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Nguyen CT. An update: maternal iodine supplementation, thyroid function tests, and child neurodevelopmental outcomes. Curr Opin Endocrinol Diabetes Obes 2023; 30:265-272. [PMID: 37417826 DOI: 10.1097/med.0000000000000824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/08/2023]
Abstract
PURPOSE OF REVIEW The impact of maternal iodine supplementation (MIS) during pregnancy on thyroid function and child neurodevelopmental outcomes in areas of mild-to-moderate iodine deficiency (MMID) remains unclear. RECENT FINDINGS Despite growing success of salt iodization programs, a 2022 meta-analysis found that 53% of pregnant patients worldwide continue to have insufficient iodine intake during pregnancy. A 2021 randomized controlled trial (RCT) found that MIS in women with mild iodine deficiency led to iodine sufficiency and positive effects on maternal thyroglobulin. A 2021 cohort study of MIS initiated prior to pregnancy was associated with lower thyroid-stimulating hormone (TSH), higher FT3, and FT4. Other cohort studies, however, found that neither salt iodization nor MIS were adequate to meet pregnancy iodine needs. Data have been mixed regarding maternal iodine status and pregnancy outcomes in patients of MMID. Meta-analyses have not shown any clear benefit on infant neurocognitive outcomes with MIS of MMID patients. A 2023 meta-analysis found that the prevalence of excess iodine intake in pregnancy was 52%. SUMMARY MMID continues to exist during pregnancy. Salt iodization alone may be insufficient to ensure adequate iodine status during pregnancy. There is an absence of high-quality data to support routine MIS in areas of MMID. However, patients with specialized diets (vegan, nondairy, no seafood, noniodized salt, and so on) may be at risk for inadequate iodine status in pregnancy. Excess iodine intake can be detrimental to the fetus and should be avoided during pregnancy.
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Affiliation(s)
- Caroline T Nguyen
- Departments of Clinical Medicine, Obstetrics, and Gynecology, Division of Endocrinology, Metabolism, and Diabetes, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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Spina V, Baldini E, Cardarelli S, Oliva C, Venarubea S, Faraoni F, Pastore G, Tittoni R, Musella A, Squarcella A, Lori E, Renzi E, Feroci R, Mastrodonato F, Ciferri F, Virili C, Centanni M, Fabiani C, Rago R, Schiavi MC, Palazzetti P, D'Armiento E, Cantisani V, Sorrenti S, Ulisse S. Iodized Salt May Not Be Sufficient to Guarantee an Adequate Iodine Intake in Pregnant Women. Nutrients 2023; 15:4182. [PMID: 37836466 PMCID: PMC10574232 DOI: 10.3390/nu15194182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023] Open
Abstract
Adequate iodine intake is of crucial importance in pregnancy to meet the thyroid hormone needs of both mother and fetus. In the present study, undertaken as a part of the surveillance actions following the introduction in Italy of a national salt iodination program in 2005, the iodine intake was investigated in 123 pregnant women and 49 control women living in the same area of central Italy. All the participants were screened for urinary iodine concentration (UIC), serum level of thyrotropin, free-thyroxine, free-triiodothyronine, and thyroid volume. Moreover, they were provided with a questionnaire on the use of iodine-containing salt or supplements. Control women had a median UIC of 102 µg/L, consistent with an iodine sufficiency, while in pregnant women the median UIC value was 108 µg/L, lower than the endorsed UIC of 150 µg/L. In addition, pregnant women showed a significantly increased median thyroid volume compared to controls. Interestingly, the median UIC did not differ between pregnant women not using iodine-containing salt or supplements and those regularly consuming iodized salt alone, while pregnant women with a daily intake of iodine-containing supplements had an adequate median UIC (168 µg/L). In conclusion, the data reported here showed that pregnant women and their fetuses are still exposed to the detrimental effects of iodine deficiency and that the consumption of iodine-containing supplements should be recommended in pregnancy.
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Affiliation(s)
- Vincenzo Spina
- Mother and Infant Department Unit, ASL-Rieti, 02100 Rieti, Italy
| | - Enke Baldini
- Department of Surgery, "Sapienza" University of Rome, 00185 Rome, Italy
| | - Silvia Cardarelli
- Department of Surgery, "Sapienza" University of Rome, 00185 Rome, Italy
| | - Cosimo Oliva
- Obstetrics and Gynaecology Unit, "S. Camillo De Lellis" Hospital, 02100 Rieti, Italy
| | - Stefano Venarubea
- Clinical Pathology Laboratory Unit, "S. Camillo De Lellis" Hospital, 02100 Rieti, Italy
| | - Franca Faraoni
- Pediatrics and Neonatology Unit, "S. Camillo De Lellis" Hospital, 02100 Rieti, Italy
| | - Giovanni Pastore
- Obstetrics and Gynaecology Unit, "S. Camillo De Lellis" Hospital, 02100 Rieti, Italy
| | - Rachele Tittoni
- Obstetrics and Gynaecology Unit, "S. Camillo De Lellis" Hospital, 02100 Rieti, Italy
| | - Angela Musella
- Obstetrics and Gynaecology Unit, "S. Camillo De Lellis" Hospital, 02100 Rieti, Italy
| | - Antonia Squarcella
- Obstetrics and Gynaecology Unit, "S. Camillo De Lellis" Hospital, 02100 Rieti, Italy
| | - Eleonora Lori
- Department of Surgery, "Sapienza" University of Rome, 00185 Rome, Italy
| | - Elisabetta Renzi
- Mother and Infant Department Unit, ASL-Rieti, 02100 Rieti, Italy
| | - Roberta Feroci
- Mother and Infant Department Unit, ASL-Rieti, 02100 Rieti, Italy
| | | | - Fabiola Ciferri
- Mother and Infant Department Unit, ASL-Rieti, 02100 Rieti, Italy
| | - Camilla Virili
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University of Rome, 04100 Latina, Italy
| | - Marco Centanni
- Department of Medico-Surgical Sciences and Biotechnologies, "Sapienza" University of Rome, 04100 Latina, Italy
| | - Cristina Fabiani
- Mother and Infant Department, "Sandro Pertini" Hospital, 00157 Rome, Italy
| | - Rocco Rago
- Mother and Infant Department, "Sandro Pertini" Hospital, 00157 Rome, Italy
| | | | | | - Eleonora D'Armiento
- Department of Internal Medicine and and Medical Specialties, "Sapienza" University of Rome, 00185 Rome, Italy
| | - Vito Cantisani
- Department of Radiological and Oncological Sciences and Pathological Anatomy, "Sapienza" University of Rome, 00185 Rome, Italy
- Teleradiology Complex Unit, ASL-Rieti, 02100 Rieti, Italy
| | | | - Salvatore Ulisse
- Department of Surgery, "Sapienza" University of Rome, 00185 Rome, Italy
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A Scoping Review of Iodine and Fluoride in Pregnancy in Relation to Maternal Thyroid Function and Offspring Neurodevelopment. Adv Nutr 2023; 14:317-338. [PMID: 36796438 DOI: 10.1016/j.advnut.2023.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 01/05/2023] [Accepted: 01/11/2023] [Indexed: 02/04/2023] Open
Abstract
Iodine (I), an essential nutrient, is important for thyroid function and therefore growth and development. Fluoride (F), also an essential nutrient, strengthens bones and teeth, and prevents childhood dental caries. Both severe and mild-to-moderate I deficiency and high F exposure during development are associated to decreased intelligence quotient with recent reports associating high levels of F exposure during pregnancy and infancy to low intelligence quotient. Both F and I are halogens, and it has been suggested that F may interfere with the role of I in thyroid function. We provide a scoping review of the literature on I and F exposure dur pregnancy and their individual effects on thyroid function and offspring neurodevelopment. We first discuss I intake and status in pregnancy and the relationship to thyroid function and offspring neurodevelopment. We follow with the F in pregnancy and offspring neurodevelopment. We then review the interaction between I and F on thyroid function. We searched for, and found only one study that assessed both I and F in pregnancy. We conclude more studies are needed.
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Rezaei M, Ataei N, Zarban A, Mobasher N, Farkhondeh T, Samarghandian S. Assessment of Iodofolic Supplementation on Thyroid Function in Pregnant Women with Iodine Sufficient Status and their Infants in Birjand. Curr Pediatr Rev 2022; 18:237-241. [PMID: 34911429 DOI: 10.2174/1573396317666211215142330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/30/2021] [Accepted: 08/27/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Maintaining iodine at sufficient levels is necessary throughout the pregnancy to prevent adverse outcomes in infants. This study aimed to assess iodofolic supplementation's impact on thyroid function in women at the end of the third trimesters of gestation. METHODS This case-control study was conducted on 130 pregnant women in the Birjand, east of Iran, during the period from August 2017 to February 2019. We assessed iodofolic supplementation effect in the women at the first trimesters of gestation and followed them at the end of the third trimesters and also their infants on days 3-5. Serum samples were obtained from women and infants for measuring levels of thyroid-stimulating hormone (TSH). Urinary iodine concentration (UIC) was also determined at the end of the third trimester. RESULTS The median serum TSH concentration in the folic acid consumed group (3.26 ± 1.91) did not significantly differ from another group (2.98 ± 1.41), (p = 0.68). There is also no considerable difference in the mean serum TSH concentration between infants born from mothers who consumed folic acid in the first trimester of pregnancy and another group (p = 0.50). The TSH concentration in all infants was below 5 μM/L. The significant difference in the mean of UIC was also not observed between pregnant women in the folic acid consumed group (188.02 ± 105.38) and iodofolic consumed group (225.77 ± 130.26), (p = 0.13). CONCLUSION Iodine intake in our study was sufficient according to the WHO recommendation and idofolic supplementation was not emphasized.
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Affiliation(s)
- Maryam Rezaei
- Medical Toxicology and Drug Abuse Research Center (MTDRC), Birjand University of Medical Sciences (BUMS), Birjand, Iran.,Department of Endocrinology, Faculty of Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | - Naeemeh Ataei
- Medical Student, Birjand University of Medical Sciences, Birjand, Iran
| | - Asghar Zarban
- Department of Biochemistry, Faculty of Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | - Nahid Mobasher
- Obsterician, Birjand University of Medical Sciences, Birjand, Iran
| | - Tahereh Farkhondeh
- Faculty of Pharmacy, Birjand University of Medical Sciences, Birjand, Iran
| | - Saeed Samarghandian
- Noncommunicable Diseases Research Center, Neyshabur University of Medical Sciences, Neyshabur, Iran
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Delshad H, Raeisi A, Abdollahi Z, Tohidi M, Hedayati M, Mirmiran P, Nobakht F, Azizi F. Iodine supplementation for pregnant women: a cross-sectional national interventional study. J Endocrinol Invest 2021; 44:2307-2314. [PMID: 33704696 DOI: 10.1007/s40618-021-01538-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/16/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Although Iran has been considered iodine replete since 2000, the first national survey of iodine intake among Iranian pregnant women in 2014 indicated that despite the adequate intake of iodine by the general population, this vulnerable group has moderate iodine deficiency. Therefore, in this national cross-sectional interventional study, we aimed to assess the iodine intake and thyroid function of Iranian pregnant women 2 years after implementing national iodine supplementation for this vulnerable group. MATERIALS AND METHODS In this cross-sectional study, we conducted a national interventional survey of pregnant women. A total of 1200 pregnant women (400 women from each trimester) from 12 provinces of Iran were recruited from the antenatal care clinics from October 2018 to March 2019. The median urinary iodine concentration (MUIC), as an indicator of iodine status in three spot urine samples, was measured, along with the serum total T4 (TT4), thyrotropin (TSH), thyroglobulin (Tg), thyroid peroxidase antibody (TPO-Ab), and iodine content of household salt. RESULTS The mean age of the cohort was 28 ± 6.2 years, with the mean gestational age of 22.7 ± 13.0 weeks. The overall MUIC (IQR) of pregnant women was 188 µg/L (124.2-263 µg/L). Also, the MUICs in the three trimesters of pregnancy were 174 µg/L (110-254), 175 µg/L (116-251), and 165 µg/L (114-235), respectively. The MUICs ≥ 150, 100-149, and < 100 µg/L were found in 63, 19.8, and 16.2% of the subjects, respectively. The mean TT4 level was 12 ± 4.5 µg/dL, and the median (IQR) level of TSH was 2.37 mIU/L (1.66-3.18 mIU/L). According to our local reference range, 118 (10.5%) pregnant women had subclinical hypothyroidism, 6 (0.53%) women had isolated hypothyroxinemia, and 65 (5.7%) women were TPO-Ab positive. Also, the median (IQR) level of Tg was 10.08 µg/dL (5.7-20.4 µg/dL), and the median iodine content of household salt was 29.6 µg/g; the iodine content was ≥ 30 µg/g in 85% of household salt. The results showed that more than 95% of households were under iodized salt coverage. CONCLUSION The results of this study indicated that iodine supplementation with at least 150 µg of iodine per day improved the iodine intake of pregnant women. Except for subclinical hypothyroidism, the prevalence of clinical hypothyroidism, clinical/subclinical thyrotoxicosis, TPO-Ab positivity, and isolated hypothyroxinemia decreased significantly, which emphasizes the importance of iodine supplementation during pregnancy.
