Mild to Moderate Iodine Deficiency and Inadequate Iodine Intake in Lactating Women in the Inland Area of Norway

Breastfed infants are dependent on an adequate supply of iodine in human milk for the production of thyroid hormones, necessary for development of the brain. Despite the importance of iodine for infant health, data on Norwegian lactating women are scarce. We measured iodine intake and evaluated iodine status and iodine knowledge among lactating women. From October to December 2018, 133 mother–infant pairs were recruited in a cross-sectional study through two public health care centers in Lillehammer and Gjøvik. Each of the women provided two human milk specimens, which were pooled, and one urine sample for analysis of iodine concentration. We used 24-h dietary recall and food frequency questionnaire (FFQ) to estimate short-term and habitual iodine intake from food and supplements. The median (P25, P75) human milk iodine concentration (HMIC) was 71 (45, 127) µg/L—of which, 66% had HMIC <100 µg/L. The median (P25, P75) urinary iodine concentration (UIC) was 80 µg/L (52, 141). The mean (± SD) 24-h iodine intake and habitual intake was 78 ± 79 µg/day and 75 ± 73 µg/day, respectively. In conclusion, this study confirms inadequate iodine intake and insufficient iodine status among lactating women in the inland area of Norway and medium knowledge awareness about iodine.

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Urinary iodine concentration: a biochemical parameter for assessing the iodine status

Mediscope ◽

10.3329/mediscope.v5i2.37146 ◽

2018 ◽

Vol 5 (2) ◽

pp. 30-35

Author(s):

GM Molla

Keyword(s):

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

Urinary Iodine Concentration ◽

Lactating Women ◽

Iodine Status ◽

Excessive Iodine ◽

Pregnancy And Lactation ◽

Neonates And Infants

Iodine is a micronutrient, which is essential for the synthesis of thyroid hormones. Thyroid hormones play a major role in the development of different functional components in different stages of life. The relationship between iodine intake level of a population and occurrences of thyroid disorders U-shaped with an increase from both low and high iodine intake. Iodine deficiency disorders (IDDs) are a major health problem worldwide in all age groups, but infants, school children, and pregnant and lactating women are vulnerable. During pregnancy and lactation, the fetus and infants are sensitive to maternal iodine intake. Even mild iodine deficiency may lead to irreversible brain damage during this period. A main cause of IDDs of neonates and infants is maternal iodine deficiency. Universal salt iodization strategy has been initiated by the World Health Organization and United Nation International Children Emergency Fund by the year 1993 for correction and prevention of iodine deficiency. Excessive iodine causes hypothyroidism, iodine-induced hyperthyroidism and autoimmune thyroid diseases. Iodine deficiency and excessive iodine, both cause goiter. There are many indicators for assessing the IDDs, such as measurement of thyroid size by palpation or ultrasonography, serum thyroid stimulating hormone, and thyroglobulin but these are less sensitive, costly and sometimes interpretation is difficult. Urinary iodine concentration (UIC) is a well-accepted, cost-efficient, and easily obtainable indicator of iodine status. Since the majority of iodine absorbed by the body is excreted in the urine, it is considered a sensitive marker of current iodine intake and can reflect recent changes in iodine status. Iodine requirements are greatly increased during pregnancy and lactation, owing to metabolic changes. During intrauterine life, maternal iodine is the only source of iodine for a fetus. UIC determines the iodine status of pregnant and lactating women. Breast milk is the only source of iodine for exclusively breastfed neonates and infants. Breast milk iodine concentration can be determined by UIC. UIC predicts the adverse health consequences of excessive iodine intake such as goiter, hypothyroidism, and hyperthyroidism. This review presents that iodine status in different groups of a population can be determined by UIC which will be helpful in assessing the iodine status in a community, finding out the cause of thyroid disorders, to predict the risk of adverse health effects of iodine deficiency and excessive iodine, and in making plan for iodine supplementation.Mediscope Vol. 5, No. 2: Jul 2018, Page 30-35

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Current iodine status in Japan: A cross-sectional nationwide survey of schoolchildren, 2014–2019

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/clinem/dgab919 ◽

2021 ◽

Author(s):

Yozen Fuse ◽

Yoshiya Ito ◽

Yoshimasa Shishiba ◽

Minoru Irie

Keyword(s):

