medicine, Rapperswil, Switzerland, and the Thrasher Research Fund, Salt Lake City, USA.

Age- and sex-adjusted iodine/creatinine ratio. A new standard in epidemiological surveys? Evaluation of three different estimates of iodine excretion based on casual urine samples and comparison to 24 h values

Article

Full-text available

May 2000
EUR J CLIN NUTR

The most accurate way to measure urinary iodine excretion in epidemiological surveys is still debated. We propose a new principle of estimating iodine excretion based on casual urine samples. A total of 123 24 h urine samples and corresponding casual urine samples were collected from 31 subjects. Iodine excretion was expressed as 24 h iodine excretion and three different estimates: iodine concentration in the casual sample, iodine/gram creatinine in the casual sample, and the new principle-iodine/creatinine ratio in the casual sample, adjusted for expected creatinine excretion of the individual. All three estimates based on casual urine samples correlated significantly to 24 h values with a r (Pearson) of 0.37 for iodine concentration, 0. 61 for iodine/creatinine ratio and 0.62 for the age- and sex-adjusted iodine/creatinine ratio. The median iodine excretion in the entire group was 143 microg/day in 24 h samples, 87 microg/l as iodine concentration, 77 microg/g creatinine as iodine/creatinine ratio and 126 microg/day as age- and sex-adjusted iodine/creatinine ratio. Age- and sex-adjusted iodine/creatinine ratio is a more accurate and unbiased estimate of iodine excretion in epidemiological surveys of adults than the two most frequently used estimated: iodine concentration and iodine/gram creatinine, as these two estimates may introduce a bias depending on the composition of the investigated group. The adjusted iodine/creatinine ratio is superior to the other estimates, especially when individual estimates of 24 h iodine excretion is required or cohorts of selected groups are investigated. Sponsorship: This work was supported by grants from the Medical Research Foundation Region Greater Copenhagen, Faroe Islands and Greenland; the Wedell-Wedellsborg Foundation; Musikforlaeggerne Agnes and Knut Morks Foundation.

High occurrence of thyroid multinodularity and low occurrence of subclinical hypothyroidism among tobacco smokers in a large population study

Article

Full-text available

Dec 2002

Tobacco smoking increases the risk of goitre and Graves' disease, but the association with thyroid nodularity and hypothyroidism has not been settled. We investigated 4649 subjects from the general population with questionnaires, thyroid ultrasonography and blood tests. The results were analysed in multivariate regression models. Tobacco smoking was associated with an increased prevalence of thyroid multinodularity (odds ratio (OR) 1.9; 95% confidence interval (CI) 1.4-2.5), but not with increased prevalence of solitary thyroid nodules. The tendency was for a stronger association in the area with the most pronounced iodine deficiency (P for interaction=0.08). Lower levels of serum TSH were found among tobacco smokers (P<0.001), but this association disappeared when adjustment was made for thyroid nodularity and thyroid Volume. The prevalence of elevated TSH levels was markedly reduced among smokers (OR 0.47; 95% CI 0.33-0.67). No association was found between smoking and hyperthyroidism. The observed associations seem to be explainable by the blocking of iodine uptake and organification in the thyroid by thiocyanate, a degradation product of cyanide in tobacco smoke.

Schomburg L, Schweizer U, Holtmann B, Floh?? L, Sendtner M, K??hrle J. Gene disruption discloses role of selenoprotein P in selenium delivery to target tissues. Biochem J 370, 397-402

Article

Full-text available

Apr 2003

Selenoprotein P (SePP), the major selenoprotein in plasma, has been implicated in selenium transport, selenium detoxification or antioxidant defence. We generated SePP-knockout mice that were viable, but exhibited reduced growth and developed ataxia. Selenium content was elevated in liver, but low in plasma and other tissues, and selenoenzyme activities changed accordingly. Our data reveal that SePP plays a pivotal role in delivering hepatic selenium to target tissues.

Association of selenium with thyroid volume and echostructure in 35- to 60-year-old French adults

Article

Full-text available

Apr 2003

To investigate the relationship between selenium status, thyroid Volume and gland echostructure. Cross-sectional. In 792 men (45-60 Years) and 1108 women (35-60 Years) from the SU.VI.MAX study, thyroid Volume and gland echostructure were determined ultrasonographically. At baseline, thyrotropin, free thyroxine, selenium, zinc, alpha-tocopherol, beta-carotene, retinol, urinary iodine and thiocyanate concentrations were measured. Alcohol consumption, smoking, and menopausal status were assessed by a questionnaire. A stepwise linear and a logistic regression model were used, adjusting for antioxidant vitamins, trace elements status and age. In women, there was an inverse association between selenium status and thyroid Volume (P=0.003). A protective effect of selenium against goiter (odds ratio (OR)=0.07, 95% confidence interval (CI)=0.008-0.6) and thyroid tIssue damage (OR=0.2, 95% CI=0.06-0.7) was observed. There was no evidence of an association between menopausal status and other antioxidant elements, thyroid Volume or thyroid hypoechogenicity. Smoking, but not alcohol consumption, was associated with an increased risk of thyroid enlargement in women (OR=3.94, 95% CI=1.64-9.48). No association between thyroid Volume, thyroid structure or selenium was found in men. Our findings suggest that selenium may protect against goiter. Selenium was related to thyroid echostructure, suggesting it may also protect against autoimmune thyroid disease.

