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This article discusses the importance and complexity of reference intervals for thyroid-stimulating hormone (TSH) levels. Reference intervals are established based on a sample of healthy individuals and are used to determine whether an individual's TSH levels are within the normal range. However, factors such as age, ethnicity, sex, iodine status, and pregnancy can affect the reference intervals for TSH. The article also highlights the impact of genetic factors on TSH reference intervals and suggests that personalized treatment based on more accurate reference intervals may improve patient outcomes. However, further research is needed to explore these possibilities. [Extracted from the article]

Background: Previous studies have reported gut microbiome alterations in Hashimoto's autoimmune thyroiditis (HT) patients. Yet, it is unknown whether an aberrant microbiome is present before clinical disease onset in participants susceptible to HT or whether it reflects the effects of the disease itself. In this study, we report for the first time a comprehensive characterization of the taxonomic and functional profiles of the gut microbiota in euthyroid seropositive and seronegative participants. Our primary goal was to determine taxonomic and functional signatures of the intestinal microbiota associated with serum thyroid peroxidase antibodies (TPOAb). A secondary aim was to determine whether different ethnicities warrant distinct reference intervals for accurate interpretation of serum thyroid biomarkers. Methods: In this cross-sectional study, euthyroid participants with (N = 159) and without (N = 1309) TPOAb were selected from the multiethnic (European Dutch, Moroccan, and Turkish) HEalthy Life In an Urban Setting (HELIUS) cohort. Fecal microbiota composition was profiled using 16S rRNA sequencing. Differences between the groups were analyzed based on the overall composition (alpha and beta diversity), as well as differential abundance (DA) of microbial taxa and functional pathways using multiple DA tools. Results: Overall composition showed a substantial overlap between the two groups (p > 0.05 for alpha-diversity; p = 0.39 for beta-diversity), indicating that TPOAb-seropositivity does not significantly differentiate gut microbiota composition and diversity. Interestingly, TPOAb status accounted for only a minor fraction (0.07%) of microbiome variance (p = 0.545). Further exploration of taxonomic differences identified 138 taxa nominally associated with TPOAb status. Among these, 13 taxa consistently demonstrated nominal significance across three additional DA methods, alongside notable associations within various functional pathways. Furthermore, we showed that ethnicity-specific reference intervals for serum thyroid biomarkers are not required, as no significant disparities in serum thyroid markers were found among the three ethnic groups residing in an iodine-replete area (p > 0.05 for thyrotropin, free thyroxine, and TPOAb). Conclusion: These findings suggest that there is no robust difference in gut microbiome between individuals with or without TPOAb in terms of alpha and beta-diversity. Nonetheless, several taxa were identified with nominal significance related to TPOAb presence. Further research is required to determine whether these changes indeed imply a higher risk of overt HT. [ABSTRACT FROM AUTHOR]

Thyroid ultrasound revealed 2.3 cm TR4 mid right nodule, 3.5 cm TR3 lower right thyroid nodule, and 4.7 cm right thyroid nodule that was incompletely visualized extending substernally. POSTER 258 I Thyroid Imaging Case Study Poster i THYROID BED EXTENSION OF THYROID MASS COMPLICATED BY TRACHEAL STENOSIS FROM MASS EFFECT Sakshi Sharma*, K. Romo, Qasim Iqbal Ochsner Clinic Foundation, USA Introduction: A goiter is defined as an enlargement of the thyroid gland regardless of etiology. POSTER 248 WITHDRAWN POSTER 249 I Thyroid Cancer Clinical Poster i IMPACT OF INCOME DISPARITY ON THYROID CANCER SURVIVAL AND SURGERY OUTCOMES: AN ANALYSIS USING... Mohammad Hussein SP 1 sp , Julia McGee* SP 2 sp , Alexandria Luu SP 2 sp , Michelle Tsang SP 2 sp , Manal Malik SP 2 sp , Eman Toraih SP 1 sp , Emad Kandil SP 3 sp SP 1 sp Department of Surgery, Tulane University School of Medicine, USA, SP 2 sp Tulane University School of Medicine, USA, SP 3 sp Division of Endocrine and Oncologic Surgery, Department of Surgery, Tulane University School of Medicine, USA Objective: Although the relationship between disparities and health outcomes of thyroid cancer patients has been studied, less is known about the specific effects of income inequalities on patient outcomes. Strap muscle retracted, swelling was present behind the left lobe of thyroid we dissected and removal done in total CONCLUSION: There are lots of site for dermoid cyst permeation usually in neck in midline But this was typical case presented in thyroid region giving totally looks like thyroid swelling misleading for thyroid diseases. Discussion: This case presents a patient who had previously undergone a right thyroid nodulectomy instead of formal lobectomy and had subsequently developed thyroid extensions outside the thyroid bed complicated by tracheal stenosis from mass effect. [Extracted from the article]

Background: We aimed to assess the long-term effects of the transition in iodine status on the incidence of thyroid disorders over 20 years of follow-up. Methods: The original prospective cohort study, started in 1999 (n = 3761), classified three regions in north China based on iodine status (insufficient iodine, more than adequate iodine, and excessive iodine, respectively) for 5 years. Subsequently, participants were followed for up to another 15 years to assess the long-term effects of shifts to adequate iodine on the incidence of thyroid disorders. Panshan transitioned from insufficient to adequate iodine, and Huanghua transitioned from excessive to more than adequate iodine. Both regions were compared with Zhangwu, in which iodine status changed from more than adequate to adequate iodine (from 214 to 167.2 μg/L). A cluster sampling method was used to select participants in the three regions. Participants completed questionnaires and underwent thyroid ultrasonography. Urinary iodine concentrations (UICs), serum thyroid hormone concentration, and thyroid antibodies were measured. Results: When the iodine status changed from insufficient to adequate (with the median UIC increasing from 88 to 141.9 μg/L), the incidence density of subclinical hyperthyroidism, positive thyroperoxidase antibody, positive thyroglobulin antibody (TgAb), and goiter decreased significantly (p < 0.05 for all). Additionally, the cumulative incidence of subclinical hypothyroidism was significantly lower compared with the region where the iodine status changed from being more than adequate to adequate (1.9% vs. 6.0%, p < 0.001). When the iodine status changed from excessive to more than adequate (median UIC from 634 to 266.7 μg/L), a significant decrease in the incidence density of subclinical hyperthyroidism, positive thyroid antibodies, positive TgAb, and goiter (p < 0.05 for all) were also found. However, an increase in thyroid nodule incidence density (17.26 vs. 28.25 per 1000 person-years, p < 0.001) was seen. Conclusions: The incidence of thyroid disorders (except for thyroid nodules) stabilized or decreased among adults in the three communities from year 5 to year 15 of follow-up. Appropriate iodine fortification is safe and effective over the long term. Restoring urinary iodine to appropriate levels reduces population risk for thyroid disorders. [ABSTRACT FROM AUTHOR]

Background: Iodine is required for the synthesis of thyroid hormone (TH), but its natural availability is limited. Dehalogenase1 (Dehal1) recycles iodine from mono- and diiodotyrosines (MIT, DIT) to sustain TH synthesis when iodine supplies are scarce, but its role in the dynamics of storage and conservation of iodine is unknown. Methods:Dehal1-knockout (Dehal1KO) mice were generated by gene trapping. The timing of expression and distribution was investigated by X-Gal staining and immunofluorescence using recombinant Dehal1-beta-galactosidase protein produced in fetuses and adult mice. Adult Dehal1KO and wild-type (Wt) animals were fed normal and iodine-deficient diets for 1 month, and plasma, urine, and tissues were isolated for analyses. TH status was monitored, including thyroxine, triiodothyronine, MIT, DIT, and urinary iodine concentration (UIC) using a novel liquid chromatography with tandem mass spectrometry method and the Sandell–Kolthoff (S-K) technique throughout the experimental period. Results: Dehal1 is highly expressed in the thyroid and is also present in the kidneys, liver, and, unexpectedly, the choroid plexus. In vivo transcription of Dehal1 was induced by iodine deficiency only in the thyroid tissue. Under normal iodine intake, Dehal1KO mice were euthyroid, but they showed negative iodine balance due to a continuous loss of iodotyrosines in the urine. Counterintuitively, the UIC of Dehal1KO mice is twofold higher than that of Wt mice, indicating that S-K measures both inorganic and organic iodine. Under iodine restriction, Dehal1KO mice rapidly develop profound hypothyroidism, while Wt mice remain euthyroid, suggesting reduced retention of iodine in the thyroids of Dehal1KO mice. Urinary and plasma iodotyrosines were continually elevated throughout the life cycles of Dehal1KO mice, including the neonatal period, when pups were still euthyroid. Conclusions: Plasma and urine iodotyrosine elevation occurs in Dehal1-deficient mice throughout life. Therefore, measurement of iodotyrosines predicts an eventual iodine shortage and development of hypothyroidism in the preclinical phase. The prompt establishment of hypothyroidism upon the start of iodine restriction suggests that Dehal1KO mice have low iodine reserves in their thyroid glands, pointing to defective capacity for iodine storage. [ABSTRACT FROM AUTHOR]

