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Niinistö S, Miettinen ME, Cuthbertson D, Honkanen J, Hakola L, Autio R, Erlund I, Arohonka P, Vuorela A, Härkönen T, Hyöty H, Krischer JP, Vaarala O, Knip M, Virtanen SM. Associations Between Serum Fatty Acids and Immunological Markers in Children Developing Islet Autoimmunity-The TRIGR Nested Case-Control Study. Front Immunol 2022; 13:858875. [PMID: 35693790 PMCID: PMC9175567 DOI: 10.3389/fimmu.2022.858875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 04/27/2022] [Indexed: 12/03/2022] Open
Abstract
Aims Altered immune functions as well as fatty acid intake and status have been associated with the development of type 1 diabetes. We aimed to study the relationship between fatty acids and immunological markers in young children with increased genetic risk for type 1 diabetes in order to define putative mechanisms related to development of islet autoimmunity. Methods Serum samples for fatty acid and immunological marker measurements were obtained in the Trial to Reduce IDDM in the Genetically at Risk (TRIGR) ancillary study (Divia) from children born between 2002 and 2007 in 15 countries. Case children (n = 95) were defined as having repeated positivity for at least two out of four diabetes-associated autoantibodies. For each case child, control children were selected matched for country and date of birth (n = 173). Serum fatty acids and immunological markers were measured from cord serum and at the age of 6 and 12 months. Spearman correlation coefficients were calculated between fatty acids and immunological markers. Results Correlations between circulating fatty acids and immunological markers were different in case children who developed islet autoimmunity than in control children already at birth continuing across the first year of life. In case children, saturated fatty acids (SFAs) showed stronger correlations with immunological markers, while in controls, polyunsaturated fatty acids (PUFAs) showed stronger correlations. Conclusions In cases, SFAs were associated with several immunological markers (CXCL10, IL-6, IL-9, IL-17, and CM-CSF) previously linked to the type 1 diabetes disease process. Findings indicate that fatty acids could have immunomodulatory potential in the early phase of the disease development, although causality between fatty acids and the immunological pathways remains to be explored. Trial registry number NCT00179777.
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Affiliation(s)
- Sari Niinistö
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Maija E. Miettinen
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - David Cuthbertson
- Health Informatics Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Jarno Honkanen
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Leena Hakola
- Unit of Health Sciences, Faculty of Social Sciences, Tampere University, Tampere, Finland
- Tampere University Hospital, Research, Development and Innovation Center, Tampere, Finland
| | - Reija Autio
- Unit of Health Sciences, Faculty of Social Sciences, Tampere University, Tampere, Finland
| | - Iris Erlund
- Department of Government Services, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Petra Arohonka
- Department of Government Services, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Arja Vuorela
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Taina Härkönen
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Heikki Hyöty
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Fimlab Laboratories, Pirkanmaa Hospital District, Tampere, Finland
| | - Jeffrey P. Krischer
- Health Informatics Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Outi Vaarala
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Mikael Knip
- Pediatric Research Center, Children’s Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, University of Helsinki, Helsinki, Finland
- Center for Child Health Research, Tampere University and Tampere University Hospital, Tampere, Finland
| | - Suvi M. Virtanen
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
- Unit of Health Sciences, Faculty of Social Sciences, Tampere University, Tampere, Finland
- Tampere University Hospital, Research, Development and Innovation Center, Tampere, Finland
- Center for Child Health Research, Tampere University and Tampere University Hospital, Tampere, Finland
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Oblak A, Arohonka P, Erlund I, Kuzmanovska S, Zaletel K, Gaberšček S. Validation of a Spectrophotometric Method for Urinary Iodine Determination on Microplate Based on Sandell-Kolthoff Reaction. Lab Med 2022; 53:376-380. [PMID: 35073580 DOI: 10.1093/labmed/lmab117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE Iodine is an essential part of the thyroid hormones thyroxine and triiodothyronine. Therefore, it is essential to monitor iodine supply in a population. The biochemical marker for assessing and controlling iodine is urinary iodine concentration (UIC). MATERIALS AND METHODS This cross-sectional study included 180 pregnant women and 308 women of reproductive age. Urine specimens from 185 of the 488 volunteers were used. The urine specimens were measured using 2 methods: (1) ammonium persulfate digestion (APD), followed by the Sandell-Kolthoff (S-K) reaction modified on microplate for spectrophotometric detection; and (2) the reference method, inductively coupled plasma mass spectrometry (ICP-MS). RESULTS The regression equation between the methods was ICP-MS method = 1.137*(APD S-K)-5.57. A Passing-Bablok regression showed no deviation from linearity (P = .17). A Bland-Altman plot showed a negative mean bias of -2.7%. CONCLUSION The APD S-K reaction modified on microplate for spectrophotometric detection of UIC can be implemented into routine work. Its results are comparable to those of laboratories worldwide and to ICP-MS.