Selenium and endocrine systems

Article

Full-text available

Apr 2005

The trace element selenium (Se) is capable of exerting multiple actions on endocrine systems by modifying the expression of at least 30 selenoproteins, many of which have clearly defined functions. Well-characterized selenoenzymes are the families of glutathione peroxidases (GPXs), thioredoxin reductases (TRs) and iodothyronine deiodinases (Ds). These selenoenzymes are capable of modifying cell function by acting as antioxidants and modifying redox status and thyroid hormone metabolism. Se is also involved in cell growth, apoptosis and modifying the action of cell signalling systems and transcription factors. During thyroid hormone synthesis GPX1, GPX3 and TR1 are up-regulated, providing the thyrocytes with considerable protection from peroxidative damage. Thyroidal D1 in rats and both D1 and D2 in humans are also up-regulated to increase the production of bioactive 3,5,3'-tri-iodothyronine (T3). In the basal state, GPX3 is secreted into the follicular lumen where it may down-regulate thyroid hormone synthesis by decreasing hydrogen peroxide concentrations. The deiodinases are present in most tissues and provide a mechanism whereby individual tissues may control their exposure to T3. Se is also able to modify the immune response in patients with autoimmune thyroiditis. Low sperm production and poor sperm quality are consistent features of Se-deficient animals. The pivotal link between Se, sperm quality and male fertility is GPX4 since the enzyme is essential to allow the production of the correct architecture of the midpiece of spermatozoa. Se also has insulin-mimetic properties, an effect that is probably brought about by stimulating the tyrosine kinases involved in the insulin signalling cascade. Furthermore, in the diabetic rat, Se not only restores glycaemic control but it also prevents or alleviates the adverse effects that diabetes has on cardiac, renal and platelet function.

The effect of selenium on thyroid status in a polution with marginal selenium and iodine status

Article

Full-text available

Jan 2006

The effects of Se on thyroid metabolism in a New Zealand population are investigated, including (a) the relationship between Se and thyroid status, and (b) the effect of Se supplementation on thyroid status. The data used come from two cross-sectional studies of Se, I, thyroid hormones and thyroid volume (studies 1 and 4), and three Se intervention studies in which thyroid hormones, Se and glutathione peroxidase (GPx) activities were measured (studies 2, 3 and 5). There were no significant correlations between Se status and measures of thyroid status after controlling for sex at baseline or after supplementation in any of the studies. When data from study 4 were divided into two groups according to plasma Se, plasma thyroxine (T4) was lower in males with higher plasma Se levels (P=0.009). Se supplementation increased plasma Se and GPx activity, but produced only small changes in plasma T4 and triiodothyronine (T3):T4 ratio. In study 2, there was a significant reduction in plasma T4 (P=0.0045). In studies 3 and 5 there were small decreases in plasma T4 and a small increase in the T3:T4 ratio, which were not significantly different from placebo groups. Lack of significant associations between plasma Se and thyroid status, and only small changes in T4 suggest that Se status in New Zealand is close to adequate for the optimal function of deiodinases. Adequate plasma Se may be approximately 0.82-0.90 micromol/l, compared with 1.00-1.14 micromol/l for maximal GPx activities.

Selenium-Dependent Pre- and Posttranscriptional Mechanisms Are Responsible for Sexual Dimorphic Expression of Selenoproteins in Murine Tissues

Article

Full-text available

Jan 2007

Important enzymes for thyroid hormone metabolism, antioxidative defense, and intracellular redox control contain selenocysteine (Sec) in their active centers. Expression of these selenoproteins is tightly controlled, and a sex-specific phenotype is observed on disturbance of selenium (Se) transport in mice. Therefore, we analyzed Se concentrations and expression levels of several selenoproteins including type I iodothyronine deiodinase (Dio1) and glutathione peroxidase (GPx) isozymes in male and female mice. On regular lab chow, serum Se levels were comparable, but serum GPx3 activity was higher in females than males (1.3-fold). Selenoprotein P (SePP) mRNA levels were higher in livers (1.3-fold) and lower in kidneys (to 31%) in female compared with male mice. Orchidectomy alleviated the sex-specific differences in SePP mRNA amounts, indicating modulatory effects of androgens on SePP expression. Female mice expressed higher levels of Dio1 mRNA in kidney (2.6-fold) and liver (1.4-fold) in comparison with male mice. This sexual dimorphic expression of Dio1 mRNA was paralleled by increased Dio1 activity in female kidney (1.8-fold) but not in liver in which males expressed higher Dio1 activity (2.8-fold). Interestingly, Se deficiency decreased Dio1 activity more effectively in males than females, and resulting hepatic enzyme levels were then comparable between the sexes. At the same time, the sex-specific difference of Dio1 activity widened in kidney. Orchidectomy or estradiol treatment of ovariectomized females impacted stronger on renal than hepatic Dio1 expression. Thus, we conclude that Se-dependent posttranscriptional mechanisms are operational that affect either translational efficiency or Dio1 stability in a sex- and tissue-specific manner.

Selenium and goiter prevalence in borderline iodine sufficiency

Article

Full-text available

Dec 2006

Selenium (Se) is required for the biosynthesis of selenocysteine-containing proteins. Several selenoenzymes, e.g. glutathione peroxidases and thioredoxin reductases, are expressed in the thyroid. Selenoenzymes of the deiodinase family regulate the levels of thyroid hormones. For clinical investigators, it is difficult to determine the role of Se in the etiology of (nodular-)goiter, because there are considerable variations of Se concentrations in different populations as reflected by dietary habits, bioavailability of Se compounds, and racial differences. Moreover, most previous clinical trials which investigated the influence of Se on thyroid volume harbored a bias due to the coexistence of severe iodine deficiency in the study populations. Therefore, we investigated the influence of Se on thyroid volume in an area with borderline iodine sufficiency. First, we investigated randomly selected probands for urinary iodine (UI) and creatinine excretion in spot urine samples and determined the prevalence of goiter and thyroid nodules by high-resolution ultrasonography. After this, we determined urinary Se excretion (USe) in probands with goiter as well as in matched probands without goiter. Adjustments between the two compared groups were made for age, gender, history of thyroid disorders, smoking, and UI excretion. The mean USe and UI rates of all 172 probands were 24 micro g Se/l or 27 micro g Se/g creatinine and 96 micro g I/l or 113 micro g I/g creatinine indicating borderline selenium (20-200 micro g/l) and iodine (100-200 micro g/l) sufficiency of the study population. Probands with goiter (n=89) showed significantly higher USe levels than probands with normal thyroid volume (n=83; P < 0.05). USe rates were not influenced by present smoking or pregnancy. In our investigation, USe was not an independent risk factor for the development of goiter. The higher USe in probands with goiter in comparison with probands with normal thyroid volume is most likely a coincidence. Se does not significantly influence thyroid volume in borderline iodine sufficiency because the iodine status is most likely the more important determinant.

