scholarly journals Iodoprophylaxis and thyroid autoimmunity: an update

2021 ◽  
Author(s):  
Claudia Teti ◽  
Marta Panciroli ◽  
Elena Nazzari ◽  
Giampaola Pesce ◽  
Stefano Mariotti ◽  
...  
Keyword(s):  
Iodine Deficiency ◽  
Thyroid Disease ◽  
Thyroid Dysfunction ◽  
Thyroid Autoimmunity ◽  
Iodine Intake ◽  
Secondary Response ◽  
Main Question ◽  
Thyroid Antibodies ◽  
Iodine Prophylaxis ◽  
Iodine Excess

AbstractAdequate iodine intake is necessary for normal thyroid function. Iodine deficiency is associated with serious complications, but also iodine excess can lead to thyroid dysfunction, and iodine supplementation aimed to prevent iodine deficiency disorders has been associated with development of thyroid autoimmunity. The epidemiology of thyroid diseases has undergone profound changes since the implementation of iodoprophylaxis, notably by means of iodine-enriched salt, specifically resulting in decreased prevalence of goiter and neonatal hypothyroidism, improved cognitive function development in infancy, and reduced incidence of more aggressive forms of thyroid cancer. The main question we address with this review is the clinical relevance of the possible effect on autoimmunity exerted by the use of iodine-enriched salt to correct iodine deficiency. In animal models, exogenous iodine is able to trigger or exacerbate thyroid autoimmunity, but it is still not clear whether the observed immunological changes are due to a direct effect of iodine on immune response, or whether they represent a secondary response to a toxic effect of iodine on thyroid tissue. Previous iodine status of a population seems to influence the functional thyroid response to increased iodine intake and possibly the development of thyroid autoimmunity. Moreover, the prevalence of thyroid antibodies, regarded as hallmark of autoimmune thyroid disease, varies between populations under the influence of genetic and environmental factors, and the presence of thyroid antibodies does not always coincide with the presence of thyroid disease or its future development. In addition, the incidence of autoimmune diseases shows a general increasing trend in the last decades. For all these reasons, available data are quite heterogeneous and difficult to analyze and compare. In conclusion, available data from long-term population surveys show that a higher than adequate population iodine intake due to a poorly controlled program of iodine prophylaxis could induce thyroid dysfunction, including thyroid autoimmunity mostly represented by euthyroid or subclinical hypothyroid autoimmune thyroiditis. Close monitoring iodine prophylaxis is therefore advised to ensure that effects of both iodine deficiency and iodine excess are avoided.

scholarly journals Increased prevalence of hyperthyroidism as an early and transient side-effect of implementing iodine prophylaxis

2007 ◽  
Vol 10 (8) ◽  
pp. 799-802 ◽  
Author(s):  
Filip Gołkowski ◽  
Monika Buziak-Bereza ◽  
Małgorzata Trofimiuk ◽  
Agata Bałdys-Waligórska ◽  
Zbigniew Szybiński ◽  
...  
Keyword(s):  
Iodine Deficiency ◽  
Thyroid Dysfunction ◽  
Thyroid Autoimmunity ◽  
Final Analysis ◽  
Iodine Intake ◽  
Thyroid Stimulating Hormone ◽  
Iodine Prophylaxis ◽  
Sudden Rise ◽  
Epidemiological Surveys ◽  
Thyroid Microsomal Antibodies

AbstractObjectiveTo assess the prevalence of hyperthyroidism just after implementation of iodine prophylaxis among adults from an area with iodine deficiency.Study design and subjectsA total of 1648 adults (age 16 years and older) were sampled from an area of southern Poland during two nationwide epidemiological surveys. Of these, 1424 adults with negative medical history for thyroid disorders qualified for final analysis. The authors compared thyroid dysfunction in participants prior to (1989–1990) and after implementation of iodine prophylaxis (1997–1999).SettingThe southern part of Poland.ResultsWe found an increase in the serum concentration of anti-thyroid microsomal antibodies from 4.9% in the years 1989–1990 to 12.1% after introduction of iodised household salt (P < 0.0001). The prevalence of hyperthyroidism (defined as thyroid-stimulating hormone < 0.4 μU ml− 1) significantly increased in the equivalent period from 4.8 to 6.5% (P = 0.009).ConclusionsWe concluded that a sudden rise in iodine intake after implementation of iodine prophylaxis among adults from the area with iodine deficiency may lead to an increase in thyroid autoimmunity and prevalence of hyperthyroidism. Those possible early side-effects appear to be only temporary and are acceptable when compared with the evident benefits of adequate iodine intake.