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Affiliation(s)
- Adrijana Oblak
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Petra Arohonka
- Finnish Institute for Health and Welfare, Department of Government Services, Helsinki, Finland
| | - Iris Erlund
- Finnish Institute for Health and Welfare, Department of Government Services, Helsinki, Finland
| | - Sonja Kuzmanovska
- Institute of Pathophysiology and Nuclear Medicine, Faculty of Medicine, Skopje, North Macedonia
| | - Katja Zaletel
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Simona Gaberšček
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Ittermann T, Albrecht D, Arohonka P, Bilek R, de Castro JJ, Dahl L, Filipsson Nystrom H, Gaberscek S, Garcia-Fuentes E, Gheorghiu ML, Hubalewska-Dydejczyk A, Hunziker S, Jukic T, Karanfilski B, Koskinen S, Kusic Z, Majstorov V, Makris KC, Markou KB, Meisinger C, Milevska Kostova N, Mullen KR, Nagy EV, Pirags V, Rojo-Martinez G, Samardzic M, Saranac L, Strele I, Thamm M, Top I, Trofimiuk-Müldner M, Ünal B, Koskinen S, Vila L, Vitti P, Winter B, Woodside JV, Zaletel K, Zamrazil V, Zimmermann M, Erlund I, Völzke H. Standardized Map of Iodine Status in Europe. Thyroid 2020; 30:1346-1354. [PMID: 32460688 DOI: 10.1089/thy.2019.0353] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background: Knowledge about the population's iodine status is important, because it allows adjustment of iodine supply and prevention of iodine deficiency. The validity and comparability of iodine-related population studies can be improved by standardization, which was one of the goals of the EUthyroid project. The aim of this study was to establish the first standardized map of iodine status in Europe by using standardized urinary iodine concentration (UIC) data. Materials and Methods: We established a gold-standard laboratory in Helsinki measuring UIC by inductively coupled plasma mass spectrometry. A total of 40 studies from 23 European countries provided 75 urine samples covering the whole range of concentrations. Conversion formulas for UIC derived from the gold-standard values were established by linear regression models and were used to postharmonize the studies by standardizing the UIC data of the individual studies. Results: In comparison with the EUthyroid gold-standard, mean UIC measurements were higher in 11 laboratories and lower in 10 laboratories. The mean differences ranged from -36.6% to 49.5%. Of the 40 postharmonized studies providing data for the standardization, 16 were conducted in schoolchildren, 13 in adults, and 11 in pregnant women. Median standardized UIC was <100 μg/L in 1 out of 16 (6.3%) studies in schoolchildren, while in adults 7 out of 13 (53.8%) studies had a median standardized UIC <100 μg/L. Seven out of 11 (63.6%) studies in pregnant women revealed a median UIC <150 μg/L. Conclusions: We demonstrate that iodine deficiency is still present in Europe, using standardized data from a large number of studies. Adults and pregnant women, particularly, are at risk for iodine deficiency, which calls for action. For instance, a more uniform European legislation on iodine fortification is warranted to ensure that noniodized salt is replaced by iodized salt more often. In addition, further efforts should be put on harmonizing iodine-related studies and iodine measurements to improve the validity and comparability of results.
