High Urinary Iodine Concentration Among Breastfed Infants and the Factors Associated with Iodine Content in Breast Milk

Background: Iodine is essential for normal growth, mental development and survival of infants. Bangladesh is an iodine deficient region. Breast milk is the only source of iodine for exclusively breast-fed infants. Routine measurement of breast milk iodine concentration is very difficult in our country due to some social and religious barriers. So, we designed this study in our population using urinary iodine as the indicator for assessing iodine status. Objectives: To assess the iodine status of lactating mothers and their breast-fed infants and to propose a method on how to predict the iodine concentration in breast milk. Materials and Methods: This observational analytical study was carried out in the department of Biochemistry, Bangabandhu Sheikh Mujib Medical University, Dhaka with active cooperation of Kumudini Womens Medical College Hospital, Mirzapur, Tangail involving fifty lactating mothers and their exclusively breast-fed infants. Early morning urine and breast milk samples were collected in dry and clean plastic container free from any chemical contamination. All statistical analyses were done by using SPSS (Statistical Programme for Social Science) 12 version software package for windows. Results: The median (range) urinary iodine concentration of lactating mothers and their breast-fed infants were 225.25 ?g/L (61.50-530.00) and 225.75 ?g/L (100.50-526.50). 96% (48) mothers had no biochemical iodine deficiency (UIE ?100?g/L), only 4% (2) mothers had mild biochemical iodine deficiency (UIE 50-99?g/L). There was no biochemical deficiency of breast-fed infants. The median (range) breast-milk iodine concentration was 157 ?g/L (54.50-431.50) which was more than three times of recommended minimum concentration (50 ?g/L). Iodine in breast milk of lactating mothers positively correlated with their urinary iodine excretion (P<0.01). Infants urinary iodine positively correlated with iodine concentration in breast milk (P<0.01) and also positively correlated with urinary iodine excretion of lactating mothers. Conclusion: Lactating mothers and their breast-fed infants in this study were found iodine sufficient. Urinary iodine concentration of lactating mothers predicts the iodine content of their breast milk. DOI: http://dx.doi.org/10.3329/jemc.v1i1.11132J Enam Med Col 2011; 1(1): 15-18

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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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Factors Associated with Urinary Iodine Concentration among Women of Reproductive Age, 20–49 Years Old, in Tanzania: A Population-Based Cross-Sectional Study

Current Developments in Nutrition ◽

10.1093/cdn/nzaa079 ◽

2020 ◽

Vol 4 (5) ◽

Author(s):

Djibril M Ba ◽

Paddy Ssentongo ◽

Muzi Na ◽

Kristen H Kjerulff ◽

Guodong Liu ◽

...

Keyword(s):

Urinary Iodine ◽

Iodine Concentration ◽

Population Based ◽

Cross Sectional Study ◽

Iodized Salt ◽

Reproductive Age ◽

Urinary Iodine Concentration ◽

Women Of Reproductive Age ◽

Cross Sectional ◽

Factors Associated

ABSTRACT Background Universal salt iodization (USI) is the most feasible and cost-effective, and equitable, approach to prevent iodine deficiency. Severe maternal iodine deficiency during pregnancy is associated with serious adverse gestational and birth outcomes. Objectives The aim was to assess iodine status and identify independent factors associated with urinary iodine concentration (UIC) among women of reproductive age in Tanzania. Methods This was a weighted, population-based, cross-sectional study in 2985 women of reproductive age (20–49 y) in Tanzania who participated in the Demographic and Health Surveys in 2015–2016 (DHS 2015–2016) and had measured UIC. Multivariable generalized linear regression was used to identify potential factors that were associated with UIC. Results The median UICs among women consuming inadequately iodized salt (93.6 μg/L; 25th and 75th percentiles: 43.1, 197.9 μg/L) and women in the lowest socioeconomic status (92.3 μg/L; 45.6, 194.4 μg/L) were below the WHO-recommended ranges (≥150 μg/L for pregnant women and ≥100 μg/L for nonpregnant women). The results of multivariable models indicated that pregnant women had 1.21 μg/L lower UIC than nonpregnant women (β = −1.21; 95% CI: −3.42, −0.12), breastfeeding women had 1.02 μg/L lower UIC than nonbreastfeeding women (β = −1.02; 95% CI: −2.25, −0.27), and women with no education had a 1.88 μg/L lower UIC compared with those with secondary/highest education (β = −1.88; 95% CI: −4.58, −0.36). Women consuming inadequately iodized salt had 6.55 μg/L lower UIC than those consuming adequately iodized salt (β = −6.55; 95% CI: −9.24, −4.33). The median UIC varied substantially across geographic zones, ranging from 83.2 μg/L (45.9, 165.3) in the Western region to 347.8 μg/L (185.0, 479.8) in the Eastern region. Conclusions Our findings indicated a great heterogeneity in median UIC across regions of Tanzania among women of reproductive age. Poverty, consuming inadequately iodized salt, and lack of education appeared to be the driving factors for lower UIC in Tanzania.