Urinary Iodine ◽

Nationwide Survey ◽

Iodine Concentration ◽

Iodine Intake ◽

Urinary Iodine Excretion ◽

Urinary Iodine Concentration ◽

Cross Sectional ◽

Iodine Status ◽

Iodine Excretion ◽

Cr Concentration

Abstract Context Japan has been regarded as a long-standing iodine sufficient country without iodine fortification; however, data on nationwide iodine status is lacking. Objective This study aimed to characterize the iodine status in Japan. Methods From 2014 through 2019 a nationwide school-based survey was conducted across all districts in Japan. Urinary iodine concentration (UIC), creatinine (Cr) concentration and anthropometry were assessed in healthy school-aged children (SAC) aged 6 to 12 years. Their iodine status is regarded as generally representative of the nation's iodine status. Results A total of 32,025 children participated. The overall median UIC was 269 μg/L which was within the WHO’s adequacy range. There was a regional difference in UIC values within 14 regions, and the lowest and highest median UIC were found in Tanegashima Island (209 μg/L) and Nakashibetsu, Hokkaido (1,071 μg/L), respectively. The median UIC ≥ 300 μg/L was observed in 12 out of 46 regions. By using estimated 24-h urinary iodine excretion (UIE), the prevalence of SAC exceeding the upper tolerable limit of iodine for Japanese children was from 5.2 to 13.7%. The UIC values did not change with age, BSA and BMI percentile, while the Cr concentration simultaneously increased suggesting the effect of urinary creatinine on UI/Cr and estimated 24-h UIE values. Conclusions The iodine intake of Japanese people is adequate, but in some areas it is excessive. The incidence and prevalence of thyroid disorders associated with iodine intake should be obtained especially in the areas where high amounts of iodine are consumed.

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The impact of iodised salt or iodine supplements on iodine status during pregnancy, lactation and infancy

Public Health Nutrition ◽

10.1017/s1368980007360965 ◽

2007 ◽

Vol 10 (12A) ◽

pp. 1584-1595 ◽

Cited By ~ 50

Author(s):

Michael B Zimmermann

Keyword(s):

Pregnant Women ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

Urinary Iodine Concentration ◽

Life Stages ◽

Lactating Women ◽

Iodine Status ◽

Iodised Salt ◽

The Impact

AbstractObjectives:Monitoring of iodine status during pregnancy, lactation and infancy is difficult as there are no established reference criteria for urinary iodine concentration (UI) for these groups; so it is uncertain whether iodized salt programs meet the needs of these life stages.Design and Subjects:The method used in this paper was: 1) to estimate the median UI concentration that reflects adequate iodine intake during these life stages; and 2) to use these estimates in a review of the literature to assess whether salt iodisation can control iodine deficiency in pregnant and lactating women, and their infants.Results:For pregnancy, recommended mean daily iodine intakes of 220-250 μg were estimated to correspond to a median UI concentration of about 150 μg l− 1, and larger surveys from the iodine sufficient countries have reported a median UI in pregnant women ≥ 140 μg l− 1. Iodine supplementation in pregnant women who are mild-to-moderately iodine deficient is beneficial, but there is no clear affect on maternal or newborn thyroid hormone levels. In countries where the iodine intake is sufficient, most mothers have median breast milk iodine concentration (BMIC) greater than the concentration (100-120 μg l− 1) required to meet an infant's needs. The median UI concentration during infancy that indicates optimal iodine nutrition is estimated to be ≥ 100 μg l− 1. In iodine-sufficient countries, the median UI concentration in infants ranges from 90-170 μg l− 1, suggesting adequate iodine intake in infancy.Conclusions:These findings suggest pregnant and lactating women and their infants in countries with successful sustained iodised salt programs have adequate iodine status.

