The association between endothelial function and autoimmune thyroiditis induced by iodine excess.

BACKGROUND: Iodine excess (IE) intake leads to lymphocyte dysfunction and contributes to autoimmune thyroiditis (AIT). Abnormal thyroid function is associated with adverse cardiovascular events, endothelial dysfunction is often an early pathophysiological feature in most cardiovascular disease. However, the relationship between iodine and the cardiovascular system is currently unclear. Therefore, the aim of this study was to investigate the effects of IE on endothelial function in mouse model. METHODS: A total of 24 NOD.H-2h4 mice were randomly divided into different groups. A sodium iodide (NaI) group supplied with 0.05% NaI water for 8 weeks. Serum levels of tumor necrosis factors α (TNFα), interleukin-6 (IL-6) and C-reactive Protein (CRP), as well as endothelin-1 (ET-1), von Willebrand factor (VWF) and thrombomodulin (THBD) were detected by Elisa. In addition, the mRNA and protein expression of these genes were measured by RT-PCR and Western blotting. RESULTS: Here, we found the urinary iodine concentration (UIC) was higher in the NaI group compared to the control group. Serum levels of ET-1, VWF, and THBD were also significantly lower in the NaI group, however, CRP serum levels are significantly increased. In aorta, the mRNA and protein expression of ET-1, VWF, THBD were downregulated, however, the expression of IL-6, CRP and TNFα mRNA and protein were upregulated in the NaI group. A correlation analysis showed negative correlation between UIC with ET-1, VWF, and THBD, similarly, negative correlation between CRP with THBD was observed. In addition, positive correlations between UIC with CRP. CONCLUSION: Collectively, in the NOD.H-2h4 mice, IE supplementation had a suppressive effect on endothelial function, and this inhibition maybe due to the increase expression of inflammatory cytokines.

Iodine Deficiency, Maternal Hypothyroxinemia and Endocrine Disrupters Affecting Fetal Brain Development: A Scoping Review.

This scoping review critically discusses the publications of the last 30 years on the impact of mild to moderate iodine deficiency and the additional impact of endocrine disrupters during pregnancy on embryonal/fetal brain development. An asymptomatic mild to moderate iodine deficiency and/or isolated maternal hypothyroxinemia might affect the development of the embryonal/fetal brain. There is sufficient evidence underlining the importance of an adequate iodine supply for all women of childbearing age in order to prevent negative mental and social consequences for their children. An additional threat to the thyroid hormone system is the ubiquitous exposure to endocrine disrupters, which might exacerbate the effects of iodine deficiency in pregnant women on the neurocognitive development of their offspring. Ensuring adequate iodine intake is therefore essential not only for healthy fetal and neonatal development in general, but it might also extenuate the effects of endocrine disruptors. Individual iodine supplementation of women of childbearing age living in areas with mild to moderate iodine deficiency is mandatory as long as worldwide universal salt iodization does not guarantee an adequate iodine supply. There is an urgent need for detailed strategies to identify and reduce exposure to endocrine disrupters according to the "precautional principle".

Long-term effect of a large dose of iodinated contrast in patients with mild thyroid dysfunction: a prospective cohort study.

BACKGROUND: More than 75 million procedures with intravascular iodine-based contrast media (ICM) are performed worldwide every year, and some patients undergoing these procedures do not have normal thyroid function. The long-term effects of ICM in patients with mild thyroid dysfunction (TD) are unclear. METHODS: This prospective cohort study was conducted in China. Patients with stable angina pectoris with total triiodothyronine (TT3) reduction, normal thyroid-stimulating hormone, and reverse triiodothyronine (rT3) were enrolled and divided into high-dose (≥100 mL ICM) and low-dose groups (<100 mL ICM). We dynamically investigated the trends in thyroid function, rT3, and thyroid antibodies one year after ICM exposure. RESULTS: A total of 154 patients completed 6 months of follow-up and 149 completed 1 year of follow-up. Thyroglobulin antibody (TGAB) levels were elevated in 41 (26.6%) patients before ICM exposure, 11 (7.1%) of whom also had elevated thyroid peroxidase antibody levels. Transient subclinical TD occurred 6 months after ICM exposure; 75.5% (34/45) of post-operative TD occurred in the high-dose group. One patient developed severe hypothyroidism with myxedema, requiring drug intervention 1 year after ICM exposure. The level of rT3 showed no statistically significant changes during post-operative follow-up ( P  = 0.848). The TGAB level decreased at 6th month ( P  < 0.001), but increased at 1 year after ICM exposure ( P  = 0.002). CONCLUSIONS: Patients with T3 reduction are at a risk of transient subclinical TD and hypothyroidism after a single large dose of ICM. Follow-up of this population at 9-12 months after ICM exposure is warranted.

