Serum Thyroglobulin Concentration Is a Weak Marker of Iodine Status in a Pregnant Population with Iodine Deficiency

Background: The standard, lifelong therapy of phenylketonuria (PKU) is a natural protein-restricted diet complemented with phenylalanine (Phe)-free L-amino acid mixtures that provide the daily necessary micronutrients. Objective: To assess thyroid function and structure and the iodine status of early-treated adult PKU (ETPKU) patients in Hungary. Methods: Sixty-nine PKU patients (aged 18–41 years) and 50 healthy controls were enrolled in the study. Thyroid hormones, serum thyroglobulin, thyroid antibodies, urinary iodine, and selenium concentrations were measured, and thyroid ultrasound was performed. Results: The incidence of thyroid dysfunction was infrequent (n = 2). Blood Phe was negatively correlated with thyroid-stimulating hormone (TSH), and PKU patients had higher free thyroxine and lower TSH levels than healthy controls. Although optimal iodine status was found in the entire PKU population, by dividing the patients according to their therapy compliance, we observed that lower therapy adherence was associated with mild iodine deficiency and lower urinary selenium levels. Conclusions: The results of this study suggest that iodine status is strongly influenced by the adherence to therapy in ETPKU patients. No or not enough medical food consumption combined with a low-Phe diet can lead to subclinical iodine deficiency.

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Serum thyroglobulin concentration as an index of iodine status in adults

The FASEB Journal ◽

10.1096/fasebj.27.1_supplement.845.11 ◽

2013 ◽

Vol 27 (S1) ◽

Author(s):

Sheila A Skeaff ◽

Christine D Thomson ◽

Winsome R Parnell

Keyword(s):

Serum Thyroglobulin ◽

Iodine Status ◽

Thyroglobulin Concentration

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High prevalence of iodine deficiency in pregnant women living in adequate iodine area

Endocrine Connections ◽

10.1530/ec-18-0131 ◽

2018 ◽

Vol 7 (5) ◽

pp. 762-767 ◽

Cited By ~ 9

Author(s):

Verônica Carneiro Borges Mioto ◽

Ana Carolina de Castro Nassif Gomes Monteiro ◽

Rosalinda Yossie Asato de Camargo ◽

Andréia Rodrigues Borel ◽

Regina Maria Catarino ◽

...

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Thyroid Volume ◽

Adverse Outcomes ◽

Urinary Iodine Concentration ◽

Serum Thyroglobulin ◽

Cross Sectional ◽

Iodine Status

Objectives Iodine deficiency during pregnancy is associated with obstetric and neonatal adverse outcomes. Serum thyroglobulin (sTg) and thyroid volume (TV) are optional tools to urinary iodine concentration (UIC) for defining iodine status. This cross-sectional study aims to evaluate the iodine status of pregnant women living in iodine-adequate area by spot UIC and correlation with sTg, TV and thyroid function. Methods Two hundred and seventy-three pregnant women were evaluated at three trimesters. All had no previous thyroid disease, no iodine supplementation and negative thyroperoxidase and thyroglobulin antibodies. Thyroid function and sTg were measured using electrochemiluminescence immunoassays. TV was determined by ultrasonography; UIC was determined using a modified Sandell–Kolthoff method. Results Median UIC was 146 µg/L, being 52% iodine deficient and only 4% excessive. TSH values were 1.50 ± 0.92, 1.50 ± 0.92 and 1.91 ± 0.96 mIU/L, respectively, in each trimester (P = 0.001). sTg did not change significantly during trimesters with median 11.2 ng/mL and only 3.3% had above 40 ng/mL. Mean TV was 9.3 ± 3.4 mL, which positively correlated with body mass index, but not with sTg. Only 4.5% presented with goitre. When pregnant women were categorized as iodine deficient (UIC < 150 µg/L), adequate (≥150 and <250 µg/L) and excessive (≥250 µg/L), sTg, thyroid hormones and TV at each trimester showed no statistical differences. Conclusions Iodine deficiency was detected frequently in pregnant women living in iodine-adequate area. sTg concentration and TV did not correlate to UIC. Our observation also demonstrated that the Brazilian salt-iodization programme prevents deficiency, but does not maintain iodine status within adequate and recommended ranges for pregnant women.