Epidemiology of thyroid disease and swelling

2011 ◽  
pp. 358-370 ◽  
Author(s):  
Mark P. J. Vanderpump
Keyword(s):  
Iodine Deficiency ◽  
Thyroid Disease ◽  
Autoimmune Thyroid Disease ◽  
Thyroid Dysfunction ◽  
Daily Intake ◽  
Urinary Iodine ◽  
Iodine Intake ◽  
Thyroid Disorders ◽  
Autoimmune Thyroid ◽  
Salt Iodization

Thyroid disorders are among the most prevalent of medical conditions. Their manifestations vary considerably from area to area and are determined principally by the availability of iodine in the diet. The limitations of epidemiological studies of thyroid disorders should therefore be borne in mind when considering the purported frequency of thyroid diseases in different communities (1). Almost one-third of the world’s population live in areas of iodine deficiency and risk the consequences despite major national and international efforts to increase iodine intake, primarily through the voluntary or mandatory iodization of salt (2). The ideal dietary allowance of iodine recommended by the WHO is 150 μ‎g iodine/day, which increases to 250 μ‎g in pregnancy and 290 μ‎g when lactating. The WHO estimates that two billion people, including 285 million school-age children still have iodine deficiency, defined as a urinary iodine excretion of less than 100 μ‎g/l. This has substantial effects on growth and development and is the most common cause of preventable mental impairment worldwide. In areas where the daily iodine intake is below 50 μ‎g, goitre is usually endemic, and when the daily intake falls below 25 μ‎g, congenital hypothyroidism is seen. The prevalence of goitre in areas of severe iodine deficiency can be as high as 80%. Iodization programmes are of proven value in reducing goitre size and in preventing goitre development and cretinism in children. Goitrogens in the diet, such as thiocyanate in incompletely cooked cassava or thioglucosides in Brassica vegetables, can explain some of the differences in prevalence of endemic goitre in areas with similar degrees of iodine deficiency. Autonomy can develop in nodular goitres leading occasionally to hyperthyroidism, and iodization programmes can also induce hyperthyroidism, especially in those aged over 40 years with nodular goitres. Autoimmune thyroiditis or hypothyroidism has not been reported to complicate salt iodization programmes. Relatively little prevalence data exist for autoimmune thyroid disease in areas of iodine deficiency (3). In iodine-replete areas, most people with thyroid disorders have autoimmune disease, ranging through primary atrophic hypothyroidism, Hashimoto’s thyroiditis, to hyperthyroidism caused by Graves’ disease. Cross-sectional studies in Europe, the USA, and Japan have determined the prevalence of hyperthyroidism, hypothyroidism, and the frequency and distribution of thyroid autoantibodies in different, mainly white, communities (1, 4–6). Recent US data have revealed differences in the frequency of thyroid dysfunction and serum antithyroid antibody concentrations in different ethnic groups (6), whereas studies from Europe have revealed the influence of dietary iodine intake on the epidemiology of thyroid dysfunction (7). Studies of incidence of autoimmune thyroid disease have only been conducted in a small number of developed countries (8–11). Following a review of the available epidemiological data, the value of screening adult populations for autoimmune thyroid disease will be considered.

scholarly journals Relevance of iodine intake as a reputed predisposing factor for thyroid cancer

2007 ◽  
Vol 51 (5) ◽  
pp. 701-712 ◽  
Author(s):  
Meyer Knobel ◽  
Geraldo Medeiros-Neto
Keyword(s):  
Thyroid Cancer ◽  
Iodine Deficiency ◽  
Animal Experiments ◽  
Experimental Studies ◽  
Epidemiological Studies ◽  
Iodine Intake ◽  
Thyroid Cell ◽  
Predisposing Factor ◽  
Iodine Prophylaxis ◽  
Iodine Excess