Effect of a Mandatory Iodization Program on Thyroid Gland Volume Based on Individuals’ Age, Gender, and Preceding Severity of Dietary Iodine Deficiency: A Prospective, Population-Based Study

Article

Full-text available

May 2007

We aimed to evaluate prospectively the effect of 4 yr of mandatory iodization of salt (13 ppm iodine) on thyroid volume in two regional areas with respectively mild and moderate iodine deficiency. Two separate cross-sectional studies were performed before (n=4649) and after (n=3570) the iodization in year 2000 in two areas with mild and moderate iodine deficiency. Women aged 18-22, 25-30, 40-45, and 60-65 yr and men aged 60-65 yr were examined. Thyroid ultrasonography was performed. A lower median thyroid volume was seen in all age groups after iodization. The largest relative decline was found among the younger females from the area with previous, moderate iodine deficiency. Only a minor decrease was seen among the youngest participants in the area with previous, mild iodine deficiency. After iodization, there were no regional differences in median thyroid volume in the age groups younger than 45 yr. When adjusted for confounders, a lower mean volume was seen among those with multiple nodules in both areas and in the group with diffuse structure in the area with moderate iodine deficiency. Before the iodization, 17.6% of the total cross-section had thyroid enlargement; after the iodization, 10.9% of the cross-section had thyroid enlargement. In this prospective study, we demonstrated a lower thyroid volume in all age groups after iodization of salt. The decline was largest in the area with former, moderate iodine deficiency. The equal volumes in the regions among the younger age groups indicate approximation to an optimal iodine intake.

Selenoproteins of the thyroid gland: Expression, localization and possible function of glutathione peroxidase 3

Article

Full-text available

Nov 2007

The thyroid gland has an exceptionally high selenium content, even during selenium deficiency. At least 11 selenoproteins are expressed, which may be involved in the protection of the gland against the high amounts of H2O2 produced during thyroid hormone biosynthesis. As determined here by in situ hybridization and Northern blotting experiments, glutathione peroxidases (GPx) 1 and 4 and selenoprotein P were moderately expressed, occurring selectively in the follicular cells and in leukocytes of germinal follicles of thyroids affected by Hashimoto's thyroiditis. Selenoprotein 15 was only marginally expressed and distributed over all cell types. GPx3 mRNA was exclusively localized to the thyrocytes, showed the highest expression levels and was down-regulated in 5 of 6 thyroid cancer samples as compared to matched normal controls. GPx3 could be extracted from thyroidal colloid by incubation with 0.5% sodium dodecyl sulfate indicating that this enzyme is (i) secreted into the follicular lumen and (ii) loosely attached to the colloidal thyroglobulin. These findings are consistent with a role of selenoproteins in the protection of the thyroid from possible damage by H2O2. Particularly, GPx3 might use excess H2O2 and catalyze the polymerization of thyroglobulin to the highly cross-linked storage form present in the colloid.

Goiter Persistence After Iodine Replenishment, the Potential Role of Selenium Deficiency in Goitrous Schoolchildren of Semirom, Iran

Article

Full-text available

Mar 2008

Despite long-standing iodine supplementation in Iran, the prevalence of goiter remains high in some areas. This suggests other nutritional deficiencies may be considered as responsible factors of goiter persistence. Therefore, we assessed the prevalence of selenium deficiency in children living in a mountainous area in Iran to evaluate its correlation with goiter. In this cross-sectional study, 1828 students from the 108 primary schools of urban and rural areas of Semirom in central Iran were selected by multistage random cluster sampling. After obtaining written consent from their parents, the children were examined for goiter grading. Grade 2 goitrous children (108 cases) were compared with non-goitrous children (111 children) as control group for serum selenium concentration. Overall, 36.7% of 1828 students had goiter. The mean and median urinary iodine excretion level was 19.3 and 18.5 mug/dl respectively. This was within normal limits. Of 219 evaluated cases, 109 children had selenium deficiency. Mean serum levels of selenium in the goitrous and control groups were 62.7 mug/l and 60.8 mug/l, respectively (p=0.42). There was a borderline significant difference of the goiter prevalence in selenium deficient and selenium sufficient subjects (40.8% vs. 54.3%, p=0.037). Twelve children had clinical or subclinical hypothyroidism. The mean (SD) serum selenium concentration of euthyroid and hypothyroid students were 61.9 (17.2) mug/l and 66.4 (11.9) mug/l respectively (p=0.35). In the area studied, selenium deficiency cannot explain high prevalence of goiter and other responsible factors should be investigated. Selenium deficiency may also have mild borderline significant protective effects on thyroid function and goiter.