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Breast Milk Iodine Concentration Is a More Accurate Biomarker of Iodine Status Than Urinary Iodine Concentration in Exclusively Breastfeeding Women

Journal of Nutrition ◽

10.3945/jn.116.242560 ◽

2017 ◽

Vol 147 (4) ◽

pp. 528-537 ◽

Cited By ~ 26

Author(s):

Susanne Dold ◽

Michael B Zimmermann ◽

Abdelmounaim Aboussad ◽

Mohamed Cherkaoui ◽

Qingzhen Jia ◽

...

Keyword(s):

Breast Milk ◽

Urinary Iodine ◽

Iodine Concentration ◽

Urinary Iodine Concentration ◽

Iodine Status ◽

Breast Milk Iodine Concentration

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Assessment of the iodine nutritional status among Chinese school-aged children

Endocrine Connections ◽

10.1530/ec-19-0568 ◽

2020 ◽

Vol 9 (5) ◽

pp. 379-386

Author(s):

Ning Yao ◽

Chunbei Zhou ◽

Jun Xie ◽

Xinshu Li ◽

Qianru Zhou ◽

...

Keyword(s):

Nutritional Status ◽

Urinary Iodine ◽

Thyroid Volume ◽

Iodine Content ◽

Iodine Concentration ◽

Iodine Intake ◽

Iodized Salt ◽

Urinary Iodine Concentration ◽

School Aged Children ◽

Goiter Prevalence

Objective The remarkable success of iodine deficiency disorders (IDD) elimination in China has been achieved through a mandatory universal salt iodization (USI) program. The study aims to estimate the relationship between urinary iodine concentration (UIC) and iodine content in edible salt to assess the current iodine nutritional status of school aged children. Methods A total of 5565 students from 26 of 39 districts/counties in Chongqing participated in the study, UIC and iodine content in table salt were measured. Thyroid volumes of 3311 students were examined by ultrasound and goiter prevalence was calculated. Results The overall median UIC of students was 222 μg/L (IQR: 150-313 μg/L). Median UIC was significantly different among groups with non-iodized salt (iodine content <5 mg/kg), inadequately iodized salt (between 5 and 21 mg/kg), adequately iodized (between 21 and 39 mg/kg) and excessively iodized (>39 mg/kg) salt (P < 0.01). The total goiter rate was 1.9% (60/3111) and 6.0% (186/3111) according to Chinese national and WHO reference values, respectively. Thyroid volume and goiter prevalence were not different within the three iodine nutritional status groups (insufficient, adequate and excessive, P > 0.05). Conclusions The efficient implementation of current USI program is able to reduce the goiter prevalence in Chongqing as a low incidence of goiter in school aged children is observed in this study. The widened UIC range of 100–299 μg/L indicating sufficient iodine intake is considered safe with a slim chance of causing goiter or thyroid dysfunction. Further researches were needed to evaluate the applicability of WHO reference in goiter diagnose in Chongqing or identifying more accurate criteria of normal thyroid volume of local students in the future.

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Iodine nutrition status in clinically euthyroid pregnant women attending in BSMMU

Bangabandhu Sheikh Mujib Medical University Journal ◽

10.3329/bsmmuj.v9i1.28942 ◽

2016 ◽

Vol 9 (1) ◽

pp. 38

Author(s):

Md. Anowar Hossain ◽

M. Abul Hasanat ◽

Murshed Ahamed Khan ◽

Jobaida Naznin ◽

Kazi Ashraful Alam ◽

...

Keyword(s):

Pregnant Women ◽

Urinary Iodine ◽

Iodine Content ◽

Iodine Concentration ◽

Nutrition Status ◽

Urinary Iodine Concentration ◽

Digestion Method ◽

Iodine Nutrition ◽

Cross Sectional ◽

Nutritional Problem

Background: Iodine deficiency disorders (IDD) are common nutritional problem globally. All groups of people are affected by it, but the pregnant women and their neonates are most vulnerable.Objectives: This study was carried out to see the iodine status of pregnant women using median urinary iodine concentration (MUI) as a measure of outcome. Methods: This cross sectional observational study assessed the MUI in casual urine samples from 225 pregnant women (75 pregnants from each trimester) and 75 non-pregnant healthy controls. The urinary iodine content was estimated in urine sample using the method of Dunn et al. with the modification of Sandell & Kolthoff (wet digestion method).Results: Median value of urinary iodine in pregnant women was 48.21Ug/L compared to 52.27

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Iodine Status and Thyroid Function in a Group of Seaweed Consumers in Norway

Nutrients ◽

10.3390/nu12113483 ◽

2020 ◽

Vol 12 (11) ◽

pp. 3483

Author(s):

Inger Aakre ◽

Lidunn Tveito Evensen ◽

Marian Kjellevold ◽

Lisbeth Dahl ◽

Sigrun Henjum ◽

...

