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Do maternal urinary iodine concentration or thyroid hormones within the normal range during pregnancy affect growth parameters at birth? A systematic review and meta-analysis.
Nazeri, P, Shab-Bidar, S, Pearce, EN, Shariat, M
Nutrition reviews. 2020;(9):747-763
Abstract
CONTEXT Iodine, an essential constituent of thyroid hormones, is required for proper growth and development. OBJECTIVE To investigate whether growth parameters at birth are associated with maternal urinary iodine concentration (UIC) or normal ranges of thyroid hormones during pregnancy. DATA SOURCES Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, electronic databases (namely, MEDLINE, Web of Science, the Cochrane Library, Scopus, and Google Scholar) were searched between January 1988 and November 2018 to identify relevant articles. DATA EXTRACTION Data from the studies included were independently extracted by 2 investigators using standardized forms developed for this review. DATA ANALYSIS The pooled mean birth weight, length, and head circumference values, and 95% confidence intervals were estimated in newborns born to women with UIC < 150 and UIC ≥150 μg/L during pregnancy. Possible linear or nonlinear associations between maternal UIC and the aforementioned anthropometric measures were evaluated. A narrative synthesis of the data was performed for thyroid hormones with levels within the normal range. RESULTS Of the 123 studies identified, 11 were eligible for inclusion in the meta-analysis. The pooled mean birth weight, length, and head circumference in newborns whose mothers had UIC < 150 μg/L vs UIC ≥150 μg/L were 2898 g vs 2900 g (P = 0.970), 49.6 cm vs 49.4 cm (P = 0.880), and 34.0 cm vs 34.1 cm (P = 0.933), respectively. Dose-response meta-analyses revealed no significant linear or nonlinear associations between maternal UIC during pregnancy and anthropometric measures at birth. Among the different thyroid function parameters evaluated, high-normal values of maternal free thyroxine and thyrotropin during pregnancy were inversely associated with neonatal birth weight. CONCLUSION This systematic review showed that birth weight may be affected by even mild variations in the normal concentrations of maternal thyroid hormones. However, in the current meta-analysis, birth anthropometric measures were not associated with maternal UIC during pregnancy.
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Intake of seaweed as part of a single sushi meal, iodine excretion and thyroid function in euthyroid subjects: a randomized dinner study.
Noahsen, P, Kleist, I, Larsen, HM, Andersen, S
Journal of endocrinological investigation. 2020;(4):431-438
Abstract
OBJECTIVE Globalisation has extended to the kitchen and the Asian cuisine has gained international popularity with sushi and seaweed now being widespread. We explored the possible acute adverse effects of an iodine load from a single sushi-and-seaweed meal as seaweed iodine may induce thyroid dysfunction. METHODS Nine euthyroid participants were randomized into three groups: Halibut maki roll with either (A) newly harvested Greenlandic seaweed salad, (B) no seaweed salad on the side, or (C) Japanese seaweed salad purchased at a local store. We collected spot urine and blood samples daily for a week for measurement of iodine and creatinine in urine, thyroid stimulating hormone (TSH), and estimated-free T4 (fT4) in serum. RESULTS All participants ingested the full meal and the drop-out was nil. No adverse effects were reported. Pre-meal urinary iodine excretion (UIE) was 75 µg/g. UIE rose (p < 0.001) by 385%, 59% and 43% for groups A, B, and C, peaked in the 6-h spot urine sample at 393, 120, and 109 µg/g, and was down to pre-meal values by day 2. Serum TSH rose (p = 0.012) 150% on day 2 and was down to pre-meal values by day 3. Serum fT4 remained at the same level. No adverse reactions were reported. CONCLUSION A sushi meal increased urinary iodine excretion by 40 µg/g, or 400 µg/g if a newly harvested seaweed salad was added. An ensuing rise in serum TSH was brief, and a single sushi meal with seaweed salad did not cause any adverse events.
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Utility of Iodine Density Perfusion Maps From Dual-Energy Spectral Detector CT in Evaluating Cardiothoracic Conditions: A Primer for the Radiologist.
Kikano, EG, Rajdev, M, Salem, KZ, Laukamp, K, Felice, CD, Gilkeson, RC, Gupta, A
AJR. American journal of roentgenology. 2020;(4):775-785
Abstract
OBJECTIVE. The purpose of this article is to outline the utility of iodine density maps for evaluating cardiothoracic disease and abnormalities. Multiple studies have shown that the variety of images generated from dual-energy spectral detector CT (SDCT) improve identification of cardiothoracic conditions. CONCLUSION. Understanding the technique of SDCT and being familiar with the features of different cardiothoracic conditions on iodine density map images help the radiologist make a better diagnosis.