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Affiliation(s)
- Till Ittermann
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Diana Albrecht
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
| | - Petra Arohonka
- Department of Government Services, Finnish Institute for Health and Welfare, Helsinki, Finland
- Department of Public Health Solutions, Finnish Institute for Health and Welfare, Helsinki, Finland
| | | | - Joao J de Castro
- Department of Endocrinology, Hospital das Forças Armadas, Lisbon, Portugal
| | - Lisbeth Dahl
- Food Security and Nutrition, Institute of Marine Research (IMR), Bergen, Norway
| | - Helena Filipsson Nystrom
- Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Endocrinology, Sahlgrenska University Hospital, Göteborg, Sweden
| | - Simona Gaberscek
- Department of Nuclear Medicine, University Medical Centre, Ljubljana, Slovenia
| | - Eduardo Garcia-Fuentes
- Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain
| | - Monica L Gheorghiu
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
- C.I. Parhon National Institute of Endocrinology, Bucharest, Romania
| | | | - Sandra Hunziker
- Department of Health Sciences and Technology, ETH, Zürich, Switzerland
| | - Tomislav Jukic
- Department of Oncology and Nuclear Medicine, Sestre Milosrdnice University Hospital Centre, Zagreb, Croatia
| | - Borislav Karanfilski
- Centre for Regional Policy Research and Cooperation "Studiorum", Skopje, North Macedonia
| | - Seppo Koskinen
- Department of Public Health Solutions, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Zvonko Kusic
- Department of Oncology and Nuclear Medicine, Sestre Milosrdnice University Hospital Centre, Zagreb, Croatia
| | - Venjamin Majstorov
- Institute of Pathophysiology and Nuclear Medicine, Ss. Cyril and Methodius University, Skopje, Former Yougoslavian Rebublic of Macedonia
| | - Konstantinos C Makris
- Cyprus International Institute for Environmental and Public Health, Cyprus University of Technology, Limassol, Cyprus
| | - Kostas B Markou
- Department of Endocrinology, Institute University of Patras Medical School, Patras, Greece
| | - Christa Meisinger
- Chair of Epidemiology, Ludwig-Maximilians Universität Munich, UNIKA-T Augsburg, Augsburg, Germany
- Independent Research Group Clinical Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Neda Milevska Kostova
- Centre for Regional Policy Research and Cooperation "Studiorum", Skopje, North Macedonia
| | - Karen R Mullen
- Belfast Health and Social Care Trust, Belfast, United Kingdom
| | - Endre V Nagy
- Division of Endocrinology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Valdis Pirags
- Department of Internal Medicine, University of Latvia, Riga, Latvia
| | - Gemma Rojo-Martinez
- Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, IBIMA, Málaga, Spain
| | - Mira Samardzic
- Department of Endocrinology and Diabetes, Institute for Sick Children, Podgorica, Montenegro
| | - Ljiljana Saranac
- Department of Pediatrics, Faculty of Medicine, University of Niš, Niš, Serbia
| | - Ieva Strele
- Department of Internal Medicine, University of Latvia, Riga, Latvia
| | - Michael Thamm
- Department of Epidemiology and Health Monitoring, Robert Koch Institute, Berlin, Germany
| | - Işık Top
- Department of Public Health, Dokuz Eylul University Medical Faculty, İzmir, Turkey
| | | | - Belgin Ünal
- Department of Public Health, Dokuz Eylul University Medical Faculty, İzmir, Turkey
| | - Seppo Koskinen
- Department of Public Health Solutions, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Lluis Vila
- Department of Endocrinology and Nutrition, Hospital de Sant Joan Despi Moisès Broggi, Barcelona, Spain
| | - Paolo Vitti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Benjamin Winter
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Jayne V Woodside
- Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom
| | - Katja Zaletel
- Department of Nuclear Medicine, University Medical Centre, Ljubljana, Slovenia
| | | | | | - Iris Erlund
- Department of Government Services, Finnish Institute for Health and Welfare, Helsinki, Finland
- Department of Public Health Solutions, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Henry Völzke
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
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Petersen E, Thorisdottir B, Thorsdottir I, Gunnlaugsson G, Arohonka P, Erlund I, Gunnarsdottir I. Iodine status of breastfed infants and their mothers' breast milk iodine concentration. Matern Child Nutr 2020; 16:e12993. [PMID: 32162412 PMCID: PMC7296790 DOI: 10.1111/mcn.12993] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 12/26/2022]
Abstract
Iodine is an essential nutrient for growth and development during infancy. Data on iodine status of exclusively (EBF) and partially breastfed (PBF) infants as well as breast milk iodine concentration (BMIC) are scarce. We aimed to assess (a) infant iodine nutrition at the age of 5.5 months by measuring urinary iodine concentration (UIC) in EBF (n = 32) and PBF (n = 28) infants and (b) mothers' breast milk iodine concentration (n = 57). Sixty mother–infant pairs from three primary health care centres in Reykjavik and vicinities provided urine and breast milk samples for iodine analysis and information on mothers' habitual diet. The mother–infant pairs were participants of the IceAge2 study, which focuses on factors contributing to infant growth and development, including body composition and breast‐milk energy content. The median (25th–75th percentiles) UIC was 152 (79–239) μg/L, with no significant difference between EBF and PBF infants. The estimated median iodine intake ranged from 52 to 86 μg/day, based on urinary data (assuming an average urine volume of 300–500 ml/day and UIC from the present study). The median (25th–75th percentiles) BMIC was 84 (48–114) μg/L. It is difficult to conclude whether iodine status is adequate in the present study, as no ranges for median UIC reflecting optimal iodine nutrition exist for infants. However, the results add important information to the relatively sparse literature on UIC, BMIC, and iodine intake of breastfed infants.