Randomized controlled trial of the effect of selenium supplementation on thyroid function in the elderly in the United Kingdom

Article

Full-text available

Feb 2008

Thyroid function depends on the essential trace mineral selenium, which is at the active center of the iodothyronine deiodinase enzymes that catalyze the conversion of the prohormone thyroxine (T(4)) to the active form of thyroid hormone, triiodothyronine (T(3)). Because selenium intake in the United Kingdom has fallen during the past 25 y, we wanted to determine whether current selenium status might be limiting conversion of T(4) to T(3) in the elderly, in whom marginal hypothyroidism is relatively common. We investigated the effect of selenium supplementation in a double-blind, placebo-controlled trial in 501 elderly UK volunteers. Similar numbers of men and women from each of 3 age groups, 60-64 y, 65-69 y, and 70-74 y, were randomly allocated to receive 100, 200, or 300 microg Se/d as high-selenium yeast or placebo yeast for 6 mo. As part of the study, plasma selenium, thyroid-stimulating hormone, and total and free T(3) and T(4) were measured. Data from 368 euthyroid volunteers who provided blood samples at baseline and 6 mo were analyzed. Although selenium status at baseline correlated weakly with free T(4) (r = -0.19, P < 0.001) and with the ratio of free T(3) to free T(4) (r = 0.12, P = 0.02), we found no evidence of any effect of selenium supplementation on thyroid function, despite significant increases in plasma selenium. However, baseline plasma selenium in our study (x: 91 microg/L) was somewhat higher than in previous supplementation studies in which apparently beneficial effects were seen. We found no indication for increasing selenium intake to benefit T(4) to T(3) conversion in the elderly UK population.

Selenium and goiter prevalence in borderline iodine sufficiency

Article

Feb 2006

It is difficult to determine the role of Selenium (Se) in the etiology of (nodular-)goiter, because there are considerable variations of Se concentrations in different populations as reflected by dietary habits, bioavailability of Se compounds and racial differences. Moreover, most previous clinical trials, which investigated the influence of Se on thyroid volume, harboured a bias due to the coexistence of severe iodine deficiency in the study populations. Therefore, we investigated the influence of Se on thyroid volume in a mildly iodine deficient area. First, we investigated randomly selected probands for iodine (UI) and creatinine excretion in spot urine samples and determined the prevalence of goiter and thyroid nodules by high resolution ultrasonography. Iodine concentration was measured manually according to the protocol described by Sandell and Kolthoff and Creatinine as described by Jaffe. Thyroid volume determination was performed using a high resolution real-time instrument. Thyroid volumes were calculated according to the spherical ellipsoid formula. After this, we determined urinary Se excretion (USe) in probands with goiter as well as in matched probands without goiter. Urinary selenium excretion was measured according to the method previously described by Vezina et al. Adjustments between the 2 compared groups were made for age, gender, history of thyroid disorders, smoking and urinary iodine excretion. The mean USe and UI rates of all 172 probands were 24µg Se/l or 27µg Se/g creatinine and 96µg I/l or 113µg I/g creatinine indicating borderline selenium (20–200µg/l) and iodine (100–200µg/l) sufficiency of the study population. Probands with goiter (n=89) showed significantly higher USe levels than probands with normal thyroid volume (n=83; p<0.05). USe rates were not influenced by current smoking or pregnancy. In our investigation, USe was not an independent risk factor for development of goiter. Se does not significantly influence thyroid volume in borderline iodine sufficiency because the iodine status is the more important determinant.

Ultraschalldiagnostik der Schilddrüse

Article

Jul 2008

Die Sonographie gehört nach der körperlichen Untersuchung an die erste Stelle zur Beurteilung oder zum Ausschluß von Strukturveränderungen der Schilddrüse. Für die Bestimmung der Schilddrüsengröße und damit zum Ausschluß oder Nachweis einer Struma ist die sonographische Volumetrie maßgebend. Einige sonographische Veränderungen sind so charakteristisch, daß sie im klinischen Zusammenhang Diagnosen ermöglichen: Struma diffusa, Zysten, Morbus Basedow und Schilddrüsenentzündungen. Bei Struma nodosa mit multiplen oder solitären Knoten ist die Sonographie für die weitere Diagnostik richtungweisend.

Concentration in the human thyroid gland

Article

Feb 1990

Recently, we found that prediagnostic serum selenium concentration was significantly lower for cases developing thyroid cancer (n=43) than for controls. We assumed that redistribution of serum selenium into the affected tissue took place in the prediagnostic period. The present study was carried out to determine the physiological concentration of selenium in the thyroid, since very few data are available in the literature. The concentrations of selenium in the thyroid (n=45) and liver samples from Norwegians who had died because of acute illness or accidents were determined by hydride generation atomic absorption spectrometry. The mean selenium concentration was found to be 0.72±0.44 μg/g in the thyroid and 0.45±0.11 μg/g in the liver tissue. The surprisingly high concentration of selenium in apparently normal thyroids indicates that selenium has important functions in this organ. The remarkably broad range, together with the observation that no significant correlation exists between thyroid and liver concentrations, suggest that factors other than the selenium status are important determinants for the selenium concentration in the thyroid gland. This observation is consistent with our hypothesis that in carcinogenesis, prediagnostic processes influence the serum-/thyroid-ratio of selenium.

Estimation of Iodine Intake from Various Urinary Iodine Measurements in Population Studies

Article

Nov 2009
THYROID

Iodine intake is often measured by a surrogate measure, namely urine iodine excretion as almost all ingested iodine is excreted in the urine. However, the methods for urine collection and the reporting of the results vary. These methods, and their advantages and disadvantages, are considered in this article. There are two main ways in which urine can be collected for iodine measurement. The first is the collection of urine over a period, usually 24 hours. The second is the collection of a spot urinary sample. Urinary iodine values can be expressed as the content or concentration and reported without modification or as a function of creatinine in the same sample. The 24-hour urine for iodine measurement is often considered as the "reference standard" for giving a precise estimate of the individual iodine excretion and thereby iodine intake. As 24-hour collections are difficult to perform for large number of persons, single spot urinary samples are preferable to the 24-hour urinary collections in population studies. The iodine concentration in urine depends on the intake of both iodine and fluid. This, and the fact that there is a considerable variability in the daily iodine intake, makes the iodine measurement in spot urine samples unreliable for evaluating individuals for iodine deficiency, though they can be used to screen for exposure to large amounts of iodine from sources such as amiodarone and certain radiographic contrast agents. In populations of at least 500 subjects, the median value of spot urinary iodine concentration is a reliable measure of the iodine intake in the population as there is a leveling out of the day-to-day variation in iodine intake and urinary volume. Expressing the urinary iodide concentration as a function of urinary creatinine is useful in correcting for the influence of fluid intake. When doing so, it is recommended to adjust for the age- and sex-specific creatinine excretion in the given population. In studies of iodine intake, the correct choice of the method for collecting urine and the format for expressing the results of urine iodine measurement is essential to avoid misinterpretation of data on the iodine status of a population or individuals.