Iodine is a trace element that is essential for the synthesis of thyroid hormone. Both chronic iodine deficiency and iodine excess have been associated with hypertrophy and hyperplasia of follicular cells, attributed to excessive secretion of TSH. This may be associated to thyroid cancer risk, particularly in women. Experimental studies have documented thyroid cancer induction by elevation of endogenous TSH, although in a small number of animals. Iodine deficiency associated with carcinogenic agents and chemical mutagens will result in a higher incidence of thyroid malignancy. Inadequate low iodine intake will result in increased TSH stimulation, increased thyroid cell responsiveness to TSH, increased thyroid cell EGF-induced proliferation, decreased TGFbeta 1 production and increased angiogenesis, all phenomena related to promotion of tumor growth. Epidemiological studies associating iodine intake and thyroid cancer led to controversial and conflicting results. There is no doubt that introduction of universal iodine prophylaxis in population previously in chronic iodine-deficiency leads to a changing pattern of more prevalent papillary thyroid cancer and declining of follicular thyroid cancer. Also anaplastic thyroid cancer is practically not seen after years of iodine supplementation. Iodine excess has also been indicated as a possible nutritional factor in the prevalence of differentiated thyroid cancer in Iceland, Hawaii and, more recently, in China. In conclusion: available evidence from animal experiments, epidemiological studies and iodine prophylaxis has demonstrated a shift towards a rise in papillary carcinoma, but no clear relationship between overall thyroid cancer incidence and iodine intake.

scholarly journals Iodine and Thyroid Function Status, and Anti-thyroid Peroxidase Antibody among Pregnant Women in Eastern Nepal

2017 ◽  
Vol 15 (2) ◽  
pp. 114-119 ◽  
Author(s):  
Lalit Narayan Chaudhary ◽  
Saroj Khatiwada ◽  
Basanta Gelal ◽  
Sharad Gautam ◽  
Madhab Lamsal ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Iodine Deficiency ◽  
Thyroid Dysfunction ◽  
Thyroid Autoimmunity ◽  
Urinary Iodine ◽  
Iodine Intake ◽  
Thyroid Peroxidase ◽  
Urinary Iodine Concentration ◽  
Free T4 ◽  
Thyroid Peroxidase Antibody

Background: Iodine deficiency, thyroid dysfunction and development of thyroid autoimmunity during pregnancy may affect mother and the developing fetus. This study was carried out to find iodine status, thyroid dysfunction and thyroid autoimmunity among pregnant women.Methods: Ninety two pregnant women from three districts of eastern Nepal (Sunsari, Morang and Jhapa) were enrolled for the study, and urine and blood samples were collected. Urinary iodine concentration (UIC), free thyroxine (free T4), thyroid stimulating hormone (TSH), thyroglobulin and anti-thyroid peroxidase (TPO) antibody levels were estimated.Results: The median UIC, mean free T4 and TSH, median thyroglobulin and anti-TPO antibody in the pregnant women were 282.2 (158.42-376) μg/L, 1.14±0.41 ng/dL, 4.57±2.56 IU/mL, 6.5 (4.0-11.0) ng/mL, 1.52 (0.97-2.23) IU/mL respectively. In sufficient (<150 μg/L), adequate (150-249 μg/L) and above requirements (250-499 μg/L) iodine intake was observed in 17 (18.5%), 22 (23.9%) and 53 (57.6%) women respectively. Subclinical hypothyroidism and overt hypothyroidism were seen in 18 (19.5%) and 1(1.1%) women, respectively. Elevated thyroglobulin (>40 ng/mL) and positive anti-TPO antibody was observed in three (3.26%) women for both.Conclusions: Iodine intake was sufficient among pregnant women recently, however, chronic iodine deficiency persisted in small fraction of pregnant women. Mild thyroid dysfunction was common, and thyroid autoimmunity was present in small portion of Nepalese pregnant women population.Keywords: Anti-thyroid peroxidase antibody; Iodine deficiency; Nepal; pregnant women; thyroid dysfunction.

scholarly journals U-shaped relationship between iodine status and thyroid autoimmunity risk in adults

2019 ◽  
Vol 181 (3) ◽  
pp. 255-266 ◽  
Author(s):  
Bin Wang ◽  
Weiwei He ◽  
Qian Li ◽  
Xi Jia ◽  
Qiuming Yao ◽  
...  
Keyword(s):  
Iodine Deficiency ◽  
Dose Response ◽  
Meta Analysis ◽  
Thyroid Autoimmunity ◽  
Epidemiological Studies ◽  
Population Based ◽  
Iodine Intake ◽  
Cross Sectional ◽  
Iodine Status ◽  
Iodine Excess