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Acne related to dietary supplements.
Zamil, DH, Perez-Sanchez, A, Katta, R
Dermatology online journal. 2020;(8)
Abstract
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.
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Iodine dose optimization in portal venous phase virtual monochromatic images of the abdomen: Prospective study on rapid kVp switching dual energy CT.
Noda, Y, Goshima, S, Nakashima, Y, Miyoshi, T, Kawai, N, Kambadakone, A, Matsuo, M
European journal of radiology. 2020;:108746
Abstract
PURPOSE To investigate iodine dose concentration required for adequate hepatic parenchymal enhancement on fast-kilovoltage-switching dual-energy computed tomography (DECT) of the abdomen based on patient body weight. MATERIALS AND METHODS The protocol of this prospective study was approved by the local Institutional Review Board and written informed consent for study participation was obtained from all patients. The study cohort of 204 consecutive patients who underwent whole body single-source DECT to screen for tumor metastases and/or recurrence after surgical resection of malignant tumors were randomly assigned to one of three protocols according to the iodine dose (400, 500, and 600 mgI/kg). For each case, two radiologists quantitatively and qualitatively reviewed three energy levels (65, 70, and 75 kilo electron volt [keV]) of the portal venous phase virtual monochromatic images (VMIs). CT numbers of the liver and the qualitative hepatic parenchymal enhancement were compared among the VMIs with the three protocols and three energy levels. RESULTS Hepatic enhancement (ΔHU > 50HU) was achieved at 65 keV with 400, 500, and 600 mgI/kg, at 70 keV with 500 and 600 mgI/kg, and at 75 keV with 600 mgI/kg. The hepatic parenchymal enhancement was graded as sufficient hepatic enhancement in 97%, 100%, and 99% at 65 keV with 400, 500, and 600 mgI/kg, 88% and 97% at 70 keV with 500 and 600 mgI/kg, and 84% at 75 keV with 600 mgI/kg, respectively. CONCLUSION The iodine dose can be reduced to 400 mgI/kg at 65 keV or 500 mgI/kg at 70 keV in DECT without compromising hepatic parenchymal enhancement.
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Interference on Iodine Uptake and Human Thyroid Function by Perchlorate-Contaminated Water and Food.
Lisco, G, De Tullio, A, Giagulli, VA, De Pergola, G, Triggiani, V
Nutrients. 2020;(6)
Abstract
BACKGROUND Perchlorate-induced natrium-iodide symporter (NIS) interference is a well-recognized thyroid disrupting mechanism. It is unclear, however, whether a chronic low-dose exposure to perchlorate delivered by food and drinks may cause thyroid dysfunction in the long term. Thus, the aim of this review was to overview and summarize literature results in order to clarify this issue. METHODS Authors searched PubMed/MEDLINE, Scopus, Web of Science, institutional websites and Google until April 2020 for relevant information about the fundamental mechanism of the thyroid NIS interference induced by orally consumed perchlorate compounds and its clinical consequences. RESULTS Food and drinking water should be considered relevant sources of perchlorate. Despite some controversies, cross-sectional studies demonstrated that perchlorate exposure affects thyroid hormone synthesis in infants, adolescents and adults, particularly in the case of underlying thyroid diseases and iodine insufficiency. An exaggerated exposure to perchlorate during pregnancy leads to a worse neurocognitive and behavioral development outcome in infants, regardless of maternal thyroid hormone levels. DISCUSSION AND CONCLUSION The effects of a chronic low-dose perchlorate exposure on thyroid homeostasis remain still unclear, leading to concerns especially for highly sensitive patients. Specific studies are needed to clarify this issue, aiming to better define strategies of detection and prevention.
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Frequency of thyroid dysfunction in pediatric patients with congenital heart disease exposed to iodinated contrast media - a long-term observational study.
Kubicki, R, Grohmann, J, Kunz, KG, Stiller, B, Schwab, KO, van der Werf-Grohmann, N
Journal of pediatric endocrinology & metabolism : JPEM. 2020;(11):1409-1415
Abstract
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.
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Consequences of Severe Iodine Deficiency in Pregnancy: Evidence in Humans.