Objective: Gestational transient thyrotoxicosis (GTT) and Graves' disease (GD) are the most common causes of hyperthyroidism during pregnancy. However, few studies have compared pregnancy outcomes of patients who had GTT with those who had GD in the first trimester of pregnancy. Methods: We conducted a prospective multicenter cohort study in China. Participants received questionnaires, physical examinations, and underwent measurements of thyrotropin (TSH), free thyroxine (fT4), thyroid peroxidase antibody (TPOAb), TSH receptor antibody (TRAb), and urinary iodine in the first trimester. The patients diagnosed with either GTT or GD and normal thyroid function (NTF) group were followed until delivery. The thyroid function and pregnancy outcomes were reported. Results: A total of 125 pregnant women with thyrotoxicosis and 246 age-matched pregnant women with NTF were included. (1) The thyroid function of the GTT group returned to normal range in the third trimester, but was consistently abnormal in the GD group. (2) The incidence of gestational diabetes mellitus (GDM) in the GTT group (11.5%, 9/78) was significantly higher than that in NTF group (4.9%, 12/246) (p = 0.037). The incidence of premature delivery in the GD untreated (30.8%, 8/26, p = 0.002) and treated groups (28.6%, 6/21, p = 0.008) was both, respectively, higher than that in the NTF group (7.7%, 19/246). Miscarriage (15.4%, 4/26 vs. 3.7%, 9/246, p = 0.026) and gestational hypertension (19.2%, 5/26 vs. 3.3%, 8/246, p = 0.004) were more prevalent in the GD untreated group than in the NTF group. (3) The presence of positive TRAb and positive TPOAb in the first trimester were independent risk factors for miscarriage (odds ratio [OR] = 5.23, confidence interval [CI] = 1.11–24.78, p = 0.037) and low birth weight infants (OR = 7.76, CI = 1.23–48.86, p = 0.029), respectively. Conclusion: In conclusion, pregnancy outcomes appear variable, according to the etiology of first trimester thyrotoxicosis. GTT appears to be associated with GDM. GD appears to be associated with an increased risk of premature delivery, gestational hypertension, and miscarriage. The diagnosis of GTT and GD patients during early pregnancy and appropriate treatment of GD patients may be associated with improved pregnancy outcomes. [ABSTRACT FROM AUTHOR]

A study published in the journal Thyroid examines the risk of progression from gestational subclinical hypothyroidism (SH) and hypothyroxinemia (IHT) to overt hypothyroidism (OH) after pregnancy. The study found that the risk of developing OH was higher in women with SH compared to those with IHT. Additionally, participants with positive thyroid peroxidase (TPO) antibodies were more likely to develop OH. The study suggests that routine measurement of TPO antibody titer and long-term monitoring of thyroid function may be beneficial for patients with gestational thyroid hypofunction. However, further research is needed to determine the potential benefits of treating subclinical thyroid hypofunction during pregnancy. [Extracted from the article]

Background: Congenital hypothyroidism due to defects in iodotyrosine deiodinase has variable phenotypes and can present as hypothyroid or with normal thyroid testing. Methods: Whole exome sequencing was performed in individuals from two families originating from different regions of Sudan. Mass spectrometry of urine and serum iodotyrosines was performed on subjects from both families. Results: A novel iodotyrosine deiodinase (IYD) mutation (c.835C>T; R279C) was identified in individuals from two Sudanese families inherited as autosomal recessive. The mutation was identified by multiple in silica analyses to likely be detrimental. Serum and urine monoiodotyrosine (MIT) and diiodotyrosine (DIT) were markedly elevated in the homozygous subjects. Conclusion: Measurement of serum and urine DIT and MIT was more sensitive than that of urine iodine or serum thyroid function tests to determine the effect of the IYD mutation. [ABSTRACT FROM AUTHOR]

Iodine is an essential component of the hormones produced by the thyroid gland and is, therefore, essential for mammalian life. A landmark trial in the early 20th century definitively demonstrated that iodine supplementation could prevent what was then known as "endemic goiter." Subsequent studies over the next decades demonstrated that iodine deficiency causes a spectrum of disease, including not just goiter, but also cretinism, intellectual impairment, and adverse obstetric outcomes. Salt iodization, first used in Switzerland and the United States in the1920s, has become the mainstay of iodine deficiency prevention efforts. The dramatic reduction in the global prevalence of iodine deficiency disorders (IDD) over the past 30 years represents an outstanding and under-recognized public health achievement. This narrative review provides an overview of critical scientific discoveries and advances in public health nutrition related to the prevention of IDD in the United States and worldwide. This review was written to commemorate the centennial of the founding of the American Thyroid Association. [ABSTRACT FROM AUTHOR]

BackgroundIodine deficiency has long been recognized as an important public health problem. Global approaches such as salt iodization that aim to overcome iodine deficiency have been successful. Meanwhile, they have led to excessive iodine consumption in some populations, thereby increasing the risks of iodine-induced thyroid dysfunction, as well as the comorbidities and mortality associated with hypothyroidism and hyperthyroidism. This study aimed to elucidate whether iodine intake is associated with mortality among U.S. adults.MethodsThis was an observational study to estimate mortality risks according to urinary iodine concentration (UIC) utilizing a nationally representative sample of 12,264 adults aged 20-80 years enrolled in the National Health and Nutrition Examination Survey (NHANES) III. Crude and multivariable Cox proportional hazards regression models were employed to investigate the association between UIC (

Optimizing iodine nutrition preconception and during pregnancy would prevent a significant number of IH cases globally.[4] In addition, identifying and treating iron deficiency in gestation may also play a role in reducing IH.[19] Overall, Han et al. provide strong evidence for increased risks of multiple adverse pregnancy and neonatal outcomes in maternal IH. One major challenge in addressing IH during pregnancy is the lack of evidence for LT4 treatment benefits. Isolated hypothyroxemia (IH) is defined as a low maternal free thyroxine (fT4) level with a normal thyrotropin (TSH) concentration. Given the substantial potential for confounding in observational studies, there is currently insufficient evidence to determine whether LT4 treatment mitigates the risk of adverse outcomes during pregnancies with IH. [Extracted from the article]

The serum thyrotropin (TSH) concentration is an effective rule-out test for primary thyroid disease when used in the context of appropriate reference intervals. The effect of thyroid antibody positivity on reference intervals for thyroid stimulating hormone (TSH) and free thyroxine (FT4) in an aged population. [Extracted from the article]

1, also cover figure of this issue).[[2], [4]] This latter aspect is not mentioned by Uchida et al., and it is relevant to briefly summarize the history of the use of iodine in the treatment of goiter and hyperthyroidism. Remission after potassium iodide therapy in patients with Graves' hyperthyroidism exhibiting thionamide-associated side effects. In this issue of I Thyroid i , Uchida et al. present a mouse model of Graves' hyperthyroidism generated by immunization of BALB/c mice with the human thyrotropin receptor A-subunit.[1] The investigators then compared the serum thyroxine (T4) and triiodothyronine (T3) levels, the intrathyroidal content of iodothyronines, as well as expression profiles of genes involved in thyroid hormonogenesis and secretion in untreated mice (GD-C) and mice treated with inorganic iodide (GD-NaI). In aggregate, these studies add additional mechanistic details on the effects of inorganic iodide in Graves' disease,[1] a treatment that has been introduced a century ago by Henry S. Plummer (1874-1936; see Fig. [Extracted from the article]

Background: Multinodular goiter (MNG) is the most common disorder of the thyroid gland. Aging and genetic mutations that impair thyroid hormone (TH) production have been implicated in the development of MNG. XB130 is an adaptor/scaffold protein predominantly expressed in the thyroid gland. XB130 deficiency leads to transient postnatal growth retardation in mice due to congenital hypothyroidism. We studied the formation of MNG and possible mechanisms in elderly mice. Methods: Thyroid glands of male and female Xb130-knockout (Xb130−/−), heterozygous (Xb130+/−), and wild-type (Xb130+/+) mice at the ages of 12–20 months were harvested for visual examination, histopathological, and immunohistological analyses. Blood and thyroid samples were collected after feeding elderly mice with a low iodine diet for 125I uptake and perchlorate discharge assay. The activity of thyroperoxidase (Tpo) was examined by spectrophotometric evaluation of iodide oxidation. Results: While moderate MNG was seen in Xb130+/+ and Xb130+/− mice, severe MNG, characterized by multiple nodules intermixed with dilated colloid-rich macrofollicles, was found only in Xb130−/− mice at 18 months. Thyrocyte cytoskeletal structure and cell adhesion molecules were disorganized, and TH production was significantly reduced. Reduced iodide organification was seen in elderly Xb130+/+ mice and further enhanced in Xb130−/− mice. In Xb130+/+ mice, Tpo shows high affinity with hydrogen peroxide (H2O2) throughout aging, but reduced affinity with iodide in an age-dependent manner. By contrast, in elderly Xb130−/− mice, the affinity of Tpo for iodide remained high, but the affinity of Tpo for H2O2 was reduced. Conclusions: The pathophysiological features in the thyroid glands of aged Xb130−/− mice closely resemble the features of MNG in humans. Moderate MNG in elderly mice was dramatically aggravated by XB130 deficiency. Reduced affinity of Tpo for H2O2 may contribute to MNG development via oxidative stress. This could be specific to XB130 deficiency but also could be a common mechanism in MNG. Its clinical relevance should be further investigated. [ABSTRACT FROM AUTHOR]

Background: The incidence of thyroid disease is generally increasing, and it is subject to major geographic variability, between and within countries. Moreover, the incidence rates and the proportion of overdiagnosis for thyroid cancer in Italy are among the highest worldwide. This study aimed to estimate population-based frequency and trends of thyroidectomies in Italy by type of surgical procedure (total/partial), indication (tumors/other conditions), sex, age, and geographical region. Materials and Methods: Age-standardized rates (ASRs) of thyroidectomies were estimated from 2001 to 2018 using the national hospital discharges database. Results: In Italy, ASRs of thyroidectomies were nearly 100 per 100,000 women in 2002–2004 and decreased to 71 per 100,000 women in 2018. No corresponding variation was shown in men (ASR 27 per 100,000 men) in the overall period. A more than twofold difference between Italian regions emerged in both sexes. The proportion of total thyroidectomies (on the sum of total and partial thyroidectomies) in the examined period increased from 78% to 86% in women and from 72% to 81% in men. Thyroidectomies for goiter and nonmalignant conditions decreased consistently throughout the period (from 81 per 100,000 women in 2002 to 49 in 2018 and from 22 to 16 per 100,000 men), while thyroidectomies for tumors increased until 2013–2014 up to 24 per 100,000 women (9 per 100,000 men) and remained essentially stable thereafter. Conclusions: The decrease in thyroidectomies for nonmalignant diseases since early 2000s in Italy may derive from the decrease of goiter prevalence, possibly as a consequence of the reduction of iodine deficiency and the adoption of conservative treatments. In a context of overdiagnosis of thyroid cancer, recent trends have suggested a decline in the diagnostic pressure with a decrease in geographic difference. Our results showed the need and also the possibility to implement more conservative surgical approaches to thyroid diseases, as recommended by international guidelines. [ABSTRACT FROM AUTHOR]

