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Groufh-Jacobsen S, Abel MH, Brantsæter AL, Andersson M, Meyer HE, Henjum S. National monitoring of iodine, sodium, and vitamin D status in toddlers and women of childbearing age - results and lessons learned from a pilot study in Norway. Food Nutr Res 2023; 67:9088. [PMID: 37691743 PMCID: PMC10492227 DOI: 10.29219/fnr.v67.9088] [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] [Received: 10/28/2022] [Revised: 06/12/2023] [Accepted: 07/05/2023] [Indexed: 09/12/2023] Open
Abstract
Background Norway is lacking a population-based national monitoring program for iodine, sodium, and vitamin D status. Objective The aim of this study was to pilot-test a study design for collecting biological samples from a country-representative sample of 2-year-old children and their mothers and to report results for iodine, salt, and vitamin D at baseline, before initiation of salt iodization in Norway. Design In a cross-sectional study, we recruited 2-year-old children and their mothers during the routine 2-year check-up through 38 randomly selected health clinics in 2021. Spot urine samples were analyzed for iodine, creatinine, and sodium, and dried blood spots from the mothers were analyzed for thyroglobulin (Tg) and 25-hydroxyvitamin D (25(OH)D). Results We aimed at including 400 mother-child pairs but recruited only 55 pairs. Major challenges were closed health clinics due to the COVID-19 pandemic, lack of motivation of the health personnel to prioritize recruiting, missing information about non-participation, and high workload for participants. The median urinary iodine concentration (UIC) was 123 (95% CI: 76, 228) µg/L in the toddlers and 83 (95% CI: 72, 99) µg/L in the mothers. The median urinary sodium concentration (UNaC) was 62 (95% CI: 37, 91) mmol/L in the toddlers and 93 (95% CI: 77, 107) mmol/L in the mothers. Of the mothers, 18% had levels of 25(OH)D <50 nmol/L (suboptimal status). Discussion and conclusion Lessons learned from the pilot study will be used to design a national monitoring program for toddlers and women of childbearing age in Norway. The results indicate that 2-year-old children and women of childbearing age in Norway may have inadequate iodine intakes at the group level, while for vitamin D, most of the mothers had adequate status.
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Affiliation(s)
- Synne Groufh-Jacobsen
- Department of Nutrition and Public Health, Faculty of Health and Sport Science, University of Agder, Kristiansand, Norway
| | - Marianne Hope Abel
- Department of Physical Health and Ageing, Norwegian Institute of Public Health, Oslo, Norway
| | - Anne Lise Brantsæter
- Department of Food Safety, Division of Climate and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Maria Andersson
- Nutrition Research Unit, University Children’s Hospital Zurich, Zurich, Switzerland
| | - Haakon E. Meyer
- Department of Physical Health and Ageing, Norwegian Institute of Public Health, Oslo, Norway
| | - Sigrun Henjum
- Department of Nursing and Health Promotion, Faculty of Health Science, Oslo Metropolitan University, Oslo, Norway
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Knøsgaard L, Andersen S, Hansen AB, Sørensen A, Vestergaard P, Andersen SL. Iodine status in Danish pregnant women after an increase in iodine fortification. Clin Endocrinol (Oxf) 2023; 98:407-414. [PMID: 35788951 DOI: 10.1111/cen.14797] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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] [Received: 04/20/2022] [Revised: 06/16/2022] [Accepted: 06/29/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Iodine fortification programmes are implemented in many countries and often associated with an increase in population iodine intake. However, the initial attempt may not be sufficient and in Denmark the level of iodine added to salt was increased in 2019. Sparse evidence is available on the impact of such modification in iodine fortification. The aim of this study was to evaluate iodine status in Danish pregnant women in 2021 after this increase in iodine fortification and compare to iodine status in 2012. DESIGN Cross-sectional study. PATIENTS Pregnant women in the North Denmark Region referred for routine obstetric ultrasound in 2021. MEASUREMENTS Participants filled out a questionnaire and delivered a spot urine. Median urinary iodine concentration (UIC) was calculated and assessed according to the recommended range in pregnancy (150-249 µg/L). RESULTS Altogether 147 pregnant women were included and 88% used iodine-containing supplements. Median UIC was overall 77 µg/L [95% confidence interval (CI): 61-96 µg/L], which was lower than in 2012 (101 µg/L [95% CI: 89-111 µg/L]) (p < 0.001). Considering sources of iodine intake in pregnancy, lower daily intake of dairy products (p = 0.008) and bread (p < 0.001) and a lower content of iodine in the supplement used (p < 0.001) was seen in 2021 compared to 2012. CONCLUSION Despite an increase in iodine fortification and frequent use of iodine-containing supplements, iodine status in pregnant women in the North Denmark Region was insufficient. Results call for continued monitoring and attention to ensure adequate iodine status during pregnancy in Denmark.