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Affiliation(s)
- H Delshad
- Micronutrient Research Office, Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - A Raeisi
- Iran's Ministry of Health and Medical Education, Tehran, Iran
| | - Z Abdollahi
- General of Nutrition Department, Iran's Ministry of Health and Medical Education, Tehran, Iran
| | - M Tohidi
- Prevention of Metabolic Disorders Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - M Hedayati
- Cellular and Molecular Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - P Mirmiran
- Nutrition Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - F Nobakht
- National IDD Program, Iran's Ministry of Health and Medical Education, Tehran, Iran
| | - F Azizi
- Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, P. O. Box 19395-4763, Tehran, Iran.
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Mulder TA, Korevaar TIM, Peeters RP, van Herwaarden AE, de Rijke YB, White T, Tiemeier H. Urinary Iodine Concentrations in Pregnant Women and Offspring Brain Morphology. Thyroid 2021; 31:964-972. [PMID: 33267727 DOI: 10.1089/thy.2020.0582] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Background: Severe maternal iodine deficiency during pregnancy leads to marked intellectual disability in the offspring. Although recent studies showed that even mild-to-moderate maternal iodine deficiency is associated with lower intelligence quotient and attention deficit hyperactivity disorder in offspring, the underlying neurobiological mechanism of these associations remains unknown. The aim of this study was to investigate the association of maternal iodine excretion during pregnancy with offspring brain morphology during pre-adolescence. Methods: This study was embedded within Generation R, a prospective population-based birth cohort in Rotterdam, the Netherlands. We included 990 mother-child pairs with data on urinary iodine concentration (UIC) and creatinine during pregnancy. The UIC was assessed at <18 and/or 18-25 weeks of gestation and offspring brain imaging data were acquired with magnetic resonance imaging (MRI) at age 10 years. We used linear regression to study the association of the iodine-to-creatinine ratio (UI/Creat) with offspring brain MRI outcomes. Results: Maternal UI/Creat during pregnancy was not consistently associated with offspring brain morphology. A low UI/Creat (<150 μg/g) during pregnancy was nominally associated with smaller total gray matter volume, but this did not survive correction for multiple testing. Also, we could not identify a linear association between continuous iodine excretion and offspring brain morphology. Instead, our results suggest a curvilinear association between UI/Creat and brain morphology. In sensitivity analyses using the World Health Organization categorization for UIC values, both low and high UI/Creat were associated with smaller total gray matter volume. Conclusions: The current study provides some but no conclusive evidence for an association of maternal iodine excretion during pregnancy with offspring brain morphology. Our results suggest that the exact definition of the reference group is important because of potential non-linear associations, which could be leveraged in future studies.
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Affiliation(s)
- Tessa A Mulder
- Generation R Study Group, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Internal Medicine, Academic Center for Thyroid Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Tim I M Korevaar
- Generation R Study Group, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Internal Medicine, Academic Center for Thyroid Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Robin P Peeters
- Department of Internal Medicine, Academic Center for Thyroid Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Antonius E van Herwaarden
- Department of Laboratory Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Yolanda B de Rijke
- Department of Clinical Chemistry, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Tonya White
- Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Radiology & Nuclear Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Henning Tiemeier
- Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Social and Behavioral Science, Harvard TH Chan School of Public Health, Boston, Massachusetts, USA
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González-Martínez S, Riestra-Fernández M, Martínez-Morillo E, Avello-Llano N, Delgado-Álvarez E, Menéndez-Torre EL. Nutritional Iodine Status in Pregnant Women from Health Area IV in Asturias (Spain): Iodised Salt Is Enough. Nutrients 2021; 13:nu13061816. [PMID: 34071767 PMCID: PMC8228027 DOI: 10.3390/nu13061816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/22/2021] [Accepted: 05/25/2021] [Indexed: 12/11/2022] Open
Abstract
Background: Iodine deficiency during pregnancy may have adverse effects on the neurodevelopment of the foetus. Recent studies of pregnant women in Asturias (Spain) indicate that nutritional iodine levels are sufficient. The objective of this study was to confirm the appropriate nutritional iodine status and to analyse the influence of the ingestion of iodine on maternal urinary iodine concentration (UIC) and thyroid function. Methods: An observational study was carried out between May and June 2017 on women in the first trimester of pregnancy from Health Area IV in Asturias. The women completed a questionnaire related to their consumption of iodine and samples were taken to analyse UIC and thyroid function. Results: Three hundred and eighteen pregnant women were involved. Of these, 51.10% used iodised salt, 48.90% consumed ≥ 2 servings of dairy products daily and 87.08% took iodine supplements. The median UIC was 171.5 μg/L (116–265 μg/L) and 60.41% of women had UIC ≥ 150 μg/L. Multivariate logistic regression analysis demonstrated that iodised salt had a protective effect on UIC < 150 μg/L (odds ratio (OR) 0.404 (0.237–0.683), p = 0.001), but not iodine supplements (OR 0.512 (0.240–1.085), p = 0.080). The average level of thyroid stimulating hormone (TSH) was 2.26 ± 0.94 mIU/L; 68.40% of pregnant women taking iodine supplements had TSH < 2.5 mIU/L compared to 30.00% of those who were not taking supplements (p = 0.031). Conclusions: The pregnant women in our health area are maintaining appropriate nutritional iodine levels. The consumption of iodised salt protects against iodine deficiency; thus, iodine supplements should be taken on an individualised basis.
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Affiliation(s)
- Silvia González-Martínez
- Endocrinology and Nutrition Service, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain; (E.D.-Á.); (E.L.M.-T.)
- Endocrinology, Nutrition, Diabetes and Obesity Research Group (ENDO), Health Research Institute of Principado de Asturias (ISPA), 33011 Oviedo, Spain;
- Correspondence:
| | - María Riestra-Fernández
- Endocrinology, Nutrition, Diabetes and Obesity Research Group (ENDO), Health Research Institute of Principado de Asturias (ISPA), 33011 Oviedo, Spain;
- Endocrinology and Nutrition Service, Hospital Universitario de Cabueñes, 33203 Gijón, Spain
| | - Eduardo Martínez-Morillo
- Clinical Biochemistry Service, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain; (E.M.-M.); (N.A.-L.)
| | - Noelia Avello-Llano
- Clinical Biochemistry Service, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain; (E.M.-M.); (N.A.-L.)
| | - Elías Delgado-Álvarez
- Endocrinology and Nutrition Service, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain; (E.D.-Á.); (E.L.M.-T.)
- Endocrinology, Nutrition, Diabetes and Obesity Research Group (ENDO), Health Research Institute of Principado de Asturias (ISPA), 33011 Oviedo, Spain;
- Faculty of Medicine, University of Oviedo, 33011 Oviedo, Spain
| | - Edelmiro Luis Menéndez-Torre
- Endocrinology and Nutrition Service, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain; (E.D.-Á.); (E.L.M.-T.)
- Endocrinology, Nutrition, Diabetes and Obesity Research Group (ENDO), Health Research Institute of Principado de Asturias (ISPA), 33011 Oviedo, Spain;
- Faculty of Medicine, University of Oviedo, 33011 Oviedo, Spain
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Willi S, Stamm L, Aldakak L, Staub K, Rühli F, Bender N. National guidelines on nutrient reference values for the healthy adult population and for pregnant or lactating women are based on heterogeneous sources of evidence: review of guidelines. Nutr Rev 2021; 79:462-478. [PMID: 33015718 DOI: 10.1093/nutrit/nuaa062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many countries provide dietary guidelines for health practitioners and/or the general population. However, there is no general, international guideline serving as a template for national dietary guidelines, and there is little to no consensus regarding reference values for different nutrients. The present review compared 27 national dietary guidelines for healthy adults as well as for pregnant and/or breastfeeding women, and analysed their quality and the evidence behind their recommendations. The guidelines were evaluated for their quality using the instrument Agree II, and found to be heterogeneous (overall quality score 14%-100%) and often insufficient (quality score < 50%) due to missing information about their methodology and sources of evidence. We analysed the evidence (number of studies, study types and publication years) of reference values of a number of nutrients using the five guidelines that provided the highest scores in the Agree II assessment. The reference values varied among guidelines, were rarely based on up-to-date meta-analyses, and were often based on insufficiently reported evidence (22/27 guidelines with quality score < 50%). We recommend systematic reviews of high quality studies to formulate future guidelines, and to use guidelines on how to write guidelines.
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Affiliation(s)
- Sandra Willi
- Institute of Evolutionary Medicine, University of Zurich, Switzerland
| | - Lea Stamm
- Institute of Evolutionary Medicine, University of Zurich, Switzerland
| | - Lafi Aldakak
- Institute of Evolutionary Medicine, University of Zurich, Switzerland
| | - Kaspar Staub
- Institute of Evolutionary Medicine, University of Zurich, Switzerland
| | - Frank Rühli
- Institute of Evolutionary Medicine, University of Zurich, Switzerland
| | - Nicole Bender
- Institute of Evolutionary Medicine, University of Zurich, Switzerland
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Wang Z, Li C, Teng Y, Guan Y, Zhang L, Jia X, Cui D, Li J, Guan H. The Effect of Iodine-Containing Vitamin Supplementation During Pregnancy on Thyroid Function in Late Pregnancy and Postpartum Depression in an Iodine-Sufficient Area. Biol Trace Elem Res 2020; 198:1-7. [PMID: 31950399 DOI: 10.1007/s12011-020-02032-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 01/01/2020] [Indexed: 10/23/2022]
Abstract
The purpose of this study was to investigate the effect of iodine supplementation during pregnancy on thyroid function and also its effect on postpartum depression in an iodine-sufficient area. Healthy pregnant women were divided into three groups: group A (vitamin iodine-150) receiving vitamin containing 150 μg iodine, group B (vitamin iodine-0) receiving vitamin without iodine, and group C (no vitamin) receiving no vitamin. General information was collected by questionnaire and thyroid function was determined in the third trimester of pregnancy. Depression was assessed 1 month postpartum by the Edinburgh postnatal depression scale (EPDS). The results showed that there was no significant difference in thyroid-stimulating hormone (TSH) level among the three groups (P > 0.05). FT4 concentration was significantly lower in group A (n = 234: 10.68 pmol/L) than in group B (n = 220: 11.47 pmol/L) and group C (n = 195: 11.64 pmol/L) (P < 0.05), However, it was still within the normal range. EPDS scores obtained from group B (3.50) and group C (3.00) were similar but markedly lower than group A (5.00) (P < 0.05). Despite the difference in the EPDS score, the prevalence of postpartum depression was not significantly different among the three groups. In conclusion, 150 μg/day iodine supplementation for pregnant women in areas with adequate iodine had little effect on thyroid function in the third trimester, and serum FT4 level could not be increased. Iodine supplementation during pregnancy also had no significant effect on postpartum depression.