Objective: Arctic living is influenced by cold winters, short summers, and excessive iodine intake from the traditional Inuit diet providing for habitation of the Arctic for centuries. This is changing and we surveyed thyroid function in populations living in Greenland. Design: Population-based cross-sectional study. Methods: Data were collected in the capital city in West Greenland and in rural East Greenland. Information on lifestyle, dietary habits, and medical history was obtained using questionnaires. Thyrotropin, free thyroxine, free triiodothyronine, thyroglobulin, and thyroglobulin antibody were measured in serum, iodine, and creatinine in spot urine samples. Results: One percent of the Greenlandic population was invited and 535 participated with an overall participation rate of 95%. Iodine excretion was 225 μg/24 hours in East Greenland and 169 μg/24 hours among West Greenland Inuit. Hyperthyroidism occurred in 10.7% of West Greenlandic Inuit (men/women: 4.3%/16.3%) and 7.8% of East Greenlandic Inuit (3.8%/12.8%). Hypothyroidism was found in 2.7% in West Greenland (0.0%/5.0%) and 5.6% (5.6%/5.6%) in East Greenland. Conclusion: Hyperthyroidism was frequent among Inuit and the occurrence of hypothyroidism was low. The pattern of hyper- and hypothyroidism among Greenlandic Inuit with adequate iodine intake was comparable with those seen in populations with iodine deficiency. Inuit may thus have adapted to excessive iodine intake over centuries, causing a need for a higher iodine intake to prevent iodine deficiency disorders. [ABSTRACT FROM AUTHOR]

Background: Despite the implementation of the universal salt iodization (USI) program for correction of iodine deficiency in China for ∼20 years, the actual iodine nutrition status of Chinese residents and the prevalence of iodine deficiency and iodine excess are issues that need to be addressed. This nationally representative cross-sectional study was conducted across all 31 provinces of mainland China to gather extensive data on iodine nutrition status and the influential factors. Methods: This study included 78,470 participants, aged 18 years or older, who were interviewed and asked to answer a questionnaire. Urine iodine concentration (UIC) was measured by the inductively coupled plasma mass spectrometry method, and goiter was examined by thyroid ultrasonography. In addition, sixty 9–11 years old school children in each province were randomly selected to evaluate the UIC and thyroid ultrasonography. The iodine nutrition status was determined according to the World Health Organization guidelines. Results: The iodized salt coverage was 95.37%. The median urine iodine (MUI) was 177.89 μg/L (interquartile range [IQR], 117.89–263.90 μg/L) and goiter prevalence was 1.17% (confidence interval [95% CI 0.95–1.43]) in the adult population. The MUI was 199.75 μg/L (IQR, 128.41–303.37 μg/L) in school-age children, and goiter prevalence was 3.50% [95% CI, 2.93–4.13]. The percentage of individuals with UIC <50 μg/L was 3.43%, <20%. Analysis indicated that sex, age, geographic factors, body mass index, and smoking habits influence the iodine nutrition level. Conclusion: The mandatory USI program has successfully eliminated iodine deficiency disorders, and the findings indicate that the iodine nutrition level in the general population is within the safe range. [ABSTRACT FROM AUTHOR]

Background: Iron deficiency affects thyroid hormone synthesis by impairing the activity of the heme-dependent thyroid peroxidase. The prevalence of iron deficiency is elevated particularly in pregnant women. This study aimed to investigate the effects of iron status on thyroid function in a nationally representative sample of mildly iodine-deficient pregnant women. Methods: The study population comprised a sample of pregnant women in Belgium during the first and third trimesters of pregnancy (n = 1241). Women were selected according to a multistage proportional-to-size stratified and clustered sampling design. Urine and blood samples were collected, and a questionnaire was completed face to face with the study nurse. Concentrations of free thyroxine (fT4), total thyroxine (T4), free triiodothyronine, thyrotropin (TSH), thyroglobulin (Tg), thyroid peroxidase antibodies, Tg antibodies, hemoglobin, serum ferritin (SF), soluble transferrin receptor, urinary iodine concentrations (UICs) were measured and body iron stores (BIS) were calculated. Results: Median UICs were 117 and 132 μg/L in the first and third trimesters of pregnancy, respectively (p < 0.05). The frequency of SF <15 μg/L was 6.2% in the first trimester and 39.6% in the third trimester of pregnancy (p < 0.05). UIC was a significant predictor of serum Tg concentrations (p < 0.01) but not of thyroid hormone or TSH concentrations. The frequency of fT4

Background: Iodine-induced hyperthyroidism (IIH) was a common issue in the early twentieth century after introduction of iodine supplementation in dietary salt. Currently, IIH is mostly encountered in Western countries as a consequence of radiographic procedures involving the administration of iodinated contrast media (ICM). However, little is known about the magnitude and clinical relevance of this issue. To assess the incidence of hyperthyroidism after ICM exposure, we performed a systematic review and meta-analysis of the literature. Methods: MEDLINE, Embase, and the Cochrane Library were systematically searched for studies published between 1946 and May 2018. Studies were considered eligible if they investigated the association between hyperthyroidism and iodinated contrast. Data on study design, baseline characteristics, and outcomes were extracted independently by two reviewers. Results: Thirty out of 1493 retrieved studies were included in the analysis. The time endpoint to assess thyroid hormone levels after ICM exposure varied between 1 and 541 days among studies, with most studies having a time endpoint between 7 and 56 days. The overall estimated prevalence of overt hyperthyroidism after ICM exposure was extremely low (0.1% [confidence interval, CI 0–0.6%]), and did not change after adjustments for baseline thyroid function status (0.3% in euthyroid patients at baseline [CI 0–1.7%]). There were no cases with overt hyperthyroidism at 7 days after ICM exposure, and the incidence was very low at 30 days (0.2% [CI 0–0.8%]). Conclusion: The incidence of IIH after ICM administration during radiographic procedures is extremely low. [ABSTRACT FROM AUTHOR]

Background: Although substantial progress has been made in recent decades in eliminating iodine deficiency, iodine deficiency disorders (IDDs) are still prevalent in European countries. Challenges include ineffective public health programs and discontinuation of IDD prevention. However, the barriers against the implementation and continuation of prevention and monitoring of IDD remain unclear. Therefore, the objective of our study was to identify potential barriers against pan-European IDD prevention and monitoring programs and to find solutions for the different challenges. Methods: We conducted a Delphi study consisting of three rounds. We identified potential participants with expertise and experience in relevant fields from all European countries, including policy makers, health care professionals, health scientists, and patient representatives. The Delphi method was conducted with open-ended questions and item ranking to achieve group consensus on potential barriers against national and pan-European IDD prevention and monitoring programs and related solutions to overcome those barriers. The answers of the Delphi rounds were analyzed using qualitative content analysis and descriptive analysis methods. In addition, we conducted two expert interviews to analyze and discuss the study results. Results: Eighty experts from 36 countries and different fields of work participated in the first Delphi round, 52 in the second, and 46 in the third. Potential barriers include challenges in the fields of knowledge and information, implementation and management, communication and cooperation, political support, and differences between the European countries. Ranked solutions addressing these barriers include cooperation with different stakeholders, gaining knowledge, sharing information, the development of a European program with national specification, European guidelines/recommendations, and European monitoring. The ranking gives a first overview as to which of these barriers would need to be solved most urgently and which solutions may be most helpful. Conclusion: In our study, we derived key information and first insights with regard to barriers against IDD prevention programs from a broad range of stakeholders. Most barriers were found in the category of implementation and management. Also a lack of political support seems to play an important role. The findings of our study may help decision makers in health policy to develop more effective IDD prevention and monitoring strategies. [ABSTRACT FROM AUTHOR]

Background: Iodine deficiency is one of the most prevalent causes of intellectual disability and can lead to impaired thyroid function and other iodine deficiency disorders (IDDs). Despite progress made on eradicating iodine deficiency in the last decades in Europe, IDDs are still prevalent. Currently, evidence-based information on the benefit/harm balance of IDD prevention in Europe is lacking. We developed a decision-analytic model and conducted a public health decision analysis for the long-term net benefit of a mandatory IDD prevention program for the German population with moderate iodine deficiency, as a case example for a European country. Methods: We developed a decision-analytic Markov model simulating the incidence and consequences of IDDs in the absence or presence of a mandatory IDD prevention program (iodine fortification of salt) in an open population with current demographic characteristics in Germany and with moderate ID. We collected data on the prevalence, incidence, mortality, and quality of life from European studies for all health states of the model. Our primary net-benefit outcome was quality-adjusted life years (QALYs) predicted over a period of 120 years. In addition, we calculated incremental life years and disease events over time. We performed a systematic and comprehensive uncertainty assessment using multiple deterministic one-way sensitivity analyses. Results: In the base-case analysis, the IDD prevention program is more beneficial than no prevention, both in terms of QALYs and life years. Health gains predicted for the open cohort over a time horizon of 120 years for the German population (82.2 million inhabitants) were 33 million QALYs and 5 million life years. Nevertheless, prevention is not beneficial for all individuals since it causes additional hyperthyroidism (2.7 million additional cases). Results for QALY gains were stable in sensitivity analyses. Conclusions: IDD prevention via mandatory iodine fortification of salt increases quality-adjusted life expectancy in a European population with moderate ID, and is therefore beneficial on a population level. However, further ethical aspects should be considered before implementing a mandatory IDD prevention program. Costs for IDD prevention and treatment should be determined to evaluate the cost effectiveness of IDD prevention. [ABSTRACT FROM AUTHOR]