Protection of Vitamin C on Oxidative Damage Caused by Long-Term Excess Iodine Exposure in Wistar Rats.

Vitamin C was reported to be able to protect against oxidative damage due to its reducibility. 120 Wistar rats were randomly divided into 4 × 2 groups, including normal iodine (NI), high iodine (HI), low vitamin C (HI + LC), and high vitamin C (HI + HC); potassium iodide (KI) and potassium iodate (KIO3) were commonly used as additives for iodized salt, so every group was also divided into KI and KIO3 groups. After 6 months' feed, the activities of antioxidant enzymes and Lipid Peroxide (MDA) content in serum, liver, kidney, brain, thyroid and lens were determined. In serum, for males, long-term excess iodine intake caused oxidative damage; in the liver, male rats in the HI + LC group had the highest MDA content, which showed that low-dose vitamin C might promote oxidative damage; in kidneys, the MDA content in the HI and HI + LC groups of females was higher; in the brain, high-dose vitamin C could increase the activity of superoxide dismutase (SOD), which was decreased by high iodine intake, and it also decreased MDA content; in the thyroid, for KIO3, the activity of SOD in the HI group was lower than NI and HI + LC; in the lens, the MDA content in females was lower than males. Long-term excess iodine exposure caused oxidative damage and showed sex difference, and vitamin C had a protective effect on it, especially for high-dose vitamin C.

Mother's iodine exposure and infants' hypothyroidism: the Japan Environment and Children's Study (JECS).

In this study, we aimed to determine the association of neonatal/post-neonatal hypothyroidism with mother's iodine exposure, especially povidone iodine disinfection, and hysterosalpingography. Participants were mother-child pairs in a Japanese birth cohort (n = 100,286). Risk factors of hypothyroidism were supplement intake, seaweed intake, other daily iodine intake, povidone iodine disinfection at delivery, and maternal history of hysterosalpingography, thyroid disease (Graves' disease and Hashimoto's thyroiditis), and medication (thiamazole and levothyroxine). Congenital hypothyroidism (CH) at age 1 year was assessed using a questionnaire. Transient hypothyroidism was defined as elevated thyroid stimulating hormone level at birth and absence of CH at age 1 year. The incidence of CH at age 1 year per 100 children was 1.1 for those born at 22-30 weeks' gestation, 0.17 following povidone iodine disinfection, and 0.07, 0.95, 0.81, 1.17, and 1.15 with a maternal history of hysterosalpingography, Graves' disease, Hashimoto's thyroiditis, thiamazole use, and levothyroxine use, respectively. Odds ratios (95% confidence intervals) of CH at age 1 year for povidone iodine disinfection, hysterosalpingography history, maternal Graves' disease, and maternal Hashimoto's thyroiditis were 1.13 (0.71-1.79), 0.47 (0.07-3.36), 7.06 (3.70-13.5), and 5.93 (2.90-12.1), respectively. For transient hypothyroidism for povidone iodine disinfection and hysterosalpingography history, these values were 1.99 (1.51-2.62) and 0.63 (0.20-1.96), respectively. Maternal thyroid disease greatly increased neonatal/post-neonatal hypothyroidism risk. Povidone iodine disinfection may increase transient hypothyroidism risk but not the risk at 1 year of age. Hysterosalpingography does not increase hypothyroidism risk from birth to age 1 year.

