Iodine-Induced hypothyroidism

Urinary iodine concentrations in preschoolers and cognitive development at 4 and 6 years of age, the Rhea mother-child cohort on Crete, Greece

BACKGROUND

Evidence regarding child iodine intake and neurodevelopment is scarce.

METHODS

We aimed to assess the impact of child iodine intake at 4 years of age on cognitive and motor development at 4 and 6 years among 304 children from the Rhea cohort on Crete, Greece. Child iodine intake was assessed via urinary iodine concentrations (UIC) measured using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and adjusted for specific gravity. Child cognitive and motor development was assessed using the McCarthy Scales of Children's Abilities (MSCA) at 4 years of age and Raven's Coloured Progressive Matrices (RCPM), Finger Tapping Test (FTT), and Trail Making Test (TMT) at 6 years. Associations were explored using multivariable-adjusted linear regression analyses with UIC categorized according to WHO criteria [insufficient intake <100 µg/L, adequate 100-299 µg/L (reference group), excessive ≥300 µg/L].

RESULTS

The children's median UIC was 249 µg/L (25-75th percentile: 181-344 μg/L). Children with UIC <100 μg/L had lower scores in the motor scale at 4 years (MSCA-motor scale: B=-10.3; 95 %CI -19.9, -0.6; n=10) and in intelligence at 6 years (RCPM-total score: B=-3.6, 95 %CI -6.8, -0.5; n=9) than children in the reference group. No associations were found with the general cognitive scale at 4 years or with TMT and FTT scales at 6 years. Children with UIC ≥300 μg/L had lower cognitive scores both at 4 (MSCA; B= -3.5; 95 %CI -6.9, -0.1; n =101) and 6 years of age (RCPM-total score; B= -1.2; 95 %CI -2.3, -0.0; n =98) than children in the reference group. No associations were observed with the motor scale at 4 years or with TMT and FTT scales at 6 years.

CONCLUSION

Our findings indicate that both low and excessive iodine intake at preschool age may adversely affect child cognitive abilities. Additionally, low iodine intake may also impact motor abilities.

Perchlorates in the treatment of hyperthyroidism and thyrotoxicosis: a comprehensive review

INTRODUCTION

Perchlorates are ionic inhibitors antagonizing iodine transport into thyrocytes, hampering thyroid hormone synthesis. Nevertheless, perchlorates are not considered as first-line treatment in hyperthyroidism and thyrotoxicosis as compared to other pharmacological and non-pharmacological interventions.

AIM

Reassessing the therapeutic role of perchlorates in hyperthyroidism and thyrotoxicosis throughout a systematic review of the Literature.

METHODS

Guidelines were searched and examined to summarize current recommendations on the use of perchlorates in the management of hyperthyroidism. Randomized and non-randomized clinical trials were also searched and reviewed to summarize the efficacy/effectiveness and safety of perchlorates in hyperthyroidisms and thyrotoxicosis.

RESULTS

The management of specific forms of hyperthyroidism was considered, including Graves' disease (GD) in non-pregnant adults, hyperthyroidisms in pregnancy, iodine media contrast-induced hyperthyroidism, amiodarone-induced hyperthyroidisms, and thyroid storm. Most of the reported studies had remarkable limitations in terms of study design (non-controlled trials, lack of blinding), low number of participants, and the lack of clinically relevant endpoints, such as cardiovascular events, cardiovascular mortality, and teratogenicity. Overall, perchlorates could be considered a second-line treatment after thionamides, radioiodine, and total thyroidectomy in both GD and hyperthyroidisms in pregnancy. The therapeutic potential of perchlorates alone or in combination with other agents could be considered a second-line treatment of iodine-related hyperthyroidisms and thyroid storm.

CONCLUSION

Despite the low level of evidence, perchlorates could be considered in such specific forms of thyroid disorders, including iodine-induced hyperthyroidism and thyroid storm.

Application and Comparison of Different Regression Models in Iodine Balance Experiment on Women of Childbearing Age and Pregnant Women

The iodine balance experiment is a traditional approach to evaluate the physiological requirement for iodine, while the simple linear regression model (SLM) and the mixed effects model (MEM) are two primary methods used to analyze iodine balance experiments. In the present study, we aimed to compare the effects of these two regression models on the evaluation of iodine balance experiments to investigate appropriate valuation methods. By constructing SLM and MEM, zero iodine balance values (IBV) were determined, and the evaluation effects were compared. No changes were made to the experimental data for women of childbearing age, and cutoff values of 600 µg/day and 1000 µg/day, respectively, were chosen for further processing of the experimental data for pregnant women. Equation combinations 1-3 (EC1-3) were obtained by fitting SLM, and zero IBV were calculated as 110.26 µg/day, 333.06 µg/day, and 434.84 µg/day, respectively. EC4-6 were obtained by fitting MEM, and zero IBV were calculated as 110.44 µg/day, 335.79 µg/day, and 418.06 µg/day, respectively. The inclusion of inter-measurement variation as a random factor in the MEM yielded EC7-8, which reduced the test power of the iodine balance experiment on women of childbearing age. Our study suggested that when experimental conditions were tightly controlled, with fewer uncertainties or significant influences, computationally straightforward and well-understood SLM was preferred. If some uncertain factors might cause large changes in the experimental results, it was advised to use a more "conservative" MEM to calculate the zero IBV. ClinicalTrials.gov Identifier: Registered at Clinicaltrials.gov, NCT03279315 (17th September 2017, retrospectively registered), NCT03710148 (18th October 2018, retrospectively registered).

Urinary haloacetic acid concentrations and thyroid function among women: Results from the TREE study

BACKGROUND

Disinfection byproducts (DBPs) have been shown to impair thyroid function in experimental models. However, epidemiological evidence is scarce.

METHODS

This study included 1190 women undergoing assisted reproductive technology (ART) treatment from the Tongji Reproductive and Environmental (TREE) cohort from December 2018 to August 2021. Serum thyrotropin (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were measured as indicators of thyroid function. FT4/FT3 and TSH/FT4 ratios were calculated as markers of thyroid hormone homeostasis. Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two most abundant HAAs, in urine were detected to assess individual DBP exposures.

RESULTS

After adjusting for relevant covariates, positive associations were observed between urinary TCAA concentrations and serum TSH and TSH/FT4 levels (e.g., percent change = 5.82 %, 95 % CI: 0.70 %, 11.21 % for TSH), whereas inverse associations were found for serum FT3 and FT4 (e.g., percent change = -1.29 %, 95 % CI: -2.49 %, -0.07 % for FT3). There also was a negative association between urinary DCAA concentration and serum FT4/FT3 (percent change = -2.49 %, 95 % CI: -4.71 %, -0.23 %). These associations were further confirmed in the restricted cubic spline and generalized additive models with linear or U-shaped dose-response relationships.

CONCLUSION

Urinary HAAs were associated with altered thyroid hormone homeostasis among women undergoing ART treatment.

Clinical and magnetic resonance imaging findings in a French bulldog puppy with genetically confirmed congenital hypothyroidism

A 7-month-old male French bulldog was referred for abnormal mentation and gait. Physical examination revealed a dome shaped calvarium and persistent bregmatic fontanelle. Neurological examination revealed proprioceptive ataxia, pelvic limb paraparesis and strabismus with moderate ventriculomegaly, thinning of the cerebral parenchyma, and widened cerebral sulci on magnetic resonance imaging. Masses were identified in the region of the thyroid, which appeared heterogeneous and hyperintense in T1-weighted and T2-weighted compared with the adjacent muscle signal masses were identified. Radiological diagnosis was hydrocephalus "ex vacuo" and goiter. Blood test revealed abnormally low total thyroxine (TT4), free thyroxine (FT4), and normal thyrotropin concentration. A diagnosis of congenital hypothyroidism was confirmed by positive genetic test for thyroid peroxidase mutation. Thyroxine supplementation treatment rapidly improved clinical signs.

Post COVID-19 Vertigo in a Patient with Hypothyroidism: A Case Report

Case Summary

Female nurse, 44-years-old with a weight of 127 pounds. She attended our emergency clinic for an urgent care due to post COVID-19 vertigo and anxiety. Her problem began with severe, short-lived attacks of objective-circular type vertigo, accompanied by nausea and vomiting. The symptoms occurred when she assumed a lying position, turn right and sat or stood upright.