Objective: Placental iodide transport is necessary for maintaining an adequate iodide supply to the developing fetus. We hypothesized that compounds from the placental barrier can compensate for decreases in maternal iodine intake and normalize fetal iodine levels. Methods: Pregnant rats administered different amounts of iodine (1.24, 2.5, 5, or 10 μg/day) were evaluated on gestational day (gd) 16 and 20. The iodine levels in maternal blood, amniotic fluid (AF), and placental tissue were estimated using As-Ce catalytic spectrophotometry. The protein and/or messenger RNA (mRNA) levels of sodium iodide symporter (NIS), pendrin, alpha-smooth muscle actin (α-SMA), and CD31 in the placental labyrinth, trophoblast cells isolated using laser capture microdissection (LCM), and/or fetomaternal thyroid were detected using immunoblotting, real-time polymerase chain reaction, and/or immunohistochemistry. Results: When iodine intake was reduced, iodine levels in maternal blood gradually decreased; however, placental iodine levels were not significantly different between groups on gd16 and gd20. Minimal changes were observed in AF iodine levels on gd16, and a mild decreasing trend was observed (iodine dose, 10 to 1.24 μg/day) on gd20. NIS protein, which was linearly distributed along the basolateral membrane of maternal–fetal thyroid follicles, gradually increased with decreasing iodine levels. Regarding iodine deficiency in the placental labyrinth on gd16 and gd20, pendrin and glycosylated NIS proteins were significantly upregulated in a dose-dependent manner. However, the mRNA levels were unchanged. Furthermore, the conversion of NIS protein from the nonglycosylated to the glycosylated form increased. In trophoblast cells isolated using LCM, PDS mRNA levels increased in the 1.24-μg/day group on gd16 but not NIS mRNA levels. There was a smaller α-SMA+ area in the labyrinth zone on gd16 and gd20; however, the proportional CD31+ area increased on gd16 and reduced on gd20 with decreased iodine levels. Conclusions: All mechanisms upregulating the expression of iodine transporters and changes in villous stroma and microvessel area in the placental labyrinth can promote iodide transfer from mother to fetus in iodine deficiency, especially before the onset of fetal thyroid function. Compensatory NIS protein regulation in the placenta against decreased iodine intake mainly occurs during translation and glycosylation modification after translation. Pendrin may be more important than NIS in the mediation of placental iodide transport. [ABSTRACT FROM AUTHOR]

Background: Mild-to-moderate iodine deficiency is still present in many countries, particularly in pregnant women. Observational studies suggest that mild-to-moderate iodine deficiency during pregnancy may be associated with impaired thyroid function and child neurodevelopment. Randomized-controlled food trials to increase iodine status are scarce. We assessed the impact of an increased intake of cod during pregnancy on maternal iodine status and infant neurodevelopment. Methods: In this randomized-controlled trial, pregnant women in Bergen, Norway, recruited through Haukeland University Hospital, were randomly assigned (1:1) to an intervention of 200 g of cod twice a week for 16 weeks (gestational week 20–36) or to continue with their standard diet (control group). Randomization was done by lottery. Primary outcome was urinary iodine concentration (UIC) (spot samples from six consecutive days) measured postintervention. Secondary outcome was infant neurodevelopment assessed by the cognitive, language, and motor scales of the Bayley Scales of Infant and Toddler Developmental third edition (Bayley-III) at 11 months of age. In addition, maternal thyroid function was measured (thyrotropin [TSH], free triiodothyronine [fT3], free thyroxine [fT4]) at baseline and postintervention. Results: Between January 2016 until February 2017, 137 women were recruited. Postintervention UIC was higher in the intervention group (n = 61) [median (interquartile range, IQR) 98 (64–145) μg/L], compared with control (n = 61) [median (IQR) 73 (52–120) μg/L] (p = 0.028), also after adjusting for baseline UIC (p = 0.048). Infants of mothers in the intervention group had a lower cognitive composite score on the Bayley-III compared with the control group (p = 0.045). There were no group differences in the Bayley III language- or motor composite scores. Maternal thyroid hormones (TSH, fT3, fT4) did not differ between the groups postintervention. Conclusions: Increased cod intake during pregnancy improved the iodine status in women with mild-to-moderate iodine deficiency, however, did not affect thyroid function. The negative effect on cognition should be followed up to assess whether this is a stable effect over time. More studies are warranted to enable good health advice on iodine nutrition in pregnancy. ClinicalTrials.gov NCT02610959. Registered November 20, 2015. [ABSTRACT FROM AUTHOR]

Background: Longitudinal data assessing the impact of iodine deficiency (ID) on mortality are scarce. We aimed to study the association between the state of iodine nutrition and the risk of total and cause-specific mortality in a representative sample of the Spanish adult population. Methods: We performed a longitudinal observational study to estimate mortality risk according to urinary iodine (UI) concentrations using a sample of 4370 subjects >18 years representative of the Spanish adult population participating in the nationwide study Di@bet.es (2008–2010). We used Cox regression to assess the association between UI at the start of the study (<50, 50–99, 100–199, 200–299, and ≥300 μg/L) and mortality during follow-up (National death registry—end of follow-up December 2016) in raw models, and adjusted for possible confounding variables: age, sex, educational level, hypertension, diabetes, obesity, chronic kidney disease, smoking, hypercholesterolemia, thyroid dysfunction, diagnosis of cardiovascular disease or cancer, area of residence, physical activity, adherence to Mediterranean diet, dairy and iodinated salt intake. Results: A total of 254 deaths were recorded during an average follow-up period of 7.3 years. The causes of death were cardiovascular 71 (28%); cancer 85 (33.5%); and other causes 98 (38.5%). Compared with the reference category with adequate iodine nutrition (UI 100–300 μg/L), the hazard ratios (HRs) of all-cause mortality in the category with UI ≥300 μg/L were 1.04 (95% confidence interval [CI 0.54–1.98]); however, in the categories with 50–99 UI and <50 μg/L, the HRs were 1.29 [CI 0.97–1.70] and 1.71 [1.18–2.48], respectively (p for trend 0.004). Multivariate adjustment did not significantly modify the results. Conclusions: Our data indicate an excess mortality in individuals with moderate-severe ID adjusted for other possible confounding factors. [ABSTRACT FROM AUTHOR]

Background: We aimed to examine the association of urinary iodine concentration with Hashimoto's thyroiditis (HT) risk, and particularly, to investigate whether the HT-related genetic variations might modify the effects of urinary iodine on HT in the Chinese Han population. Methods: We conducted a case–control study with 1723 Chinese (731 cases, 992 controls). The associations between urinary iodine concentration and HT risk were analyzed using logistic regression models. The effects of interactions between the genetic risk scores (GRSs) and urinary iodine on HT risk were assessed by including the respective interaction terms in the models. We also applied restricted cubic spline regression to estimate the possible nonlinear relationship. The multinomial logistic regression models were performed to determine the associations of urinary iodine with euthyroid-HT and hypothyroidism-HT. Results: After controlling for potential confounders, the odds of HT increased with increasing quartiles of urinary iodine concentration: adjusted odds ratios (ORs) and 95% confidence intervals [CIs] were 1.45 [1.06–1.99], 1.66 [1.17–2.34], and 2.07 [1.38–3.10] for the quartiles 2, 3, and 4, respectively, compared with the first quartile (p for trend <0.001). Multivariable restricted cubic spline regression analysis further demonstrated that there was a near-linear association between urinary iodine concentration and HT risk (p-overall <0.001; p-nonlinear = 0.074). However, we did not find significant interactions between urinary iodine and GRSs on the risk of HT (all p for interaction >0.05). Interestingly, we found that each increment of urinary iodine was associated with a more than twofold increase in the odds of hypothyroidism-HT (adjusted OR = 2.64 [CI = 1.73–4.05]), but not with euthyroid-HT (p > 0.05). Conclusions: Higher urinary iodine concentration was associated with increased risk of HT, and this association was near linear, indicating that increased urinary iodine has a continuous and graded impact on HT risk. Moreover, the iodine-HT association was not modified by genetic predisposition to HT. Interestingly, urinary iodine concentration was significantly associated with increased risk of hypothyroidism. [ABSTRACT FROM AUTHOR]

Background: Subclinical hypothyroidism is diagnosed based on serum thyrotropin (TSH) reference intervals, which in turn are affected by many factors. Methods: Data were acquired from a Chinese nationally representative cross-sectional study of 78,470 participants (TIDE study). The total study population were participants from the TIDE program, and the reference population was a subset of the total population defined by the National Academy of Clinical Biochemistry (NACB) guidelines. Serum concentrations of thyroid hormones, TSH, thyroid antibodies, and urine iodine concentration (UIC) were measured. Results: The geometric mean serum TSH (2.5th–97.5th) for the reference population (defined by the NACB) and total population was 2.28 mIU/L (0.74–7.04 mIU/L) and 2.34 mIU/L (0.61–8.33 mIU/L), respectively. In the reference population, increase in UIC was significantly associated with increase in the 50th and 97.5th centiles and decrease in the 2.5th centile of TSH. The median TSH was significantly higher in women than in men (2.41 mIU/L vs. 2.16 mIU/L, p-value <0.001). Increased age was significantly associated with an increased TSH, 97.5th centile. For each 10-year increase in the population age, the TSH 97.5th centile increased by 0.534 mIU/L. The prevalence of subclinical hypothyroidism diagnosed according to the assay-recommended interval (Roche 0.27–4.2 mIU/L) and NACB standard interval in the TIDE study (0.74–7.04 mIU/L) differed significantly (Roche 13.61% vs. TIDE 3.00%, p < 0.05). However, there was no significant difference in future cardiovascular disease, reflected by the Framingham risk score, between the 0.27–4.2 and 4.2–7.04 mIU/L TSH groups. Conclusions: Serum TSH concentration significantly increased with increase in iodine intake. Thus, iodine intake must be considered in establishing TSH reference intervals. To avoid overdiagnosis and overtreatment of subclinical hypothyroidism, different areas should use individual serum TSH reference intervals. [ABSTRACT FROM AUTHOR]