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Affiliation(s)
- Zixiao Wang
- Department of Endocrinology and Metabolism and Institute of Endocrinology, The First Hospital of China Medical University, 155 Nanjing Bei Street, Shenyang, 110001, Liaoning, People's Republic of China
| | - Chenyang Li
- Department of Gynaecology and Obstetrics, Shenyang Maternity and Child Health Hospital, Shenyang, 110000, Liaoning, People's Republic of China
| | - Ying Teng
- Department of Gynaecology and Obstetrics, Shenyang Fifth People Hospital, Shenyang, 110023, Liaoning, People's Republic of China
| | - Yunping Guan
- Department of Gynaecology and Obstetrics, Shenyang Maternity and Child Health Hospital, Shenyang, 110000, Liaoning, People's Republic of China
| | - Li Zhang
- Department of Gynaecology and Obstetrics, Shenyang Maternity and Child Health Hospital, Shenyang, 110000, Liaoning, People's Republic of China
| | - Xi Jia
- Department of Gynaecology and Obstetrics, Shenyang Maternity and Child Health Hospital, Shenyang, 110000, Liaoning, People's Republic of China
| | - Dandan Cui
- Department of Gynaecology and Obstetrics, Shenyang Maternity and Child Health Hospital, Shenyang, 110000, Liaoning, People's Republic of China
| | - Jing Li
- Department of Gynaecology and Obstetrics, Shenyang Maternity and Child Health Hospital, Shenyang, 110000, Liaoning, People's Republic of China
| | - Haixia Guan
- Department of Endocrinology and Metabolism and Institute of Endocrinology, The First Hospital of China Medical University, 155 Nanjing Bei Street, Shenyang, 110001, Liaoning, People's Republic of China.
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Dineva M, Fishpool H, Rayman MP, Mendis J, Bath SC. Systematic review and meta-analysis of the effects of iodine supplementation on thyroid function and child neurodevelopment in mildly-to-moderately iodine-deficient pregnant women. Am J Clin Nutr 2020; 112:389-412. [PMID: 32320029 DOI: 10.1093/ajcn/nqaa071] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 03/18/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Mild-to-moderate iodine deficiency, particularly in pregnancy, is prevalent; this is of concern because observational studies have shown negative associations with child neurodevelopment. Although neither the benefits nor the safety of iodine supplementation in pregnancy in areas of mild-to-moderate deficiency are well researched, such supplementation is increasingly being recommended by health authorities in a number of countries. OBJECTIVES By reviewing the most recent published data on the effects of iodine supplementation in mildly-to-moderately deficient pregnant women on maternal and infant thyroid function and child cognition, we aimed to determine whether the evidence was sufficient to support recommendations in these areas. METHODS A systematic review of randomized controlled trials (RCTs), non-RCT interventions, and observational studies was conducted. To identify relevant articles, we searched the PubMed and Embase databases. We defined mild-to-moderate iodine deficiency as a baseline median urinary iodine concentration (UIC) of 50-149 µg/L. Eligible studies were included in meta-analyses. RESULTS In total, 37 publications were included-10 RCTs, 4 non-RCT interventions, and 23 observational studies. Most studies showed no effect of iodine supplementation on maternal or infant thyroid-stimulating hormone and free thyroxine. Most RCTs found that supplementation reduced maternal thyroglobulin and in 3 RCTs, it prevented or diminished the increase in maternal thyroid volume during pregnancy. Three RCTs addressed child neurodevelopment; only 1 was adequately powered. Meta-analyses of 2 RCTs showed no effect on child cognitive [mean difference (MD): -0.18; 95% CI: -1.22, 0.87], language (MD: 1.28; 95% CI: -0.28, 2.83), or motor scores (MD: 0.28; 95% CI: -1.10, 1.66). CONCLUSIONS There is insufficient good-quality evidence to support current recommendations for iodine supplementation in pregnancy in areas of mild-to-moderate deficiency. Well-designed RCTs, with child cognitive outcomes, are needed in pregnant women who are moderately deficient (median UIC < 100 µg/L). Maternal intrathyroidal iodine stores should be considered in future trials by including appropriate measures of preconceptional iodine intake.This review was registered at www.crd.york.ac.uk/prospero as CRD42018100277.
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Affiliation(s)
- Mariana Dineva
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Harry Fishpool
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Margaret P Rayman
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Jeewaka Mendis
- Surrey Clinical Trials Unit, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Sarah C Bath
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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Rodriguez-Diaz E, Pearce EN. Iodine status and supplementation before, during, and after pregnancy. Best Pract Res Clin Endocrinol Metab 2020; 34:101430. [PMID: 32792134 DOI: 10.1016/j.beem.2020.101430] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Iodine intake is essential for the production of thyroid hormone. Iodine deficiency remains a public health problem in many regions around the world. Iodine deficiency can present as a spectrum of disorders depending on the degree of severity. Pregnant and lactating women are particularly vulnerable to iodine deficiency disorders because of their increased iodine requirements. Severe maternal iodine deficiency has been associated with cretinism or impaired neurodevelopment in children as well as obstetric complications. Universal salt iodization has been shown to prevent these disorders in severely iodine deficient areas. Recently, observational studies have demonstrated an association between mild-to-moderate iodine deficiency and poorer cognitive outcomes in children. In this review, we describe the iodine requirements for pregnant and lactating women, how population iodine status can be assessed, the effects of maternal iodine deficiency and excess, and current data regarding efficacy of iodine supplementation for women who are pregnant or lactating.
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Affiliation(s)
- Eduardo Rodriguez-Diaz
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, 720 Harrison Avenue Suite 8100, Boston, MA 02118, USA.
| | - Elizabeth N Pearce
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, 720 Harrison Avenue Suite 8100, Boston, MA 02118, USA.
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12
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Delshad H, Azizi F. Iodine nutrition in pregnant and breastfeeding women: sufficiency, deficiency, and supplementation. Hormones (Athens) 2020; 19:179-186. [PMID: 31776808 DOI: 10.1007/s42000-019-00160-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 11/12/2019] [Indexed: 10/25/2022]
Abstract
Iodine is a micronutrient used by the thyroid gland to produce thyroid hormones, which manage different aspects of body metabolism. Humans depend on exogenous sources of iodine to maintain the normal concentration of thyroid hormones. Pregnancy alters iodine turnover and is associated with significant changes in thyroid function. Daily iodine requirement during pregnancy increases to 250 μg, compared with 150 μg for nonpregnant women. According to recent guidelines of scientific organizations, to improve maternal thyroid status and to prevent child neurocognitive defects, all pregnant and breastfeeding women should take 150 μg of iodine supplementation, not only in iodine-deficient regions but also in iodine-sufficient areas. However, some recent studies have confirmed that iodine supplementation of mildly iodine-deficient pregnant women has no clear benefits as concerns maternal thyroid function or child neurodevelopment.
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Affiliation(s)
- Hossein Delshad
- Micronutrient Research Office, Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Velenjak, Parvaneh Avenue No. 24, Research Institute for Endocrine Sciences, Tehran, Islamic Republic of Iran.
| | - Fereidoun Azizi
- Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran
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Elebrashy I, Kamal Eldein HA, Abd-Elstar H, Ghanem N, Mousa S, Assem M, Rashed L, Salit M, Abd-Elraoof M, Dorgham A, Mansour A, Mahmoud M, Saif A. Assessment of thyroid functions and thyroid volume in normal pregnant Egyptian females. Gynecol Endocrinol 2020; 36:122-125. [PMID: 31230489 DOI: 10.1080/09513590.2019.1631279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The normal range of thyroid functions during pregnancy differs between ethnic groups. This study assessed the thyroid functions in normal pregnant Egyptian females. Thyroid peroxidase antibodies (TPO Abs) and thyroid volume were also assessed. The study included 150 normal pregnant Egyptian females, recruited from Cairo University Hospital Antenatal Care Clinic (50 in each trimester), with 40 age-matched non-pregnant females, as a control group. Serum thyroid stimulating hormone (TSH) and TPO Abs were measured. Thyroid volume was assessed by ultrasonography. TSH ranges were 0.21-1.7, 0.52-3.2 and 0.72-2.6 mIU/L during first, second and third trimesters, respectively. The mean TSH level in pregnant females was significantly lower than that of non-pregnant women (1.2 ± 0.7 vs 2.7 ± 0.9 mIU/L, p < .001). TPO Abs were significantly higher in the first trimester compared to both second and third trimesters (p < .001 for both). Thyroid volume of pregnant females was non-significantly higher than that of non-pregnant control subjects (p = .126). A significant positive correlation was found between thyroid volume and body mass index in pregnant females (p < 0.001). Our study established trimester-specific reference ranges for thyroid functions in normal pregnant Egyptian females. A larger population-based study would help to confirm those ranges. Thyroid volume was non-significantly higher than that of non-pregnant control subjects.
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Affiliation(s)
| | | | - Hoda Abd-Elstar
- Departments of Internal Medicine, Cairo University, Cairo, Egypt
| | - Nashwa Ghanem
- Departments of Internal Medicine, Cairo University, Cairo, Egypt
| | - Shrook Mousa
- Departments of Internal Medicine, Cairo University, Cairo, Egypt
| | - Maha Assem
- Departments of Internal Medicine, Cairo University, Cairo, Egypt
| | - Laila Rashed
- Department of Medical Biochemistry, Cairo University, Cairo, Egypt
| | - Mohamed Salit
- Department of Obstetrics and Gynecology, Cairo University, Cairo, Egypt
| | - Maged Abd-Elraoof
- Department of Obstetrics and Gynecology, Cairo University, Cairo, Egypt
| | - Ahmed Dorgham
- Departments of Internal Medicine, Cairo University, Cairo, Egypt
| | - Ahmed Mansour
- Departments of Internal Medicine, Cairo University, Cairo, Egypt
| | - Mohamed Mahmoud
- Departments of Internal Medicine, Cairo University, Cairo, Egypt
| | - Aasem Saif
- Departments of Internal Medicine, Cairo University, Cairo, Egypt
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Verhagen NJE, Gowachirapant S, Winichagoon P, Andersson M, Melse-Boonstra A, Zimmermann MB. Iodine Supplementation in Mildly Iodine-Deficient Pregnant Women Does Not Improve Maternal Thyroid Function or Child Development: A Secondary Analysis of a Randomized Controlled Trial. Front Endocrinol (Lausanne) 2020; 11:572984. [PMID: 33123091 PMCID: PMC7573140 DOI: 10.3389/fendo.2020.572984] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/31/2020] [Indexed: 12/25/2022] Open
Abstract
Background: Iodine deficiency during pregnancy may be associated with lower offspring IQ, but there are few data on the safety and efficacy of maternal iodine supplementation on child development. In a previously reported multi-center randomized trial conducted in Thailand and India, we assessed the effect of iodine supplementation in mildly iodine-deficient pregnant women on offspring development. In this secondary analysis of that trial, we report data only from the Thai pregnant women in the study, who were more iodine deficient at entry. Methods: Pregnant women in Bangkok, Thailand, were randomized to receive daily 200 μg oral iodine or placebo until delivery. We assessed thyroid size and thyroid function during pregnancy and cognitive and motor development at ages 1, 2, and 5.7 years. The trial was registered at www.clinicaltrials.gov/NCT00791466. Findings: Women (n = 514) entered the trial between November 2008 and March 2011 at a mean ± SD gestational age of 11 ± 2.8 weeks; their median (IQR) UIC was 112 (75, 170) μg/L. Mean compliance with supplementation was 88%. We assessed 397 mothers in the 3rd trimester, 231 infants at age 2 y, and 157 children at mean age 5.7 y. During pregnancy, there was a slightly greater decrease in free and total thyroxine concentrations in the iodine group (p < 0.05). At age 2 years, the iodine group had borderline lower scores for combined fine and gross motor function (p = 0.05), but there were no other significant differences in development. At 5.7 years, there were no significant group differences in child development. Conclusion: Daily iodine supplementation in mildly iodine deficient pregnant women was associated with small negative effects on maternal thyroxine concentrations, but did not affect child development. The safety and efficacy of iodine supplementation in mildly-iodine deficient pregnant women needs to be evaluated further in large randomized controlled trials.