Background Iodine status has long been regarded as an environmental determinant for thyroid dysfunction, but its relationship with thyroid autoimmunity (TAI) is still controversial. Our study aimed to elucidate the relationship between iodine status and TAI through both a population-based study and a dose–response meta-analysis of eligible epidemiological studies. Methods A population-based, cross-sectional study was firstly carried out, which enrolled a total of 2808 Chinese adults. Odds ratio (OR) with 95% confidence interval (95% CI) was calculated through logistic regression analysis. A dose–response meta-analysis of eligible epidemiological studies was also carried out. Results The cross-sectional study showed an U-shaped relationship between iodine intake and TAI in adults. Compared with those with more than adequate iodine status, individuals with iodine deficiency, adequate iodine status and iodine excess all had higher risk of TAI, and the adjusted ORs were 1.50 (95% CI 1.03–2.17, P = 0.032), 1.50 (95% CI 1.09–2.07, P = 0.013) and 1.68 (95% CI 1.11–2.53, P = 0.014), respectively. The dose–response meta-analysis included 22 epidemiological studies with a total of 69,987 participants and further validated the U-shaped relationship between iodine intake and TAI in adults, which proved the significantly increased risk of TAI among individuals with either iodine deficiency or iodine excess. Stratified analysis of studies with low risk of confounding bias also identified similar findings. Conclusion The study suggests an U-shaped relationship between iodine intake and TAI in adults, and both iodine deficiency and iodine excess are risk factors of TAI in adults. The underlying mechanisms need to be elucidated in future studies.

scholarly journals Thyroid dysfunction in region of excess iodine intake of eastern Nepal

2018 ◽  
Vol 4 (8) ◽  
pp. 214
Author(s):  
Zheng Feei Ma ◽  
Hongxia Zhang
Keyword(s):  
Pregnant Women ◽  
Iodine Deficiency ◽  
Thyroid Dysfunction ◽  
Iodine Intake ◽  
Micronutrient Deficiencies ◽  
Iodine Excess ◽  
Excess Iodine

Iodine deficiency is one of most common micronutrient deficiencies worldwide, the consequences of excess iodine should not be ignored. Both chronic iodine excess and iodine deficiency can result in thyroid dysfunction in populations, especially children and pregnant women if not corrected. This is because children and pregnant women are very vulnerable to iodine deficiency and sensitive to iodine changes

scholarly journals Increased frequency of positive antithyroid antibody in nodular goiter

2016 ◽  
Vol 8 (2) ◽  
pp. 109
Author(s):  
Md. Shah Emran ◽  
M.A. Hasanat ◽  
Md. Qamrul Hassan ◽  
Ahmed Abu Saleh ◽  
Murshed Ahamed Khan ◽  
...  
Keyword(s):  
Thyroid Autoimmunity ◽  
Nodular Goiter ◽  
Cross Sectional Study ◽  
Iodine Intake ◽  
Thyroid Tumor ◽  
Common Belief ◽  
Thyroid Antibodies ◽  
Cross Sectional ◽  
Healthy Control ◽  
Selection Of

<p><strong>Background:</strong> Nodular goiter is mostly a benign thyroid tumor. A change of frequency of nodular goiter in areas with sufficient iodine intake has been documented in several reports. However, contrary to common belief it may also be associated with autoimmunity is being observed recently by many investigators.</p><p><strong>Objectives:</strong> To observe association between thyroid autoimmunity and nodular goiter.</p><p><strong> Methods:</strong> This cross sectional study included two hundred cases and one hundred controls. Clinically suspected nodular thyroid patients were confirmed by USG. Selection of healthy control was done after exclusion of nodule clinically and by USG. Data were collected through a structured questionnaire.</p><p><strong>Results:</strong> Frequency of positive anti-thyroid antibodies was significantly higher in nodular goiter cases, when anti-TPO and anti-TG considered together (42.5% vs. 25.0%; χ<sup>2</sup>=8.792, p=0.003) as well as individually (anti-TPO: 37.0% vs. 20.0%; χ<sup>2</sup>=8.955, p=0.004 and anti-TG: 31.0% vs. 9.0%; χ<sup>2</sup>=17.861, p&lt;0.001) in the patients with nodular goiter than that of control. Conversely, there was no statistical difference between STN and MNG for antibody status when considered together (41.lvs. 42.5%; χ<sup>2</sup>=0.093; p=0.769) or separately (for anti-TPO: 34.2% vs. 38.6%; χ<sup>2</sup>=0.374, p=0.648 and anti TG: 27.4% vs. 33.1%; χ<sup>2</sup>=0.698, p=0.431). Also there was no statistical disparity for frequency of positivity of the two antibodies in STN (p=0.359) and MNG (p=0.167).</p><p><strong>Conclusion:</strong> Significant number of nodular goiter cases was positive for anti-thyroid antibodies.</p>

scholarly journals Iodine Status in Schoolchildren and Pregnant Women of Lazio, a Central Region of Italy