Interventions

The patient received medical prescription for hypothyroidism, vertigo and anxiety symptoms. Oral route feeding was started and was well tolerated.

Outcomes

The patient showed good evolution with the treatment. Currently, she is at home with daily intake of levothyroxine and losartan without complications.

Conclusion

The clinical case suggests that in patients with hypothyroidism, COVID-19 infection may trigger and exacerbate vertigo and anxiety.

Chloride/Multiple Anion Exchanger SLC26A Family: Systemic Roles of SLC26A4 in Various Organs

Solute carrier family 26 member 4 (SLC26A4) is a member of the SLC26A transporter family and is expressed in various tissues, including the airway epithelium, kidney, thyroid, and tumors. It transports various ions, including bicarbonate, chloride, iodine, and oxalate. As a multiple-ion transporter, SLC26A4 is involved in the maintenance of hearing function, renal function, blood pressure, and hormone and pH regulation. In this review, we have summarized the various functions of SLC26A4 in multiple tissues and organs. Moreover, the relationships between SLC26A4 and other channels, such as cystic fibrosis transmembrane conductance regulator, epithelial sodium channel, and sodium chloride cotransporter, are highlighted. Although the modulation of SLC26A4 is critical for recovery from malfunctions of various organs, development of specific inducers or agonists of SLC26A4 remains challenging. This review contributes to providing a better understanding of the role of SLC26A4 and development of therapeutic approaches for the SLC26A4-associated hearing loss and SLC26A4-related dysfunction of various organs.

Association between Consumption of Iodine-Rich Foods and Thyroid Cancer Prevalence: Findings from a Large Population-Based Study

The influence of iodine-rich foods on thyroid cancer (TC) risk remains inadequately understood. Therefore, we aimed to comprehensively investigate the relationship between three iodine-rich food groups and TC prevalence using extensive data from a large Korean population. We assessed the dietary intake of 169,057 participants in the Korean Genome and Epidemiology Study (2004-2013) using a food frequency questionnaire. The top-three iodine-rich food groups (including egg, seaweed, and dairy) were selected based on Korean dietary reference intakes and categorized by weekly consumption frequency. We conducted multiple logistic regression models to examine the relationship between food consumption and TC prevalence. After adjusting for confounding factors, higher seaweed consumption (>5 times/week) was significantly associated with lower TC prevalence (odds ratio [OR], 95% confidence interval [CI] = 0.42, 0.32-0.56, p-value < 0.001). In contrast, compared with moderate dairy consumption (3-4 times/week), lower dairy product intake (<1 time/week) was associated with higher TC prevalence (OR, 95% CI = 1.32, 1.05-1.67, p-value = 0.017). Our findings suggest that sufficient seaweed consumption may offer protection against TC, and incorporating dairy products into the diet may lower TC incidence in the Korean population. The most significant limitations of our study are the absence of 24 h urine samples for iodine status assessment and the lack of clinical data on the diagnosis of thyroid cancer.

Perioperative Care of a Child With Hyperthyroidism

In pediatric-aged patients, hyperthyroidism generally results from the autoimmune disorder, Graves' disease (GD). Excessive levels of thyroid hormones (triiodothyronine and thyroxine) result in irritability, emotional lability, nervousness, tremors, palpitations, tachycardia, and arrhythmias. The risk of morbidity and mortality is increased when surgical intervention is required in patients with hyperthyroidism due to the potential for the development of thyroid storm (TS). A 3-year, 1-month-old child with a past medical history of GD presented for total thyroidectomy when pharmacologic control with methimazole was not feasible due to intolerance following development of a serum sickness-like illness. Prior to surgery, his thyrotoxicosis symptoms worsened with fever, tachycardia, diaphoresis, and hypertension. He subsequently developed TS and was admitted to the pediatric intensive care unit where management included hydrocortisone, potassium iodide, and β-adrenergic blockade with esmolol and propranolol. Thyroid studies improved prior to surgery, and a total thyroidectomy was successfully completed. Corticosteroid therapy was slowly tapered as an outpatient, and he was discharged home on hospital day 9. Following discharge, his signs and symptoms of thyrotoxicosis resolved, and he was started on oral levothyroxine replacement therapy. The remainder of his postoperative and post-discharge course were unremarkable. Only two case reports of perioperative pediatric TS have been published in the past 20 years. Our case serves as an important reminder of the signs of TS in children and to outline the treatment options in a pediatric patient, especially in those unable to tolerate first-line pharmacologic therapies such as methimazole or propylthiouracil.

Does consumption of pearl millet cause goiter? A systematic review of existing evidence

Millets (defined here to also include sorghum) have been consumed in Asian and African countries for centuries, and have in recent years become increasingly popular in Western countries, especially because of their proven health and environmental benefits. Nevertheless, some concerns have been raised that their consumption can interfere with thyroid function and cause goiter. This systematic review aimed to investigate the link between millet consumption and goiter. We found nine papers that were relevant to this topic and included them in this review. Among nine papers eight were on pearl millet and one was on fonio millet. The findings of the review indicate that published literature on the association of pearl millet and increased goiter prevalence are not compelling and strong enough to assert that pearl millet consumed as part of a balanced diet can lead to goiter in the general population. To ensure appropriate factual messaging about millets, we need more scientific research to conclusively state whether millet consumption mediates goitrogenic effects.

Evaluation of dermal toxicity and toxicokinetics of povidone‑iodine in Göttingen minipigs

BACKGROUND

Povidone‑iodine (PVP-I) is an effective and commonly used broad-spectrum antiseptic; limited information exists around its long-term safety and impact on endocrine disruption. We assessed the dermal toxicity and toxicokinetics following a once-daily application of 7.5% (w/v) and 10% (w/v) PVP-I in Göttingen Minipigs® for up to 39 weeks.

METHODS

An in vivo study was conducted in male (n = 27) and female (n = 27) minipigs. Animals were randomized into untreated control, 7.5% and 10% PVP-I, and matching vehicle treatment groups. Animals were assessed for general in-life measurements, including skin irritation and organ weights. Serum samples were analyzed for PVP, total iodine, triiodothyronine [T3], thyroxine [T4], thyroid stimulating hormone [TSH], and toxicokinetic parameters.

RESULTS

Neither 7.5% nor 10% PVP-I affected general in-life measurements. Increased mean thyroid gland absolute weights were noted with 7.5% and 10% PVP-I. Serum levels of PVP, T3, T4, and TSH in the 7.5% and 10% PVP-I treatment group animals were similar to those in vehicle treatment group animals. Mean total serum iodine concentration was 52- and 13-fold higher with 7.5% and 10% PVP-I, respectively, vs respective vehicle treatments. There was no dose-dependent increase in mean maximum serum concentration and area under the curve from 0 to 24 h for PVP, T3, T4, and TSH, nor accumulation of PVP, T3, T4, or TSH in the study.

CONCLUSION

Once-daily dermal application of 7.5% and 10% PVP-I for up to 39 weeks was safe and well tolerated in Göttingen Minipigs® and was not associated with skin irritation, thyroid dysfunction, or endocrine disruption. As the anatomy and physiology of the minipig skin closely resembles that of human skin, the findings of this study suggest that 7.5% and 10% PVP-I may be translated into antimicrobial benefits for humans without the risk of endocrine disruption.

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

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

Hypothyroidism-Etiologies, Evaluation, and Emergency Care

Thyroid hormone affects every human organ system and is a vital component of metabolism. Common and easily treatable, hypothyroidism does not usually require emergency management. However, myxedema coma is the decompensated form of hypothyroidism and can be life threatening if not treated expediently.

What are the risks associated with lipiodol hysterosalpingography? A literature review

INTRODUCTION

Hysterosalpingography is widely used as a first-line investigation for infertility, and may also be therapeutic, increasing pregnancy rates. Aqueous and oil-based contrast agents can be used. Some studies suggest Lipiodol hysterosalpingography has a greater therapeutic effect on fertility than aqueous contrast, though this is contentious. There are additionally safety concerns surrounding Lipiodol hysterosalpingography. This review summarises the adverse effects associated with Lipiodol hysterosalpingography, particularly on thyroid function.