AMIODARONE AND THYROID DYSFUNCTION.

Thyroid gland has a key role in maintaining the body homeostasis. Thyroxine is the main hormone secreted from the thyroid gland, its effect being predominantly achieved after the intracellular conversion of thyroxine to triiodothyronine, which exhibits a higher affinity for the receptor complex, thus modifying gene expression of the target cells. Amiodarone is one of the most commonly used antiarrhythmics in the treatment of a broad spectrum of arrhythmias, usually tachyarrhythmias. Amiodarone contains a large proportion of iodine, which is, in addition to the intrinsic effect of the medication, the basis of the impact on thyroid function. It is believed that 15%-20% of patients treated with amiodarone develop some form of thyroid dysfunction. Amiodarone may cause amiodarone-induced hypothyroidism (AIH) or amiodarone-induced thyrotoxicosis (AIT). AIT is usually developed in the areas with too low uptake of iodine, while AIH is developed in the areas where there is a sufficient iodine uptake. Type 1 AIT is more common among patients with an underlying thyroid pathology, such as nodular goiter or Graves' (Basedow's) disease, while type 2 mostly develops in a previously healthy thyroid. AIH is more common in patients with previously diagnosed Hashimoto's thyroiditis. Combined types of the diseases have also been described. Patients treated with amiodarone should be monitored regularly, including laboratory testing and clinical examinations, to early detect any deviations in the functioning of the thyroid gland. Supplementary levothyroxine therapy is the basis of AIH treatment. In such cases, amiodarone therapy quite often need not be discontinued. Type 1 AIT is treated with thyrostatic agents, like any other type of thyrotoxicosis. If possible, the underlying amiodarone therapy should be discontinued. In contrast to type 1 AIT, the basic pathophysiological substrate of which is the increased synthesis and release of thyroid hormones, the basis of type 2 AIT is destructive thyroiditis caused by amiodarone, desethylamiodarone as its main metabolite, and an increased iodine uptake. Glucocorticoid therapy is the basis of treatment for this type of disease.

Effects of Molecular Iodine/Chemotherapy in the Immune Component of Breast Cancer Tumoral Microenvironment.

Molecular iodine (I2) induces apoptotic, antiangiogenic, and antiproliferative effects in breast cancer cells. Little is known about its effects on the tumor immune microenvironment. We studied the effect of oral (5 mg/day) I2 supplementation alone (I2) or together with conventional chemotherapy (Cht+I2) on the immune component of breast cancer tumors from a previously published pilot study conducted in Mexico. RNA-seq, I2 and Cht+I2 samples showed significant increases in the expression of Th1 and Th17 pathways. Tumor immune composition determined by deconvolution analysis revealed significant increases in M0 macrophages and B lymphocytes in both I2 groups. Real-time RT-PCR showed that I2 tumors overexpress T-BET (p = 0.019) and interferon-gamma (IFNγ; p = 0.020) and silence tumor growth factor-beta (TGFß; p = 0.049), whereas in Cht+I2 tumors, GATA3 is silenced (p = 0.014). Preliminary methylation analysis shows that I2 activates IFNγ gene promoter (by increasing its unmethylated form) and silences TGFß in Cht+I2. In conclusion, our data showed that I2 supplements induce the activation of the immune response and that when combined with Cht, the Th1 pathways are stimulated. The molecular mechanisms involved in these responses are being analyzed, but preliminary data suggest that methylation/demethylation mechanisms could also participate.

Iodine monitoring models contribute to avoid adverse birth outcomes related more than adequate iodine intake.