Selenium status, sex hormones, and thyroid function in young women

Article

Feb 2008
J TRACE ELEM MED BIO

The aim of the study was to identify those parameters characterising selenium status and sex hormones secretion, which are responsible for the changes in indicators of thyroid function, and to reveal the correlation structure of parameters expressing selenium status, sex hormones secretion and thyroid function, if any exist. The general approach in this work was essentially the same as in our previous report (cf. [Zagrodzki P, Ratajczak R, Wietecha-Posłuszny R. The interaction between selenium status, sex hormones, and thyroid metabolism in adolescent girls during the luteal phase of their menstrual cycle. Biol Trace Elem Res 2007; 120: 51-60]), but the study group and parameters' spectrum were different. Thirty-six women aged 23.5+/-0.6 years were investigated. The parameters of interest were: plasma selenium concentration (Se) and plasma glutathione peroxidase activity (GPX3) (indicators of selenium status); serum estradiol (E2), progesterone (P4), follicle-stimulating hormone (FSH), luteotropic hormone (LH), and age of menarche (indicators of sex hormones secretion); thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), anti-thyroid peroxidase antibodies in serum (anti-TPO), and thyroid volume (indicators of thyroid function). Our findings show that Se, GPX3, P4, LH, FSH, TSH and fT4 were interrelated. The pairs of parameters: GPX3 and P4; LH and FSH exhibited the strongest associations. The thyroid function parameters were mainly influenced by GPX3 and P4. Partial least-squares method corroborated our hypothesis about the existence of complex interactions among selenium status, sex hormones secretion, and thyroid function in healthy young women in the luteal phase.

On the importance of selenium and iodine metabolism for thyroid hormone biosynthesis and human health

Article

Nov 2008
MOL NUTR FOOD RES

The trace elements iodine and selenium (Se) are essential for thyroid gland functioning and thyroid hormone biosynthesis and metabolism. While iodine is needed as the eponymous constituent of the two major thyroid hormones triiodo-L-thyronine (T3), and tetraiodo-L-thyronine (T4), Se is essential for the biosynthesis and function of a small number of selenocysteine (Sec)-containing selenoproteins implicated in thyroid hormone metabolism and gland function. The Se-dependent iodothyronine deiodinases control thyroid hormone turnover, while both intracellular and secreted Se-dependent glutathione peroxidases are implicated in gland protection. Recently, a number of clinical supplementation trials have indicated positive effects of increasing the Se status of the participants in a variety of pathologies. These findings enforce the notion that many people might profit from improving their Se status, both as a means to reduce the individual health risk as well as to balance a Se deficiency which often develops during the course of illness. Even though the underlying mechanisms are still largely uncharacterised, the effects of Se appear to be exerted via multiple different mechanisms that impact most pronounced on the endocrine and the immune systems.

Thyroxine and 3,5,3′-Triiodothyronine Content of Thyroglobulin in Thyroid Needle Aspirates in Hyperthyroidism and Hypothyroidism*

Article

Jun 1987

Peter Laurberg

Thyroglobulin (Tg) was obtained by fine needle aspiration from patients with untreated hyperthyroidism due to Graves' disease and untreated hypothyroidism to determine whether alterations in its T4 and T3 content could account for the disproportionately high serum T3 compared to serum T4 found in both diseases. For comparison aspiration was performed from normal thyroid tissue in euthyroid patients operated for solitary thyroid lesions. The average amounts of Tg aspirated were: normal 177 +/- 52 (SE) micrograms, n = 7, hyperthyroidism 82 +/- 32 micrograms (n = 8); hypothyroidism 4.6 +/- 1.9 micrograms, n = 9. The iodothyronine content of Tg was, normal, T4 3.7 +/- 0.5 mol/mol, T3 0.28 +/- 0.04 mol/mol, T4/T3 13.7 +/- 1.4; hyperthyroidism, T4 3.8 +/- 1.0, T3 0.59 +/- 0.15, T4/T3 6.8 +/- 1.1; hypothyroidism, T4 3.3 +/- 0.5, T3 0.54 +/- 0.09, T4/T3 6.8 +/- 0.7. The iodine content of Tg was 28 +/- 3.1 atoms/mol in the euthyroid subjects and 31 +/- 7.3 atoms/mol in hyperthyroid patients. Hence, both untreated hyperthyroidism and untreated hypothyroidism were characterized by Tg with a normal T4 but a relatively high T3 content. This is probably related to the prolonged hyperstimulation of functioning follicular cells present in both diseases. The relatively high T3 content of Tg could not alone explain the relatively high T3 production compared to T4 production in these two thyroid diseases.