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Thyroglobulin as a marker of iodine nutrition status in the general population

Acta Endocrinologica ◽

10.1530/eje-09-0262 ◽

2009 ◽

Vol 161 (3) ◽

pp. 475-481 ◽

Cited By ~ 58

Author(s):

Pernille Vejbjerg ◽

Nils Knudsen ◽

Hans Perrild ◽

Peter Laurberg ◽

Allan Carlé ◽

...

Keyword(s):

Iodine Deficiency ◽

Age Groups ◽

Urinary Iodine ◽

Thyroid Volume ◽

Nutrition Status ◽

Iodine Nutrition ◽

Serum Thyroglobulin ◽

Cross Sectional ◽

Iodine Status ◽

Reference Limit

ObjectiveThe iodine status of a population is traditionally evaluated by either urinary iodine (UI) excretion or by some measure of thyroid volume and the prevalence of goitre. In this prospective study of a mandatory iodization programme, we aimed to evaluate serum thyroglobulin (Tg) as a marker of iodine status in the population.MethodsTwo identical cross-sectional studies were performed before (1997–1998,n=4649) and after (2004–2005,n=3570) the initiation of the Danish iodization programme in two areas with mild and moderate iodine deficiency. Serum Tg was measured from blood samples. Thyroid volume was measured by ultrasonography.ResultsBefore iodization, the median serum Tg was considerably higher in moderate than in mild iodine deficiency. Iodization led to a lower serum Tg in all examined age groups. The marked pre-iodization difference in Tg level between the regions was eliminated. The prevalence of Tg above the suggested reference limit (40 μg/l) decreased from 11.3 to 3.7% (P<0.0001). Using bootstrapping, we demonstrated a higher efficacy of Tg than of thyroid volume to show a difference between pre- and post-iodization values.ConclusionWe found serum Tg to be a suitable marker of iodine nutrition status in the population. The results may suggest that the Danish iodization programme has led to a sufficient iodine intake, even if the median UI excretion is still marginally low according to WHO criteria.

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Evaluating iodine deficiency in pregnant women and young infants—complex physiology with a risk of misinterpretation

Public Health Nutrition ◽

10.1017/s1368980007360898 ◽

2007 ◽

Vol 10 (12A) ◽

pp. 1547-1552 ◽

Cited By ~ 40

Author(s):

P Laurberg ◽

S Andersen ◽

R I Bjarnadóttir ◽

A Carlé ◽

AB Hreidarsson ◽

...

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Maternal Blood ◽

Review Of The Literature ◽

Free T4 ◽

Serum Thyroglobulin ◽

Small Children ◽

Iodine Status ◽

Young Infants

AbstractObjective:To review methods for evaluating iodine deficiency in pregnant women and young infants and to discuss factors to be considered in the interpretation of their results.Design:Review of the literature regarding the various methods available for assessing iodine status.Setting:Population surveys and research studies.Subjects:Pregnant women and young infants.Results:Several factors to consider when assessing iodine status in pregnant women and young infants include: 1) the urinary iodine (UI) concentration (μg l-1) is not interchangeable with 24 h UI excretion (μg per 24 h); 2) the concentration of iodine in a spot or casual urine sample cannot be used to diagnose iodine deficiency in an individual; 3) a moderate fall in the concentration of serum free T4 during pregnancy is not a sign of maternal iodine deficiency; 4) an increase in the concentration of serum thyroglobulin (Tg) during pregnancy is not a sign of maternal iodine deficiency; 5) a higher concentration of TSH and Tg in cord blood than in maternal blood is not a sign of iodine deficiency in the mother or neonate; and 6) thyroid function in a full-term foetus, a neonate or a small child is not more sensitive to a mild iodine deficiency than in the mother.Conclusions:If the iodine status of pregnant women and small children is not to be misjudged, the above six factors need to be taken into account.

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Iodine status and its determinants in subpopulation of pregnant women in rural Central India

International Journal of Reproduction Contraception Obstetrics and Gynecology ◽

10.18203/2320-1770.ijrcog20180191 ◽

2018 ◽

Vol 7 (2) ◽

pp. 665

Author(s):

Surekha A. Tayade ◽

Shakuntala Chhabra

Keyword(s):