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Affiliation(s)
- Nicole J. E. Verhagen
- Division of Human Nutrition, Wageningen University and Research, Wageningen, Netherlands
| | | | | | - Maria Andersson
- Division of Gastroenterology and Nutrition, Children's Research Centre, University Children's Hospital Zurich, Zurich, Switzerland
| | - Alida Melse-Boonstra
- Division of Human Nutrition, Wageningen University and Research, Wageningen, Netherlands
| | - Michael B. Zimmermann
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
- *Correspondence: Michael B. Zimmermann
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Abstract
It is well known that severe iodine deficiency during pregnancy may cause impaired brain development in the child, with effects on cognitive and motor function, hearing and speech. Whether mild-to-moderate deficiency also affects neurological development is less well known, but in the past decade a number of observational studies have been conducted to answer this question and these studies are reviewed in this article. The picture is now emerging that even mild-to-moderate iodine deficiency during pregnancy may be associated with subtle impairments in cognition and school performance, although the evidence from randomised controlled trials is still lacking. As global efforts to eradicate iodine deficiency in populations continue, it is more likely that mild-to-moderate, rather than severe, iodine deficiency will be the issue of concern in pregnancy, and therefore further research in regions of mild-to-moderate deficiency is required to strengthen the research base and to inform public-health policy.
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16
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Carosa E, Lenzi A, Jannini EA. Thyroid hormone receptors and ligands, tissue distribution and sexual behavior. Mol Cell Endocrinol 2018; 467:49-59. [PMID: 29175529 DOI: 10.1016/j.mce.2017.11.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/07/2017] [Accepted: 11/08/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Eleonora Carosa
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Andrea Lenzi
- Chair of Endocrinology, Department of Experimental Medicine, University of Rome Sapienza, Rome, Italy
| | - Emmanuele A Jannini
- Chair of Endocrinology & Medical Sexology (ENDOSEX), Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
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Abstract
OBJECTIVE The World Health Organization, the United Nations Children's Fund, and the International Council for the Control of Iodine Deficiency Disorders recommend a median urinary iodine concentration (UIC) in pregnant women between 150 µg/L and 249 µg/L. In the present study, we evaluated whether in the urban area of Cassino (central Italy), after a national salt iodination program (30 mg/kg) was introduced in 2005, the increased demand of iodine during pregnancy was satisfied. METHODS Between January 2016 and April 2017, 99 pregnant women were enrolled to evaluate UIC in spot urine samples, serum level of thyrotropin, free thyroxine, antithyroglobulin and antithyroperoxidase autoantibodies, and thyroid volume by ultrasonography. Eighty clinically healthy non-pregnant women were evaluated as controls. RESULTS The median UIC was of 97.7 µg/L and 110.3 µg/L, respectively, in control and pregnant women. A significant increase (P < 0.001) of median thyroid volume was found in pregnant women, relative to control women, being, respectively, 10.4 mL (range 3.68-19.49 mL) and 7.16 mL (range 2.57-14.00 mL). A positive correlation was found between thyroid volume and anthropometric parameters, and an inverse correlation was identified between free thyroxine serum levels and anthropometric parameters. CONCLUSIONS This observational study found that the majority of pregnant women and their fetuses appear not to be protected from the detrimental consequences of iodine deficiency. Therefore, the identification of new strategies to increase the knowledge and awareness of the general population regarding the beneficial effects of iodine supplementation during pregnancy is highly required.
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18
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Miulescu RD, Mihai AD. The Treatment of Hypothyroidism in Pregnancy. ROMANIAN JOURNAL OF DIABETES NUTRITION AND METABOLIC DISEASES 2017. [DOI: 10.1515/rjdnmd-2017-0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Hypothyroidism is a pathologic condition generated by the thyroid hormone deficiency. The American Thyroid Association advises for the screening of hypothyroidism beginning at 35 years and thereafter every 5 years in people at high risk for this condition: females older than 60 years, pregnant women, patients with other autoimmune disease or patients with a history of neck irradiation. In pregnant women, hypothyroidism can been associated with adverse effect for both mother and child. The „Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum“ recommends the treatment of maternal overt hypothyroidism: females with a thyrotropin (TSH) level higher than the trimester-specific reference interval and decreased free thyroxine (FT4), and females for which TSH level is higher than 10.0 mIU/L, irrespective of the FT4 value, with administration of oral levothyroxine. The goal of treatment of maternal overt hypothyroidism is to bring back the serum TSH values to the reference range specific for the pregnancy trimester. The Guidelines of the „European Thyroid Association for the Management of Subclinical Hypothyroidism in Pregnancy and in Children“ recommends treatment of pregnancy associated subclinical hypothyroidism with the following levothyroxine doses: „1.20 μg/kg/day for TSH≤4.2 mU/l, 1.42 μg/kg/day for TSH >4.2-10 and 2.33 μg/kg/day for overt hypothyroidism“. The „Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum“ and the „European Thyroid Association for the Management of Subclinical Hypothyroidism in Pregnancy and in Children“ do not recommend the treatment of isolated hypothyroxinemia in pregnancy.
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Affiliation(s)
- Rucsandra Dănciulescu Miulescu
- "Carol Davila" University of Medicine and Pharmacy, Bucharest Romania
- "N.C.Paulescu" National Institute of Diabetes, Nutrition and Metabolic Diseases, 5-7 Ion Movila Street, District 2, Postal Code 11420, Bucharest , Romania
| | - Andrada Doina Mihai
- "Carol Davila" University of Medicine and Pharmacy, Bucharest Romania
- "N.C.Paulescu" National Institute of Diabetes, Nutrition and Metabolic Diseases, Bucharest , Romania
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Harding KB, Peña‐Rosas JP, Webster AC, Yap CMY, Payne BA, Ota E, De‐Regil LM. Iodine supplementation for women during the preconception, pregnancy and postpartum period. Cochrane Database Syst Rev 2017; 3:CD011761. [PMID: 28260263 PMCID: PMC6464647 DOI: 10.1002/14651858.cd011761.pub2] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Iodine is an essential nutrient required for the biosynthesis of thyroid hormones, which are responsible for regulating growth, development and metabolism. Iodine requirements increase substantially during pregnancy and breastfeeding. If requirements are not met during these periods, the production of thyroid hormones may decrease and be inadequate for maternal, fetal and infant needs. The provision of iodine supplements may help meet the increased iodine needs during pregnancy and the postpartum period and prevent or correct iodine deficiency and its consequences. OBJECTIVES To assess the benefits and harms of supplementation with iodine, alone or in combination with other vitamins and minerals, for women in the preconceptional, pregnancy or postpartum period on their and their children's outcomes. SEARCH METHODS We searched Cochrane Pregnancy and Childbirth's Trials Register (14 November 2016), and the WHO International Clinical Trials Registry Platform (ICTRP) (17 November 2016), contacted experts in the field and searched the reference lists of retrieved studies and other relevant papers. SELECTION CRITERIA Randomized and quasi-randomized controlled trials with randomisation at either the individual or cluster level comparing injected or oral iodine supplementation (such as tablets, capsules, drops) during preconception, pregnancy or the postpartum period irrespective of iodine compound, dose, frequency or duration. DATA COLLECTION AND ANALYSIS Two review authors independently assessed trial eligibility, risk of bias, extracted data and conducted checks for accuracy. We used the GRADE approach to assess the quality of the evidence for primary outcomes.We anticipated high heterogeneity among trials, and we pooled trial results using random-effects models and were cautious in our interpretation of the pooled results. MAIN RESULTS We included 14 studies and excluded 48 studies. We identified five ongoing or unpublished studies and two studies are awaiting classification. Eleven trials involving over 2700 women contributed data for the comparisons in this review (in three trials, the primary or secondary outcomes were not reported). Maternal primary outcomesIodine supplementation decreased the likelihood of the adverse effect of postpartum hyperthyroidism by 68% (average risk ratio (RR) 0.32; 95% confidence interval (CI) 0.11 to 0.91, three trials in mild to moderate iodine deficiency settings, 543 women, no statistical heterogeneity, low-quality evidence) and increased the likelihood of the adverse effect of digestive intolerance in pregnancy by 15 times (average RR 15.33; 95% CI 2.07 to 113.70, one trial in a mild-deficiency setting, 76 women, very low-quality evidence).There were no clear differences between groups for hypothyroidism in pregnancy or postpartum (pregnancy: average RR 1.90; 95% CI 0.57 to 6.38, one trial, 365 women, low-quality evidence, and postpartum: average RR 0.44; 95% CI 0.06 to 3.42, three trials, 540 women, no statistical heterogeneity, low-quality evidence), preterm birth (average RR 0.71; 95% CI 0.30 to 1.66, two trials, 376 women, statistical heterogeneity, low-quality evidence) or the maternal adverse effects of elevated thyroid peroxidase antibodies (TPO-ab) in pregnancy or postpartum (average RR 0.95; 95% CI 0.44 to 2.07, one trial, 359 women, low-quality evidence, average RR 1.01; 95% CI 0.78 to 1.30, three trials, 397 women, no statistical heterogeneity, low-quality evidence), or hyperthyroidism in pregnancy (average RR 1.90; 95% CI 0.57 to 6.38, one trial, 365 women, low-quality evidence). All of the trials contributing data to these outcomes took place in settings with mild to moderate iodine deficiency. Infant/child primary outcomesCompared with those who did not receive iodine, those who received iodine supplements had a 34% lower likelihood of perinatal mortality, however this difference was not statistically significant (average RR 0.66; 95% CI 0.42 to 1.03, two trials, 457 assessments, low-quality evidence). All of the perinatal deaths occurred in one trial conducted in a severely iodine-deficient setting. There were no clear differences between groups for low birthweight (average RR 0.56; 95% CI 0.26 to 1.23, two trials, 377 infants, no statistical heterogeneity, low-quality evidence), neonatal hypothyroidism/elevated thyroid-stimulating hormone (TSH) (average RR 0.58; 95% CI 0.11 to 3.12, two trials, 260 infants, very low-quality evidence) or the adverse effect of elevated neonatal thyroid peroxidase antibodies (TPO-ab) (average RR 0.61; 95% CI 0.07 to 5.70, one trial, 108 infants, very low-quality evidence). All of the trials contributing data to these outcomes took place in areas with mild to moderate iodine deficiency. No trials reported on hypothyroidism/elevated TSH or any adverse effect beyond the neonatal period. AUTHORS' CONCLUSIONS There were insufficient data to reach any meaningful conclusions on the benefits and harms of routine iodine supplementation in women before, during or after pregnancy. The available evidence suggested that iodine supplementation decreases the likelihood of postpartum hyperthyroidism and increases the likelihood of the adverse effect of digestive intolerance in pregnancy - both considered potential adverse effects. We considered evidence for these outcomes low or very low quality, however, because of study design limitations and wide confidence intervals. In addition, due to the small number of trials and included women in our meta-analyses, these findings must be interpreted with caution. There were no clear effects on other important maternal or child outcomes though these findings must also be interpreted cautiously due to limited data and low-quality trials. Additionally, almost all of the evidence came from settings with mild or moderate iodine deficiency and therefore may not be applicable to settings with severe deficiency.More high-quality randomised controlled trials are needed on iodine supplementation before, during and after pregnancy on maternal and infant/child outcomes. However, it may be unethical to compare iodine to placebo or no treatment in severe deficiency settings. Trials may also be unfeasible in settings where pregnant and lactating women commonly take prenatal supplements with iodine. Information is needed on optimal timing of initiation as well as supplementation regimen and dose. Future trials should consider the outcomes in this review and follow children beyond the neonatal period. Future trials should employ adequate sample sizes, assess potential adverse effects (including the nature and extent of digestive intolerance), and be reported in a way that allows assessment of risk of bias, full data extraction and analysis by the subgroups specified in this review.