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Urinary Iodine Concentration as an Indicator of Iodine Status and its Correlation with the Thyroid Hormones and Hemoglobin Levels in First Trimester Pregnant Women - An Exploratory Study

Current Research in Nutrition and Food Science Journal ◽

10.12944/crnfsj.9.3.07 ◽

2021 ◽

Vol 9 (3) ◽

pp. 791-799

Author(s):

Syeda Farha S ◽

Asna Urooj

Keyword(s):

Pregnant Women ◽

Iron Status ◽

Urinary Iodine ◽

Iodine Concentration ◽

First Trimester ◽

Iodine Intake ◽

Urinary Iodine Concentration ◽

Cross Sectional ◽

Iodine Status ◽

The Impact

During pregnancy, the daily requirement of iodine increases making those most at-risk population for iodine deficiency disorders. The available confined data shows that pregnant women are iodine deficient even in iodine sufficient regions with this background the objectives of the current study were to assess the urinary iodine concentration (UIC) and evaluate the relationship between the levels of hemoglobin, UIC, and thyroid status in first-trimester pregnant women. A cross-sectional hospital-based study with a total sample size of n=110 pregnant women at the13th week of gestation in the Mysuru district was selected. The UIC, anthropometric measurements, iodine intake, and selected biochemical parameters (TSH, FT3, FT4, and Hb) were assessed. The data was analysed using SPSS (v 16.0). Spearman’s rank correlation test was used to analyse correlations. The Mann- Whitney U test was used to compare differences between groups. ANOVA was used to study the comparison of pregnancy complications with UIC and hemoglobin. The median UIC (mUIC) was 194.2 µg/L and Hb was 10.5 g/dL. Even though the mUIC was normal, around 38.2% had insufficient UIC. Significant inverse relationship between UIC and TSH (r = -0.487, p<0.001), Hb and TSH (r = -0.355, p < 0.001), and between TSH and iodine intake (r=-0.476, p<0.001) were observed. It was interesting to observe that those with insufficient UIC were found to have mild anaemia and low FT4 levels and those with excess UIC had lower TSH levels. The pregnant women in the present study were found to have the normal median urinary iodine concentration and were mildly anaemic. Increased attention among pregnant women should be focused on iodine status along with iron status and thyroid functions. Larger comparative studies need to be performed to study the impact of altered iodine status on neonatal outcomes.

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Adequate Urinary Iodine Concentration among Infants in the Inland Area of Norway

Nutrients ◽

10.3390/nu13061826 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1826

Author(s):

Kjersti Sletten Bakken ◽

Tonje Eiane Aarsland ◽

Synne Groufh-Jacobsen ◽

Beate Stokke Solvik ◽

Elin Lovise Folven Gjengedal ◽

...

Keyword(s):

Breast Milk ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

World Health ◽

Public Healthcare ◽

Urinary Iodine Concentration ◽

Cross Sectional ◽

Iodine Status ◽

Breastfed Infants

Considering the importance of iodine to support optimal growth and neurological development of the brain and central nervous system, this study aimed to assess and evaluate iodine status in Norwegian infants. We collected data on dietary intake of iodine, iodine knowledge in mothers, and assessed iodine concentration in mother’s breast milk and in infant’s urine in a cross-sectional study at two public healthcare clinics in the inland area of Norway. In the 130 mother–infant pairs, the estimated infant 24-h median iodine intake was 50 (IQR 31, 78) µg/day. The median infant urinary iodine concentration (UIC) was 146 (IQR 93, 250) µg/L and within the recommended median defined by the World Health Organization for this age group. Weaned infants had a higher UIC [210 (IQR 130, 330) µg/L] than exclusively breastfed infants [130 (IQR 78, 210) µg/L] and partially breastfed infants [135 (IQR 89, 250) µg/L], which suggest that the dietary data obtained in this study did not capture the accurate iodine intake of the included infants. The iodine status of infants in the inland area of Norway seemed adequate. Weaned infants had higher UIC compared to breastfed infants, suggesting early access and consumption of other sources of iodine in addition to breast milk.

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Iodine nutrition of pregnant and lactating women in Hong Kong, where intake is of borderline sufficiency

Public Health Nutrition ◽

10.1017/s1368980007360989 ◽

2007 ◽

Vol 10 (12A) ◽

pp. 1600-1601 ◽

Cited By ~ 9

Author(s):

Annie WC Kung

Keyword(s):

Hong Kong ◽

Breast Milk ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

Normal Serum ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Cross Sectional ◽