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Affiliation(s)
- Erna Petersen
- Department of Clinical Nutrition, Landspitali University Hospital, Reykjavik, Iceland.,Unit for Nutrition Research, Faculty of Food Science and Nutrition, Landspitali University Hospital, University of Iceland, Reykjavik, Iceland
| | - Birna Thorisdottir
- Unit for Nutrition Research, Faculty of Food Science and Nutrition, Landspitali University Hospital, University of Iceland, Reykjavik, Iceland
| | - Inga Thorsdottir
- School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | - Geir Gunnlaugsson
- Faculty of Sociology, Anthropology and Folkloristics, School of Social Sciences, University of Iceland, Reykjavik, Iceland
| | - Petra Arohonka
- Forensic Toxicology Unit, Biochemistry Laboratory, Finnish Institute for Health and Welfare (THL), Helsinki, Finland
| | - Iris Erlund
- Forensic Toxicology Unit, Biochemistry Laboratory, Finnish Institute for Health and Welfare (THL), Helsinki, Finland
| | - Ingibjörg Gunnarsdottir
- Department of Clinical Nutrition, Landspitali University Hospital, Reykjavik, Iceland.,Unit for Nutrition Research, Faculty of Food Science and Nutrition, Landspitali University Hospital, University of Iceland, Reykjavik, Iceland
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5
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Adalsteinsdottir S, Tryggvadottir EA, Hrolfsdottir L, Halldorsson TI, Birgisdottir BE, Hreidarsdottir IT, Hardardottir H, Arohonka P, Erlund I, Gunnarsdottir I. Insufficient iodine status in pregnant women as a consequence of dietary changes. Food Nutr Res 2020; 64:3653. [PMID: 31983913 PMCID: PMC6958617 DOI: 10.29219/fnr.v64.3653] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 11/28/2019] [Accepted: 12/04/2019] [Indexed: 02/05/2023] Open
Abstract
Background Historically, Iceland has been an iodine-sufficient nation due to notably high fish and milk consumption. Recent data suggest that the intake of these important dietary sources of iodine has decreased considerably. Objective To evaluate the iodine status of pregnant women in Iceland and to determine dietary factors associated with risk for deficiency. Methods Subjects were women (n = 983; 73% of the eligible sample) attending their first ultrasound appointment in gestational weeks 11–14 in the period October 2017–March 2018. Spot urine samples were collected for assessment of urinary iodine concentration (UIC) and creatinine. The ratio of iodine to creatinine (I/Cr) was calculated. Median UIC was compared with the optimal range of 150–249 μg/L defined by the World Health Organization (WHO). Diet was assessed using a semiquantitative food frequency questionnaire (FFQ), which provided information on main dietary sources of iodine in the population studied (dairy and fish). Results The median UIC (95% confidence interval (CI)) and I/Cr of the study population was 89 μg/L (42, 141) and 100 (94, 108) μg/g, respectively. UIC increased with higher frequency of dairy intake, ranging from median UIC of 55 (35, 79) μg/L for women consuming dairy products <1 time per week to 124 (98, 151) μg/L in the group consuming dairy >2 times per day (P for trend <0.001). A small group of women reporting complete avoidance of fish (n = 18) had UIC of 50 (21, 123) μg/L and significantly lower I/Cr compared with those who did not report avoidance of fish (58 (34, 134) μg/g vs. 100 (94, 108) μg/g, P = 0.041). Women taking supplements containing iodine (n = 34, 3.5%) had significantly higher UIC compared with those who did not take supplements (141 (77, 263) μg/L vs. 87 (82, 94), P = 0.037). Conclusion For the first time, insufficient iodine status is being observed in an Icelandic population. There is an urgent need for a public health action aiming at improving iodine status of women of childbearing age in Iceland.