Toloza, FJK, Motahari, H, Maraka, S
Frontiers in endocrinology. 2020;:409
Abstract
Iodine is a necessary micronutrient for the production of thyroid hormones and normal human development. Despite the significant worldwide strategies for the prevention and control of iodine deficiency, it is still a prevalent public health issue, especially in pregnant women. Severe iodine deficiency during pregnancy and neonatal period is associated with many major and irreversible adverse effects, including an increased risk of pregnancy loss and infant mortality, neonatal hypothyroidism, cretinism, and neuropsychomotor retardation. We will review the impact of severe iodine deficiency on maternofetal, neonatal, and offspring outcomes. We will also discuss its epidemiology, classification of iodine deficiency severity, and current recommendations to prevent iodine deficiency in childbearing age and pregnant women.
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Multiple nutritional factors and thyroid disease, with particular reference to autoimmune thyroid disease.
Rayman, MP
The Proceedings of the Nutrition Society. 2019;(1):34-44
Abstract
Hashimoto's thyroiditis (HT) and Graves' disease (GD) are examples of autoimmune thyroid disease (AITD), the commonest autoimmune condition. Antibodies to thyroid peroxidase (TPO), the enzyme that catalyses thyroid-hormone production and antibodies to the receptor for the thyroid-stimulating hormone, are characteristic of HT and GD, respectively. It is presently accepted that genetic susceptibility, environmental factors, including nutritional factors and immune disorders contribute to the development of AITD. Aiming to investigate the effect of iodine, iron and selenium in the risk, pathogenesis and treatment of thyroid disease, PubMed and the Cochrane Library were searched for relevant publications to provide a narrative review. Iodine: chronic exposure to excess iodine intake induces autoimmune thyroiditis, partly because highly-iodinated thyroglobulin (Tg) is more immunogenic. The recent introduction of universal salt iodisation can have a similar, although transient, effect. Iron: iron deficiency impairs thyroid metabolism. TPO is a haem enzyme that becomes active only after binding haem. AITD patients are frequently iron-deficient since autoimmune gastritis, which reduces iron absorption and coeliac disease which causes iron loss, are frequent co-morbidities. In two-thirds of women with persistent symptoms of hypothyroidism despite appropriate levothyroxine therapy, restoration of serum ferritin above 100 µg/l ameliorated symptoms. Selenium: selenoproteins are essential to thyroid action. In particular, the glutathione peroxidases remove excessive hydrogen peroxide produced there for the iodination of Tg to form thyroid hormones. There is evidence from observational studies and randomised controlled trials that selenium, probably as selenoproteins, can reduce TPO-antibody concentration, hypothyroidism and postpartum thyroiditis. Appropriate status of iodine, iron and selenium is crucial to thyroid health.
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Stable Iodine Distribution Among Children After the 2011 Fukushima Nuclear Disaster in Japan: An Observational Study.
Nishikawa, Y, Kohno, A, Takahashi, Y, Suzuki, C, Kinoshita, H, Nakayama, T, Tsubokura, M
The Journal of clinical endocrinology and metabolism. 2019;(5):1658-1666
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Abstract
CONTEXT Intake of stable iodine helps prevent childhood thyroid cancer in nuclear emergencies, but there is limited case information. OBJECTIVE We identified the intake rate and the factors associated with no intake among children who did not take stable iodine after the Fukushima disaster. DESIGN Retrospective observational study. SETTING Data were obtained from thyroid cancer screenings performed from August through November 2017. PARTICIPANTS Children in Miharu Town, Fukushima, Japan. INTERVENTION No intervention. MAIN OUTCOME MEASURES We performed multilevel logistic regression analysis at the regional and individual levels. We qualitatively examined the reasons for no intake of stable iodine based on closed- and open-ended questions. RESULTS The rate of distribution was 94.9%, but the intake rate was only 63.5%. Intake was lower in those aged 0 to 2 years compared with those aged ≥3 years (OR, 0.21; 95% CI, 0.11 to 0.36). Parents' intake was positively associated with their children's intake (OR, 61.0; 95% CI, 37.9 to 102.9). The variance partition coefficient for regions was 0.021, suggesting that the intake of stable iodine was more likely affected by individual than by regional factors. Closed-ended questions showed that the main reason for avoiding intake was concern about safety. Open-ended questions for other reasons revealed issues related to the distribution method, information about the effects and adverse effects of iodine, and instructions for iodine intake. There were no symptomatic adverse effects claimed to the town. CONCLUSIONS The distribution and consumption of stable iodine occurred in Miharu Town after the Fukushima disaster. To prepare for future nuclear emergencies, it is important to explain to both children and parents the need for intake of stable iodine, particularly among young children.