Lactating Women

AbstractObjective: To describe the iodine nutrition of pregnant and lactating women in Hong Kong, where intake is of borderline sufficiency.Design: Review of cross-sectional and prospective studies.Setting: China, Hong Kong Special Administrative Region (SAR).Subjects: Pregnant and lactating women.Results: Studies of pregnant women in Hong Kong SAR have revealed an increase in the urinary iodine (UI) concentration as pregnancy advances. A significant percentage of women had a sub-normal serum thyroid hormone concentration at full term. Although iodine is concentrated by the mammary gland, 19% of all mothers had low iodine concentrations in their breast milk. The moderate correlation between the concentrations of iodine in breast milk and urine suggests that an adequate maternal urinary iodine concentration cannot reliably indicate that an infant is getting enough iodine in breast milk. Therefore, some breast-fed infants may still be at risk of low iodine intake, and additional iodine supplements, other than salt iodisation, would be warranted in this population.Conclusions: The currently recommended intake of iodine through universal salt iodisation may not be adequate for pregnant and lactating women, and supplementation during pregnancy and lactation should be further considered in light of the latest recommendations.

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The Reliability of Iodine Concentration in Diaper-Retrieved Infant Urine Using Urine Collection Pads, and in Their Mothers’ Breastmilk

Biomolecules ◽

10.3390/biom10020295 ◽

2020 ◽

Vol 10 (2) ◽

pp. 295

Author(s):

Kjersti Sletten Bakken ◽

Ingvild Oma ◽

Synne Groufh-Jacobsen ◽

Beate Stokke Solvik ◽

Lise Mette Mosand ◽

...

Keyword(s):

Intraclass Correlation ◽

Urinary Iodine ◽

Correlation Coefficients ◽

Iodine Concentration ◽

Cross Sectional Study ◽

Iodine Intake ◽

Public Healthcare ◽

Urinary Iodine Concentration ◽

Childbearing Age ◽

Cross Sectional

Mild to moderate iodine deficiency is common among women of childbearing age. Data on iodine status in infants are sparse, partly due to the challenges in collecting urine. Urinary iodine concentration (UIC) is considered a good marker for recent dietary iodine intake and status in populations. The aim of this study was to investigate the reliability of iodine concentration measured in two spot-samples from the same day of diaper-retrieved infant urine and in their mothers’ breastmilk. We collected urine and breastmilk from a sample of 27 infants and 25 mothers participating in a cross-sectional study at two public healthcare clinics in Norway. The reliability of iodine concentration was assessed by calculating the intraclass correlation coefficients (ICC) and the coefficient of variation (CV). The ICC for infants’ urine was 0.64 (95% confidence interval (CI) 0.36–0.82), while the ICC for breastmilk was 0.83 (95% CI 0.65–0.92) Similarly, the intraindividual CV for UIC was 0.25 and 0.14 for breastmilk iodine concentration (BIC). Compared to standard methods of collecting urine for measuring iodine concentration, the diaper-pad collection method does not substantially affect the reliability of the measurements.

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Iodine status of consumers of milk-alternative drinks v. cows’ milk: data from the UK National Diet and Nutrition Survey

British Journal Of Nutrition ◽

10.1017/s0007114520003876 ◽

2020 ◽

pp. 1-9

Author(s):

M. Dineva ◽

M. P. Rayman ◽

S. C. Bath

Keyword(s):

At Risk ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

Urinary Iodine Concentration ◽

Nutrition Survey ◽

Iodine Status ◽

Adults And Children ◽

The Uk

Abstract Milk is the main source of iodine in the UK; however, the consumption and popularity of plant-based milk-alternative drinks are increasing. Consumers may be at risk of iodine deficiency as, unless fortified, milk alternatives have a low iodine concentration. We therefore aimed to compare the iodine intake and status of milk-alternative consumers with that of cows’ milk consumers. We used data from the UK National Diet and Nutrition Survey from years 7 to 9 (2014–2017; before a few manufacturers fortified their milk-alternative drinks with iodine). Data from 4-d food diaries were used to identify consumers of milk-alternative drinks and cows’ milk, along with the estimation of their iodine intake (µg/d) (available for n 3976 adults and children ≥1·5 years). Iodine status was based on urinary iodine concentration (UIC, µg/l) from spot-urine samples (available for n 2845 adults and children ≥4 years). Milk-alternative drinks were consumed by 4·6 % (n 185; n 88 consumed these drinks exclusively). Iodine intake was significantly lower in exclusive consumers of milk alternatives than cows’ milk consumers (94 v. 129 µg/d; P < 0·001). Exclusive consumers of milk alternatives also had a lower median UIC than cows’ milk consumers (79 v. 132 µg/l; P < 0·001) and were classified as iodine deficient by the WHO criterion (median UIC < 100 µg/l), whereas cows’ milk consumers were iodine sufficient. These data show that consumers of unfortified milk-alternative drinks are at risk of iodine deficiency. As a greater number of people consume milk-alternative drinks, it is important that these products are fortified appropriately to provide a similar iodine content to that of cows’ milk.