Keyword(s):

Thyroid Function ◽

Urinary Iodine ◽

Iodine Content ◽

Iodine Concentration ◽

Iodine Intake ◽

Thyroid Stimulating Hormone ◽

Urinary Iodine Concentration ◽

Free Triiodothyronine ◽

Iodine Status ◽

Excessive Iodine

Seaweeds, or macroalgae, may be a good dietary iodine source but also a source of excessive iodine intake. The main aim in this study was to describe the iodine status and thyroid function in a group of macroalgae consumers. Two urine samples were collected from each participant (n = 44) to measure urinary iodine concentration (UIC) after habitual consumption of seaweed. Serum thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), and peroxidase autoantibody (TPOAb), were measured in a subgroup (n = 19). A food frequency questionnaire and an iodine-specific 24 h recall were used to assess iodine intake and macroalgae consumption. The median (p25–p75) UIC was 1200 (370–2850) μg/L. Median (p25–p75) estimated dietary iodine intake, excluding macroalgae, was 110 (78–680) μg/day, indicating that seaweed was the major contributor to the iodine intake. TSH levels were within the reference values, but higher than in other comparable population groups. One third of the participants used seaweeds daily, and sugar kelp, winged kelp, dulse and laver were the most common species. Labelling of iodine content was lacking for a large share of the products consumed. This study found excessive iodine status in macroalgae consumers after intake of dietary seaweeds. Including macroalgae in the diet may give excessive iodine exposure, and consumers should be made aware of the risk associated with inclusion of macroalgae in their diet.

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Iodine status of postpartum women and their infants aged 3, 6 and 12 months – Mother and Infant Nutrition Investigation (MINI)

British Journal Of Nutrition ◽

10.1017/s000711452100129x ◽

2021 ◽

pp. 1-24

Author(s):

Ying Jin ◽

Jane Coad ◽

Sheila Skeaff ◽

Shao J Zhou ◽

Louise Brough

Keyword(s):

Exclusive Breastfeeding ◽

Infant Nutrition ◽

Urinary Iodine ◽

Iodine Concentration ◽

Protective Mechanism ◽

Postpartum Women ◽

Urinary Iodine Concentration ◽

Iodine Status ◽

Breastfed Infants ◽

Iodine Excretion

Abstract To alleviate the re-emergence of iodine deficiency in New Zealand, two strategies, the mandatory fortification of bread with iodised salt (2009) and a government-subsidised iodine supplement for breastfeeding women (2010) were introduced. Few studies have investigated mother and infant iodine status during the first postpartum year, this study aimed to describe iodine status of mothers and infants at three, six, twelve months postpartum (3MPP,6MPP,12MPP). Partitioning of iodine excretion between urine and breastmilk of exclusive breastfeeding women at 3MPP was determined. In total 87 mother-infant pairs participated in the study. Maternal and infant spot urinary iodine concentration (UIC) and breastmilk iodine concentration (BMIC) were determined. The percentage of women who took iodine-containing supplements decreased from 46% at 3MPP to 6% at 12MPP. Maternal median UIC (MUIC) at 3MPP [82(46,157)µg/L], 6MPP [85(43,134)µg/L] and 12MPP [95(51,169)µg/L] < 100µg/L. The use of iodine-containing supplements increased MUIC and BMIC only at 3MPP. Median BMIC at all time points were below 75µg/L. Infant MUIC at 3MPP [115(69,182)µg/L] and 6MPP [120(60,196)µg/L] were below 125µg/L. Among exclusive breastfeeding women at 3MPP, an increased partitioning of iodine into breastmilk (highest proportion 60%) was shown at lower iodine intakes, along with a reduced fractional iodine excretion in urine (lowest proportion 40%), indicating a protective mechanism for breastfed infants’ iodine status. In conclusion, this cohort of postpartum women was iodine deficient. Iodine status of their breastfed infants were suboptimal. Lactating women who do not consume iodine rich foods and those who become pregnant again should take iodine-containing supplements.

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Characterization of Genetic Variants in the SLC5A5 Gene and Associations With Breast Milk Iodine Concentration in Lactating Women of African Descent: The NUPED Study

Frontiers in Nutrition ◽

10.3389/fnut.2021.692504 ◽

2021 ◽

Vol 8 ◽

Author(s):

Sicelosethu S. Siro ◽

Jeannine Baumgartner ◽

Maryke Schoonen ◽

Jennifer Ngounda ◽

Linda Malan ◽

...