Nutrients ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1647 ◽  
Author(s):  
Baldini ◽  
Virili ◽  
D’Armiento ◽  
Centanni ◽  
Ulisse
Keyword(s):  
Pregnant Women ◽  
Health Care Providers ◽  
Iodine Deficiency ◽  
Iodine Intake ◽  
World Health ◽  
Urinary Iodine Concentration ◽  
Care Providers ◽  
Iodine Prophylaxis ◽  
Italian Regions ◽  
Epidemiological Surveys

The inhabitants of Lazio, similarly to those of other Italian regions, have been historically exposed to the detrimental effects of an inadequate intake of iodine. The latter is a micronutrient essential for the biosynthesis of thyroid hormones (TH). Iodine deficiency is responsible for a number of adverse effects on human health known as iodine deficiency disorders (IDD), the most common of which worldwide are goiter and hypothyroidism. In order to reduce IDD, a national salt iodination program was started in Italy in 2005. In this article we reviewed the available data regarding iodine intake in the Lazio population before and after the introduction of the national salt iodination program, in order to evaluate its efficacy and the eventual problem(s) limiting its success. On the whole, the information acquired indicates that, following the introduction of the program, the dietary iodine intake in the Lazio population is improved. There is, however, still much work ahead to ameliorate the iodine prophylaxis in this region. In fact, although a generally adequate iodine intake in school-age children has been observed, there are still areas where a mild iodine insufficiency is present. Moreover, two independent epidemiological surveys on pregnant women evidenced a low urinary iodine concentration with respect to the reference range conceived by the World Health Organization. These findings demonstrate the need for greater attention to the iodine prophylaxis by health care providers (i.e., obstetricians, gynecologists, pediatricians, etc.), and the implementation of effective advertising campaigns aimed at increasing the knowledge and awareness of the favorable effects of iodine supplementation on population health.

Comparative screening for thyroid disorders in old age in areas of iodine deficiency, long‐term iodine prophylaxis and abundant iodine intake

1997 ◽  
Vol 47 (1) ◽  
pp. 87-92 ◽  
Author(s):  
István Szabolcs ◽  
Jan Podoba ◽  
Joachim Feldkamp ◽  
Orsolya Dohán ◽  
Ildikó Farkas ◽  
...  
Keyword(s):  
Old Age ◽  
Iodine Deficiency ◽  
Iodine Intake ◽  
Thyroid Disorders ◽  
Iodine Prophylaxis

scholarly journals Role of thyroid dysfunction and thyroid autoimmunity in infertile women: study done in 450 bedded maternity hospital of Delhi, India

2017 ◽  
Vol 6 (6) ◽  
pp. 2597
Author(s):  
Jyotsana Gupta ◽  
Charu Lata Bansal ◽  
Sangita Nangia Ajmani ◽  
Ajay Kumar Ajmani
Keyword(s):  
Thyroid Function ◽  
Thyroid Dysfunction ◽  
Thyroid Autoimmunity ◽  
Control Group ◽  
Study Group ◽  
Thyroid Antibodies ◽  
Free T4 ◽  
Infertile Women ◽  
Antithyroid Antibodies ◽  
The Mean

Background: the aim was to study the prevalence of abnormal thyroid function and thyroid autoimmunity in infertile women and in general population (control group) and to correlate the thyroid dysfunction with presence of anti-thyroid antibodies. It was a case control study. The study was carried out at Department of obstetrics and gynaecology, Kasturba Hospital, Delhi. Population of the study was fifty infertile women in whom other causes of infertility are excluded and fifty fertile women attending out- patient department with other complaints.Methods: All the women enrolled in the study were non pregnant, clinically euthyroid (with no signs and symptoms of thyroid disorders and no documented abnormal thyroid function test) and no known autoimmune disorder. Detailed history and a thorough general physical examination, including thyroid examination was done. Haemogram, blood group, fasting and post prandial blood sugar, VDRL, transabdominal ultrasound, TSH, free T3, free T4, and antithyroid per-oxidase antibody assay was done using the ELISA technique.Results: The mean age of the study group was found 28.38±2.45 years, 22% had abnormal thyroid function, 20% had antithyroid antibodies positive and the mean TSH of the study group was 4.61±1.72µIU/ml. The mean age of the control group was found to be 29.10±2.01 years, 12% had abnormal thyroid function, 10% had antithyroid antibodies positive and the mean TSH of the control group was 3.89±1.56µIU/ml.Conclusions: Thyroid dysfunction and anti-thyroid antibodies were more prevalent in patients with infertility. A statistically significant correlation was established between thyroid autoimmunity and thyroid dysfunction in infertile women in the study.

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