KEY FINDINGS

331 articles were identified. Of these, 46 met inclusion criteria. 3 further articles were identified from reference lists. Complications typically cited in the literature include pain, intravasation, life-threatening oil embolism, and lipogranuloma formation. Emerging evidence suggests that Lipiodol hysterosalpingography may also impact maternal and neonatal thyroid function. Women may develop hypo- or hyperthyroidism. Thyroid dysfunction is clinically significant as even subclinical hypothyroidism reduces fertility, increases the risk of pregnancy complications including miscarriage, pre-eclampsia and perinatal mortality, and adversely impacts foetal neurodevelopment. One study suggested a possible link with neonatal congenital hypothyroidism.

CONCLUSION

There is emerging evidence to suggest that Lipiodol hysterosalpingography can cause hypo- or hyperthyroidism, in addition to known adverse effects of pain, intravasation, oil embolism, and lipogranuloma formation.

IMPLICATIONS FOR PRACTICE

Given the significance of these risks, and contention surrounding whether Lipiodol truly increases pregnancy rates compared to aqueous mediums, careful consideration is required in the selection of contrast agent. In particular, Lipiodol hysterosalpingography may not be suitable for women with pre-existing thyroid dysfunction.

Influence of medications on thyroid function in dogs: An update

Erroneous thyroid function test results can occur because of drugs that alter thyroid hormone physiology in one or more aspects, including synthesis, secretion, distribution, and metabolism. Research since publication of the last review in the Journal of Veterinary Internal Medicine (JVIM) 20 years ago has evaluated the effects of amiodarone, zonisamide, inhalant anesthetics, clomipramine, trilostane, and toceranib on thyroid function tests in the dog. In addition, recent work on the effects of glucocorticoids, sulfonamides, phenobarbital, and nonsteroidal anti-inflammatory drugs will be reviewed. Awareness of these effects is necessary to avoid misdiagnosis of hypothyroidism and unnecessary treatment.

Iodine-Induced Hypothyroidism After Chemoembolization With Ethiodized Oil: A Case of Failure to Escape From Wolff-Chaikoff Effect (WCE)

Wolff-Chaikoff effect (WCE) is an acute physiologic response of the thyroid gland to high levels of iodine. The WCE is usually temporary, and the thyroid gland adjusts to high iodine levels within days or weeks. It is a protective mechanism and a failure to escape from it can result in thyroid dysfunction. Hypothyroidism is rare but more likely in patients who have had thyroid disease, are under stress, or are exposed to high iodine concentrations for a long time. The use of iodinated contrast media in radiologic studies or invasive medical procedures is a common source of excessive iodine exposure and can lead to thyroid disfunction. Despite the frequent use of contrast media in health care, the thyroid dysfunction associated with their use is poorly recognized. We report a patient who developed iodine-induced hypothyroidism after chemoembolization of recurrent chylothorax with ethiodized oil (Lipiodol®, Villepinte, France). This case report raises awareness of the importance of the physiologic WCE as well as the relevance of monitoring thyroid function when using iodinated contrast media in patients with specific risk factors.

Two Japanese Infants With Hypothyroidism Following Exposure to Iodinated Contrast Media

We report 2 Japanese infants with hypothyroidism requiring levothyroxine (LT4) replacement therapy following exposure to iodinated contrast media (ICM). Patient 1 was born at 32 weeks gestation. He had congenital heart disease and underwent contrast-enhanced computed tomography (CT) on day 22 (estimated amount of iodine: 600 mg/kg/dose). The newborn mass screening showed normal thyrotropin (thyroid-stimulating hormone; TSH) levels at day 4, but high TSH and low free thyroxine levels on retest at day 44. LT4 replacement therapy was administered on days 46 to 74. No hypothyroidism requiring LT4 replacement therapy was observed afterward. The ultrasonography showed a hypoplastic thyroid gland. Patient 2 was born full-term. She had congenital heart disease and underwent contrast-enhanced CT on day 52 (estimated amount of iodine: 1500 mg/kg/dose). The newborn mass screening showed normal TSH levels on day 4, but high TSH levels on retest on day 62. LT4 replacement therapy was administered from day 65 to 3 years of age. Genetic analysis showed a heterozygous variant of DUOX2. Exposure to ICM can result in hypothyroidism, requiring LT4 replacement therapy. The severity of hypothyroidism may depend on risk factors, such as genetic predisposition, preterm birth, thyroid hypoplasia, or early exposure to ICM.

Adequacy of Iodine Status and Associations with Gut Health: A Prospective Cohort Study among Infants in 8 Low- and Middle-Income Countries

BACKGROUND

Environmental enteric dysfunction increases the likelihood of micronutrient deficiencies among infants, but few studies have assessed the potential impact of gut health on urinary iodine concentration (UIC) among this vulnerable group.

OBJECTIVES

We describe the trends of iodine status among infants from 6 to 24 mo old and examine the associations between intestinal permeability, inflammation, and UIC from 6 to 15 mo of age.

METHODS

Data from 1557 children enrolled in this birth cohort study conducted in 8 sites were included in these analyses. UIC was measured at 6, 15, and 24 mo of age by using the Sandell-Kolthoff technique. Gut inflammation and permeability were assessed using the concentrations of fecal neopterin (NEO), myeloperoxidase (MPO) and alpha-1-antitrypsin (AAT), and lactulose-mannitol ratio (LM). A multinomial regression analysis was used to assess the classified UIC (deficiency or excess). Linear mixed regression was used to test the effect of interactions among biomarkers on logUIC.

RESULTS

All studied populations had adequate (≥100 μg/L) to excess (≥371 μg/L) median UIC at 6 mo. Between 6 and 24 mo, 5 sites displayed a significant decline in the infant's median UIC. However, median UIC remained within the optimal range. An increase of NEO and MPO concentrations by +1 unit in ln scale reduced the risk of low UIC by 0.87 (95% CI: 0.78-0.97) and 0.86 (95% CI: 0.77-0.95), respectively. AAT moderated the association between NEO and UIC (P < 0.0001). The shape of this association appears to be asymmetric and in a reverse J-shape, with a higher UIC observed at both lower NEO and AAT concentrations.

CONCLUSIONS

Excess UIC was frequent at 6 mo and tended to normalize at 24 mo. Aspects of gut inflammation and increased permeability appear to reduce the prevalence of low UIC in children aged 6 to 15 mo. Programs addressing iodine-related health should consider the role of gut permeability in vulnerable individuals.

Iodide Excess Inhibits Thyroid Hormone Synthesis Pathway Involving XBP1-Mediated Regulation

Iodine is an essential micronutrient for producing thyroid hormone (TH); however, iodide excess can lead to adverse thyroidal effects. Unfortunately, the lack of a proper in vitro model system hampered the studies of the effect of iodide excess on thyroid physiology and pathology. Here, we demonstrated that excessive iodide intake downregulated the genes related to TH synthesis in the thyroids of mice. Since sodium iodide has no effect on these genes in cultured cell lines, we developed a three-dimensional (3D) culture system to enable the murine thyrocytes to form organoids in vitro with thyroid follicle-like structures and function and found that the in vivo effect of iodide excess could be mimicked in these thyroid organoids. Our data indicate that iodide excess mainly activated the XBP1-mediated unfolded protein response in both murine thyroid and thyroid organoids, while activation of XBP1 was able to mimic the sodium iodide effect on genes for the synthesis of TH in murine thyroid organoids. Lastly, our results suggest that XBP1 might transcriptionally repress the genes involved in the synthesis of TH. Based on these findings, we propose that iodide excess inhibits the transcription of genes related to TH synthesis through a mechanism involving XBP1-mediated action.

Influence of sex, age and thyroid function indices on dual-energy computed tomography-derived quantitative parameters of thyroid in patients with or without Hashimoto's thyroiditis

PURPOSE

To study the influence of sex, age and thyroid function indices on dual-energy computed tomography (DECT)-derived quantitative parameters of thyroid in patients with or without Hashimoto's thyroiditis (HT).