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Changing Dietary Habits in Veneto Region over Two Decades: Still a Long Road to Go to Reach an Iodine-Sufficient Status

Nutrients ◽

10.3390/nu12082399 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2399 ◽

Cited By ~ 1

Author(s):

Simona Censi ◽

Jacopo Manso ◽

Susi Barollo ◽

Alberto Mondin ◽

Loris Bertazza ◽

...

Keyword(s):

Dietary Habits ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

Iodized Salt ◽

Urinary Iodine Concentration ◽

Milk Product ◽

Veneto Region ◽

School Students ◽

Iodine Status

Background: Fifteen years after a nationwide voluntary iodine prophylaxis program was introduced, the aims of the present study were: (a) to obtain an up-to-date assessment of dietary iodine intake in the Veneto region, Italy; and (b) to assess dietary and socioeconomic factors that might influence iodine status. Methods: Urinary iodine concentration (UIC) was obtained in 747 school students (median age 13 years; range: 11–16 years). Results: The median UIC was 111 μg/L, with 56% of samples ≥ 100 μg/L, but 26% were < 50 μg/L, more frequently females. Iodized salt was used by 82% of the students. The median UIC was higher among users of iodized salt than among non-users, 117.0 ug/L versus 90 ug/L (p = 0.01). The median UIC was higher in regular consumers of cow’s milk than in occasional consumers, 132.0 μg/L versus 96.0 μg/L (p < 0.01). A regular intake of milk and/or the use of iodized salt sufficed to reach an adequate median UIC, although satisfying only with the combined use. A trend towards higher UIC values emerged in regular consumers of cheese and yogurt. Conclusion: Iodine status has improved (median UIC 111.0 μg/L), but it is still not adequate as 26% had a UIC < 50 μg/L in the resident population of the Veneto region. A more widespread use of iodized salt but also milk and milk product consumption may have been one of the key factors in achieving this partial improvement.

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Dried Blood Spot Thyroglobulin as a Biomarker of Iodine Status in Pregnant Women

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2016-2829 ◽

2016 ◽

Vol 102 (1) ◽

pp. 23-32 ◽

Cited By ~ 30

Author(s):

Sara Stinca ◽

Maria Andersson ◽

Sandra Weibel ◽

Isabelle Herter-Aeberli ◽

Ralph Fingerhut ◽

...

Keyword(s):

Pregnant Women ◽

Reference Range ◽

Urinary Iodine ◽

Iodine Intake ◽

Dried Blood Spot ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Cross Sectional ◽

Iodine Status ◽

Blood Spot

Abstract Context: Thyroglobulin (Tg) could be a sensitive biomarker of iodine nutrition in pregnant women (PW). A dried blood spot (DBS) assay would simplify collection and transport in field studies. Objectives: Our aims were to (1) establish and test a reference range for DBS-Tg in PW; (2) determine whether co-measurement of Tg antibodies (Abs) is necessary to define population iodine status. Design, Setting, and Participants: Standardized cross-sectional studies of 3870 PW from 11 countries. For the DBS-Tg reference range, we included TgAb-negative PW (n = 599) from 3 countries with sufficient iodine intake. Main Outcome Measures: We measured the urinary iodine concentration and DBS thyroid-stimulating hormone, total thyroxin, Tg, and TgAb. Results: In the reference population, the median DBS-Tg was 9.2 μg/L (95% confidence interval, 8.7 to 9.8 μg/L) and was not significantly different among trimesters. The reference range was 0.3 to 43.5 μg/L. Over a range of iodine intake, the Tg concentrations were U-shaped. Within countries, the median DBS-Tg and the presence of elevated DBS-Tg did not differ significantly between all PW and PW who were TgAb-negative. Conclusions: A median DBS-Tg of ∼10 μg/L with <3% of values ≥44 μg/L indicated population iodine sufficiency. Concurrent measurement of TgAb did not appear necessary to assess the population iodine status.

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