BACKGROUND: Iodine plays an important role in pregnancy. How to maintain adequate iodine intake amongst pregnant women in each trimester of pregnancy to prevent adverse birth outcomes in central China is a challenge for clinical practice. METHODS: 870 pregnant women and their infants were enrolled in the study. Urinary iodine concentration (UIC) was measured using an inductively coupled plasma mass spectrometry (ICP-MS). Maternal and newborn information were obtained during follow-up. Multinomial logistic regression models were established. RESULTS: Median UIC of pregnant women was 172 ± 135 µg/L which is currently considered to be sufficient. Multivitamin supplements containing iodine, iodized salt intake and frequent milk intake were significantly associated with higher UIC. Multivariate logistic regression analysis showed that multivitamin supplements containing iodine and milk consumption were risk factors for more than adequate iodine (UIC ≥ 250 µg/L). Iodine-rich diet was significantly related to heavier birthweight, larger head circumference and longer femur length of the newborns while more than adequate iodine intake (UIC ≥ 250 µg/L) was a risk factor for macrosomia. Logistic regression models based on potential risk factors involving iodine containing supplements and iodine-rich diet were established to predict and screen pregnant women with high risk of more than adequate iodine intake among local pregnant women in different trimesters and guide them to supplement iodine reasonably to prevent the risk. CONCLUSIONS: Multivitamin supplements containing iodine and milk consumption were risk factors for maternal UIC ≥ 250 µg/L which was a risk factor for macrosomia. Iodine monitoring models were established to provide guidance for pregnant women to reduce the risk of more than adequate iodine intake, thereby contributing to reduce the risk of having a macrosomia.

Excessive Prenatal Supplementation of Iodine and Fetal Goiter: Report of Two Cases Using Three-dimensional Ultrasound and Magnetic Resonance Imaging.

Fetal thyroid complications in pregnancy are uncommon, and are commonly related to the passage of substances through the placenta. The excessive iodine intake during the pregnancy is a well-known mechanism of fetal thyroid enlargement or goiter, and invasive procedures have been proposed for the treatment of fetal thyroid pathologies. In the present report, we demonstrate two cases from different centers of prenatal diagnosis of fetal thyroid enlargement and/or goiter in three fetuses (one pair of twins, wherein both fetuses were affected, and one singleton pregnancy). The anamnesis revealed the ingestion of iodine by the patients, prescribed from inadequate vitamin supplementation. In both cases, the cessation of iodine supplement intake resulted in a marked reduction of the volume of the fetal thyroid glands, demonstrating that conservative treatment may be an option in those cases. Also, clinicians must be aware that patients may be exposed to harmful dosages or substances during pregnancy.

As complicações fetais da tireoide na gravidez são incomuns e são comumente relacionadas à passagem de substâncias pela placenta. A ingestão excessiva de iodo durante a gravidez é um mecanismo bem conhecido de aumento da tireoide ou bócio fetal, e procedimentos invasivos foram propostos para o tratamento de patologias da tireoide fetal. No presente relato de caso, demonstramos dois casos de diferentes centros de diagnóstico pré-natal de aumento da tireoide fetal e/ou bócio em três fetos (um par de gêmeos, em que ambos os fetos foram afetados, e uma gravidez única). A anamnese revelou a ingestão de iodo pelos pacientes prescrita por suplementação inadequada de vitaminas. Nos dois casos, a interrupção da ingestão de suplemento de iodo resultou em uma redução acentuada do volume das glândulas tireoides fetais, demonstrando que o tratamento conservador pode ser uma opção nestes casos. Além disso, os médicos devem estar cientes de que as pacientes podem ser expostas a doses ou substâncias nocivas durante a gravidez.

Iodoprophylaxis and thyroid autoimmunity: an update.

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

Excessive prenatal supplementation of iodine and fetal goiter: report of two cases using three-dimensional ultrasound and magnetic resonance imaging / Suplementação pré-natal excessiva de iodo e bócio fetal: Relato de dois casos utilizando ultrassonografia tridimensional e ressonância magnética

Abstract Fetal thyroid complications in pregnancy are uncommon, and are commonly related to the passage of substances through the placenta. The excessive iodine intake during the pregnancy is a well-known mechanism of fetal thyroid enlargement or goiter, and invasive procedures have been proposed for the treatment of fetal thyroid pathologies. In the present report, we demonstrate two cases from different centers of prenatal diagnosis of fetal thyroid enlargement and/or goiter in three fetuses (one pair of twins, wherein both fetuses were affected, and one singleton pregnancy). The anamnesis revealed the ingestion of iodine by the patients, prescribed from inadequate vitamin supplementation. In both cases, the cessation of iodine supplement intake resulted in a marked reduction of the volume of the fetal thyroid glands, demonstrating that conservative treatmentmay be an option in those cases. Also, clinicians must be aware that patients may be exposed to harmful dosages or substances during pregnancy.