MATERIAL AND METHODS

A total of 198 consecutive patients who underwent DECT scan of neck due to unilateral thyroid lesions were retrospectively enrolled. Iodine concentration (IC), total iodine content (TIC) and volume of normal thyroid lobe were calculated. Influences of sex, age and thyroid function indices on DECT-derived parameters in overall study population, subgroup patients with, and those without HT were assessed using Mann-Whitney U test, Student's T-test, and Spearman correlation analyses, respectively, as appropriate.

RESULTS

HT group showed significantly lower IC and TIC, while higher volume than No-HT group (all p < 0.001). The volume was larger in male than that in female in overall study population and No-HT group (p = 0.047 and 0.010, respectively). There was no significant difference in any DECT-derived parameters between low (≤ 35 years) and high (> 35 years) age group in all three groups (all p > 0.05). TPOAb and TgAb correlated positively with IC and TIC, and negatively with volume in overall study population (all p < 0.05). TPOAb and TgAb also correlated positively with IC in HT group (p = 0.002 and 0.007, respectively).

CONCLUSION

DECT-derived parameters of thyroid differed significantly between patients with and without HT. Sex and thyroid function indices could affect the DECT-derived parameters. Aforementioned physiological factors should be considered when analyzing the DECT-derived parameters of thyroid.

Optimizing Growth: The Case for Iodine

Iodine is an essential micronutrient and component of thyroid hormone. An adequate dietary iodine intake is critical to maintain and promote normal growth and development, especially during vulnerable life stages such as pregnancy and early infancy. The role of iodine in cognitive development is supported by numerous interventional and observational studies, and when iodine intake is too low, somatic growth is also impaired. This can be clearly seen in cases of untreated congenital hypothyroidism related to severe iodine deficiency, which is characterized, in part, by a short stature. Nevertheless, the impact of a less severe iodine deficiency on growth, whether in utero or postnatal, is unclear. Robust studies examining the relationship between iodine and growth are rarely feasible, including the aspect of examining the effect of a single micronutrient on a process that is reliant on multiple nutrients for optimal success. Conversely, excessive iodine intake can affect thyroid function and the secretion of optimal thyroid hormone levels; however, whether this affects growth has not been examined. This narrative review outlines the mechanisms by which iodine contributes to the growth process from conception onwards, supported by evidence from human studies. It emphasizes the need for adequate iodine public health policies and their robust monitoring and surveillance, to ensure coverage for all population groups, particularly those at life stages vulnerable for growth. Finally, it summarizes the other micronutrients important to consider alongside iodine when seeking to assess the impact of iodine on somatic growth.

The impact of prolonged, maternal iodine exposure in early gestation on neonatal thyroid function

CONTEXT

Hysterosalpingography (HSG) using oil-soluble contrast medium (OSCM) improves pregnancy rates but results in severe and persistent iodine excess, potentially impacting the fetus and neonate.

OBJECTIVE

To determine the incidence of thyroid dysfunction in newborns conceived within six months of OSCM HSG.

DESIGN

Offspring study of a prospective cohort of women who underwent OSCM HSG.

SETTING

Auckland region, New Zealand (2020-2022).

PARTICIPANTS

Offspring from the SELFI (Safety and Efficacy of Lipiodol in Fertility Investigations) study cohort (n=57).

MEASUREMENTS

All newborns had a dried blood spot card for TSH measurement 48 hours after birth as part of New Zealand's Newborn Metabolic Screening Programme. Forty-one neonates also had a heel prick serum sample at one week to measure thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3). Maternal urine iodine concentration (UIC) and TSH in the six months after OSCM HSG were retrieved from the SELFI study for analyses.

PRIMARY OUTCOME

Incidence of hypothyroidism in the neonatal period.

RESULTS

There was no evidence of primary hypothyroidism on newborn screening (TSH 2-10 mIU/L). All neonates tested at one week had normal serum TSH, FT4, and FT3 levels. However, increasing maternal peak UIC levels during pregnancy were associated with lower TSH levels (p= 0.006), although also associated with lower FT4 levels (p=0.032).

CONCLUSIONS

While pre-conceptional OSCM HSG in women did not result in neonatal hypothyroidism, gestational iodine excess was associated with a paradoxical lowering of neonatal TSH levels despite lower FT4 levels. These changes likely reflect alterations in deiodinase activity in the fetal hypothalamic-pituitary axis from iodine excess.

TRIAL REGISTRATION

https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12620000738921, identifier 12620000738921.

Knowns and unknowns about congenital hypothyroidism: 2022 update

Several excellent guidelines and expert opinions on congenital hypothyroidism (CH) are currently available. Nonetheless, these guidelines do not address several issues related to CH in detail. In this review, the authors chose the following seven clinical issues that they felt were especially deserving of closer scrutiny in the hope that drawing attention to them through discussion would help pediatric endocrinologists and promote further interest in the treatment of CH. 1. How high should the levothyroxine (L-T4) dose be for initial treatment of severe and permanent CH? 2. What is the optimal method for monitoring treatment of severe CH? 3. At what level does maternal iodine intake during pregnancy affect fetal and neonatal thyroid function? 4. Does serum thyroglobulin differ between patients with a dual oxidase 2 (DUOX2) variants and those with excess iodine? 5. Who qualifies for a genetic diagnosis? 6. What is the best index for distinguishing transient and permanent CH? 7. Is there any cancer risk associated with CH? The authors discussed these topics and jointly edited the manuscript to improve the understanding of CH and related issues.

Stable thyroid function despite regular use of povidone-iodine throat spray for SARS-CoV-2 prophylaxis

BACKGROUND

It is unclear whether unintentional ingestion of povidone-iodine following its application to the oropharyngeal space could affect thyroid function.

OBJECTIVE

To examine thyroid function among individuals who regularly apply povidone-iodine throat spray for SARS-CoV-2 prophylaxis.

METHODS

We designed a case-control study to compare thyroid function among participants who received povidone-iodine throat spray three times a day for 42 days ('cases') and those who received vitamin C ('controls'). Thyroid function was assessed by profiling serum TSH, free T3, and free T4; iodine status was estimated using serum thyroglobulin level, while infection status was determined by measuring anti-SARS-CoV-2 antibody against the nucleocapsid antigen. All measurements were performed in pairs, at baseline and 42 days later. Pre-post changes in thyroid function were compared between groups, before and after stratification according to baseline TSH quartiles.

RESULTS

A total of 177 men (117 cases and 60 controls) (mean age, 32.2 years) were included. Despite comparable demographics and clinical profiles, no clinically or statistically significant differences were observed in thyroid indices between 'cases' and 'controls' before and after stratification according to TSH quartiles. None of the participants developed symptomatic hypo- or hyperthyroidism throughout the study. Post-hoc analysis did not reveal differences in thyroid function according to infection status.

CONCLUSIONS

Data from this study support the overall safety of povidone-iodine use in the oropharyngeal space for SARS-CoV-2 prophylaxis among individuals with normal thyroid function and subclinical thyroid disease.

The SELFI Study: Iodine Excess and Thyroid Dysfunction in Women Undergoing Oil-Soluble Contrast Hysterosalpingography

CONTEXT

Hysterosalpingography (HSG) with oil-soluble contrast medium (OSCM) improves pregnancy rates. However, OSCM has high iodine content and long half-life, leading to potential iodine excess.

OBJECTIVE

This work aimed to determine the pattern of iodine excess after OSCM HSG and the effect on thyroid function.

METHODS

A prospective cohort study was conducted of 196 consecutive consenting eligible women without overt hypothyroidism or hyperthyroidism. All completed the study with compliance greater than 95%. Participants underwent OSCM HSG (Auckland, 2019-2021) with serial monitoring of thyrotropin (TSH), free thyroxine (FT4), and urine iodine concentration (UIC) for 24 weeks. The main outcome measure was the development of subclinical hypothyroidism (SCH), defined as a nonpregnant TSH greater than 4 mIU/L with normal FT4 (11-22 pmol/L) in those with normal baseline thyroid function.