Background: There has been tremendous progress over the past 25 years to control iodine deficiency disorders (IDDs) through universal salt iodization (USI). In 2019, using the median urinary iodine concentration (MUIC), only 19 countries in the world are classified as iodine deficient; in contrast in 1993, using the total goiter rate (TGR), 113 countries were classified as iodine deficient. However, few analyses have tried to quantify the global health and economic benefits of USI programs, and the shift from TGR to MUIC as the main indicator of IDDs complicates assessment of progress. Methods: We used a novel approach to estimate the impact of USI on IDDs, applying a regression model derived from observational data on the relationship between the TGR and the MUIC from 24 countries. The model was used to generate hypothetical national TGR values for 2019 based on current MUIC data. TGR in 1993 and modeled TGR in 2019 were then compared for 139 countries, and using consequence modeling, the potential health and economic benefits realized between 1993 and 2019 were estimated. Results: Based on this approach, the global prevalence of clinical IDDs (as assessed by the TGR) fell from 13.1% to 3.2%, and 720 million cases of clinical IDDs have been prevented by USI (a reduction of 75.9%). USI has significantly reduced the number of newborns affected by IDDs, with 20.5 million cases prevented annually. The resulting improvement in cognitive development and future earnings suggest a potential global economic benefit of nearly $33 billion. However, 4.8 million newborns will be affected by IDDs in 2019, who will experience life-long productivity losses totaling a net present value of $12.5 billion. Conclusions: The global improvements in iodine status over the past 25 years have resulted in major health and economic benefits, mainly in low- and middle-income countries. Efforts should now focus on sustaining this achievement and expanding USI to reach the continuing large number of infants who remain unprotected from IDDs. [ABSTRACT FROM AUTHOR]

Background: Insufficient or excessive iodine intake during gestation may compromise adaptive mechanisms in maternal thyroid function and lead to adverse pregnancy outcomes. In this context, we aimed to study the effects of maternal iodine status in the first and third trimesters of gestation on obstetric and neonatal outcomes in an iodine-sufficient population in Rio de Janeiro, Brazil. Methods: A total of 214 pregnant women in the first trimester of gestation were enrolled and prospectively followed until delivery between 2014 and 2017. All participants were ≥18 and ≤35 years, had a spontaneous single pregnancy, and had no history of thyroid or other chronic diseases, nor were they taking iodine-containing supplements at enrollment. In the first trimester, we obtained clinical information and determined thyroid function and the urinary iodine concentration (UIC) of the participants. Thyroid function and UIC were reassessed in the third trimester. Iodine status was determined by the median of UIC obtained from six urine spot samples by the inductively coupled plasma mass spectrometry method. Pregnancy and neonatal outcomes and delivery information were obtained from medical records. Results: The median UIC in the whole population was 219.7 μg/L. The prevalence of UIC <150 μg/L was 17.2%, and 38.7% had UIC ≥250 μg/L. Gestational diabetes (GDM) was higher in the group with UIC 250–499 μg/L (n = 77) compared with the group with UIC 150–249 μg/L (n = 94) (20.3% vs. 9.7%, p < 0.05). Ultimately, UIC ≥250 μg/L was an independent risk factors for GDM (relative risk [RR] = 2.9 [confidence interval, CI = 1.1–7.46], p = 0.027) and hypertensive disorders of pregnancy (HDP) (RR = 4.6 [CI = 1.1–18.0], p = 0.029). Among 196 live-born newborns, lower birth length was observed in infants whose mothers had UIC <150μg/L (n = 37) in the first trimester compared with those with UIC 150–249 μg/L (n = 86) (median interquartile range: 48.0 [2.2] vs. 49.0 [4.0] cm, p = 0.01). Maternal UIC <150 μg/L was negatively associated with birth length of newborns (Exp (B) = 0.33 [CI = 0.1–0.9], p = 0.03). Conclusions: In a population whose median iodine intake is sufficient, extensive individual variation occurs. Such abnormalities are associated with increased GDM and HDP when UIC is ≥250 μg/L, and lower infant birth length when UIC is <150 μg/L. [ABSTRACT FROM AUTHOR]

Background: Iodine is important in both thyroid function and human metabolism. Studies have explored the effect of iodine on metabolic disorders through thyroid function. This study aimed to investigate the relationship between iodine status and metabolic disorders, such as metabolic syndrome (MetS), hypertension, impaired glucose metabolism, central obesity, and dyslipidemia. Methods: A total of 51,795 subjects aged ≥18 years from the TIDE (Thyroid Disorders, Iodine Status and Diabetes, a national epidemiological cross-sectional study) program were included. The prevalence of metabolic disorders and its related diseases was calculated based on the level of urinary iodine concentrations (UICs) using the chi-square method. To further explore whether the prevalence was associated with UIC, quadratic and UIC-stratified logistic regression models were used. Results: The prevalence of metabolic disorders as a function of UIC was found to be U-shaped with a lower prevalence of 76.0% at an UIC of 300–499 μg/L. Participants with an UIC of 300–499 μg/L showed an association with metabolic disorders (odds ratio [OR] = 0.857, 95% confidence interval [CI 0.796–0.922]) and hypertension (OR = 0.873 [CI 0.814–0.936]). An UIC of 300–799 μg/L was found to be associated with the occurrence of MetS and impaired glucose tolerance. An UIC of 500–799 μg/L was associated with the occurrence of prediabetes (OR = 0.883 [CI 0.797–0.978]). An UIC of ≥300 μg/L was associated with the occurrence of hypertriglyceridemia, hypercholesterolemia, and high levels of low-density lipoprotein cholesterol. Furthermore, an UIC of <100 μg/L showed an association with hypertension (OR = 1.097 [CI 1.035–1.162]) and hypercholesterolemia (OR = 1.178 [CI 1.117–1.242]). Conclusions: The association between UICs in adults and metabolic disorders and its related diseases is U-shaped. The association between UIC and metabolic disorders disappears in cases of iodine deficiency (<100 μg/L) or excess (≥500 μg/L). [ABSTRACT FROM AUTHOR]

Background: Globally, iodine deficiency has been drastically reduced since the introduction of salt iodization programs; nonetheless, many populations remain at-risk for iodine deficiency. This study aimed to assess the iodine status among women of reproductive age in Uzbekistan and to identify factors associated with iodine deficiency, including the availability of adequately iodized salt at the household level. Methods: A cross-sectional household survey was conducted to produce region-specific estimates of the household coverage with adequately iodized salt and iodine status among women for each of the 14 regions in Uzbekistan. Other information, such as socioeconomic status, lactation and pregnancy, residence, age, and consumption of iodine supplements, was also collected. Results: Overall, 36% of 3413 households had adequately iodized salt (iodine concentration >15 ppm [parts per million (mg I/kg salt)]), 20% had inadequately iodized salt (5–14 ppm), and 44% had salt without detectable iodine (<5 ppm). Adequate iodization was found in 33.2% of the 2626 salt samples taken from retail packages labeled as "iodized," 36.5% of the 96 samples taken from retail packages without mention of iodization, and 50.5% of the 674 samples without the original packaging (p < 0.001). The median urinary iodine concentration (UIC) of 140.9 μg/L (95% confidence interval [CI 132.4–150.7]) in nonpregnant nonlactating women indicated adequate iodine status, while for nonpregnant lactating and pregnant women, the median UIC of 112.9 μg/L [CI 99.3–128.4] and 117.3 μg/L [CI 101.8–139.9], respectively, indicated borderline adequacy. Significant differences in UIC (p < 0.001) were found between nonpregnant nonlactating women living in households with adequately iodized salt (UIC 208.9 μg/L), inadequately iodized salt (UIC 139.1 μg/L), and noniodized salt (UIC 89.9 μg/L). Conclusions: Coverage with adequately iodized salt is low in Uzbekistan, and women in households with poorly iodized salt have substantially worse iodine status; claims on packaging about salt iodization do not reflect salt iodine content. This highlights the importance and effectiveness of salt iodization and the need to strengthen this program in Uzbekistan. [ABSTRACT FROM AUTHOR]

Background: Prevention and treatment of iodine deficiency-related diseases remain an important public health challenge. Iodine deficiency can have severe health consequences, such as cretinism, goiter, or other thyroid disorders, and it has economic implications. Our aim was to give an overview of studies applying decision-analytic modeling to evaluate the effectiveness and/or cost-effectiveness of iodine deficiency-related prevention strategies or treatments related to thyroid disorders. Methods: We performed a systematic literature search in PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online), EMBASE (Excerpta Medica Database), Tuft's Cost-Effectiveness Analysis Registry, and National Health System Economic Evaluation Database (NHS EED) to identify studies published between 1985 and 2018 comparing different prevention or treatment strategies for iodine deficiency and thyroid disorders by applying a mathematical decision-analytic model. Studies were required to evaluate patient-relevant health outcomes (e.g., remaining life years, quality-adjusted life years [QALYs]). Results: Overall, we found 3950 studies. After removal of duplicates, abstract/title, and full-text screening, 17 studies were included. Eleven studies evaluated screening programs (mainly newborns and pregnant women), five studies focused on treatment approaches (Graves' disease, toxic thyroid adenoma), and one study was about primary prevention (consequences of iodine supplementation on offspring). Most of the studies were conducted within the U.S. health care context (n = 7). Seven studies were based on a Markov state-transition model, nine studies on a decision tree model, and in one study, an initial decision tree and a long-term Markov state-transition model were combined. The analytic time horizon ranged from 1 year to lifetime. QALYs were evaluated as health outcome measure in 15 of the included studies. In all studies, a cost-effectiveness analysis was performed. None of the models reported a formal model validation. In most cases, the authors of the modeling studies concluded that screening is potentially cost-effective or even cost-saving. The recommendations for treatment approaches were rather heterogeneous and depending on the specific research question, population, and setting. Conclusions: Overall, we predominantly identified decision-analytic modeling studies evaluating specific screening programs or treatment approaches; however, there was no model evaluating primary prevention programs on a population basis. Conclusions deriving from these studies, for example, that prevention is cost-saving, need to be carefully interpreted as they rely on many assumptions. [ABSTRACT FROM AUTHOR]