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Affiliation(s)
- Kimberly B Harding
- Micronutrient InitiativeResearch and Evaluation180 Elgin Street, Suite 1000OttawaONCanadaK2P 2K3
| | - Juan Pablo Peña‐Rosas
- World Health OrganizationEvidence and Programme Guidance, Department of Nutrition for Health and Development20 Avenue AppiaGenevaGESwitzerland1211
| | - Angela C Webster
- The University of SydneySydney School of Public HealthEdward Ford Building A27SydneyNSWAustralia2006
| | - Constance MY Yap
- Westmead HospitalDepartment of Diabetes and EndocrinologyCorner Hawkesbury and Darcy RoadsWestmeadNSWAustralia2145
| | - Brian A Payne
- Ministry of Health BarbadosNational Nutrition CenterSt MichaelBarbados
| | - Erika Ota
- St. Luke's International University, Graduate School of Nursing SciencesGlobal Health Nursing10‐1 Akashi‐choChuo‐KuTokyoJapan104‐0044
| | - Luz Maria De‐Regil
- Micronutrient InitiativeResearch and Evaluation180 Elgin Street, Suite 1000OttawaONCanadaK2P 2K3
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Alexander EK, Pearce EN, Brent GA, Brown RS, Chen H, Dosiou C, Grobman WA, Laurberg P, Lazarus JH, Mandel SJ, Peeters RP, Sullivan S. 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum. Thyroid 2017; 27:315-389. [PMID: 28056690 DOI: 10.1089/thy.2016.0457] [Citation(s) in RCA: 1323] [Impact Index Per Article: 189.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2011, significant clinical and scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid disease in women during pregnancy, preconception, and the postpartum period. METHODS The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations. The guideline task force had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members. RESULTS The revised guidelines for the management of thyroid disease in pregnancy include recommendations regarding the interpretation of thyroid function tests in pregnancy, iodine nutrition, thyroid autoantibodies and pregnancy complications, thyroid considerations in infertile women, hypothyroidism in pregnancy, thyrotoxicosis in pregnancy, thyroid nodules and cancer in pregnant women, fetal and neonatal considerations, thyroid disease and lactation, screening for thyroid dysfunction in pregnancy, and directions for future research. CONCLUSIONS We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid disease in pregnant and postpartum women. While all care must be individualized, such recommendations provide, in our opinion, optimal care paradigms for patients with these disorders.
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Affiliation(s)
- Erik K Alexander
- 1 Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital and Harvard Medical School , Boston, Massachusetts
| | - Elizabeth N Pearce
- 2 Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine , Boston, Massachusetts
| | - Gregory A Brent
- 3 Department of Medicine, VA Greater Los Angeles Healthcare System and David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Rosalind S Brown
- 4 Division of Endocrinology, Boston Children's Hospital , Harvard Medical School, Boston, Massachusetts
| | - Herbert Chen
- 5 Department of Surgery, University of Alabama at Birmingham , Birmingham, Alabama
| | - Chrysoula Dosiou
- 6 Division of Endocrinology, Stanford University School of Medicine , Stanford, California
| | - William A Grobman
- 7 Department of Obstetrics and Gynecology, Northwestern University , Chicago, Illinois
| | - Peter Laurberg
- 8 Departments of Endocrinology & Clinical Medicine, Aalborg University Hospital , Aalborg, Denmark
| | - John H Lazarus
- 9 Institute of Molecular Medicine, Cardiff University , Cardiff, United Kingdom
| | - Susan J Mandel
- 10 Division of Endocrinology, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Robin P Peeters
- 11 Department of Internal Medicine and Rotterdam Thyroid Center, Erasmus Medical Center , Rotterdam, The Netherlands
| | - Scott Sullivan
- 12 Department of Obstetrics and Gynecology, Medical University of South Carolina , Charleston, South Carolina
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21
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Pearce EN, Lazarus JH, Moreno-Reyes R, Zimmermann MB. Consequences of iodine deficiency and excess in pregnant women: an overview of current knowns and unknowns. Am J Clin Nutr 2016; 104 Suppl 3:918S-23S. [PMID: 27534632 PMCID: PMC5004501 DOI: 10.3945/ajcn.115.110429] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Severe iodine deficiency during development results in maternal and fetal hypothyroidism and associated serious adverse health effects, including cretinism and growth retardation. Universal salt iodization is the first-line strategy for the elimination of severe iodine deficiency. Iodine supplementation is recommended for vulnerable groups in severely iodine-deficient regions where salt iodization is infeasible or insufficient. A recent clinical trial has informed best practices for iodine supplementation of severely iodine-deficient lactating mothers. Because of successful programs of universal salt iodization in formerly severely iodine-deficient regions around the world, public health concern has shifted toward mild to moderate iodine deficiency, which remains prevalent in many regions, especially among pregnant women. Observational studies have shown associations between both mild maternal iodine deficiency and mild maternal thyroid hypofunction and decreased child cognition. Iodine supplementation has been shown to improve indexes of maternal thyroid function, even in marginally iodine-deficient areas. However, no data are yet available from randomized controlled trials in regions of mild to moderate iodine insufficiency on the relation between maternal iodine supplementation and neurobehavioral development in the offspring; thus, the long-term benefits and safety of such supplementation are uncertain. Although it is clear that excessive iodine intake can cause alterations in thyroid function in susceptible individuals, safe upper limits for iodine intake in pregnancy have not been well defined. Well-designed, prospective, randomized controlled trials that examine the effects of iodine supplementation on maternal thyroid function and infant neurobehavioral development in mildly to moderately iodine-deficient pregnant women are urgently needed. In addition, clinical data on the effects of iodine excess in pregnant and lactating women are needed to inform current recommendations for safe upper limits on chronic iodine ingestion in general and on iodine supplementation in particular.
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Affiliation(s)
- Elizabeth N Pearce
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, MA;
| | - John H Lazarus
- Thyroid Research Group, Institute of Molecular and Experimental Medicine, Cardiff University, University Hospital of Wales, Cardiff, United Kingdom
| | - Rodrigo Moreno-Reyes
- Department of Nuclear Medicine, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium; and
| | - Michael B Zimmermann
- Human Nutrition Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
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Celik H, Guldiken S, Celik O, Taymez F, Dagdeviren N, Tuğrul A. IODINE DEFICIENCY IN PREGNANT WOMEN LIVING IN WESTERN TURKEY (EDIRNE). ACTA ENDOCRINOLOGICA-BUCHAREST 2016; 12:14-18. [PMID: 31258794 DOI: 10.4183/aeb.2016.14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Objective Data about iodine status in pregnant women in Turkey is not sufficient. We aimed to determine the iodine status, goiter prevalence, iodized salt consumption among first trimester pregnant women living in Edirne. Design and setting Cross-sectional study was performed on pregnant women living in Edirne. Subjects and methods A total of 275 pregnant women in their first trimester were examined regarding iodized salt use, median urinary iodine concentration (UIC), presence or absence of goitre and thyroid function. Goitre status was determined by palpation. Participants filled out a questionnaire, which included questions regarding sociodemographic features, iodized salt consumption, knowledge, and behavior regarding iodine deficiency. UIC was measured using colorimetric method based on Sandell-Kolthoff reaction. Thyroid hormones and TSH were measured by chemiluminescence immunoassays. Results While the proportion of iodized salt use was 96.6%, UIC was below 150 μg/L in 88.4 % of the women. The median UIC was 77 μg/L, indicating insufficient iodine intake. Total goitre rate was 19.3%. Conclusions Our study shows that iodine deficiency is a serious problem among pregnant women in Edirne. We suggest that pregnant women living in Edirne should be supplemented by iodine-containing preparations in addition to iodized salt.
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Affiliation(s)
- H Celik
- Trakya University - Division of Endocrinology and Metabolism, Department of Internal Medicine, Edirne, Turkey
| | - S Guldiken
- Trakya University - Division of Endocrinology and Metabolism, Department of Internal Medicine, Edirne, Turkey
| | - O Celik
- Acıbadem University - Division of Endocrinology and Metabolism, Department of Internal Medicine, Edirne, Turkey
| | - F Taymez
- Trakya University - Department of Family Medicine, Edirne, Turkey
| | - N Dagdeviren
- Trakya University - Department of Family Medicine, Edirne, Turkey
| | - A Tuğrul
- Trakya University - Division of Endocrinology and Metabolism, Department of Internal Medicine, Edirne, Turkey
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Coccaro C, Tuccilli C, Prinzi N, D'Armiento E, Pepe M, Del Maestro F, Cacciola G, Forlini B, Verdolotti S, Bononi M, Nacca R, Baldini E, Cirillo G, Ulisse S. Consumption of iodized salt may not represent a reliable indicator of iodine adequacy: Evidence from a cross-sectional study on schoolchildren living in an urban area of central Italy. Nutrition 2015; 32:662-6. [PMID: 26897110 DOI: 10.1016/j.nut.2015.12.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/01/2015] [Accepted: 12/12/2015] [Indexed: 11/28/2022]
Abstract
OBJECTIVE It has been established that iodine prophylaxis prevents endemic goiter. In this study we reported the amount of iodized salt sold by the retailers of Cassino, a city of central Italy. The aim of the study was to evaluate the effects of an iodine prophylaxis program started in 2005 on urinary iodine concentration (UIC) and thyroid volume (TV), and their correlation with anthropometric parameters in a population of schoolchildren. METHODS The study included 234 schoolchildren (119 girls and 115 boys) ages 13 to 14 y. Each student provided a morning urine sample for UIC determination, and TV was evaluated by ultrasonography. Body weight and height also were measured. Each participant completed a questionnaire reporting the presence of thyroid disease and the consumption of iodized salt and iodine-rich food. RESULTS The percentage of iodized salt sold by local markets was 42.4%. Median UIC in schoolchildren was 133.9 μg/L (range 33.2-819.5 μg/L), with 71 children having mild (range 50.1-99.9 μg/L) and 10 moderate (range 33.2-48.8 μg/L) iodine deficiency. Eleven children showed excessive iodine intake (range 300.4-819.5 μg/L). Median UIC was higher in children using iodized salt or consuming milk. Goiter prevalence was 3.8%. A positive correlation between TV and body weight, height, and surface was observed. CONCLUSIONS The data reported may suggest the presence of an adequate iodine intake in the population of Cassino despite the low percentage of iodized salt sold by local retailers. This indicates that silent iodine prophylaxis through the consumption of iodine-rich or iodine-enriched food is of importance in the prevention of iodine deficiency disorders.