RESULTS

Iodine excess (UIC ≥ 300 μg/L) was almost universal (98%) with UIC peaking usually by 4 weeks. There was marked iodine excess, with 90% and 17% of participants having UIC greater than or equal to 1000 μg/L and greater than 10 000 μg/L, respectively. Iodine excess was prolonged with 67% having a UIC greater than or equal to 1000 μg/L for at least 3 months. SCH developed in 38%; the majority (96%) were mild (TSH 4-10 mIU/L) and most developed SCH by week 4 (75%). Three participants met the current treatment guidelines (TSH > 10 mIU/L). Thyroxine treatment of mild SCH tended to improve pregnancy success (P = .063). Hyperthyroidism (TSH < 0.3 mIU/L) occurred in 9 participants (5%).

CONCLUSION

OSCM HSG resulted in marked and prolonged iodine excess. SCH occurred frequently with late-onset hyperthyroidism occasionally. Regular thyroid function tests are required for 6 months following this procedure.

Evidence-based review of chlorhexidine gluconate and iodine in the preoperative skin preparation of young infants

PURPOSE

The preoperative preparation of young infants' skin requires special considerations. Commonly used solutions for preparing the skin preoperatively include chlorhexidine (CHG) and iodine. The Centers for Disease Control and Prevention (CDC) has recommendations for preparing skin for surgery and other invasive procedures for adults, but they do not have recommendations for young infants' skin. The purpose of this evidence-based literature review is to synthesize the literature, compare, and inform healthcare providers about the safety and efficacy of CHG and iodine as preoperative preparation solutions for young infants' skin. For this project young infants is defined as infants less than 48 weeks' postmenstrual age and those born prematurely and less than 28 days old.

CONCLUSIONS

We analyze 19 articles that met the inclusion criteria. Three discussion themes emerge: systemic absorption, dermatologic burns, and CHG and iodine efficacy.

PRACTICE IMPLICATIONS

We need more research regarding the safety and efficacy of CHG and iodine solutions for preoperative preparation of young infants' skin. Findings suggest the cautious use of CHG and iodine solutions on patients born at or before 28 weeks' postmenstrual age, especially those less than 28 days postnatal age.

Modulatory Effects of Arctostaphylos uva-urs Extract In Ovo Injected into Broiler Embryos Contaminated by Aflatoxin B1

In ovo injection of nutrients can modulate the embryo’s physiological responses against aflatoxin B1 (AFB1) embryotoxicity. This hypothesis was tested using in ovo injection of Arctostaphylos uva-ursi (Ar. uu.) methanolic extract. The total polyphenols, total flavonoids, total antioxidant capacity, and GC-MS analysis were all assessed in the Ar. uu. methanolic extract. A total of 180 ten-day-old embryonated eggs were distributed into six groups of 30 replicates each. The first group was used as a control (non-injected), and the second, third, fourth, fifth, and sixth groups were injected with 10 µ double-distilled water (DDW), 500 µL methanol, 0.01 g Ar. uu./500 µL methanol, 50 ng AFB1/10 µL DDW, and 50 ng AFB1 in 10 µ DDW + 0.01 g Ar. uu./500 µL methanol, respectively. The relative embryo weight, residual yolk sac weight, tibia length and weight, and survival were recorded. Total and differential leukocytes, oxidative stress, and humoral immune responses were observed. The residual yolk sac was lower (p < 0.05) in the Ar. uu. group than other groups. The embryonic growth (tibia weight and length) was enhanced in AFB1 + Ar. uu.-injected embryos compared with those injected with AFB1 alone. In conclusion, in ovo injection of Arctostaphylos uva-ursi could modulate AFB1-induced toxicity in chicken embryos.

Simulations of radioiodine exposure and protective thyroid blocking in a new biokinetic model of the mother-fetus unit at different pregnancy ages

In the case of nuclear incidents, radioiodine may be released. After incorporation, it accumulates in the thyroid and enhances the risk of thyroidal dysfunctions and cancer occurrence by internal irradiation. Pregnant women and children are particularly vulnerable. Therefore, thyroidal protection by administering a large dose of stable (non-radioactive) iodine, blocking radioiodide uptake into the gland, is essential in these subpopulations. However, a quantitative estimation of the protection conferred to the maternal and fetal thyroids in the different stages of pregnancy is difficult. We departed from an established biokinetic model for radioiodine in pregnancy using first-order kinetics. As the uptake of iodide into the thyroid and several other tissues is mediated by a saturable active transport, we integrated an uptake mechanism described by a Michaelis–Menten kinetic. This permits simulating the competition between stable and radioactive iodide at the membrane carrier site, one of the protective mechanisms. The Wollf–Chaikoff effect, as the other protective mechanism, was simulated by adding a total net uptake block for iodide into the thyroid, becoming active when the gland is saturated with iodine. The model’s validity was confirmed by comparing predicted values with results from other models and sparse empirical data. According to our model, in the case of radioiodine exposure without thyroid blocking, the thyroid equivalent dose in the maternal gland increases about 45% within the first weeks of pregnancy to remain in the same range until term. Beginning in the 12th pregnancy week, the equivalent dose in the fetal thyroid disproportionately increases over time and amounts to three times the dose of the maternal gland at term. The maternal and fetal glands’ protection increases concomitantly with the amount of stable iodine administered to the mother simultaneously with acute radioiodine exposure. The dose–effect curves reflecting the combined thyroidal protection by the competition at the membrane carrier site and the Wolff–Chaikoff effect in the mother are characterized by a mean effective dose (ED₅₀) of roughly 1.5 mg all over pregnancy. In the case of the fetal thyroid, the mean effective doses for thyroid blocking, taking into account only the competition at the carrier site are numerically lower than in the mother. Taking into account additionally the Wolff–Chaikoff effect, the dose–effect curves for thyroidal protection in the fetus show a shift to the left over time, with a mean effective dose of 12.9 mg in the 12th week of pregnancy decreasing to 0.5 mg at term. In any case, according to our model, the usually recommended dose of 100 mg stable iodine given at the time of acute radioiodine exposure confers a very high level of thyroidal protection to the maternal and fetal glands over pregnancy. For ethical reasons, the possibilities of experimental studies on thyroid blocking in pregnant women are extremely limited. Furthermore, results from animal studies are associated with the uncertainties related to the translation of the data to humans. Thus model-based simulations may be a valuable tool for better insight into the efficacy of thyroidal protection and improve preparedness planning for uncommon nuclear or radiological emergencies.

MECHANISMS IN ENDOCRINOLOGY: The pathophysiology of transient congenital hypothyroidism

Transient congenital hypothyroidism (TCH) refers to congenital hypothyroidism which spontaneously resolves in the first few months or years of life. Currently, there is a paucity of reliable markers predicting TCH at diagnosis, and the diagnosis is established following the withdrawal of levothyroxine therapy around 3 years of age. The incidence of TCH is increasing, and it is a major contributor to the overall increase in the incidence of CH in recent studies. Both genetic factors, in particular mutations affecting DUOX2 and DUOXA2, and environmental factors, for example, iodine deficiency and excess, anti- TSHR antibodies and exposure to antithyroid or iodine-rich medications, may cause TCH. Resolution of TCH in childhood may reflect both normal thyroid physiology (decreased thyroid hormone biosynthesis requirements after the neonatal period) and clearance or cessation of environmental precipitants. The relative contributions and interactions of genetic and environmental factors to TCH, and the extent to which TCH may be prevented, require evaluation in future population-based studies.

Myxedema Coma Precipitated by Iohexol: Case Report and Brief Literature Review on the Wolff-Chaikoff Effect

Background: Failure to escape from the Wolff-Chaikoff effect (WCE) causes hypothyroidism. Methods: This is the first report of myxedema coma after iohexol administration. The failure of the escape phenomenon in this patient was longer than existing reports. Results: The patient received 42,000 mg of iodine in iohexol cumulatively and developed myxedema coma after 16 days. She was subsequently found to have pre-existing primary hypothyroidism that was treated with levothyroxine 50 μg daily, but had defaulted treatment. She was discharged with levothyroxine 100 μg daily and this was weaned to 50 μg daily over 12 months. Conclusions: Iodine-based contrast media (ICM) can aggravate primary hypothyroidism. In severe cases, it may precipitate myxedema coma. Patients with thyroid disorders should be informed to monitor for aggravation of their symptoms after ICM administration. Long-term follow-up of thyroid function may be needed in patients who fail to escape from the WCE.