Family History ◽

High Risk ◽

Pregnant Women ◽

Iodine Deficiency ◽

Tertiary Care ◽

Central India ◽

Iodized Salt ◽

High Risk Population ◽

Iodine Status ◽

Rich Food

Background: There is an increased demand for iodine and thyroid hormones, in pregnancy starting from the early weeks of pregnancy suggesting that there may be a need for additional supplements of iodine in high risk population to prevent iodine deficiency and its associated disorders. Hence this study was undertaken to determine the iodine status and its determinants in a subpopulation of pregnant women from a rural area of Central India.Methods: A hospital based, cross-sectional, observational study was carried out among pregnant women seeking antenatal care at Kasturba Hospital of MGIMS, Sewagram, a rural tertiary care institute in central India. Information was collected about demographic variables, use of iodized salt, iodine rich food and goitrogens as part of diet and other determinants. Spot urine samples were obtained, and assessment of urine iodine concentration was done by using Sandell-Kolthoff reaction.Results: Among 250 pregnant women of first trimester, iodine deficiency (ID) was present in 11.8 %, of which 59.25% had mild deficiency, 33.33% moderate deficiency and 7.4% severe deficiency. More women with iodine deficiency were of higher age, had less formal education and belonged to lower middle and lower economic class. Higher number of women with iodine deficiency had family history of thyroid disorders compared to iodine sufficient (18.51% versus 5.58%), more iodine deficient commonly had goitrogens (cabbage, cauliflower, radish, sweet potato, soya etc) as part of their meals (77.77% versus 68.60%), lesser women with ID ate iodine rich food (fish, milk yoghurt, bread) (18.51% versus 68.60%) and fewer of them used iodized salt during food preparation (25.92% versus 69.95%) compared to iodine sufficient, with a significant difference.Conclusions: Iodine deficiency is prevalent in pregnant women in this geographic region of central India. Age, low socioeconomic status, lack of education, family history, low intake of iodized salt and iodine rich food and more consumption of goitrogenic food as part of diet are risk factors. Appropriate health education, promoting use of iodized salt, quality assurance of universal salt iodization by household survey and screening in high risk group is suggested.

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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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Iodine deficiency in pregnant women living in the South East of the UK: the influence of diet and nutritional supplements on iodine status

British Journal Of Nutrition ◽

10.1017/s0007114513004030 ◽

2014 ◽

Vol 111 (9) ◽

pp. 1622-1631 ◽

Cited By ~ 60

Author(s):

Sarah C. Bath ◽

Alan Walter ◽

Andrew Taylor ◽

John Wright ◽

Margaret P. Rayman

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

World Health ◽

The South ◽

Childbearing Age ◽

Iodine Status ◽

Supplement Use ◽

Iodine Excretion ◽

The Uk

Iodine is a key component of the thyroid hormones which are crucial for brain development. Adequate intake of iodine in pregnancy is important as in utero deficiency may have lifelong consequences for the offspring. Data on the iodine status of UK pregnant women are sparse, and there are no such data for pregnant women in the South East of the UK. A total of 100 pregnant women were recruited to a cross-sectional study carried out at the Royal Surrey County Hospital, Guildford, at their first-trimester visit for an ultrasound scan. The participants provided a spot-urine sample (for the measurement of urinary iodine concentration (UIC) and creatinine concentration) and 24 h iodine excretion was estimated from the urinary iodine:creatinine ratio. Women completed a general questionnaire and a FFQ. The median UIC (85·3 μg/l) indicated that the group was iodine deficient by World Health Organisation criteria. The median values of the iodine:creatinine ratio (122·9 μg/g) and of the estimated 24 h iodine excretion (151·2 μg/d) were also suggestive of iodine deficiency. UIC was significantly higher in women taking an iodine-containing prenatal supplement (n 42) than in those not taking such a supplement (P< 0·001). In the adjusted analyses, milk intake, maternal age and iodine-containing prenatal supplement use were positively associated with the estimated 24 h urinary iodine excretion. Our finding of iodine deficiency in these women gives cause for concern. We suggest that women of childbearing age and pregnant women should be given advice on how to improve their iodine status through dietary means. A national survey of iodine status in UK pregnant women is required.

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Association of Maternal Iodine Status With Child IQ: A Meta-Analysis of Individual Participant Data

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2018-02559 ◽

2019 ◽

Vol 104 (12) ◽

pp. 5957-5967 ◽

Cited By ~ 27

Author(s):

Deborah Levie ◽

Tim I M Korevaar ◽

Sarah C Bath ◽

Mario Murcia ◽

Mariana Dineva ◽

...