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Affiliation(s)
- Solveig Adalsteinsdottir
- Unit for Nutrition Research, Landspitali University Hospital and Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland
| | - Ellen Alma Tryggvadottir
- Unit for Nutrition Research, Landspitali University Hospital and Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland
| | - Laufey Hrolfsdottir
- Unit for Nutrition Research, Landspitali University Hospital and Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland.,Institution of Health Science Research, University of Akureyri and Akureyri Hospital, Akureyri, Iceland
| | - Thorhallur I Halldorsson
- Unit for Nutrition Research, Landspitali University Hospital and Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland.,Centre for Fetal Programming, Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| | - Bryndis Eva Birgisdottir
- Unit for Nutrition Research, Landspitali University Hospital and Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland
| | | | - Hildur Hardardottir
- Department of Obstetrics and Gynecology, Landspitali University Hospital, Reykjavík, Iceland.,Faculty of Medicine, University of Iceland Reykjavík, Iceland
| | - Petra Arohonka
- Forensic Toxicology Unit, National Institute for Health and Welfare, Helsinki, Finland
| | - Iris Erlund
- Forensic Toxicology Unit, National Institute for Health and Welfare, Helsinki, Finland
| | - Ingibjorg Gunnarsdottir
- Unit for Nutrition Research, Landspitali University Hospital and Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland
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Abel MH, Korevaar TI, Erlund I, Villanger GD, Caspersen IH, Arohonka P, Alexander J, Meltzer HM, Brantsæter AL. Iodine Intake is Associated with Thyroid Function in Mild to Moderately Iodine Deficient Pregnant Women. Thyroid 2018; 28:1359-1371. [PMID: 30132420 PMCID: PMC6157349 DOI: 10.1089/thy.2018.0305] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Studies indicate that mild to moderate iodine deficiency in pregnancy may have a long-term negative impact on child neurodevelopment. These effects are likely mediated via changes in maternal thyroid function, since iodine is essential for the production of thyroid hormones. However, the impact of iodine availability on thyroid function during pregnancy and on thyroid function reference ranges are understudied. The aim of this study was to investigate the association between iodine intake and thyroid function during pregnancy. DESIGN In a population-based pregnancy cohort including 2910 pregnant women participating in The Norwegian Mother and Child Cohort Study, we explored cross sectional associations of maternal iodine intake measured (1) by a food frequency questionnaire and (2) as iodine concentration in a spot urine sample, with plasma thyroid hormones and antibodies. RESULTS Biological samples were collected in mean gestational week 18.5 (standard deviation 1.3) and diet was assessed in gestational week 22. Median iodine intake from food was 121 μg/day (interquartile range 90, 160), and 40% reported use of iodine-containing supplements in pregnancy. Median urinary iodine concentration (UIC) was 59 μg/L among those who did not use supplements and 98 μg/L in the women reporting current use at the time of sampling, indicating mild to moderate iodine deficiency in both groups. Iodine intake as measured by the food frequency questionnaire was not associated with the outcome measures, while UIC was inversely associated with FT3 (p = 0.002) and FT4 (p < 0.001). Introduction of an iodine-containing supplement after gestational week 12 was associated with indications of lower thyroid hormone production (lower FT4, p = 0.027, and nonsignificantly lower FT3, p = 0.17). The 2.5th and 97.5th percentiles of TSH, FT4, and FT3 were not significantly different by groups defined by calculated iodine intake or by UIC. CONCLUSION The results indicate that mild to moderate iodine deficiency affect thyroid function in pregnancy. However, the differences were small, suggesting that normal reference ranges can be determined based on data also from mildly iodine deficient populations, but this needs to be further studied. Introducing an iodine-containing supplement might temporarily inhibit thyroid hormone production and/or release.
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Affiliation(s)
- Marianne Hope Abel
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
- Department of Nursing and Health Promotion, Faculty of Health Sciences, OsloMet - Oslo Metropolitan University, Oslo, Norway
- Department of Nutrition, Tine SA, Oslo, Norway
| | - Tim I.M. Korevaar
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
- Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Iris Erlund
- Genomics and Biomarkers Unit, National Institute for Health and Welfare, Helsinki, Finland
| | - Gro Dehli Villanger
- Division of Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Ida Henriette Caspersen
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Petra Arohonka
- Genomics and Biomarkers Unit, National Institute for Health and Welfare, Helsinki, Finland
| | - Jan Alexander
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Helle Margrete Meltzer
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Anne Lise Brantsæter
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
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