Background: Mandatory universal salt iodization (USI) has been implemented in China for 20 years. Although iodine deficiency disorders are effectively controlled, the risk of excess iodine have been debated. Methods: A nationally representative cross-sectional study with 78,470 enrolled participants, aged 18 years or older, from all 31 provincial regions of mainland China was performed. The participants were given a questionnaire and underwent B-mode ultrasonography of the thyroid. Serum concentrations of thyroid hormones, thyroid antibodies, and urine iodine concentration (UIC) were measured. Results: The median UIC of the adult population was 177.89 μg/L. The weighted prevalence of thyroid disorders in adults were as follows: 0.78% of overt hyperthyroidism, 0.44% of subclinical hyperthyroidism, 0.53% of Graves' disease, 1.02% of overt hypothyroidism, 12.93% of subclinical hypothyroidism, 14.19% of positive thyroid antibodies, 10.19% of positive thyroid peroxidase antibodies, 9.70% of positive thyroglobulin antibodies, 1.17% of goiter, and 20.43% of thyroid nodules. Iodine excess was only associated with higher odds of overt hyperthyroidism and subclinical hypothyroidism, while iodine deficiency was significantly associated with higher odds of most thyroid disorders. In addition, increased iodine intake was significantly associated with elevated serum thyrotropin levels but was inversely associated with thyroid antibodies and thyroid nodules. Conclusions: The long-term mandatory USI program with timely adjustments is successful in preventing iodine deficiency disorders, and it appears to be safe. The benefits outweigh the risks in a population with a stable median iodine intake level of up to 300 μg/L. [ABSTRACT FROM AUTHOR]

Background: A population-based reference interval (RI) of thyroid hormones in pregnancy using a standardized methodology is crucial for clinicians to make accurate diagnoses and important for the comparison of test results obtained from different analytic platforms. Methods: We enrolled 600 healthy Chinese women to obtain longitudinal serum samples across gestation, after exclusion of subjects with antibodies to thyroid peroxidase, thyroglobulin or thyrotropin receptor. Gestational age-specific RIs were constructed by using polynomial regression equations with MLwiN. Results: Free thyroxine (fT4) levels rose to a peak at the 7th–8th gestational weeks and then declined gradually till 28th week, while thyrotropin (TSH) level decreased from early pregnancy to a nadir at the 9th week. The data support the recent notion by the American Thyroid Association to raise the TSH upper RI to 4.0 mIU/L. We also demonstrate that thyroid hormone reference ranges are not affected in a mildly iodine-deficient population and by including women with the presence of antibodies against thyroid peroxidase and thyroglobulin who are otherwise healthy. Conclusions: The study highlights a methodology in constructing gestational age-specific thyroid function test RIs on different analytic platforms to provide a better interpretation and comparison of results obtained across different platforms. [ABSTRACT FROM AUTHOR]

Background: Thyroid disorders such as subclinical hypothyroidism and isolated maternal hypothyroxinemia are understudied in pregnant women, despite their possible adverse effects on the health of mother and child. Also, the role of iodine deficiency in developing such disorders has not yet been fully understood. Methods: The present national population-based cross-sectional study was conducted on 1080 randomly recruited pregnant women, aged 20–40 from 12 provinces of Iran from 2013 to 2014. Serum concentrations of thyrotropin, T4, thyroid peroxidase antibody (TPOAb), and triiodothyronine (T3) resin uptake values were measured in fasting blood samples, and urinary iodine concentration (UIC) was measured in three separate urine samples. Multinomial logistic regression was run to analyze the possible risk factors regarding thyroid disorders. To clarify the role of iodine in thyroid status specifically, the determinants of UIC and its correlations with thyroid function tests were investigated independently and through subgroup analysis. Results: Isolated hypothyroxinemia was the most common thyroid disorder (9.9%), followed by subclinical hypothyroidism (8%). In comparison to euthyroid pregnant women, isolated hypothyroxinemia was more likely in pregnant women older than 30 years (odds ratio [OR] = 1.6), in the second and the third trimesters (OR = 2.62 and 2.12 respectively), with history of multiparity (OR = 1.72), residing in rural areas (OR = 1.57) and in the capital province of the country (OR = 3.3). Subclinical hypothyroidism was more likely in TPOAb positive pregnant women (OR = 2.56). All the mentioned ORs were statistically significant (p < 0.05). The UIC did not correlate significantly with any of the thyroid function tests in the study population. Subgroup analysis showed a significant correlation between UIC and T4 in pregnant women with subclinical hypothyroidism (p < 0.05). Conclusion: Isolated maternal hypothyroxinemia was the most prevalent thyroid disorder in Iranian pregnant women and its associated risk factors were identified. Although the calculated prevalence of thyroid disorders was expected in a moderately iodine deficient setting, no correlations between UICs and thyroid function tests were found at the individual level. The contribution of iodine deficiency to thyroid condition for each pregnant woman may be more evident in pregnant women with certain thyroid disorders or those with long-term iodine deficiency. [ABSTRACT FROM AUTHOR]

With the advent of advanced MRI technology to study the impact of non-neurological diseases on the brain, thyroidologists worldwide have sought to identify the structural and functional brain manifestations of hypothyroidism in children and adults. They used a combination of two MRI platforms to assess both brain structure and brain function in adults with newly diagnosed untreated hypothyroidism, based on thyrotropin measurements above the reference range and free thyroxine below. [Extracted from the article]

In the area of thyroid nodules and cancer, Danese and Pontecorvi reported that ultrasonography improved the diagnostic accuracy of fine-needle aspiration (FNA) of thyroid nodules by comparison of a series of ~5000 done with ultrasonography with 5000 done when only palpation of the nodule was the guide for needle placement ([15]). The January 2003 issue of I Thyroid i was entirely devoted to a highly cited series of articles entitled: laboratory medicine practice guidelines; laboratory support for the diagnosis and monitoring of thyroid disease compiled by Baloch I et al. i ([30]). The table of contents for the original studies was segregated into the major thyroid fields, including thyroid cancer and nodules; epidemiology; immunology, autoimmunity and Graves' ophthalmopathy; iodine and endemic goiter; pregnancy and fetal development; thyroid dysfunction; thyroid economy; thyroid radiology and nuclear medicine; and thyroid surgery. 48 Francis GL, Waguespack SG, Bauer AJ, Angelos P, Benvenga S, Cerutti JM, Dinauer CA, Hamilton J, Hay ID, Luster M, Parisi MT, Rachmiel M, Thompson GB, Yamashita S, American Thyroid Association Guidelines Task Force2015Management guidelines for children with thyroid nodules and differentiated thyroid cancer. [Extracted from the article]

Background: Severe maternal iodine deficiency can impact fetal brain development through effects on maternal and/or fetal thyroid hormone availability. The effects of mild-to-moderate iodine deficiency on thyroid function are less clear. The aim was to investigate the association of maternal urinary iodine concentration corrected for creatinine (UI/Creat) with thyroid function and autoantibodies in a mild-to-moderate iodine-deficient pregnant population. Methods: This study was embedded within the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy (SELMA) study. Clinical reference ranges were determined by the 2.5th and 97.5th population-based percentile cutoffs. The associations of UI/Creat with thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), total T4 (TT4), and total T3 (TT3) were studied using multivariable linear regression in thyroid peroxidase antibody (TPOAb)-negative women. The association of UI/Creat with TPOAb and thyroglobulin antibody (TgAb) positivity was analyzed using multivariable logistic regression. Results: Urinary iodine and thyroid function were measured at a median (95% range) gestational age of 10 (6–14) weeks in 2009 women. The median (95% range) UI/Creat was 85 μg/g (36–386) and the UI/Creat was below 150 μg/g in 80.1% of women. Reference ranges did not differ substantially by UI/Creat. A lower UI/Creat was associated with a lower TSH (p = 0.027), a higher TT4 (p = 0.032), and with a corresponding trend toward slightly higher fT4 (p = 0.081), fT3 (p = 0.079), and TT3 (p = 0.10). UI/Creat was not associated with the fT4/fT3 (p = 0.94) or TT4/TT3 ratios (p = 0.63). Women with a UI/Creat of 150–249 μg/g had the lowest prevalence of TPOAb positivity (6.1%), while women with a UI/Creat of <150 μg/g had a higher prevalence (11.0%, odds ratio [OR] confidence interval [95% CI] 1.84 [1.07–3.20], p = 0.029). Women with a UI/Creat ≥500 μg/g showed the highest prevalence and a higher risk of TPOAb positivity, however, only a small proportion of women had such a UI/Creat (12.5%, OR, [95% CI] 2.36 [0.54–10.43], p = 0.26). Conclusions: We could not identify any meaningful differences in thyroid function reference ranges. Lower iodine availability was associated with a slightly lower TSH and a higher TT4. Women with adequate iodine intake had the lowest risk of TPOAb positivity. [ABSTRACT FROM AUTHOR]

Background: Insufficient production of thyroid hormones results in hypothyroidism, while overproduction results in hyperthyroidism. These are common adult disorders, with hypothyroidism more common in the elderly. Jordan has had past problems with dietary iodine deficiency but there are no published studies assessing the population prevalence of these disorders in the Arab Middle East. Methods: A cross-sectional study was conducted in three representative areas of Jordan. There were 7085 participants with a mean age of 40.8 years. Participants completed a questionnaire and had blood taken for thyroid analysis. Results:Hypothyroidism: The prevalence of any hypothyroidism (already diagnosed and/or identified by blood testing) was 17.2% in females and 9.1% in males. Undiagnosed prevalence was 8% and 6.2% for females and males, respectively. The prevalence of subclinical hypothyroidism, defined as high serum thyrotropin (TSH) and normal serum-free thyroxine (fT4), was 5.98% among females and 4.40% among males. The prevalence of overt hypothyroidism, defined as high TSH and low fT4, was 2.00% among females and 1.80% among males. Only 53.5% (55.3% for females, 42.1% males) of those previously diagnosed with hypothyroidism had TSH levels within the appropriate range. Hyperthyroidism: The prevalence of any hyperthyroidism (already diagnosed and/or identified by blood testing) was 1.8% in females and 2.27% in males. The undiagnosed prevalence was 1.4% and 2.1% for females and males, respectively. The prevalence of subclinical hyperthyroidism (low TSH and normal fT4) was 1.20% and 1.80% among males and females accordingly. The prevalence of overt hyperthyroidism (low TSH and high fT4) was 0.2% among females and 0.3% among males. About 85.7% (83.3% for females, 100% males) of those previously diagnosed with hyperthyroidism had TSH levels within the appropriate range. Conclusions: The results of this study reveal that the total prevalence of thyroid dysfunction among adult females and males in Jordan is very high compared with international statistics, particularly in the rates of undiagnosed cases. This indicates the need for further assessment of the value of screening for adult hypothyroidism in Jordan. [ABSTRACT FROM AUTHOR]