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Affiliation(s)
- Carmela Coccaro
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | - Chiara Tuccilli
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | - Natalie Prinzi
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | | | - Mario Pepe
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | - Francesca Del Maestro
- Nursing School of Cassino, "Sapienza" University of Rome and University of Cassino and South Lazio, Italy
| | - Giovanni Cacciola
- UOC of Radiology, Department of Diagnostic, ASL Frosinone, "Santa Scolastica" Hospital, Cassino, Italy
| | - Benedetto Forlini
- UOC of Radiology, Department of Diagnostic, ASL Frosinone, "Santa Scolastica" Hospital, Cassino, Italy
| | - Sergio Verdolotti
- UOC of Radiology, Department of Diagnostic, ASL Frosinone, "Santa Scolastica" Hospital, Cassino, Italy
| | - Marco Bononi
- Nursing School of Cassino, "Sapienza" University of Rome and University of Cassino and South Lazio, Italy
| | - Remo Nacca
- UOC of Nephrology and Dialysis, ASL Frosinone, "Santa Scolastica" Hospital, Cassino, Italy
| | - Enke Baldini
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | - Giovanni Cirillo
- UOC of Clinical Pathology, ASL Frosinone, "Santa Scolastica" Hospital, Cassino, Italy
| | - Salvatore Ulisse
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy.
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Caron P. Neurocognitive outcomes of children secondary to mild iodine deficiency in pregnant women. ANNALES D'ENDOCRINOLOGIE 2015; 76:248-52. [PMID: 25934357 DOI: 10.1016/j.ando.2015.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 01/30/2015] [Indexed: 11/19/2022]
Abstract
Iodine deficiency is the most important preventable cause of brain damage worldwide. During pregnancy, severe iodine deficiency causes endemic cretinism, whereas mild-to-moderate iodine deficiency impairs neurocognitive function of the offspring. Numerous reports demonstrate the impact of iodine supplementation on prevention of cretinism, and recent studies evaluate the effects of iodine prophylaxis on neurocognitive development in children of women with mild-to-moderate iodine deficiency. Iodine prophylaxis is generally well tolerated without side effects for the pregnant women and the offspring. In France, the iodine status was recently considered as satisfactory in children and adult population, but regional studies conducted during the last two decades have shown that healthy women are mild-to-moderately iodine deficient during pregnancy. According to recent World Heath Organization guidelines, systematic iodine prophylaxis is recommended in women planning a pregnancy, during gestation and lactation in order to prevent maternal, neonatal and infantile consequences of mild-to-moderate iodine deficiency.
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Affiliation(s)
- Philippe Caron
- Service d'endocrinologie, maladies métaboliques et nutrition, pôle cardiovasculaire et métabolique, CHU Larrey, 24, chemin de Pouvourville, TSA 30030, 31059 Toulouse cedex, France.
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25
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Bricaire L, Groussin L. Pathologies thyroïdiennes et grossesse. Rev Med Interne 2015; 36:203-10. [DOI: 10.1016/j.revmed.2014.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 07/29/2014] [Indexed: 10/24/2022]
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Ristić-Medić D, Dullemeijer C, Tepsić J, Petrović-Oggiano G, Popović T, Arsić A, Glibetić M, Souverein OW, Collings R, Cavelaars A, de Groot L, van't Veer P, Gurinović M. Systematic review using meta-analyses to estimate dose-response relationships between iodine intake and biomarkers of iodine status in different population groups. Nutr Rev 2014; 72:143-61. [PMID: 24697303 DOI: 10.1111/nure.12092] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The objective of this systematic review was to identify studies investigating iodine intake and biomarkers of iodine status, to assess the data of the selected studies, and to estimate dose-response relationships using meta-analysis. All randomized controlled trials, prospective cohort studies, nested case-control studies, and cross-sectional studies that supplied or measured dietary iodine and measured iodine biomarkers were included. The overall pooled regression coefficient (β) and the standard error of β were calculated by random-effects meta-analysis on a double-log scale, using the calculated intake-status regression coefficient (β) for each individual study. The results of pooled randomized controlled trials indicated that the doubling of dietary iodine intake increased urinary iodine concentrations by 14% in children and adolescents, by 57% in adults and the elderly, and by 81% in pregnant women. The dose-response relationship between iodine intake and biomarkers of iodine status indicated a 12% decrease in thyroid-stimulating hormone and a 31% decrease in thyroglobulin in pregnant women. The model of dose-response quantification used to describe the relationship between iodine intake and biomarkers of iodine status may be useful for providing complementary evidence to support recommendations for iodine intake in different population groups.
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28
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Bénéfices et risques d’une supplémentation en iode des femmes enceintes : une revue des études observationnelles et expérimentales en régions de carence iodée légère à modérée. Rev Epidemiol Sante Publique 2014; 62:65-74. [DOI: 10.1016/j.respe.2013.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 07/26/2013] [Accepted: 08/19/2013] [Indexed: 11/19/2022] Open
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An assessment of the iodine status and the correlation between iodine nutrition and thyroid function during pregnancy in an iodine sufficient area. Eur J Clin Nutr 2014; 68:397-400. [DOI: 10.1038/ejcn.2013.273] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 08/21/2013] [Accepted: 08/21/2013] [Indexed: 11/09/2022]
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30
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Taylor PN, Okosieme OE, Dayan CM, Lazarus JH. Therapy of endocrine disease: Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis. Eur J Endocrinol 2014; 170:R1-R15. [PMID: 24088547 DOI: 10.1530/eje-13-0651] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Although the detrimental effects of severe iodine deficiency are well recognised, the benefits of correcting mild-to-moderate iodine deficiency are uncertain. OBJECTIVES We undertook a systematic review of the impact of iodine supplementation in populations with mild-to-moderate iodine deficiency. METHODS We searched Medline and the Cochrane library for relevant articles published between January 1966 and April 2013, which investigated the effect of iodine supplementation on maternal and newborn thyroid function, infant neurodevelopment and cognitive performance in school-age children. The quality of studies was graded and eligible trials were evaluated in the meta-analysis. RESULTS Nine randomised controlled trials (RCTs) and eight observational studies met the inclusion criteria. Controlled trials on infant neurodevelopment were lacking; gestational iodine supplementation reduced maternal thyroid volume and serum thyroglobulin and in some studies prevented a rise in serum thyroid-stimulating hormone. None of the intervention trials recorded an excess frequency of thyroid dysfunction in contrast to observational studies. A pooled analysis of two RCTs which measured cognitive function in school-age children showed modest benefits of iodine supplementation on perceptual reasoning (standardised mean difference (SMD) 0.55; 95% CI 0.05, 1.04; P=0.03) and global cognitive index (SMD 0.27; 95% CI 0.10, 0.44; P=0.002) with significant heterogeneity between studies. CONCLUSION Iodine supplementation improves some maternal thyroid indices and may benefit aspects of cognitive function in school-age children, even in marginally iodine-deficient areas. Further large prospective controlled studies are urgently required to clarify these findings and quantify the risk/benefits of iodine supplementation in regions previously believed to be iodine sufficient such as the UK.
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Affiliation(s)
- Peter N Taylor
- Thyroid Research Group, Institute of Molecular and Experimental Medicine (IMEM), Cardiff University School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
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31
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Zhou SJ, Anderson AJ, Gibson RA, Makrides M. Effect of iodine supplementation in pregnancy on child development and other clinical outcomes: a systematic review of randomized controlled trials. Am J Clin Nutr 2013; 98:1241-54. [PMID: 24025628 DOI: 10.3945/ajcn.113.065854] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Routine iodine supplementation during pregnancy is recommended by leading health authorities worldwide, even in countries where the iodine status of the population is sufficient. OBJECTIVES We evaluated the efficacy and safety of iodine supplementation during pregnancy or the periconceptional period on the development and growth of children. Secondary outcomes included pregnancy outcome and thyroid function. DESIGN A systematic review of randomized controlled trials (RCTs) was conducted. PUBMED, MEDLINE, EMBASE, CINAHL, PsycINFO, and Cochrane Central Register of Controlled Trials databases were searched to identify relevant RCTs. RESULTS Fourteen publications that involved 8 trials met the inclusion criteria. Only 2 included trials reported the growth and development of children and clinical outcomes. Iodine supplementation during pregnancy or the periconceptional period in regions of severe iodine deficiency reduced risk of cretinism, but there were no improvements in childhood intelligence, gross development, growth, or pregnancy outcomes, although there was an improvement in some motor functions. None of the remaining 6 RCTs conducted in regions of mild to moderate iodine deficiency reported childhood development or growth or pregnancy outcomes. Effects of iodine supplementation on the thyroid function of mothers and their children were inconsistent. CONCLUSIONS In this review, we highlight a lack of quality evidence of the effect of prenatal or periconceptional iodine supplementation on growth and cognitive function of children. Although contemporary RCTs of iodine supplementation with outcomes addressing childhood development are indicated, conduct of such RCTs may not be feasible in populations where iodine supplementation in pregnancy is widely practiced.
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Affiliation(s)
- Shao J Zhou
- Women's & Children's Health Research Institute, North Adelaide, Australia (AJA, MM, and SJZ); the School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, Australia (MM); and the FOODplus Research Centre, School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, Australia (AJA, RAG, MM, and SJZ)
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Abstract
In 2001, Dietary Reference Intakes (DRIs) for iodine were set for the different gender and life-stage groups by the Institute of Medicine. Because of the serious consequences of iodine deficiency for the developing fetus and infant, there is particular interest in further understanding optimal iodine nutrition and improving the monitoring of iodine status, particularly during infancy, pregnancy, and lactation. This review discusses the basis for the current DRIs for iodine and the evidence that may be needed for considering and conducting the reevaluation of one or more of the DRIs.
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Affiliation(s)
- Paula R. Trumbo
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, MD
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Abstract
This review describes historical iodine deficiency in the U.K., gives current information on dietary sources of iodine and summarises recent evidence of iodine deficiency and its association with child neurodevelopment. Iodine is required for the production of thyroid hormones that are needed for brain development, particularly during pregnancy. Iodine deficiency is a leading cause of preventable brain damage worldwide and is associated with impaired cognitive function. Despite a global focus on the elimination of iodine deficiency, iodine is a largely overlooked nutrient in the U.K., a situation we have endeavoured to address through a series of studies. Although the U.K. has been considered iodine-sufficient for many years, there is now concern that iodine deficiency may be prevalent, particularly in pregnant women and women of childbearing age; indeed we found mild-to-moderate iodine deficiency in pregnant women in Surrey. As the major dietary source of iodine in the U.K. is milk and dairy produce, it is relevant to note that we have found the iodine concentration of organic milk to be over 40% lower than that of conventional milk. In contrast to many countries, iodised table salt is unlikely to contribute to U.K. iodine intake as we have shown that its availability is low in grocery stores. This situation is of concern as the level of U.K. iodine deficiency is such that it is associated with adverse effects on offspring neurological development; we demonstrated a higher risk of low IQ and poorer reading-accuracy scores in U.K. children born to mothers who were iodine-deficient during pregnancy. Given our findings and those of others, iodine status in the U.K. population should be monitored, particularly in vulnerable subgroups such as pregnant women and children.