Gestational and childhood urinary iodine concentrations and children's cognitive function in a longitudinal mother-child cohort in rural Bangladesh

BACKGROUND

Severe iodine deficiency adversely affects neurodevelopment; however, evidence regarding the association of non-severe deficiency and child cognitive functioning is inconclusive.

METHODS

This prospective mother-child cohort study was nested in a population-based nutritional supplementation trial in Bangladesh (Maternal and Infant Nutrition Interventions in Matlab [MINIMat]). Participants with data on cognitive abilities at 5 and 10 years of age (n = 1530) and at least one measurement of urinary iodine concentration (UIC) (gestational week 8, 5, and 10 years) were selected. Cognitive abilities were assessed using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) and Wechsler Intelligence Scale for Children (WISC-IV). UICs were measured with inductively coupled plasma mass spectrometry and thereafter adjusted for specific gravity.

RESULTS

Median UICs in our population: (282 μg/L [pregnancy]; 406 μg/L [5 years]; 294 μg/L [10 years]) indicated that iodine intake corresponded to above 'adequate' or even 'excessive', according to the WHO classification. Maternal 'UIC <150 μg/L' was associated with lower full-scale and verbal scores at 5 and 10 years, although the associations were weakened in the fully adjusted models. A tendency of decreased verbal scores was also observed for maternal 'UIC ≥500 μg/L' but not for the corresponding child iodine category (≥300 μg/L). Child 'UIC <100 μg/L' was associated with lower processing speed (B=-3.1, 95% CI [-6.2, -0.1]; P-value = 0.041) compared with the reference group (100 μg/L≤ UIC <300 μg/L).

CONCLUSIONS

Current findings add to the growing evidence of a causal association of early-life iodine intake with cognitive development, indicating that low iodine intake during childhood is associated with reduced processing speed and non-optimal gestational iodine intake is weakly associated with slightly poorer verbal development outcomes.

Effect of Moderate-to-Severe Iodine Deficiency in Early Pregnancy on Subclinical Hypothyroidism: A Longitudinal Study in an Iodine-Sufficient Region in China

Objective

To investigate iodine status among pregnant women in an iodine-sufficient region in China after the implementation of revised universal salt iodization (USI) standards in 2012 and assess the association between urinary iodine concentrations (UIC) in early pregnancy and the incidence of subclinical hypothyroidism (SCH) in euthyroid women negative for antithyroid Ab during different trimesters.

Methods

We measured the iodine status of 1,264 pregnant women, and performed follow-up assessment of thyroid function at 20 and 30 weeks of gestation among a cohort of 250 euthyroid women. We assessed the association of UIC in the 1st trimester with the incidence of SCH in subsequent trimesters. UIC and serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) were measured.

Results

The median UIC was 135.95 μg/L among 1,264 women. Serum FT4 level was significantly higher in the group of UIC 150 to 249 μg/L compared with other UIC groups (P &lt; 0.001). TSH was significantly higher in the UIC more than or equal to 250 μg/L group than the UIC 150 to 249 g/L group (P = 0.043). Of the 250 euthyroid women negative for antithyroid Ab (TSH value of 2.5–3.55 mU/L) in the 1st trimester, pregnant women with UIC lower than 100 μg/L in the 1st trimester exhibited a significantly increased risk of SCH (odds ratio [OR] = 2.47; 95% confidence interval [CI] = 1.22–5.71; P = 0.012, according to the Chinese Medical Association criteria; OR = 5.22, 95% CI = 1.73–6.09, P = 0.004, according to ATA criteria) during the latter half of pregnancy compared with the UIC 150 to 249 μg/L group.

Conclusion

Moderate-to-severe iodine deficiency (UIC lower than 100 μg/L) in the 1st trimester was associated with a significantly higher risk of SCH during the 2nd or 3rd trimesters among euthyroid pregnant women who had negative for antithyroid Ab. Women with SCH during pregnancy require regular UIC tests to maintain appropriate iodine status.

Thyroid dysfunction in Greece: Results from the national health examination survey EMENO

Background

Nationwide data on thyroid disease prevalence in Greece is lacking. Using the national health examination survey EMENO data resources, we aimed to estimate the prevalence of hypothyroidism and hyperthyroidism and associated risk factors in adults living in Greece.

Methods

A random sample of the adults (≥18 years) living in Greece was drawn by multi-stage stratified random sampling based on the 2011 census. During home visits, trained interviewers administered a standardized questionnaire to study participants. All participants answered questions concerning demographic parameters (e.g., age, sex, degree of urbanization, income) and questions concerning smoking habits, alcohol, dietary habits and psychological parameters such as anxiety and thyroid disease. Weighted logistic regression models were fitted to assess factors associated with thyroid disease.

Results

In total, 6006 individuals were recruited in the Greek Health Examination Survey EMENO (response rate 72%) of whom 5981 were eligible for this study. The prevalence of thyroid disease was 9%, where 0.4% was related to hyperthyroidism and 8.6% to hypothyroidism. The prevalence of thyroid disease was higher in women (14.9%) than men (2.7%) (p<0.001). The highest rates of thyroid disease were observed in former iodine-deficient areas. A decrease in the prevalence of thyroidopathies with increasing alcohol consumption was found. Thyroid disease was associated with anxiety in men. Multivariable regression analysis showed that age, geographic area, and smoking were related to thyroid disease.

Conclusion

The prevalence of thyroid disease in Greece is higher in women. Age, habits, and characteristics of geographic areas determine the distribution of thyroidopathies in Greece.

Association Between Newborn Thyroid-Stimulating-Hormone Concentration and Neurodevelopment and Growth: a Systematic Review

Iodine nutrition during pregnancy can affect newborn thyroid-stimulating-hormone concentration (TSH). Associations of newborn TSH with the neurodevelopment and growth of children are inconsistent. The aim of the study was to systematically review the literature on the associations between newborn TSH and childhood neurodevelopment and growth. Databases including PubMed, Scopus, CINAHL, Embase, PsycINFO, WHO, and Iodine Global Network were searched for eligible studies. Seventeen studies were included. Neurodevelopment was assessed using different tools in children aged 1-12 years of age. The associations between newborn TSH and cognitive development were negative in studies from iodine deficient populations, while a null association was found in studies from iodine sufficient populations. A null association between TSH and psychomotor development was observed regardless of iodine status of the study populations. There was no evidence of an association between newborn TSH and child anthropometry, but evidence of negative association was found between newborn TSH and birthweight. Although the associations between newborn TSH and neurodevelopment may differ based on the iodine status of populations, most of the included studies did not adjust for the key confounders and had a small sample size. Quality data-linkage studies that utilize newborn TSH data from newborn screening with adequate adjustment for potential confounders are warranted to better understand the relationship between newborn TSH and neurodevelopment and growth in children. CRD42020152878.

Endocrine system dysfunction and chronic heart failure: a clinical perspective

Chronic heart failure (CHF) leads to an excess of urgent ambulatory visits, recurrent hospital admissions, morbidity, and mortality regardless of medical and non-medical management of the disease. This excess of risk may be attributable, at least in part, to comorbid conditions influencing the development and progression of CHF. In this perspective, the authors examined and described the most common endocrine disorders observed in patients with CHF, particularly in individuals with reduced ejection fraction, aiming to qualify the risks, quantify the epidemiological burden and discuss about the potential role of endocrine treatment. Thyroid dysfunction is commonly observed in patients with CHF, and sometimes it could be the consequence of certain medications (e.g., amiodarone). Male and female hypogonadism may also coexist in this clinical context, contributing to deteriorating the prognosis of these patients. Furthermore, growth hormone deficiency may affect the development of adult myocardium and predispose to CHF. Limited recommendation suggests to screen endocrine disorders in CHF patients, but it could be interesting to evaluate possible endocrine dysfunction in this setting, especially when a high suspicion coexists. Data referring to long-term safety and effectiveness of endocrine treatments in patients with CHF are limited, and their impact on several "hard" endpoints (such as hospital admission, all-cause, and cardiovascular mortality) are still poorly understood.