Keyword(s):

Iodine Deficiency ◽

Meta Analysis ◽

Urinary Iodine ◽

First Trimester ◽

Individual Participant Data ◽

Verbal Iq ◽

Iodine Status ◽

Child Neurodevelopment ◽

Individual Participant ◽

In Pregnancy

Abstract Context Although the consequences of severe iodine deficiency are beyond doubt, the effects of mild to moderate iodine deficiency in pregnancy on child neurodevelopment are less well established. Objective To study the association between maternal iodine status during pregnancy and child IQ and identify vulnerable time windows of exposure to suboptimal iodine availability. Design Meta-analysis of individual participant data from three prospective population-based birth cohorts: Generation R (Netherlands), INMA (Spain), and ALSPAC (United Kingdom); pregnant women were enrolled between 2002 and 2006, 2003 and 2008, and 1990 and 1992, respectively. Setting General community. Participants 6180 mother-child pairs with measures of urinary iodine and creatinine concentrations in pregnancy and child IQ. Exclusion criteria were multiple pregnancies, fertility treatment, medication affecting the thyroid, and preexisting thyroid disease. Main Outcome Measure Child nonverbal and verbal IQ assessed at 1.5 to 8 years of age. Results There was a positive curvilinear association of urinary iodine/creatinine ratio (UI/Creat) with mean verbal IQ only. UI/Creat <150 µg/g was not associated with lower nonverbal IQ (−0.6 point; 95% CI: −1.7 to 0.4 points; P = 0.246) or lower verbal IQ (−0.6 point; 95% CI: −1.3 to 0.1 points; P = 0.082). Stratified analyses showed that the association of UI/Creat with verbal IQ was only present up to 14 weeks of gestation. Conclusions Fetal brain development is vulnerable to mild to moderate iodine deficiency, particularly in the first trimester. Our results show that potential randomized controlled trials investigating the effect of iodine supplementation in women with mild to moderate iodine deficiency on child neurodevelopment should begin supplementation not later than the first trimester.

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Iodine deficiency in pregnant women in Sweden: a national cross-sectional study

European Journal of Nutrition ◽

10.1007/s00394-019-02102-5 ◽

2019 ◽

Vol 59 (6) ◽

pp. 2535-2545 ◽

Cited By ~ 4

Author(s):

Sofia Manousou ◽

Maria Andersson ◽

Robert Eggertsen ◽

Sandra Hunziker ◽

Lena Hulthén ◽

...

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Geometric Mean ◽

Iodized Salt ◽

National Study ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Cross Sectional ◽

Iodine Status ◽

Supplement Use

Abstract Purpose Voluntary salt iodization at 50 mg/kg salt ensures adequate iodine nutrition in Swedish school-aged children, but iodine status in pregnant women is uncertain. Methods We conducted a cross-sectional national study of 743 pregnant women, at median gestational age of 23 weeks (IQR 9, 38), recruited from maternal health care centers. We measured: urinary iodine concentration (UIC) and urinary creatinine concentration in spot urine samples; thyroglobulin (Tg), thyroid-stimulating hormone (TSH), and total thyroxine (tT4) on dried blood spots (DBS); and thyreoperoxidase antibodies in serum samples. Data on dietary supplement use were obtained, and women were classified as supplement users (consuming multivitamins containing ≥ 150 µg iodine/day) and non-supplement users (no supplements or < 150 µg iodine/day from supplements). Results Overall median UIC [bootstrapped 95% confidence interval (CI)] was 101 µg/L (95, 108; n = 737): 149 µg/L (132, 164) in supplement users (n = 253) and 85 µg/L (79, 92) in non-supplement users (n = 440) (p < 0.001). Overall geometric mean DBS-Tg (95% CI) was 22.1 μg/L (20.8, 23.5; n = 675) and the prevalence of elevated DBS-Tg was 19%. DBS-Tg was lower in supplement users (n = 229) than in non-supplement users (n = 405) (19.1 vs 24.4 μg/L, p < 0.001). DBS-TSH, DBS-tT4, and S-TPOab positivity did not differ between the two groups. Conclusions Pregnant women in Sweden have inadequate iodine nutrition. Women not taking iodine supplements containing ≥ 150 µg iodine/day are affected by mild iodine deficiency and are at higher risk for increased thyroid activity, while maintaining euthyroidism. Iodine intake should be improved in women both before and after conception by promotion of iodized salt instead of non-iodized salt. We urge regular monitoring of iodine status in the general Swedish population, as well as in risk groups.

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