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Donnay S, Arena J, Lucas A, Velasco I, Ares S. Iodine supplementation during pregnancy and lactation. Position statement of the working group on disorders related to iodine deficiency and thyroid dysfunction of the Spanish Society of Endocrinology and Nutrition. ACTA ACUST UNITED AC 2013; 61:27-34. [PMID: 24035326 DOI: 10.1016/j.endonu.2013.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 05/06/2013] [Indexed: 10/26/2022]
Abstract
Severe and mild iodine deficiency during pregnancy and lactation affects thyroid function of the mother and neonate as well as the infant's neuropsychological development. Studies performed in Spain confirm that most women are iodine deficient during pregnancy and lactation. Pregnant and breast feeding women and women planning to become pregnant should take iodine supplements.
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Affiliation(s)
- Sergio Donnay
- Unidad de Endocrinología y Nutrición, Hospital Universitario Fundación Alcorcón, Madrid, España
| | | | - Anna Lucas
- Servicio de Endocrinología y Nutrición, Hospital Germans Trias i Pujol, Barcelona, España
| | - Inés Velasco
- Servicio de Ginecología y Obstetricia, Hospital de Riotinto, Huelva, España
| | - Susana Ares
- Servicio de Neonatología, Hospital Universitario La Paz, Madrid, España
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Brucker-Davis F, Panaïa-Ferrari P, Gal J, Fénichel P, Hiéronimus S. Iodine Supplementation throughout Pregnancy Does Not Prevent the Drop in FT4 in the Second and Third Trimesters in Women with Normal Initial Thyroid Function. Eur Thyroid J 2013; 2:187-94. [PMID: 24847452 PMCID: PMC4017760 DOI: 10.1159/000350882] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/21/2013] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES The aim of the study was to determine the evolution of thyroid tests throughout pregnancy and postpartum in healthy women with and without iodine supplementation. METHODS This was a prospective, randomized, interventional study of iodine supplementation (150 μg/day) from the first trimester until 3 months postpartum versus controls. 111 pregnant women with normal initial thyroid tests were enrolled, undergoing comprehensive thyroid assessment at each trimester. We present results of longitudinal and cross-sectional analyses. RESULTS Initial ioduria suggested mild iodine deficiency in both groups, while third-trimester ioduria rose to levels of iodine sufficiency in the iodine-supplemented group. In the longitudinal study, free T4 (FT4) levels decreased in the second and third trimesters compared to the first trimester in both groups, with no change in TSH, and rose postpartum, though lower than the first trimester. FT3 levels and the total T4 (TT4)/thyroxine-binding globulin (TBG) ratio followed the same evolution as FT4. TT4 levels rose due to TBG increase. Thyroglobulin (Tg) of iodine group remained stable, contrasting with the rise in the control group. In the cross-sectional study, there was no difference between the two groups in thyroid tests at any time-point, except for lower Tg in the second trimester and postpartum visits in the iodine group. CONCLUSIONS In healthy, mildly iodine-deficient pregnant women, a 'drop' of FT4 and TT4/TBG without TSH increase occurs between the first and second trimesters, and is not prevented by iodine supplementation, suggesting physiology. Therefore, FT4 is valuable to assess thyroid function in pregnancy in clinical practice with appropriate trimester-specific reference range. It brings up reflection on threshold for diagnosis and treatment of hypothyroxinemia.
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Affiliation(s)
- Françoise Brucker-Davis
- Department of Endocrinology, Diabetology and Reproductive Medicine, Nice, France
- Institut National de la Recherche Médicale, UMR U895, Université Nice-Sophia Antipolis, Nice, France
- *Dr. Françoise Brucker-Davis, Department of Endocrinology, Diabetology and Reproductive Medicine, l'Archet Hospital 2, CHU Nice, 151 route de Saint-Antoine, FR-06200 Nice (France), E-Mail
| | | | - Jocelyn Gal
- Department of Biostatistics, CHU de Nice, UMR U895, Université Nice-Sophia Antipolis, Nice, France
| | - Patrick Fénichel
- Department of Endocrinology, Diabetology and Reproductive Medicine, Nice, France
- Institut National de la Recherche Médicale, UMR U895, Université Nice-Sophia Antipolis, Nice, France
| | - Sylvie Hiéronimus
- Department of Endocrinology, Diabetology and Reproductive Medicine, Nice, France
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Pearce EN. Monitoring and effects of iodine deficiency in pregnancy: still an unsolved problem? Eur J Clin Nutr 2013; 67:481-4. [DOI: 10.1038/ejcn.2012.215] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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De Groot L, Abalovich M, Alexander EK, Amino N, Barbour L, Cobin RH, Eastman CJ, Lazarus JH, Luton D, Mandel SJ, Mestman J, Rovet J, Sullivan S. Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2012; 97:2543-65. [PMID: 22869843 DOI: 10.1210/jc.2011-2803] [Citation(s) in RCA: 728] [Impact Index Per Article: 60.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE The aim was to update the guidelines for the management of thyroid dysfunction during pregnancy and postpartum published previously in 2007. A summary of changes between the 2007 and 2012 version is identified in the Supplemental Data (published on The Endocrine Society's Journals Online web site at http://jcem.endojournals.org). EVIDENCE This evidence-based guideline was developed according to the U.S. Preventive Service Task Force, grading items level A, B, C, D, or I, on the basis of the strength of evidence and magnitude of net benefit (benefits minus harms) as well as the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence. CONSENSUS PROCESS The guideline was developed through a series of e-mails, conference calls, and one face-to-face meeting. An initial draft was prepared by the Task Force, with the help of a medical writer, and reviewed and commented on by members of The Endocrine Society, Asia and Oceania Thyroid Association, and the Latin American Thyroid Society. A second draft was reviewed and approved by The Endocrine Society Council. At each stage of review, the Task Force received written comments and incorporated substantive changes. CONCLUSIONS Practice guidelines are presented for diagnosis and treatment of patients with thyroid-related medical issues just before and during pregnancy and in the postpartum interval. These include evidence-based approaches to assessing the cause of the condition, treating it, and managing hypothyroidism, hyperthyroidism, gestational hyperthyroidism, thyroid autoimmunity, thyroid tumors, iodine nutrition, postpartum thyroiditis, and screening for thyroid disease. Indications and side effects of therapeutic agents used in treatment are also presented.
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Affiliation(s)
- Leslie De Groot
- University of Rhode Island, Providence, Rhode Island 02881, USA
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Abstract
Iodine requirements are increased ≥ 50% during pregnancy. Iodine deficiency during pregnancy can cause maternal and fetal hypothyroidism and impair neurological development of the fetus. The consequences depend upon the timing and severity of the hypothyroidism; the most severe manifestation is cretinism. In moderate-to-severely iodine-deficient areas, controlled studies have demonstrated that iodine supplementation before or during early pregnancy eliminates new cases of cretinism, increases birthweight, reduces rates of perinatal and infant mortality and generally increases developmental scores in young children by 10-20%. Mild maternal iodine deficiency can cause thyroid dysfunction but whether it impairs cognitive and/or neurologic function in the offspring remains uncertain. Two meta-analyses have estimated that iodine-deficient populations experience a mean reduction in IQ of 12-13.5 points. In nearly all regions affected by iodine deficiency, salt iodisation is the most cost-effective way of delivering iodine and improving maternal and infant health.
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Affiliation(s)
- Michael B Zimmermann
- Laboratory for Human Nutrition, Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland.
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Caron P. Dysthyroïdies et grossesse. Presse Med 2011; 40:1174-81. [DOI: 10.1016/j.lpm.2011.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2011] [Revised: 06/13/2011] [Accepted: 09/27/2011] [Indexed: 11/29/2022] Open
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40
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Abstract
Adequate iodine intake is required for the synthesis of thyroid hormones that are important for normal fetal and infant neurodevelopment. In this review, we discuss iodine physiology during pregnancy and lactation, methods to assess iodine sufficiency, the importance of adequate iodine nutrition, studies of iodine supplementation during pregnancy and lactation, the consequences of hypothyroidism during pregnancy, the current status of iodine nutrition in the United States, the global efforts toward achieving universal iodine sufficiency, and substances that may interfere with iodine use.
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Affiliation(s)
| | - Elizabeth N. Pearce
- Corresponding author. Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, 88 East Newton Street, Evans 201, Boston, MA 02118.
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Abstract
OBJECTIVE To evaluate the peer-reviewed literature on iodine deficiency and hypothyroxinemia in pregnancy. METHODS We review published studies on isolated hypothyroxinemia in pregnancy, methodology of free thyroxine (T4) assays, impact of iodine deficiency on free T4 levels, and status of ongoing prospective randomized trials of isolated hypothyroxinemia during pregnancy. RESULTS Hypothyroxinemia during pregnancy is common. Studies have demonstrated the pivotal role exerted by maternal T4 on fetal brain development and the negative impact of hypothyroxinemia on neurobehavioral performance in offspring. Two intervention studies have demonstrated a positive effect on neurodevelopment in children of mothers promptly supplemented with iodine compared with the neurodevelopment in children of nonsupplemented mothers. Free T4 assays presently in clinical use have limitations. Preliminary results of the Controlled Antenatal Thyroid Study (CATS) are somewhat mixed, and the National Institutes of Health Maternal Fetal Medicine Thyrotropin Study (TSH Study) will be completed in 2015. Knowledge regarding the impact of isolated hypothyroxinemia has progressed, but major questions remain. An optimal diagnostic test for free T4 during pregnancy (accurate, inexpensive, and widely available) remains elusive. Trimester-specific normative data and normal ranges from different geographic regions do not exist. CONCLUSIONS Data published to date are insufficient to recommend levothyroxine therapy in pregnant women with isolated hypothyroxinemia. Adequate iodine intake should be recommended before conception and early in pregnancy.
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Affiliation(s)
- Roberto Negro
- Division of Endocrinology, V. Fazzi Hospital, 73100, Lecce, Italy.
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Stagnaro-Green A, Abalovich M, Alexander E, Azizi F, Mestman J, Negro R, Nixon A, Pearce EN, Soldin OP, Sullivan S, Wiersinga W. Guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and postpartum. Thyroid 2011; 21:1081-125. [PMID: 21787128 PMCID: PMC3472679 DOI: 10.1089/thy.2011.0087] [Citation(s) in RCA: 951] [Impact Index Per Article: 73.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Alex Stagnaro-Green
- Department of Medicine, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia 20037, USA.
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Abstract
Iodine is a necessary element for the production of thyroid hormone. We will review the impact of dietary iodine status on thyroid function in pregnancy. We will discuss iodine metabolism, homeostasis, and nutritional recommendations for pregnancy. We will also discuss the possible effects of environmental contaminants on iodine utilization in pregnant women.