The estimation of iodine in thyroidal amino acids by alkaline ashing

Article

Nov 1967
S Afr J Med Sci

Correlations between parameters of body selenium status and peripheral thyroid parameters in the low selenium region

Article

Apr 1995

The following were measured in 380 male and female inhabitants of Prague (n the age range 6-65 years):selenium in serum and urine, iodine in urine, thyroid-stimulating hormone, thyroid volume, thyroxine (T4), triiodothyronine (T3), ankle jerk time, pulse rate and body fat. Correlations were calculated to assess the influence of Se upon the thyroid hormone parameters and their peripheral effects in Se-deficient regions both by using the linear correlation analysis and by using the multiple linear correlation analysis and the analysis of variance. Many significant linear correlations were found for whole groups of examined persons, for the individual groups (boys, men, girls and women) as well as for subgroups, according to the age and sex. We conclude, from the analytical results of Se indices (serum, hair, urine) reported previously, and on the basis of the statistical demonstration of the influence of selenium upon thyroid hormone levels and the peripheral effects in the group of Prague inhabitants in connection with the previously documented role of Se in pathways resulting in the synthesis of physiologically active thyroid hormone, that inhabitants of Prague are selenium deficient. Concurrent deficiency of selenium may modify and even worsen iodine deficiency disorders of various stages. Multiple linear correlation analysis followed by analysis of variance of subgroups indicated a coincidence of the effects of some measured parameters upon the peripheral manifestation of thyroid hormone state as well as highlighting the effect of other independent variables of thyroid hormone metabolism than those measured in the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Selenium administration does not cause thyroid insufficiency in subjects with mild iodine deficiency and sufficient selenium intake

Article

Jul 2014

Selenium is a trace element essential for the activity of type I 5'-deiodinase which converts thyroxine (T4) to 3,5,3'-triiodothyronine (T3). In iodine deficient hypothyroid children at low selenium dietary intake the supplementation of selenium induced a significant decrement of serum FT4 and T4 concentrations and an increase of serum TSH concentrations. Since in western countries selenium tablets begin to be largely consumed as a diet integrator, we have administered 100 micrograms/day of selenium as selenium methionine to 8 euthyroid female subjects with a positive iodine-perchlorate discharge test who had a previous episode of subacute or postpartum thyroiditis. We have studied subjects with positive iodine-perchlorate discharge test since the test indicates the existence of a subtle defect of thyroid hormone synthesis and therefore these subjects are prone to develop thyroid dysfunction. In contrast to previous findings in hypothyroid children at low iodine and selenium dietary intake, the supplementation of selenium did not decompensate thyroid hormone synthesis of euthyroid subjects with reduced thyroid iodine organification. The lack of any effect of selenium on thyroid hormone synthesis even in subjects with subtle thyroid hormone synthesis defect may be due to the fact that these subjects had a sufficient selenium dietary intake before selenium supplementation and an only marginally reduced dietary iodine intake.

On the determinants of the creatinine clearance: A population study

Article

Apr 1996
J Hum Hypertens

The objective of this study was to define the normal urinary creatinine clearance and its determinants. The creatinine clearance was measured in both sexes in a large random Belgian population sample (BIRNH: Belgian interuniversity Research on Nutrition and Health) by measuring serum creatinine and the 24 h urinary creatinine excretion. At a mean age of 50.8 years in 2,075 men and 50.1 years in 1,933 women the mean creatinine clearance was 101 +/- 30.5 and 86.9 +/- 25.8 ml/min respectively. In multiple regression analysis the creatinine clearance in both sexes correlated negatively with age and positively with weight and 24 h urinary sodium, potassium, calcium and magnesium (all P < 0.0001). Total R2 was 0.40 in men and 0.35 in women. After adjustment for age, height and weight no significant relationship exists between the 24 h urinary creatinine clearance and either systolic or diastolic blood pressure. Serum creatinine increased with age, more so in women, and was at all ages higher in men compared to women. The creatinine clearance decreased with age in both sexes. Our study demonstrates the existence of highly significant associations between urinary cations and the creatinine clearance, independent of total caloric intake.

Serum selenium levels in multinodular goitre

Article

Dec 1998

Serum selenium levels were measured in 22 patients with a multinodular goitre and compared to 15 normal controls using atomic absorption spectrophotometry. The serum selenium was significantly low in these patients (patients' mean = 9.6 +/- 1.24 mcg/l, versus control mean = 11.7 +/- 1.64 mcg/l and P < 0.005). Serum T4 and T3 were within the normal range in all patients and controls. Their levels correlated positively, though weakly, with the serum selenium levels (r = 0.4 and 0.36, respectively). The control selenium levels in this study were lower than the reported figures from some European countries, but they were close to those from other studies in Egypt. It seems that Egypt is a low selenium area. A wide-scale epidemiological study is recommended, together with the examination of the possible preventive role of selenium supplementation in areas of endemic goitre.

Iodine and zinc, but not selenium and copper, deficiency exists in a male Turkish population with endemic goiter

Article

Oct 1999

Although endemic goiter has been shown to have a high prevalence in Turkey, little is known about the concentration of urinary iodine, plasma selenium (Se), copper (Cu), and zinc (Zn) in these patients. We studied on 140 male patient with endemic goiter (mean age: 22.2 +/- 0.19 yr) and 140 healthy male subjects (mean age: 21.8 +/- 0.28 yr). Daily urinary iodine excretion was determined by the ionometric method. Plasma Se, Zn, and Cu were determined by using atomic absorption spectrometry. Daily urinary iodine excretion was found to be significantly lower in the patient group (38.7 +/- 2.26 microg/d) than that of controls (50.73 +/- 2.56 microg/day, p = 0.001). Plasma Zn concentrations were also found to be significantly lower in the patient group (1.04 +/- 0.03 microg/mL) than that of controls (1.16 +/- 0.02 microg/mL, p = 0.001). No significant difference was determined in Se and Cu concentrations between the patient and control groups. Our study shows that a moderate iodine deficiency exists in both patients with endemic goiter and control subjects, which indicates the important role of iodine deficiency in the etiopathogenesis of endemic goiter in Turkey. Zinc deficiency may also contribute to the pathogenesis of endemic goiter. However, Se and Cu do not seem to have any role in the etiopathogenesis of endemic goiter in Turkey. A community-based iodine fortification program throughout the country may be proposed to take over the problem, which also can prevent the contributing effects of other element deficiencies that occur when iodine deficiency is the prevailing factor.