Background: Thyroid cancer patients with radioiodine-refractory (RAI-R) disease, resulting from insufficient RAI delivery and/or RAI resistance, have increased mortality and limited treatment options. To date, studies have largely focused on tumor mutations associated with different stages of disease, which could provide prognostic value for RAI-R disease. It was hypothesized that germline variants contributing to intrinsic differences in iodine metabolism, tumor microenvironment, and/or immune surveillance are associated with RAI-R disease. Methods: Whole-genome genotyping data analysis was performed on 1145 Caucasian (CAU) patients, 244 of whom were RAI-R, and 55 African American (AA) patients, nine of whom were RAI-R. Germline-variant association studies were conducted using candidate genes involved in iodine metabolism or DNA-damage repair, as well as genome-wide association analysis. Initial data indicated several notable variants in a small number of patients (n = 7), who were later determined to be AA patients of >80% African ancestry (n = 37). This led to the study focusing on germline single nucleotide polymorphisms uniquely associated with RAI-R AA patients. Sanger sequencing was performed to validate risk alleles and identify the incidence of the common somatic mutations BRAFV600E, NRASQ61R, and HRASQ61R in AA patients whose primary tumor samples were available (28/55). Results: TG, BRCA1, and NSMCE2 haplotypes were identified as being uniquely associated with RAI-R AA patients of >80% African ancestry. All patients with the TG haplotype (n = 4) had a biochemical incomplete response to RAI therapy. Patients with the NSMCE2 haplotype (n = 4) were diagnosed at a young age (13, 17, 17, and 26 years old) with distant metastatic disease at initial diagnosis. The BRCA1 haplotype co-occurred in three out of four patients with the NSMCE2 haplotype. The incidence of BRAFV600E appears lower in papillary thyroid carcinomas from AA patients of >80% African ancestry (3/14; 21%) than in AA patients of <80% African ancestry (6/9; 67%), albeit only just approaching statistical significance (p = 0.077). The tumors available from three RAI-R AA patients were negative for BRAFV600E, NRASQ61R, and HRASQ61R. Conclusions: The identification of candidate RAI-R risk haplotypes may allow early stratification of clinical manifestations of RAI-R disease followed by early intervention and personalized treatment strategies. Functional annotation of candidate RAI-R risk haplotypes may provide insights into the mechanisms underlying RAI-R disease. [ABSTRACT FROM AUTHOR]

Background: In areas with incomplete salt iodization coverage, infants and children aged 6–24 months weaning from breast milk and receiving complementary foods are at risk of iodine deficiency. However, few data exist on the risk of excessive iodine intake in this age group. Thyroglobulin (Tg) is a sensitive marker of iodine intake in school-age children and adults and may be used to estimate the optimal iodine intake range in infancy. The aim of this study was to assess the association of low and high iodine intakes with Tg and thyroid function in weaning infants. Methods: This multicenter cross-sectional study recruited infants aged 6–24 months (n = 1543; Mage = 12.2 ± 4.6 months) receiving breast milk with complementary foods, from seven countries in areas with previously documented deficient, sufficient, or excessive iodine intake in schoolchildren or pregnant women. Urinary iodine concentration (UIC) and Tg, total thyroxine, and thyrotropin were measured using dried blood spot testing. Results: Median UIC ranged from 48 μg/L (interquartile range 31–79 μg/L) to 552 μg/L (interquartile range 272–987 μg/L) across the study sites. Median Tg using dried blood spot testing was high (>50 μg/L) at estimated habitual iodine intakes <50 μg/day and >230 μg/day. Prevalence of overt thyroid disorders was low (<3%). Yet, subclinical hyperthyroidism was observed in the countries with the lowest iodine intake. Conclusions: Tg is a sensitive biomarker of iodine intake in 6- to 24-month-old infants and follows a U-shaped relationship with iodine intake, suggesting a relatively narrow optimal intake range. Infants with low iodine intake may be at increased risk of subclinical thyroid dysfunction. In population monitoring of iodine deficiency or excess, assessment of iodine status using UIC and Tg may be valuable in this young age group. [ABSTRACT FROM AUTHOR]

Background: In 2007 and 2015, two studies were conducted in Ribeirão Preto, São Paulo, Brazil, on schoolchildren of both sexes attending schools of three different socioeconomic levels (school 1: low; school 2: middle; school 3: high). Methods: Iodine concentrations were measured in samples of kitchen salt from the home provided by the schoolchildren and in urine samples, and these levels were compared to the thyroid volume by clinical assessment. Results: In 2007, a marked discrepancy in iodine concentrations was found in salt samples in 300 schoolchildren of both sexes (age range 8–10 years). Urinary iodine excretion >100 μg/L was detected in all cases, and 55.2% had concentrations of >300 μg/L (considered to be the upper limit by the World Health Organization). There was no increase in thyroid volume among the schoolchildren. In 2015, after a change in the norms for salt iodination from 20–60 to 15–45 mg/kg, the study was repeated in 295 schoolchildren (age range 8–10 years) from the same three schools studied previously. An improved standardization of iodine concentration was observed in the salt samples provided by the children, as well as a significant reduction in ioduria, with 10.9% of the samples showing an iodine concentration of <100 μg/L and with a reduction to 30.5% of samples with >300 μg/L. An increase in thyroid volume was also observed in a greater proportion of children from school 1, with a 7.92%, 5.19%, and 0.85% prevalence of goiter at schools 1, 2, and 3, respectively. Conclusions: Despite the limitations of the present study, which include sample size and thyroid evaluation by palpation, it is inferred that the iodination of the Ribeirão Preto schoolchildren studied is adequate. However, the individual iodine intake of some students was <100 μg/L, and some students also had an increased thyroid volume, raising the possibility of a deterioration of iodine intake in 2015 compared to 2007. [ABSTRACT FROM AUTHOR]

Background: The necessity of iodine supplementation in lactating mothers residing in countries with sustained salt iodization programs for iodine sufficiency of breast-fed infants remains unclear. The aims of this study were to investigate the effect of iodine supplementation on iodine status and growth parameters of lactating mothers and breast-fed infants and to compare these data with that of formula-feeding mothers and their infants during the first year of infancy. Methods: In this multicenter, double-blinded, randomized clinical trial conducted in four healthcare centers in Tehran (Iran), healthy lactating mothers and their term newborns aged 3–5 days were randomly assigned to treatment groups: placebo, 150 μg/day iodine, or 300 μg/day iodine. They were followed up for 12 months. Formula-fed infants aged 30–45 days and their mothers were randomly selected from the same centers. The primary outcomes were maternal and infant urinary iodine concentrations (UICs), breast-milk iodine concentrations (BMICs), and infant growth parameters, measured at 1, 2, 4, 6, 9, and 12 months during routine health visits. The formula-fed group was assessed at 2, 4, 6, 9, and 12 months of age. Analysis was by per protocol principle using mixed-effects models. Results: Mother–newborn pairs (n = 180) in treatment groups and partially/exclusively formula-feeding mother–infant pairs (n = 60) participated between October 2014 and January 2016. Median baseline UICs in the treatment groups were 84 μg/L (interquartile range [IQR] 41–143 μg/L) in mothers and 208 μg/L (IQR 91–310 μg/L) in their infants. The values in the formula-fed group were 76 μg/L (IQR 40–144 μg/L) in mothers and 121 μg/L (IQR 66–243 μg/L) in infants. The 300 μg/day iodine group showed significantly higher UICs and BMICs than did the other treatment groups; infant UICs in the 150 μg/day iodine, placebo, and formula-fed groups were similar. Infants in all groups showed iodine sufficiency (median UIC ≥100 μg/L) throughout the study period. Anthropometric measurements were similar between the treatment and formula-fed groups over the study period, except at the last follow-up visit at 12 months. Conclusion: Supplementation of breast-feeding mothers with either 300 or 150 μg/day iodine improved their iodine status. However, the iodine status of infants in all groups studied indicated iodine sufficiency during the first year of infancy, demonstrating that in countries with effective salt iodization program, iodine supplementation for lactating mothers is unnecessary. [ABSTRACT FROM AUTHOR]