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Affiliation(s)
- Christina Yarrington
- Department of Obstetrics and Gynecology, Boston Medical Center, Boston, MA 02118, USA
| | - Elizabeth N. Pearce
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, 88 East Newton Street, Evans 201, Boston, MA 02118, USA
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Moleti M, Di Bella B, Giorgianni G, Mancuso A, De Vivo A, Alibrandi A, Trimarchi F, Vermiglio F. Maternal thyroid function in different conditions of iodine nutrition in pregnant women exposed to mild-moderate iodine deficiency: an observational study. Clin Endocrinol (Oxf) 2011; 74:762-8. [PMID: 21521276 DOI: 10.1111/j.1365-2265.2011.04007.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE We examined the effect of different conditions of nutritional iodine intake on maternal thyroid function throughout gestation in a cohort of healthy, anti-thyroid antibody-negative women from a mild-moderately iodine-deficient (ID) area. DESIGN Observational cohort study. PATIENTS The study included 168 women receiving prenatal preparations containing 150 μg of iodine from early pregnancy (150-I group); 105 women who had regularly used (>2 years) iodized salt prior to becoming pregnant (I-salt group); 160 women neither taking iodine supplements nor using iodized salt (no-I group). MEASUREMENTS Maternal TSH, FT3 and FT4 were determined throughout gestation. RESULTS Mean TSH concentrations were higher among the 150-I women than in the remaining two groups, and in a high proportion of them, TSH values were found to exceed the upper limit for gestational age. Conversely, the prevalence of low free-thyroxine levels in the 150-I women was similar to that observed in the I-salt women and markedly lower than that recorded for the no-I group. CONCLUSIONS The regular use of iodine-containing supplements proved effective in reducing the risk of inappropriately low FT4 levels during pregnancy. The observed TSH increase in 150-I women may be because of a transient stunning effect on the thyroid gland, occurring as a result of the abrupt increase in daily iodine intake. Whilst the importance of gestational iodine supplementation is undisputed, we believe that in mild-moderately ID areas, women considering conception should be advised to take iodine supplementation for several months prior to pregnancy.
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Affiliation(s)
- Mariacarla Moleti
- Dipartimento Clinico-Sperimentale di Medicina e Farmacologia-Sezione di Endocrinologia, University of Messina, Messina, Italy
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Vila L, Serra-Prat M, de Castro A, Palomera E, Casamitjana R, Legaz G, Barrionuevo C, Muñoz JA, García AJ, Lal-Trehan S, García A, Durán J, Puig-Domingo M. Iodine nutritional status in pregnant women of two historically different iodine-deficient areas of Catalonia, Spain. Nutrition 2011; 27:1029-33. [PMID: 21621389 DOI: 10.1016/j.nut.2010.11.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 10/21/2010] [Accepted: 11/27/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Catalonia (Spain) has a historically worse situation of mild iodine deficiency in the Pyrenees Mountains compared with the coastal region. The aim of this study was to evaluate the current iodine status in pregnant women living in these two areas. METHODS An epidemiologic prospective survey included 267 consecutive pregnancies in the Catalan mountains (n = 139) and coast (n = 128) studied during the first trimester; an additional subset of 135 women from the initial cohort was available for evaluation in the third trimester. Urinary iodine (UI) was measured, and questionnaires to determine iodized salt and sea fish consumption and potassium iodide supplementation were administered. RESULTS The median UI in the first trimester was 163 μg/L for the entire cohort, with differences between mountain and coastal regions (209 versus 142 μg/L, P = 0.007). The highest prevalence of iodized salt consumption was in the mountain area (58% versus 36.4%, P < 0.001). For the entire group, a higher median UI was found in iodized salt consumers compared with non-consumers (193 versus 134 μg/L, P < 0.001). In the third trimester, an increase of median UI was seen in those to whom iodine supplements were given during pregnancy (190 versus 154 μg/L, P = 0.015). CONCLUSION A reversal in the historically iodine-deficient situation was observed in the Catalan Pyrenees compared with the coastal area, with a globally acceptable iodine status in pregnant women of the two geographic locations. Iodized salt consumption seems to have contributed to maintaining an acceptable iodine status in this population.
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Affiliation(s)
- Lluis Vila
- Endocrinology and Nutrition Department, Hospital Sant Joan Despí, Moisès Broggi, Barcelona, Spain.
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Iodine deficiency in pregnancy: the effect on neurodevelopment in the child. Nutrients 2011; 3:265-73. [PMID: 22254096 PMCID: PMC3257674 DOI: 10.3390/nu3020265] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 02/08/2011] [Accepted: 02/15/2011] [Indexed: 11/17/2022] Open
Abstract
Iodine is an integral part of the thyroid hormones, thyroxine (T4) and tri-iodothyronine (T3), necessary for normal growth and development. An adequate supply of cerebral T3, generated in the fetal brain from maternal free T4 (fT4), is needed by the fetus for thyroid hormone dependent neurodevelopment, which begins in the second half of the first trimester of pregnancy. Around the beginning of the second trimester the fetal thyroid also begins to produce hormones but the reserves of the fetal gland are low, thus maternal thyroid hormones contribute to total fetal thyroid hormone concentrations until birth. In order for pregnant women to produce enough thyroid hormones to meet both her own and her baby’s requirements, a 50% increase in iodine intake is recommended. A lack of iodine in the diet may result in the mother becoming iodine deficient, and subsequently the fetus. In iodine deficiency, hypothyroxinemia (i.e., low maternal fT4) results in damage to the developing brain, which is further aggravated by hypothyroidism in the fetus. The most serious consequence of iodine deficiency is cretinism, characterised by profound mental retardation. There is unequivocal evidence that severe iodine deficiency in pregnancy impairs brain development in the child. However, only two intervention trials have assessed neurodevelopment in children of moderately iodine deficient mothers finding improved neurodevelopment in children of mothers supplemented earlier rather than later in pregnancy; both studies were not randomised and were uncontrolled. Thus, there is a need for well-designed trials to determine the effect of iodine supplementation in moderate to mildly iodine deficient pregnant women on neurodevelopment in the child.
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Marco A, Vicente A, Castro E, Eva Perez C, Rodríguez O, Merchan MA, Sastre J, Cánovas B, Maqueda E, Peña V, López J. Patterns of iodine intake and urinary iodine concentrations during pregnancy and blood thyroid-stimulating hormone concentrations in the newborn progeny. Thyroid 2010; 20:1295-9. [PMID: 20950254 DOI: 10.1089/thy.2010.0046] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Appropriate maternal intake of iodine during pregnancy is essential for maternal thyroxine production and thyroid status of the fetus. It should be possible to enhance iodine intake during pregnancy by using iodine fortified salt or taking iodine supplements. In the present report we determined the status of iodine nutrition in pregnant women who were stratified on the basis of their history of taking or not taking iodized salt or iodine supplements. The study was performed in Toledo (Spain), a region in which prior studies have noted borderline iodine sufficiency. Iodine nutrition was assessed by measuring urinary iodine concentration (UIC) and neonatal thyrotropin (TSH). METHODS UIC was measured in 525 pregnant women. They were grouped according to their history of iodine intake. Diet Group 1 patients (n = 69) did not take iodized salt or iodine supplements during pregnancy. Diet Group 2 patients (n = 75) took iodized salt but not iodine supplements during pregnancy. Diet Group 3 patients (n = 381) took iodine supplements during pregnancy. Plasma determinations included TSH, free thyroxine, thyroid peroxidase antibody, and thyroglobulin antibody. UIC was measured in a single urine sample from all the pregnant women. Neonatal TSH was measured in capillary spot blood from all the neonates as part of a screening for congenital metabolic abnormalities. RESULTS The median UIC in all subjects was 164 μg/L (interquartile range [IR]: 116-245). The median UICs in Diet Groups 1, 2, and 3 were 134.5 (IR: 90-196), 146 (IR: 103-205), and 183 (IR: 124-261) μg/L, respectively (p = not significant [NS] for Diet Group 1 vs. 2; p < 0.01 for Diet Group 2 vs. 3; all other comparisons NS). The median (IR) TSH of the neonates in all Diet Groups was 1.0 (IR: 0.7-1.6) μU/mL. Only 2 neonates had blood TSH concentrations >5 mU/L. Neonatal blood TSH concentrations were similar in all Diet Groups. CONCLUSIONS In a region with a history of borderline iodine deficiency the UICs were below 150 μg/L in a substantial percentage of pregnant women who did not take iodine supplements, regardless of whether or not they took iodized salt. Our results support the use of iodine supplements from the start of the pregnancy, or even before pregnancy in women who live in regions with a history of even small degrees of iodine deficiency. In addition, neonate TSH screening is not the best tool to assess whether the iodine status in populations is ideal.
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Affiliation(s)
- Amparo Marco
- Endocrinology and Nutrition Service, Complejo Hospitalario de Toledo, Toledo, Spain.
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Limbert E, Prazeres S, São Pedro M, Madureira D, Miranda A, Ribeiro M, Jacome de Castro J, Carrilho F, Oliveira MJ, Reguengo H, Borges F. Iodine intake in Portuguese pregnant women: results of a countrywide study. Eur J Endocrinol 2010; 163:631-5. [PMID: 20643757 DOI: 10.1530/eje-10-0449] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Iodine is the key element for thyroid hormone synthesis, and its deficiency, even moderate, is harmful in pregnancy, when needs are increased, because of its potential deleterious effects on fetal brain development. In Portugal, no recent data on iodine intake exists. The objective of this countrywide study was to analyze iodine status in pregnant Portuguese women in order to propose adequate measures to the health authorities. SUBJECTS AND METHODS Using a fast colorimetric method, urine iodine concentration (UIC) was evaluated in 3631 pregnant women followed in 17 maternity hospitals from hinterland and coastal areas in Continental Portugal and the Portuguese islands of Açores and Madeira. RESULTS Median UIC value was 84.9 μg/l (range 67.6-124.1) in Continental Portugal, 69.5 μg/l in Madeira, and 50.0 μg/l in Açores. The percentage of satisfactory values (>150 μg/l) was 16.8, ranging from 8.8 to 34.1 in the Continent, and being 8.2 in Madeira and 2.3 in Açores. The percentage of values below 50 μg/l was 23.7, ranging from 14.0 to 37.4 in the Continent, 33.7 in Madeira, and 50.0 in Açores. CONCLUSIONS Our results point to an inadequate iodine intake in pregnant women assisted in most Portuguese maternity hospitals. Considering the potential deleterious effects of inadequate iodine supply in pregnancy, iodine supplementation is strongly recommended in this period of life.
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Affiliation(s)
- E Limbert
- Department of Endocrinology, Instituto Português de Oncologia de Lisboa de Francisco Gentil, Rua Professor Lima Basto, Lisboa, Portugal.
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Melse-Boonstra A, Jaiswal N. Iodine deficiency in pregnancy, infancy and childhood and its consequences for brain development. Best Pract Res Clin Endocrinol Metab 2010; 24:29-38. [PMID: 20172468 DOI: 10.1016/j.beem.2009.09.002] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Iodine deficiency during foetal development and early childhood is associated with cognitive impairment. Randomised clinical studies in school-aged children encountered in the literature indicate that cognitive performance can be improved by iodine supplementation, but most studies suffer from methodological constraints. Tests to assess cognitive performance in the domains that are potentially affected by iodine deficiency need to be refined. Maternal iodine supplementation in areas of mild-to-moderate iodine deficiency may improve cognitive performance of the offspring, but randomised controlled studies with long-term outcomes are lacking. Studies in infants or young children have not been conducted. The best indicators for iodine deficiency in children are thyroid-stimulating hormone (TSH) in newborns and thyroglobulin (Tg) in older children. Urinary iodine may also be useful but only at the population level. Adequate salt iodisation will cover the requirements of infants and children as well as pregnant women. However, close monitoring remains essential.
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Affiliation(s)
- Alida Melse-Boonstra
- Division of Human Nutrition, Wageningen University, 6700 EV Wageningen, the Netherlands.
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