Impact of Iodinated Contrast Media in Patients Received Percutaneous Coronary Intervention: Focus on Thyroid Disease

BACKGROUND

With the rapid advance in percutaneous coronary intervention (PCI) technology, patients absorb large volume of iodinated contrast media (ICM). Recent studies suggested that ICM may lead to hyperthyroidism, but the association between ICM volume and thyroid is still unclear. We sought to evaluate the long-term influence of ICM on thyroid dysfunction and disease in patients received PCI.

METHODS

This single-center retrospective study included consecutive coronary artery disease (CAD) patients. A covariance (ANCOVA) model was performed to evaluate the change of serum TSH, FT3 and FT4 before and one-year after the PCI procedure. Restricted cubic splines and logistic regression were performed to evaluate the association between ICM volume and thyroid disease.

RESULTS

2062 patients met inclusion criteria (1381 patients in the low-volume group and 681 patients in the high-volume group). The high-volume group was 0.238 ± 0.092 pmol/L higher than the low-volume group (P = 0.010) in the serum FT4. Restricted cubic splines show that there were linear dose-response relationships for ICM volume and composite endpoint and hyperthyroidism. In all models, there were significant differences in composite endpoint between the two groups. (OR 1.75, 95% CI (1.05, 2.92), P = 0.032, OR 1.73, 95% CI (1.01-2.96), P= 0.032 and OR 1.83, 95% CI (1.09-3.06), P= 0.022, respectively). The positive results were also showed for hyperthyroidism in all models (OR 2.35, 95% CI (1.14-4.84), P = 0.021, OR 10.36, 95% CI (1.20-89.00), P = 0.033 and OR 2.35, 95% CI (1.13-4.87), P = 0.022, respectively).

CONCLUSION

The present analysis gives an overview that ICM volume is associated with an increased risk of thyroid dysfunction and thyroid disease.

The Iodine Rush: Over- or Under-Iodination Risk in the Prophylactic Use of Iodine for Thyroid Blocking in the Event of a Nuclear Disaster

Iodine is an essential element for the production of thyroid hormones (THs). Both deficient and excess iodine intakes may precipitate in adverse thyroidal events. Radioactive iodine (RI) is a common byproduct of nuclear fission processes. During nuclear emergencies RI may be released in a plume, or cloud, contaminating the environment. If inhaled or ingested, it may lead to internal radiation exposure and the uptake of RI mainly by the thyroid gland that absorbs stable iodine (SI) and RI in the same way. A dose of radiation delivered to the thyroid gland is a main risk factor for the thyroid cancer development. The SI prophylaxis helps prevent childhood thyroid cancer. The thyroid gland saturation with prophylactic SI ingestion, reduces the internal exposure of the thyroid by blocking the uptake of RI and inhibiting iodide organification. However, negative impact of inadequate SI intake must be considered. We provide an overview on the recommended iodine intake and the impact of SI and RI on thyroid in children and adolescents, discussing the benefits and adverse effects of the prophylactic SI for thyroid blocking during a nuclear accident. The use of SI for protection against RI may be recommended in cases of radiological or nuclear emergencies, moreover the administration of iodine for prophylactic purposes should be cautious. Benefits and risks should also be considered according to age. Adverse effects from iodine administration cannot be excluded. Precise indications are mandatory to use the iodine for thyroid blocking. Due to this natural adaption mechanism it's possible to tolerate large doses of iodine without clinical effects, however, a prolonged assumption of the iodine when not needed can be dangerous and may precipitate in severe thyroidal and non-thyroidal negative effects.

Possible Iodine-Induced Thyrotoxicosis in a Previously Healthy Adolescent following Administration of Iodinated Contrast Media

Introduction. Jod-Basedow Syndrome refers to a paradoxical phenomenon in which large loads of iodine can cause hyperthyroidism. It is most commonly seen in populations already at risk for thyroid disease or those with underlying kidney disease. Case Presentation. We present a case of an acutely ill 17-year-old boy with symptomatic hyperthyroidism following an iodinated contrast CT scan to rule out appendicitis. Discussion/Conclusion. This case underscores the importance of recognizing this phenomenon even in the pediatric population and in those with no preexisting history of thyroid disease. Course complications including bronchospasm, hypertension, transaminitis, and bilateral palmar desquamating rash are rare and highlight the complexities involved in the disease state and in managing side effect profiles of treatment.

Associations between newborn thyroid-stimulating hormone concentration and neurodevelopment and growth of children at 18 months

The study aimed to assess the associations between newborn thyroid-stimulating hormone (TSH) concentration, a marker of iodine nutrition in early life, and childhood neurodevelopment and growth using data collected from two pregnancy studies, one in a borderline iodine-deficient setting (DHA to Optimize Mother Infant Outcome (DOMInO) Study) and one in an iodine-sufficient setting (Pregnancy Iodine and Neurodevelopment in Kids (PINK) Study). TSH data were obtained from routine newborn screening. Neurodevelopment was assessed at 18 months using the Bayley Scales of Infant and Toddler Development, third edition (Bayley-III). Weight, height and head circumference were measured at 18 months. In total, 1467 children were included in the analysis. Comparing the highest with the lowest TSH quartile, the mean differences (MD) in the Bayley-III scores ranged from -2·0 (95 % CI -4·7, 0·7) to -2·2 (95 % CI -5·8, 1·3) points in DOMInO and 1·0 (95 % CI -1·6, 3·6) to 2·0 (95 % CI -0·4, 4·4) points in PINK in the cognitive, language and motor scales; the MD in the anthropometric z scores ranged from -0·01 (95 % CI -0·5, 0·5) to -0·5 (95 % CI -0·9, -0·1) in both studies. A 1 mIU/l increase in TSH was associated with -0·3 (95 % CI -0·9, 0·2) point and 0·2 (95 % CI -0·3, 0·7) point changes in the mean cognitive score in the DOMInO and PINK, respectively. A null association between TSH and growth was also observed in both studies. Longitudinal studies that utilise newborn TSH data and examine neurodevelopmental outcomes at later ages are warranted, as neurodevelopmental assessments in older children are more predictive of later achievement.

Associations of exposure to cadmium, antimony, lead and their mixture with gestational thyroid homeostasis

Maintaining thyroid homeostasis during pregnancy is vital for fetal development. The few studies that have investigated associations between metal exposure and gestational thyroid function have yielded mixed findings. To evaluate the association of exposure to a mixture of toxic metals with thyroid parameters in 824 pregnant women from the Rhea birth cohort in Crete, Greece. Concentrations of three toxic metals [cadmium (Cd), antimony (Sb), lead (Pb)] and iodine were measured in urine using inductively coupled plasma mass spectrometry and thyroid hormones [Thyroid Stimulating Hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3)] were measured in serum in early pregnancy. Associations of individual metals with thyroid parameters were assessed using adjusted regression models, while associations of the metal mixture with thyroid parameters were assessed using Bayesian Kernel Machine Regression (BKMR).Women with high (3rd tertile) concentrations of urinary Cd, Sb and Pb, respectively, had 13.3 % (95%CI: 2.0 %, 23.2 %), 12.5 % (95%CI: 1.8 %, 22.0 %) and 16.0 % (95%CI: 5.7 %, 25.2 %) lower TSH compared to women with low concentrations (2nd and 1st tertile). In addition, women with high urinary Cd had 2.2 % (95%CI: 0.0 %, 4.4 %) higher fT4 and 4.0 % (95%CI: -0.1 %, 8.1 %) higher fT3 levels, and women with high urinary Pb had 4 % (95%CI: 0.2 %, 8.0 %) higher fT3 levels compared to women with low exposure. The negative association of Cd with TSH persisted only when iodine sufficiency was unfavorable. BKMR attested that simultaneous exposure to toxic metals was associated with decreased TSH and increased fT3 and revealed a potential synergistic interaction of Cd and Pb in association with TSH. The present results suggest that exposure to toxic metals even at low levels can alter gestational thyroid homeostasis.

Thyroid crisis caused by metastatic thyroid cancer: an autopsy case report

BACKGROUND

Thyroid crisis is a life-threatening condition in thyrotoxic patients. Although differentiated thyroid cancer is one of the causes of hyperthyroidism, reports on thyroid crisis caused by thyroid cancer are quite limited. Here, we describe a case of thyroid crisis caused by metastatic thyroid cancer.