Validation of Ultrasonography of the Thyroid Gland for Epidemiological Purposes

Article

Dec 1999

Ultrasonography of the thyroid is often used in epidemiological surveys, thus thorough characterization of the interobserver variation of the different parameters obtained is important. Various methods have been used for measuring thyroid volume, and different formulas have been used for calculation of thyroid volume from the measured dimensions. In this article, two principles of thyroid volume measurement are described in detail: the wellknown method based on the three axes of each lobe and a new principle based on planimetry in two planes. The interobserver variation of the examination and the measuring procedure in itself were tested on 25 participants in a population study. A comparison of postmortem ultrasonography of the thyroid and results of an autopsy was performed. Good correlation and agreement between observers was found for thyroid volume (r = 0.98) and prevalence of thyroid nodules (kappa = 0.72), whereas echogenecity and echopattern showed little agreement. The correlation of thyroid volume by ultrasonography to autopsy results was satisfactory (r = 0.93), but the volume tended to be slightly underestimated even when using the formula pi/6(= 0.52)*length*width*depth. No major differences were found between the performance of the two principles of volume calculation. We conclude that when the measuring procedure is well defined, results of ultrasonography are comparable between observers for thyroid volume and prevalence of thyroid nodules, but not for echogenecity or echopattern. The formula of length*depth*width*pi/6 is suitable for thyroid volume measurement.

Knudsen N, Bulow I, Jorgensen T, Laurberg P, Ovesen L, Perrild H. Goitre prevalence and thyroid abnormalities at ultrasonography: a comparative epidemiological study in two regions with slightly different iodine status. Clin Endocrinol (Oxf) 53, 479-485

Article

Oct 2000

The association between severe iodine deficiency and endemic goitre is well established, but little information is available on the relation between milder degrees of iodine deficiency and goitre prevalence. In a comparative epidemiological study performed in two regions in Denmark, we examined 4649 subjects from the general population, women aged 18-65 years and men aged 60-65 years. Ultrasonography and palpation of the thyroid was performed in all participants. Iodine excretion was measured in casual urine samples. Previous thyroid disease was detected by questionnaires, personal interviews and tracing of records. The median iodine excretion was 61 microg/l (mild iodine deficiency (ID)) and 45 microg/l (moderate ID) in the two regions. Median thyroid volume at ultrasonography was 11. 9 ml (mild ID) and 13.6 ml (moderate ID), P <0.001, and thyroid enlargement was found in 15.0% (mild ID) and 22.6% (moderate ID), P<0.001. Goitre prevalence increased in both regions with age to the age group 40-45 years, but not after that age. Subjects who had moved from the moderate ID to the mild ID area had the same prevalence of thyroid enlargement as the subjects staying permanently in the mild ID area. Thyroid nodules at ultrasonography were found in 30% in both regions, but nodules were larger and more often palpable in the moderate ID area. Palpable goitre was found in 9.8% (mild ID) and 14.6% (moderate ID), P<0.001. The greatest regional difference in thyroid abnormalities was found among men. Marked differences in the prevalence of thyroid abnormalities were found in these regions with modest differences in iodine excretion.

Status of Selenium and Antioxidant Enzymes of Goitrous Children Is Lower Than Healthy Controls and Nongoitrous Children with High Iodine Deficiency

Article

Feb 2001

In order to investigate the relations of iodine deficiency and/or goiter with selenium (Se) and antioxidant enzyme (AOE) status, we determined the relevant parameters of goitrous high school children living in an endemic goiter area of Turkey. Subjects were selected by a simple random sampling technique after screening the whole population of the high schools of two towns by neck palpation. The results of the goitrous group (n = 48, aged 15-18 yr) were compared with those of nongoitrous control children (n = 49) from the same populations, and with an outside control group (n = 24) from a lower-goiter-prevalence area. The overall prevalence of goiter was 39.6% in the high school population of the area. Activities of erythrocyte AOE (glutathion peroxidase, catalase, and superoxide dismutase) and concentrations of plasma and erythrocyte Se and urinary iodine were found to be significantly lower in goitrous children than both in-region and out-region of the control groups. When the whole study group was reclassified according to the severity of iodine deficiency, it was found that the AOE and Se status of those control children without goiter but with high iodine deficiency was significantly higher than goitrous children, although they did not differ from nondeficient control group. This might be the result of the possibility that goitrous children are exposed of oxidative stress, which may introduce alterations to the antioxidant defense system and/or the antioxidant status is relatively lower in goitrous children than those children who are highly iodine-deficient but did not develop goiter. The results of this study seem to support the view that the risk of goiter development may be higher in highly iodine-deficient children with lower enzymatic antioxidant and Se status.

Iodine and Selenium Deficiency in School-children in an Endemic Goiter Area in Turkey

Article

Jul 2002

Endemic goiter is one of the most important health problems in Turkey. However, there are not enough studies associated with iodine and selenium status. This study was carried out to establish the effects of iodine and selenium levels on thyroid gland size and thyroid functions in 73 healthy school-children, 7-12 years old (mean 9.56 +/- 1.77 years), 38 girls (52%) and 35 boys (48%), living in an endemic goiter area. Goiter was found in 32 of the children (43.8%) by palpation, and 56 of the children (76.7%) by ultrasonography. Mean serum T3 and TSH levels were in the upper limit of normal, and mean serum T4 levels were within the normal limits, but mean serum thyroglobulin levels were higher than the normal limits. Mean serum selenium level was 30.84 +/- 23.04 microg/l, and mean urinary iodine level was 3.91 +/- 3.77 microg/dl, appropriate for moderate iodine and selenium deficiency. Thyroid volumes of the children were negatively correlated with serum selenium levels, but there was no correlation with urinary iodine levels and thyroid hormones. In conclusion, school-children in this area had significant goiter problems, probably due to the iodine and selenium deficiencies.