Resumo As complicações fetais da tireoide na gravidez são incomuns e são comumente relacionadas à passagem de substâncias pela placenta. A ingestão excessiva de iodo durante a gravidez é um mecanismo bem conhecido de aumento da tireoide ou bócio fetal, e procedimentos invasivos foram propostos para o tratamento de patologias da tireoide fetal. No presente relato de caso, demonstramos dois casos de diferentes centros de diagnóstico pré-natal de aumento da tireoide fetal e/ou bócio em três fetos (um par de gêmeos, em que ambos os fetos foram afetados, e uma gravidez única). A anamnese revelou a ingestão de iodo pelos pacientes prescrita por suplementação inadequada de vitaminas. Nos dois casos, a interrupção da ingestão de suplemento de iodo resultou em uma redução acentuada do volume das glândulas tireoides fetais, demonstrando que o tratamento conservador pode ser uma opção nestes casos. Além disso, os médicos devem estar cientes de que as pacientes podem ser expostas a doses ou substâncias nocivas durante a gravidez.

Iodine nutrition optimization: are there risks for thyroid autoimmunity?

Iodine deficiency is still the main cause of preventable thyroid disorders, worldwide. To optimize iodine intake, programs of voluntary or mandatory iodization of salt have been implemented in several iodine-deficient countries and iodine sufficiency has been achieved in many. Despite the clear beneficial effects on thyroid health, some concerns have been raised on the presumed detriment of iodine prophylaxis on thyroid autoimmunity. Very recent studies aimed at evaluating the long-term consequences of iodine supplementation on thyroid autoimmunity and related dysfunction, have clearly demonstrated that the early post-iodization increase in thyroid antibody positivity is largely transient and not clinically relevant, since the prevalence of overt thyroid dysfunction has remained reassuring low over two decades. The recommended iodine intake is therefore safe with regard to thyroid autoimmunity, the benefits largely outweighing the risks in a population with a stable median iodine concentration not exceeding 300 µg/L. Thus, a possible increase in thyroid autoimmunity should not represent a limitation to promoting iodine supplementation in the general population, also taking into account the steady rise in prevalence of autoimmune disorders which has occurred in the last few decades because of environmental factors other than iodine.

Primary thyroid dysfunction after single intravenous iodinated contrast exposure in young children: a propensity score matched analysis.

BACKGROUND: Data suggest an increased risk of thyroid dysfunction following iodine-based contrast material (IBCM) in children. OBJECTIVE: To estimate the prevalence of thyroid stimulating hormone (TSH) abnormalities following exposure to a single dose of intravenous IBCM during computed tomography (CT) in young children. MATERIALS AND METHODS: Inpatients ≤24 months of age who underwent a single CT with intravenous IBCM (exposed cohort) or abdominal ultrasound (US) (unexposed cohort) examination and had a TSH value obtained within 90 days after imaging between January 2009 to November 2018 were identified. Propensity score matching with 20 variables was performed. Primary thyroid dysfunction was defined by abnormally high or low TSH value. Multivariable logistic regression identified risk factors, including intravenous IBCM, for thyroid dysfunction. RESULTS: From the eligible 4,215 imaging examinations, 114 unique patients were included in the propensity matched population (n=57 per group). Thyroid dysfunction was identified in 14% (8/57) and 7% (4/57) of the IBCM-exposed and IBCM-unexposed cohorts, respectively. No patient in either cohort was started on thyroid hormone supplementation within the 3 months after imaging. Intravenous IBCM exposure was not a significant predictor of thyroid dysfunction on univariable (odds ratio [OR]=2.16, 95% confidence interval [CI]=0.61-7.64, P=0.23) or multivariable (OR=2.61, 95% CI=0.65-10.55, P=0.18) analyses. Significant independent predictors of post-imaging thyroid dysfunction included height (OR=1.25, P=0.0095) and trisomy 21 (OR=4.04, P=0.019). CONCLUSION: Hospitalized children ≤24 months of age who received a single dose of intravenous IBCM for CT examination had a similar prevalence of TSH abnormalities compared to a propensity score matched group who underwent abdominal US. One dose of intravenous IBCM likely does not cause prolonged TSH abnormalities; however, larger studies are needed.