Keyword(s):

Breast Milk ◽

Pregnant Women ◽

Genetic Variants ◽

African Descent ◽

Urinary Iodine ◽

Iodine Concentration ◽

Urinary Iodine Concentration ◽

Lactating Women ◽

Significant Difference ◽

Women Of African Descent

Background: The sodium iodide symporter is responsible for the transfer of iodine into breast milk and is encoded for by the SLC5A5 gene. The role of genetic variants in the SLC5A5 gene locus in relation to the transfer of iodine from plasma into breast milk in healthy lactating individuals has, to our knowledge, not been explored.Objective: To identify and characterize possible genetic variants of the SLC5A5 gene in women of African descent living in urban South Africa, and to study associations with breast milk iodine concentrations (BMIC) in lactating women.Methods: This study is affiliated to the Nutrition during Pregnancy and Early Development (NuPED) cohort study (n = 250 enrolled pregnant women). In a randomly selected sub-sample of 32 women, the SLC5A5 gene was sequenced to identify known and novel variants. Of the identified variants, genotyping of selected variants was performed in all pregnant women who gave consent for genetic analyses (n = 246), to determine the frequency of the variants in the study sample. Urinary iodine concentration (UIC) in spot urine samples and BMIC were measured to determine iodine status. Associations of SLC5A5 genetic variants with BMIC were studied in lactating women (n = 55).Results: We identified 27 variants from sequencing of gene exomes and 10 variants were selected for further study. There was a significant difference in BMIC between the genotypes of the rs775249401 variant (P = 0.042), with the homozygous GG group having lower BMIC [86.8 (54.9–167.9) μg/L] compared to the (A) allele carriers rs775249401(AG+AA) [143.9 (122.4–169.3) μg/L] (P = 0.042). Of the rs775249401(GG), 49% had UIC <100 μg/L and 61% had BMIC <100 μg/L. On the other hand, 60% of the rs775249401(AG+AA) carriers had UIC <100 μg/L, and none had a BMIC <100 μg/L.Conclusion: Our results suggest that A-allele carriers of rs775249401(AG+AA) are likely to have higher iodine transfer into breast milk compared to the homozygous GG counterparts. Thus, genetic variations in the SLC5A5 gene may play an important role in the transfer of iodine from plasma into breast milk and may partially explain inter-individual variability in BMIC.

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Iodine nutrition in elementary state schools of Queretaro, Mexico: correlations between urinary iodine concentration with global nutrition status and social gap index

Arquivos Brasileiros de Endocrinologia & Metabologia ◽

10.1590/s0004-27302013000600010 ◽

2013 ◽

Vol 57 (6) ◽

pp. 473-482 ◽

Cited By ~ 9

Author(s):

Pablo García-Solís ◽

Juan Carlos Solís-S ◽

Ana Cristina García-Gaytán ◽

Vanessa A. Reyes-Mendoza ◽

Ludivina Robles-Osorio ◽

...

Keyword(s):

Urinary Iodine ◽

Iodine Content ◽

Iodine Concentration ◽

Iodine Intake ◽

Overweight And Obesity ◽

Nutrition Status ◽

Urinary Iodine Concentration ◽

Elementary State ◽

State Schools ◽

Global Nutrition

OBJECTIVE AND METHODS: To estimate median urinary iodine concentration (UIC), and to correlate it with global nutrition indicators and social gap index (SGI) in 50 elementary state schools from 10 municipalities in the State of Queretaro, Mexico. RESULTS: 1,544 students were enrolled and an above of requirements of iodine intake was found (median UIC of 297 µg/L). Iodine status was found as deficient, adequate, more than adequate and excessive in 2, 4, 19 and 25 schools, respectively. Seventy seven percent of table salt samples showed adequate iodine content (20-40 ppm), while 9.6% of the samples had low iodine content (< 15 ppm). Medians of UIC per school were positively correlated with medians of body mass index (BMI) by using the standard deviation score (SDS) (r = 0.47; p < 0.005), height SDS (r = 0.41; p < 0.05), and overweight and obesity prevalence (r = 0.41; p < 0.05). Medians of UIC per school were negatively correlated with stunting prevalence (r = -0.39; p = 005) and social gap index (r = -0.36; p < 0.05). Best multiple regression models showed that BMI SDS and height were significantly related with UIC (p < 0.05). CONCLUSIONS: There is coexistence between the two extremes of iodine intake (insufficient and excessive). To our knowledge, the observed positive correlation between UIC and overweight and obesity has not been described before, and could be explained by the availability and consumption of snack food rich in energy and iodized salt.

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