Selenium, the Thyroid, and the Endocrine System

Article

Jan 2006

Recent identification of new selenocysteine-containing proteins has revealed relationships between the two trace elements selenium (Se) and iodine and the hormone network. Several selenoproteins participate in the protection of thyrocytes from damage by H(2)O(2) produced for thyroid hormone biosynthesis. Iodothyronine deiodinases are selenoproteins contributing to systemic or local thyroid hormone homeostasis. The Se content in endocrine tissues (thyroid, adrenals, pituitary, testes, ovary) is higher than in many other organs. Nutritional Se depletion results in retention, whereas Se repletion is followed by a rapid accumulation of Se in endocrine tissues, reproductive organs, and the brain. Selenoproteins such as thioredoxin reductases constitute the link between the Se metabolism and the regulation of transcription by redox sensitive ligand-modulated nuclear hormone receptors. Hormones and growth factors regulate the expression of selenoproteins and, conversely, Se supply modulates hormone actions. Selenoproteins are involved in bone metabolism as well as functions of the endocrine pancreas and adrenal glands. Furthermore, spermatogenesis depends on adequate Se supply, whereas Se excess may impair ovarian function. Comparative analysis of the genomes of several life forms reveals that higher mammals contain a limited number of identical genes encoding newly detected selenocysteine-containing proteins.

Effect of age on sexually dimorphic selenoprotein expression in mice

Article

Nov 2007

Clinical data suggest that selenium (Se) supplementation decreases disease predisposition and severity and accelerates recovery in a variety of pathologies. Pre-supplementation Se levels and sex represent important determinants of these Se-dependent health effects. Accordingly, we previously reported on sexually dimorphic expression patterns of Se-dependent glutathione peroxidase 1, type I deiodinase, and selenoprotein P in young mice. In the present study we investigated whether these differences vary with age. The strong sexual dimorphic expression of hepatic type I deiodinase that was observed in young mice vanished both at the mRNA and enzyme activity level by 1 year of age. In contrast, the strong sex-specific differences in renal type I deiodinase mRNA expression were sustained with age. Accordingly, deiodinase enzymatic activities differed in male and female kidneys, largely independent of age [average of 6.8 vs. 15.7 pmol/(min mg) in males vs. females]. In parallel, hepatic Se concentrations and glutathione peroxidase activities increased in female mice compared to male littermates, establishing a new sexual dimorphism in liver. Thus, age represents another important modifier of the dynamic sex- and tissue-specific selenoprotein expression patterns. These data highlight again the unique physiological regulatory mechanisms that have evolved to control Se metabolism according to the actual needs of the organism.

Peroxides and Peroxide-Degrading Enzymes in the Thyroid

Article

Oct 2008
ANTIOXID REDOX SIGN

Iodination of thyroglobulin is the key step of thyroid hormone biosynthesis. It is catalyzed by thyroid peroxidase and occurs within the follicular space at the apical plasma membrane. Hydrogen peroxide produced by thyrocytes as an oxidant for iodide may compromise cellular and genomic integrity of the surrounding cells, unless these are sufficiently protected by peroxidases. Thus, peroxidases play two opposing roles in thyroid biology. Both aspects of peroxide biology in the thyroid are separated in space and time and respond to the different physiological states of the thyrocytes. Redox-protective peroxidases in the thyroid are peroxiredoxins, glutathione peroxidases, and catalase. Glutathione peroxidases are selenoenzymes, whereas selenium-independent peroxiredoxins are functionally linked to the selenoenzymes of the thioredoxin reductase family through their thioredoxin cofactors. Thus, selenium impacts directly and indirectly on protective enzymes in the thyroid, a link that has been supported by animal experiments and clinical observations. In view of this relationship, it is remarkable that rather little is known about selenoprotein expression and their potential functional roles in the thyroid. Moreover, selenium-dependent and -independent peroxidases have rarely been examined in the same studies. Therefore, we review the relevant literature and present expression data of both selenium-dependent and -independent peroxidases in the murine thyroid.

Jan 1988
113-1109

R Gutekunst
W Becker
R Hehrmann
T Olbricht
P Pfannenstiel
Ultraschalldiagnostik
Schilddruse

Gutekunst R, Becker W, Hehrmann R, Olbricht T & Pfannenstiel P. Ultraschalldiagnostik der Schilddruse. Deutsche Medizinische Wochenschrift 1988 113 1109-12.

Selenium and goiter prevalence in borderline iodine sufficiency (doi:10.1530/eje.1.02302) Association of selenium with thyroid volume and echostructure in 35-to 60-year-old French adults

Jan 2003
807-812

Vf Brauer
U Schweizer
J Kohrle
R Paschke
H Derumeaux
P Valeix
K Castetbon
M Bensimon
Mc Boutron-Ruault
J Arnaud
S Hercberg

Brauer VF, Schweizer U, Kohrle J & Paschke R. Selenium and goiter prevalence in borderline iodine sufficiency. European Journal of Endocrinology 2006 155 807–812. (doi:10.1530/eje.1.02302) 11 Derumeaux H, Valeix P, Castetbon K, Bensimon M, Boutron- Ruault MC, Arnaud J & Hercberg S. Association of selenium with thyroid volume and echostructure in 35-to 60-year-old French adults. European Journal of Endocrinology 2003 148 309–315. (doi:10.1530/eje.0.1480309)

164 www.eje-online.org in children with concurrent selenium and iodine deficiency

Jan 2011

EUROPEAN JOURNAL OF ENDOCRINOLOGY (2011) 164 www.eje-online.org in children with concurrent selenium and iodine deficiency.

eje-online.org in children with concurrent selenium and iodine deficiency

www.eje-online.org in children with concurrent selenium and iodine deficiency.

Selenium status, thyroid volume, and multiple nodule formation in an area with mild iodine deficiency

Abstract

No full-text available

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