Prevalence of Iodine-Induced Hyperthyroidism After Administration of Iodinated Contrast During Radiographic Procedures: A Systematic Review and Meta-Analysis of the Literature.

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.

Frequency of thyroid dysfunction in pediatric patients with congenital heart disease exposed to iodinated contrast media - a long-term observational study.

Background The thyroid gland of patients with congenital heart disease may be exposed to large doses of iodine from various sources. We assessed the thyroid response after iodine exposure during conventional angiography in cardiac catheterization and angiographic computer tomography in childhood. Methods Retrospective mid- to long-term follow-up of 104 individuals (24% neonates, 51% infants, 25% children) with a median age and body weight of 104 days [0-8 years] and 5.3 kg [1.6-20]. Serum levels of thyroid-stimulating hormone, free triiodthyronine and free thyroxine were evaluated at baseline and after excess iodine. We also assessed risk factors that may affect thyroid dysfunction. Results Baseline thyroidal levels were within normal range in all patients. The mean cumulative iodinate contrast load was 6.6 ± 1.6 mL/kg. In fact, 75% had experienced more than one event involving iodine exposure, whose median frequency was three times per patient [1-12]. During the median three years follow-up period [0.5-10], the incidence of thyroid dysfunction was 15.4% (n=16). Those patients developed acquired hypothyroidism (transient n=14, long-lasting n=2 [both died]) with 10 of them requiring temporary replacement therapy for transient thyroid dysfunction, while four patients recovered spontaneously. 88 individuals (84.6%) remained euthyroid. Repeated cardiac interventions, use of drugs that interfere with the thyroid and treatment in the intensive care unit at the index date were strong predictors for acquired thyroid dysfunction. Conclusions The incidence of acquired hypothyroidism after iodine excess was 15.4%. However, most patients developed only transient hypothyroidism. Systemic iodine exposure seems to be clinically and metabolically well tolerated during long-term follow-up.

Acne related to dietary supplements.

Multiple prescription medications may cause or aggravate acne. A number of dietary supplements have also been linked to acne, including those containing vitamins B6/B12, iodine, and whey, as well as "muscle building supplements" that may be contaminated with anabolic-androgenic steroids (AAS). Acne linked to dietary supplements generally resolves following supplement discontinuation. Lesions associated with high-dose vitamin B6 and B12 supplements have been described as monomorphic and although pathogenesis is unknown, a number of hypotheses have been proposed. Iodine-related acne may be related to the use of kelp supplements and has been reported as monomorphic, inflammatory pustules on the face and upper trunk. Whey protein supplements, derived from milk and used for bodybuilding, are associated with papulonodular acne involving the trunk and sometimes the face. Finally, AAS-induced acne has been described as acne fulminans, acne conglobata, and acne papulopustulosa. With studies indicating that about half of US adults report using dietary supplements, it is important that dermatologists directly ask acne patients about their supplement use and educate them on the potential risks of even seemingly innocuous dietary supplements.

Iodine-Induced Retinopathy: A Case Report

Potassium iodide is used as an iodine supplement in salt as part of a national program in Turkey. An overdose of iodine has a toxic effect on the retinal pigment epithelium and photoreceptors. The case presented here is a patient who developed retinopathy following consumption of an excessive dose of iodine.

Consequences of Iodine Deficiency and Excess in Pregnancy and Neonatal Outcomes: A Prospective Cohort Study in Rio de Janeiro, Brazil.

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.

Development of New Biokinetic-Dosimetric Models for the Simulation of Iodine Blockade in the Case of Radioiodine Exposure in Man.