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Affiliation(s)
- Louise Knøsgaard
- Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Stig Andersen
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
- Department of Geriatrics, Aalborg University Hospital, Aalborg, Denmark
| | - Annebirthe Bo Hansen
- Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark
| | - Anne Sørensen
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
- Department of Obstetrics and Gynecology, Aalborg University Hospital, Aalborg, Denmark
| | - Peter Vestergaard
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
- Department of Endocrinology, Aalborg University Hospital, Aalborg, Denmark
- Steno Diabetes Center North Jutland, Aalborg University Hospital, Aalborg, Denmark
| | - Stine Linding Andersen
- Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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Riis J, Andersen SL, Gade GV, Danielsen MB, Jorgensen MG, Carlé A, Torp-Pedersen C, Andersen S. Raised mortality in old adults with a history of hyperthyroidism following iodine fortification. Clin Endocrinol (Oxf) 2022; 96:255-262. [PMID: 34743350 DOI: 10.1111/cen.14627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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] [Received: 06/16/2021] [Revised: 08/13/2021] [Accepted: 10/17/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVE A transient rise in the occurrence of hyperthyroidism ensued the introduction of iodine fortification (IF) of salt in Denmark. Older adults are at risk of complications to hyperthyroidism that could prove fatal to vulnerable individuals. We evaluated the association between thyroid function and mortality in older adults before and after nationwide implementation of IF. DESIGN Retrospective cohort study. PATIENTS All 68-year-olds from the general population in the city of Randers were invited to participate in a clinical study in 1988 and followed until death, emigration or end of study (31 December 2017) using Danish registries. MEASUREMENTS Baseline measures comprised of a questionnaire, physical examination and blood and urine samples. Kaplan-Meier survival curves and Cox regression were used to determine the association between thyroid function and death before and after IF. Time-stratification of results before and after IF was employed due to violation of proportional hazards assumptions in Cox regression. RESULTS Median urinary iodine concentration was 42 µg/L at baseline consistent with moderate iodine deficiency. Hyperthyroidism (thyrotropin < 0.4 mIU/L) occurred in 37 (9.1%) participants. Kaplan-Meier survival curves showed an increase in mortality among participants with hyperthyroidism after IF. There was no significant association between hyperthyroidism and mortality before IF compared to euthyroid participants, but after IF hyperthyroid subjects had an increased mortality (adjusted hazard ratio: 2.22, 95% confidence interval: 1.44-3.44). CONCLUSIONS IF was associated with raised mortality among older adults with a history of hyperthyroidism and moderate iodine deficiency. Our results highlight the need for cautious iodine supplementation and for monitoring of IF.
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Affiliation(s)
- Johannes Riis
- Department of Geriatric Medicine, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Stine L Andersen
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
- Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark
| | - Gustav V Gade
- Department of Geriatric Medicine, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Mathias B Danielsen
- Department of Geriatric Medicine, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Martin G Jorgensen
- Department of Geriatric Medicine, Aalborg University Hospital, Aalborg, Denmark
| | - Allan Carlé
- Department of Endocrinology, Aalborg University Hospital, Aalborg, Denmark
| | - Christian Torp-Pedersen
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
- Department of Cardiology and Clinical Investigation, Nordsjaellands Hospital, Hillerød, Denmark
| | - Stig Andersen
- Department of Geriatric Medicine, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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Brough L, Gunn CA, Weber JL, Coad J, Jin Y, Thomson JS, Mauze M, Kruger MC. Iodine and Selenium Intakes of Postmenopausal Women in New Zealand. Nutrients 2017; 9:nu9030254. [PMID: 28282932 PMCID: PMC5372917 DOI: 10.3390/nu9030254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 11/18/2022] Open
Abstract
Iodine and selenium are required for thyroid function. This study investigated iodine and selenium intakes in healthy, women aged 50–70 years (n = 97) from three cities in the North Island of New Zealand, after mandatory fortification of bread with iodised salt. Iodine and selenium concentrations were determined in 24-h urine samples; daily intakes were extrapolated from amounts in urine (90% and 55% of daily intake, respectively). Three day diet diaries (3DDD) also estimated selenium and iodine (excluding iodised salt) intake. Median urinary iodine concentration (UIC) was 57 (41, 78) µg/L, indicating mild iodine deficiency. Estimated median iodine intake based on urine was 138 (100, 172) µg/day, below Recommended Dietary Intake (RDI) (150 µg/day) with 25% below Estimated Average Requirement (EAR) (100 µg/day). Estimated median selenium intake was 50 (36, 71) µg/day based on urine and 45 (36, 68) µg/day using 3DDD, below RDI (60 µg/day) with 49%–55% below EAR (50 µg/day). Median bread intakes were low at 1.8 (1.1, 2.7) serves/day; 25% consumed ≤1 serve/day. Although population iodine intakes improved following mandatory fortification, some had low intakes. Selenium intakes remain low. Further research should investigate thyroid function of low consumers of iodine fortified bread and/or selenium in New Zealand.