CASE PRESENTATION

A 91-year-old woman was admitted to our hospital because of loss of appetite. Two years prior to this hospitalization, she presented with subclinical thyrotoxicosis and was diagnosed with histologically unidentified thyroid cancer with multiple metastases, and she refused aggressive medical interventions. On admission, she exhibited extreme thyrotoxicosis, and the presence of fever, severe tachycardia, impaired consciousness, and heart failure revealed the presence of thyroid crisis. All thyroid autoantibodies were negative. Multidisciplinary conservative treatment was initiated; however, she died on the fifth day after admission. Autopsy revealed the presence of primary anaplastic thyroid carcinoma and multiple metastatic foci arising from follicular thyroid carcinoma. Both primary and metastatic follicular thyroid carcinoma likely induced thyrotoxicosis, which could have been exacerbated by anaplastic thyroid carcinoma.

CONCLUSIONS

Even though the trigger of thyroid crisis in this patient is not clear, the aggravated progression of her clinical course suggests that careful monitoring of thyroid hormones and appropriate intervention are essential for patients with thyroid cancer.

MicroRNA expression profiles of the thyroid after goiter formation and involution in rats under different iodine regimens

BACKGROUND

Thyroid damage occurs during experimental iodine-deficient goiter and involution with iodine supplementation. This study investigated the dynamic microRNAs (miRNAs) expression profiles in iodine-deficient thyroids during adequate and excessive iodine supplementation.

METHODS

Twenty-four female Wistar rats were randomly divided into control, low-iodine (LI), LI-1I, and LI-2I groups. The LI-1I and LI-2I groups were fed a LI diet for 12 weeks, followed by a onefold (adequate) or twofold (excessive) physiological dose of iodine for 4 weeks to induce involution. The miRNA expression profiles were evaluated and the potential functions of the differentially expressed miRNAs identified were explored.

RESULTS

In the LI group, 20 miRNAs were downregulated and 8 were upregulated. After involution, 21 miRNAs recovered to the control group levels in the LI-1I group, which was more than the 17 that recovered in the LI-2I group. In addition, 8 new differentially expressed miRNAs were identified in the LI-1I group, which was less than the 13 found in the LI-2I group. Bioinformatics analyses indicated that all differentially expressed miRNAs were involved in different processes and pathways, such as autoimmune thyroid disease and the Ras signaling pathway.

CONCLUSION

Differentially expressed miRNAs are involved in iodine-deficient goiter formation and involution. Supplementation with adequate, not excessive, iodine may be more beneficial to restore homeostasis.

Computer-aided ration calculation (Diet Check Munich© ) versus blood profile in raw fed privately owned dogs

Many dog owners create nutritionally imbalanced raw meat-based diets (RMBD) with information from the Internet and pseudo-scientific books, some even use pre-prepared frozen raw feed from online shops, local butchers or other providers. The risk of nutritional imbalances is therefore present. Blood profiles for dogs fed RMBD are promoted by laboratories as a simple tool for the owner to check the nutritional supply situation. Veterinarian nutrition specialists seem to be consulted less frequently and, in most cases, when blood analyses show deviations from reference ranges. The aim of the present study was to evaluate whether a RMBD blood profile reflects possible malnutrition according to a computer-aided ration check and to assess its clinical relevance. Using standardized questionnaires, the average daily rations of 104 dogs, 83 of which were fed raw diets versus 21 commercially fed dogs, were analysed using Diet Check Munich©, based on the National Research Council values. Afterwards, the SYNLAB.vet GmbH 'Barfer-Profil' test including calcium, phosphate, calcium/phosphate ratio, vitamin A, vitamin D, copper, zinc and iodine with additional parameters taurine, urea, uric acid and creatinine was carried out. No significant correlation between nutrient supply and associated blood parameters could be detected. Diet calculation revealed significantly more nutritional imbalances in the RMBD group than in the control group. Low plasma taurine could be detected only in the RMBD group. After participating, 30% of the dog owners (RMBD group) decided to adjust their dogs' diets at the nutrition consultation of the Clinic for Small Animal Internal Medicine of the LMU Munich. Based on these results, for most parameters a RMBD blood profile is not an appropriate tool to monitor a dog's nutrition and computer-aided ration calculation remains the gold standard for detecting nutritional imbalances.

2021 European Thyroid Association Guidelines for the Management of Iodine-Based Contrast Media-Induced Thyroid Dysfunction

Given the fact that a large number of radiological examinations using iodine-based contrast media (ICM) are performed in everyday practice, clinicians should be aware of potential ICM-induced thyroid dysfunction (TD). ICM can induce hyperthyroidism (Hyper) or hypothyroidism (Hypo) due to supraphysiological concentrations of iodine in the contrast solution. The prevalence of ICM-induced TD varies from 1 to 15%. ICM-induced Hyper is predominantly found in regions with iodine deficiency and in patients with underlying nodular goiter or latent Graves' disease. Patients at risk for ICM-induced Hypo include those with autoimmune thyroiditis, living in areas with sufficient iodine supply. Most cases of ICM-induced TD are mild and transient. In the absence of prospective clinical trials on the management of ICM-induced TD, an individualized approach to prevention and treatment, based on patient's age, clinical symptoms, pre-existing thyroid diseases, coexisting morbidities and iodine intake must be advised. Treatment of ICM-induced Hyper with antithyroid drugs (in selected cases in combination with sodium perchlorate) should be considered in patients with severe or prolonged hyperthyroid symptoms or in older patients with underlying heart disease. It is debated whether preventive therapy with methimazole and/or perchlorate prior to ICM administration is justified. In ICM-induced overt Hypo, temporary levothyroxine may be considered in younger patients with symptoms of Hypo, with an underlying autoimmune thyroiditis and in women planning pregnancy. Additional clinical trials with clinically relevant endpoints are warranted to further aid in clinical decision-making in patients with ICM-induced TD.

Lifestyle is associated with thyroid function in subclinical hypothyroidism: a cross-sectional study

BACKGROUND

Few studies have focused on the association between lifestyle and subclinical hypothyroidism (SCH). The purpose of this study was to investigate the association between lifestyle and thyroid function in SCH.

METHODS

This study was a part of a community-based and cross-sectional study, the Epidemiological Survey of Thyroid Diseases in Fujian Province, China. A total of 159 participants with SCH (81 males and 78 females) and 159 euthyroid (87 males and 72 females) participants without any missing data were included in the analysis. General information and lifestyle information including sleep, exercise, diet and smoking habits of the participants was collected by questionnaire and Pittsburgh sleep quality index scale (PSQI) was collected. Thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroid peroxidase antibody (TPOAb), thyroid globulin antibody (TgAb) and urine iodine concentration (UIC) were tested. Thyroid homeostasis parameter thyroid' s secretory capacity (SPINA-GT), Jostel's TSH index (TSHI), thyrotroph T4 sensitivity index (TTSI) were calculated. Logistic regression and multiple linear regression were performed to assess associations.

RESULTS

Compared with euthyroid subjects, patients with SCH were more likely to have poor overall sleep quality (15.1 vs.25.8 %, P = 0.018) and l less likely to stay up late on weekdays (54.7 vs. 23.9 % P < 0.001). In SCH group, exercise was the influencing factor of TSH (β= -0.224, P = 0.004), thyroid secretory capacity (β = 0.244, P = 0.006) and thyrotropin resistance (β = 0.206, P = 0.009). Iodine excess was the influencing factor of thyroid secretory capacity (β = 0.209, P = 0.001) and pituitary thyroid stimulating function (β = 0.167, P = 0.034). Smoking was the influencing factor of pituitary thyroid stimulating function (β = 0.161, P = 0.040). Staying up late on weekends was the influencing factor of thyroid secretory capacity (β = 0.151, P = 0.047). After adjusting for possible confounders, logistic regression showed that those with poor overall sleep quality assessed by PSQI and iodine excess had an increased risk of SCH (OR 2.159, 95 %CI 1.186-3.928, P = 0.012 and OR 2.119, 95 %CI 1.008-4.456, P = 0.048, respectively).

CONCLUSIONS

Lifestyle including sleep, smoking, diet and exercise was closely related to thyroid function especially thyroid homeostasis in SCH.