In the case of nuclear incidents, radioiodine may be liberated. After incorporation it accumulates in the thyroid and by internal irradiation enhances the risk of cancer occurrence. By administering a large dose of non-radioactive iodine the uptake of radioiodine into the gland can be inhibited ("iodine blockade"). Biokinetic models using first order kinetics are not suited to simulate iodine blockade, as the uptake into the gland is mediated by a saturable active transport. Therefore, we integrated an uptake mechanism described by a Michaelis-Menten kinetic into a simple ICRP biokinetic model. We moreover added a total uptake blocking mechanism representing the Wolff-Chaikoff effect becoming active when the gland is saturated with iodine. The validity of the model was ascertained by comparison with IMBA software. The competition of radioiodine and stable iodine at the membrane carrier site was modeled according to the rate law for monomolecular reactions for competing substrates. Our simulations show that competition for the uptake at the membrane carrier site accounts for about 60% and the saturation of the gland with iodine for over 35% of the total protective efficacy that exceeds 95%. Following acute radioiodine exposure, it is preferable to administer a single large dose of stable iodine. In the case of continuous radioiodine exposure, a single dose of stable iodine is less effective than after an acute exposure and splitting the total available dose and shortening the dosage intervals enhance efficacy. Model-based simulations may be a useful tool to develop antidote dosage schemes for uncommon emergencies.

Low-keV and Low-kVp CT for Positive Oral Contrast Media in Patients with Cancer: A Randomized Clinical Trial.

Background Substantial gain in the attenuation of iodine on low-kVp and dual-energy CT processed low-keV virtual monochromatic images provides an opportunity for customization of positive oral contrast media administration. Purpose To perform an intrapatient comparison of bowel labeling, opacification, and taste preference with iodinated oral contrast medium (ICM) in standard (sICM) and 25%-reduced (rICM) concentrations at low tube voltage (100 kVp) or on low-energy (50-70 keV) virtual monochromatic images compared with barium-based oral contrast medium (BCM) at 120 kVp. Materials and Methods In this prospective clinical trial, 200 adults (97 men, 103 women; mean age, 63 years ± 13 [standard deviation]) who weighed less than 113 kg and who were undergoing oncologic surveillance (from April 2017 to July 2018) and who had previously undergone 120-kVp abdominopelvic CT with BCM randomly received sICM (7.2 g iodine) or rICM (5.4 g iodine) and underwent 100-kVp CT or dual-energy CT (80/140 kVp) scans to be in one of four groups (n = 50 each): sICM/100 kVp, rICM/100 kVp, sICM/dual-energy CT, and rICM/dual-energy CT. Qualitative analysis was performed for image quality (with a five-point scale), extent of bowel labeling, and homogeneity of opacification (with a four-point scale). Intraluminal attenuation of opacified small bowel was measured. A post-CT patient survey was performed to indicate contrast medium preference, taste of ICM (with a five-point scale), and adverse effects. Data were analyzed with analogs of analysis of variance. Results All CT studies were of diagnostic image quality (3.4 ± 0.3), with no difference in the degree of bowel opacification between sICM and rICM (P > .05). Compared with BCM/120 kVp (282 HU ± 73), mean attenuation was 78% higher with sICM/100 kVp (459 HU ± 282) and 26%-121% higher at sICM/50-65 keV (50 keV = 626 HU ± 285; 65 keV = 356 HU ± 171). With rICM, attenuation was 46% higher for 100 kVp (385 HU ± 215) and 19%-108% higher for 50-65 keV (50 keV = 567 HU ± 270; 65 keV = 325 HU ± 156) compared with BCM (P < .05). A total of 171 of 200 study participants preferred ICM to BCM, with no taste differences between sICM and rICM (3.9 ± 0.6). Fifteen participants had diarrhea with BCM, but none had diarrhea with ICM. Conclusion A 25%-reduced concentration of iodinated oral contrast medium resulted in acceptable bowel labeling while yielding substantially higher luminal attenuation at low-kVp and low-keV CT examinations with improved preference in patients undergoing treatment for cancer. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Laghi in this issue.