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Affiliation(s)
- Louise Brough
- Massey Institute of Food Science and Technology, School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
| | - Caroline A Gunn
- Massey Institute of Food Science and Technology, School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
- Fonterra Research & Development Centre, Private Bag 11029, Dairy Farm Road, Palmerston North 4442, New Zealand.
| | - Janet L Weber
- Massey Institute of Food Science and Technology, School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
| | - Jane Coad
- Massey Institute of Food Science and Technology, School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
| | - Ying Jin
- Massey Institute of Food Science and Technology, School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
| | - Jasmine S Thomson
- Massey Institute of Food Science and Technology, School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
| | - Mathilde Mauze
- Massey Institute of Food Science and Technology, School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
| | - Marlena C Kruger
- Massey Institute of Food Science and Technology, School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
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Condo D, Huyhn D, Anderson AJ, Skeaff S, Ryan P, Makrides M, Mühlhaüsler BS, Zhou SJ. Iodine status of pregnant women in South Australia after mandatory iodine fortification of bread and the recommendation for iodine supplementation. Matern Child Nutr 2016; 13. [PMID: 27982512 DOI: 10.1111/mcn.12410] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/02/2016] [Accepted: 11/11/2016] [Indexed: 12/25/2022]
Abstract
Mandatory iodine fortification of bread was introduced in 2009 in Australia in response to the reemergence of iodine deficiency. The aim of this study was to assess iodine intake, urinary iodine concentration (UIC) and their correlation in pregnant women (n = 783) recruited from South Australia 2 years following mandatory iodine fortification. Total iodine intake (food and supplements) and UIC were assessed at study entry (<20 weeks') and at 28 weeks' gestation. Mean (±SD) total iodine intake at study entry and 28 weeks' gestation was 307 ± 128 μg/day and 300 ± 127 μg/day, respectively. Overall, 85.9% of women met the estimated average intake (≥160 μg/day) for iodine in pregnancy, but only 44.5% met the estimated average intake from food alone. The main food sources of iodine were dairy foods and iodine-fortified bread. Median (interquartile range) UIC at study entry and 28 weeks' gestation was 189 μg/L and 172 μg/L, respectively. At study entry, median UIC was higher in women taking supplements containing iodine ≥150 μg/day compared with those containing iodine <150 μg/day (221 μg/L vs. 163 μg/L, p = .003) and those not taking supplements containing iodine (221 μg/L vs. 159 μg/L, p < .001). At 28 weeks' gestation, the median UIC for the groups was 187, 152 and 141 μg/L, respectively (each of the two comparisons yielded p < .001). Total iodine intake (food and supplements) from all women was positively, though weakly, correlated with UIC (r = .23, p < .001). In conclusion, pregnant women in South Australia are iodine sufficient postmandatory iodine fortification of bread. However, without iodine supplementation, it may be difficult to achieve a UIC >150 μg/L.
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Affiliation(s)
- Dominique Condo
- Women's and Children's Health Research Institute, North Adelaide, South Australia, Australia.,Deakin University, School of Exercise and Nutrition Sciences, Geelong, Australia.,Deakin University, Institute for Physical Activity and Nutrition (I-PAN), Geelong, Australia
| | - Dao Huyhn
- FOOD plus Research Centre, School of Agriculture, Food & Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia, Australia
| | - Amanda J Anderson
- Women's and Children's Health Research Institute, North Adelaide, South Australia, Australia.,Healthy Mothers, Babies and Children, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Sheila Skeaff
- Department of Human Nutrition, University of Otago, Dunedin, New Zealand
| | - Philip Ryan
- School of Population Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Maria Makrides
- Women's and Children's Health Research Institute, North Adelaide, South Australia, Australia.,Healthy Mothers, Babies and Children, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,School of Paediatrics & Reproductive Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Beverly S Mühlhaüsler
- Women's and Children's Health Research Institute, North Adelaide, South Australia, Australia.,FOOD plus Research Centre, School of Agriculture, Food & Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia, Australia
| | - Shao J Zhou
- Women's and Children's Health Research Institute, North Adelaide, South Australia, Australia.,FOOD plus Research Centre, School of Agriculture, Food & Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia, Australia
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