Background: Pregnant women are particularly vulnerable to iodine deficiency. Considering the rural–urban disparities in nutritional status in Pakistan, this study aimed to assess regional influences on nutritional iodine status of pregnant women in Pakistan. Methods: Data were collected from 1246 pregnant women in all trimesters of pregnancy who visited antenatal clinics for routine checkups in five Khyber Pakhtunkhwa province districts. Information concerning iodized salt intake and knowledge of iodine deficiency disorders (IDD) was obtained through an interview questionnaire. Goiter and urinary iodine concentration (UIC) levels were assessed by the palpation method and Sandell–Kolthoff reaction, respectively. Logistic regression analysis was used to quantify associations between residence (rural–urban), pregnancy trimester, and previous pregnancy outcomes with knowledge about IDD, iodized salt intake, presence of goiter, and UIC <150 μg/L. Results: Among study participants, 87.7% had no knowledge about IDD, and only 21.0% were consuming iodized salt. Goiter was present in 25.5% of the women. The median UIC level was 131 μg/L, and 41.3% of study participants had a UIC ≥150 μg/L. There were no significant differences between pregnant women from rural and urban settings in regions with a solid socioeconomic status with respect to knowledge about IDD, iodized salt intake, iodine deficiency, and goiter prevalence. Urban–rural differences were observed only in socioeconomically disadvantaged districts. Only pregnant women living in the Lakki Marwat district had higher odds of having knowledge of IDD and iodized salt intake than those from rural regions. Trimesters of pregnancy and previous pregnancy outcomes had no significant effect on the outcome measures. Conclusions: Relative to a national nutrition survey conducted in Pakistan in 2011, the results from this study indicate that UIC levels remained stable with mild iodine deficiency, whereas rates of goiter and iodized salt intake remained high and low, respectively, especially in rural areas. Rural–urban disparities were observed only in socioeconomically disadvantaged districts, and these disparities limit the effectiveness of the IDD prevention program in rural areas in Pakistan. Thus, implementation of mandatory salt iodization requires improvement, and program effectiveness should be continuously monitored to prevent adverse health effects of iodine deficiency during pregnancy. [ABSTRACT FROM AUTHOR]

Background: Milk is a major source of iodine in human nutrition. Because both iodine content and the consumption of milk and dairy vary widely over time and populations, their contribution to iodine intake must be evaluated regularly. A recent national iodine survey found Israel's population to be mildly iodine deficient, possibly due to unmonitored changes in the food content of dietary iodine. Accounting for dairy iodine content can help guide efforts to prevent iodine deficiency. Objectives: This study aimed to determine the iodine concentration of dairy products typically consumed in the Israeli diet, and to estimate iodine intake from dairy products among Israeli adults. Methods: Iodine was analyzed in 33 selected dairy products that account for 89% of the total population's dairy intake according to the “MABAT” Israeli National Health and Nutrition survey. Based on these data, the distribution of iodine intake from milk, dairy, and dairy-based foods in the adult population was calculated. Results: Israeli milk is rich in iodine, with a mean concentration of 22 μg/100 g. However, due to low dairy consumption, the mean iodine intake from milk and dairy was only 34 μg/day (median 23 μg/day; range: 0–337 μg/day) or 22% of the recommended daily allowance. Self-reported intake among poor, male, and Arab subgroups was even lower. Conclusions: Because Israeli milk and dairy products are iodine rich, their contribution to the population's iodine intake would increase if they were consumed in greater amounts, particularly by high-risk groups. Dairy's potential contribution to iodine nutrition should be considered in recommendations for dairy consumption and iodine prophylaxis. [ABSTRACT FROM AUTHOR]

Background: Iodine deficiency has long been recognized as an important public health problem. Global approaches such as salt iodization that aim to overcome iodine deficiency have been successful. Meanwhile, they have led to excessive iodine consumption in some populations, thereby increasing the risks of iodine-induced thyroid dysfunction, as well as the comorbidities and mortality associated with hypothyroidism and hyperthyroidism. This study aimed to elucidate whether iodine intake is associated with mortality among U.S. adults. Methods: This was an observational study to estimate mortality risks according to urinary iodine concentration (UIC) utilizing a nationally representative sample of 12,264 adults aged 20–80 years enrolled in the National Health and Nutrition Examination Survey (NHANES) III. Crude and multivariable Cox proportional hazards regression models were employed to investigate the association between UIC (<50, 50–99, 100–299, 300–399, and ≥400 μg/L) and mortalities (all-cause, cardiovascular, and cancer). In sensitivity analyses, the study adjusted for total sodium intake and fat/calorie ratio in addition to other potential confounders. Stratum-specific analyses were also conducted to estimate the effects of UIC on mortality according to age, sex, race/ethnicity, and estimated glomerular filtration rate category. Results: Over a median follow-up of 19.2 years, there were 3159 deaths from all causes. Participants with excess iodine exposure (UIC ≥400 μg/L) were at higher risk for all-cause mortality compared to those with adequate iodine nutrition (hazard ratio = 1.19 [confidence interval 1.04–1.37]). Elevated hazard ratios of cardiovascular and cancer mortality were also found, but the confidence interval of the effect estimates included the null value for both outcomes. Low UIC was not associated with increased mortality. Restricted cubic spline models showed similar results for all outcomes. The results did not change substantially after adjusting for total sodium intake and fat/calorie ratio. None of the potential interactions were statistically significant on a multiplicative scale. Conclusion: Higher all-cause mortality among those with excess iodine intake compared to individuals with adequate iodine intake highlights the importance of monitoring population iodine status. Further studies with longitudinal measures of iodine status are needed to validate these results and to assess the potential risks excess iodine intake may have on long-term health outcomes. [ABSTRACT FROM AUTHOR]

Background: Severe iodine deficiency during pregnancy results in neurodevelopmental disorders in children, while the consequences of mild to moderate iodine deficiency (MMID) are uncertain. The concentration of iodine in the thyroid is the most accurate indicator of iodine nutrition. This study aimed to evaluate whether the iodine stores in the thyroid cover the needs of the mother and the fetus in iodine-sufficient and MMID conditions by inductively coupled plasma-mass spectrometry. Methods: One hundred four-week-old female Wistar rats were randomly divided into MMID (low iodine intake [L]) and normal (normal iodine intake [N]) groups. The rats were fed for the next three months, and after pregnancy they were further divided into two subgroups, respectively: low iodine pregnancy (LP) and low iodine pregnancy with iodine supplement (LP+), and normal iodine intake pregnancy (NP) and normal iodine intake pregnancy with iodine supplement (NP+). The iodine intake of pregnant rats in the NP+ and LP+ groups was twice as much as in the NP and LP groups. The rats were sacrificed on gestational day 15 and postnatal day 7. The iodine concentration in the thyroid of the maternal and newborn rats, maternal serum, placenta, and amniotic fluid were determined by inductively coupled plasma-mass spectrometry. Results: The concentration of iodine in the thyroid of the N group was significantly higher than that in the L group before pregnancy. The concentration of iodine in the maternal thyroids of the LP group decreased during pregnancy, whereas that of the NP group did not change significantly. There was no significant difference in the iodine concentration in the thyroid of mothers and offspring between the NP and NP+ groups, but it was significant between LP and LP+ groups. The concentration of iodine in amniotic fluid was significantly different between the four groups. Conclusion: There is sufficient iodine storage in the thyroid of maternal rats with normal iodine intake during pregnancy, and there is no need for iodine supplementation. However, iodine stores are insufficient in rats with MMID. Iodine supplementation can increase the iodine concentration in the thyroid of maternal rats with MMID and their offspring, as well as in the amniotic fluid during pregnancy. [ABSTRACT FROM AUTHOR]

Background: Because of their increased need for iodine, pregnant women are among the high-risk groups for iodine deficiency. The purpose of this study was to evaluate the effectiveness of an educational program on the iodine nutrition status of pregnant women. Methods: In this randomized controlled trial, 100 pregnant women were randomly selected from five healthcare centers in the southern region of Tehran, the capital of Iran. In the intervention group, pregnant women received a four-month educational program, which included two face-to-face educational sessions, using a researcher-designed educational pamphlet in the second and third trimesters, and two follow-up telephone calls. Knowledge, attitude, and practice (KAP) scores, urinary iodine concentration (UIC), and salt iodine content were assessed at baseline and four months after the intervention. Results: At baseline, there were significant associations between knowledge and attitude ( r = 0.38, p = 0.03) between practice and UIC ( r = 0.28, p = 0.01) and between UIC and iodine content of salt ( r = 0.24, p = 0.009). Although a significant difference was found in mean KAP scores between the two groups after the educational intervention, scores were significantly higher in the intervention group compared with controls ( p < 0.01). There were no significant differences in UIC and iodine content of salt between the two groups at follow-up. Conclusions: Despite educational intervention increasing KAP among women regarding the importance of iodine and iodized salt consumption during pregnancy, their iodine status did not improve. Considering the main socio-environmental determinants of iodine deficiency, in particular, the monitoring of salt fortification, prescribing iodine containing supplements as well as improving health literacy in pregnant women seem essential strategies. [ABSTRACT FROM AUTHOR]

Background: Iodine deficiency is a major public-health problem throughout the world, especially for pregnant women, and it is considered the most common cause of preventable intellectual impairment. In the United States, iodine status in pregnant women is considered mildly deficient. Therefore, the Endocrine Society, the American Thyroid Association, the Teratology Society, and the American Academy of Pediatrics recommend that women receive prenatal vitamins containing 150 μg of iodine daily during preconception, pregnancy, and lactation. The objectives of this study were to evaluate awareness of iodine nutrition among obstetricians and midwives in the United States, and to document current clinical practice regarding recommendations for iodine supplementation for women during preconception, pregnancy, and lactation. Methods: All midwife members of the American College of Nurse-Midwives (ACNM) and all obstetrician members of the American Medical Association (AMA) were invited to participate in a web-based survey. Results: A total of 199 midwives and 277 obstetricians participated in the survey. One third of both obstetricians and midwives considered iodine status in U.S. pregnant women to be deficient. Although almost all obstetricians and midwives would recommend prenatal multivitamins, most reported rarely or never recommending iodine-containing multivitamins for women planning pregnancy (68.7% and 70.2%, respectively), pregnant women (66% and 67.1%), or lactating women (68.7% and 71.7%). Of the respondents who did report prescribing iodine-containing supplements, 85% recommended supplementation during the first trimester and 75-80% during the second and third trimesters. However, of those who did recommend iodine supplementation, only 45% would prescribe the recommended 150 μg of iodine daily during pregnancy. Overall, 75% of U.S. obstetricians and midwives do not recommend or would recommend an inadequate amount of iodine during preconception, pregnancy, and lactation. Conclusions: Despite the important consequences of iodine deficiency for pregnant women and the recommendations of many medical societies, the majority of U.S. obstetricians and midwives who participated in this survey do not recommend iodine-containing vitamins in women planning pregnancy, during pregnancy, and during lactation. [ABSTRACT FROM AUTHOR]