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

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.

Download Full-text

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.

Download Full-text

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.

Download Full-text

The Association of Therapy Adherence and Thyroid Function in Adult Patients with Phenylketonuria

Annals of Nutrition and Metabolism ◽

10.1159/000501301 ◽

2019 ◽

Vol 75 (1) ◽

pp. 16-23 ◽

Cited By ~ 1

Author(s):

Csaba Sumanszki ◽

Erika Kiss ◽

Erika Simon ◽

Erika Galgoczi ◽

Aron Soos ◽

...

Keyword(s):

Thyroid Function ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Thyroid Stimulating Hormone ◽

Healthy Controls ◽

Serum Thyroglobulin ◽

Therapy Adherence ◽

Iodine Status ◽

Amino Acid Mixtures ◽

Therapy Compliance

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.

Download Full-text

Indicators of Iodine Status in Pregnancy and Postpartum in a Group of Pregnant Women from Perimarine Area of Romania

ARS Medica Tomitana ◽

10.2478/arsm-2020-0013 ◽

2020 ◽

Vol 26 (2) ◽

pp. 63-69

Author(s):

Scrinic Olesea ◽

Delia Corina Elena ◽

Toma Geanina Mirela ◽

Circo Eduard

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodine Intake ◽

Iodized Salt ◽

Urinary Iodine Concentration ◽

Urinary Creatinine ◽

Iodine Status ◽

In Pregnancy

Abstract Objective: Assessment of iodine nutritional status in pregnant women in the perimarine area of Romania, a region without iodine deficiency. Adequate iodine intake is the main source for normal thyroid function, ensuring the need for maternal thyroid hormones during pregnancy, but also for the development and growth of children in the fetal and postpartum period. Material and method: Prospective study performed on 74 pregnant women in the first 2 trimesters of pregnancy, originating from the perimarin area. The following indicators of iodine status were analyzed: urinary iodine concentration (UIC), the ratio between urinary iodine concentration and urinary creatinine (UIC/UCr), the prevalence of maternal goiter and the value of neonatal TSH (thyroid stimulating hormone). Results: The mean gestational age was 11 weeks. The ways of iodine intake are: iodized salt - 59.4%, iodized salt and iodine supplements- 23%, only iodine supplements -10.8% and 6.8% consume only non-iodized salt. The median of UIC was 133.03 mcg/l considered insufficient iodine intake (normal in pregnancy UIC >150 mcg/l), but the adjustment of UIC to urinary creatinine reveals a median of 152.83 mcg/g, a value that reflects an adequate iodine intake. The prevalence of goiter was 25.6% characteristic for a moderate iodine deficiency. The prevalence of neonatal TSH >5 mIU/L was registered in 18.8% characteristic of mild iodine deficiency. Conclusions: Monitoring of the iodine nutritional status is recommended for the prevention of disorders due to iodine deficiency under the conditions of universal salt iodization. Perimarine areas considered sufficient in iodine may show variations in iodine status in subpopulations under certain physiological conditions, such as pregnancy. An indicator of iodine status of the population is UIC, but the UIC/UCr ratio may be a more optimal indicator for pregnant women, to avoid possible overestimated results of iodine deficiency in pregnancy.

Download Full-text

Iodine deficiency among Belgian pregnant women not fully corrected by iodine-containing multivitamins: a national cross-sectional survey

British Journal Of Nutrition ◽

10.1017/s0007114512004473 ◽

2012 ◽

Vol 109 (12) ◽

pp. 2276-2284 ◽

Cited By ~ 32

Author(s):

Stefanie Vandevijvere ◽

Sihame Amsalkhir ◽

Ahmed Bensouda Mourri ◽

Herman Van Oyen ◽

Rodrigo Moreno-Reyes

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Intake ◽

Urinary Iodine Concentration ◽

Childbearing Age ◽

Third Trimester ◽

Cross Sectional Survey ◽

Cross Sectional ◽

Iodine Status

Low iodine intake during pregnancy may cause thyroid dysfunction in pregnant women and their newborn. In the present study, iodine status among a nation-wide representative sample of Belgian pregnant women in the first and third trimester of pregnancy was determined, and determinants of iodine status were assessed 1 year after the introduction of bread fortified with iodised salt. The women were selected according to a multistage proportionate-to-size sampling design. Urine samples were collected and a general questionnaire was completed face to face with the study nurse. The median urinary iodine concentration (UIC) among pregnant women (n1311) was 124·1 μg/l and 122·6 μg/g creatinine when corrected for urinary creatinine. The median UIC in the first trimester (118·3 μg/l) was significantly lower than that in the third trimester (131·0 μg/l) but significantly higher than among non-pregnant women (84·8 μg/l). Iodine-containing supplement intake was reported by 60·8 % of the women and 57·4 % of the women took this supplement daily. The risk of iodine deficiency was significantly higher in younger women, in women not taking iodine-containing supplements, with low consumption of milk and dairy drinks and during autumn. Women with a higher BMI had a higher risk of iodine deficiency but the risk was lower in women who reported alcohol consumption. The median UIC during pregnancy indicates iodine deficiency in Belgium and some women are at a higher risk of deficiency. The current low iodine intake in women of childbearing age precludes the correction of iodine deficiency in pregnant women supplemented with multivitamins containing 150 μg iodine as recommended.

Download Full-text

A cross-sectional study on iodine status among pregnant and non-pregnant women of Tripura: a North-Eastern state of India

International Journal of Research in Medical Sciences ◽

10.18203/2320-6012.ijrms20190359 ◽

2019 ◽

Vol 7 (2) ◽

pp. 486

Author(s):

Nilratan Majumder ◽

Balaram Sutradhar ◽

Saradindu Riang ◽

Shib Sekhar Datta

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Cross Sectional Study ◽

Iodine Intake ◽

Urinary Iodine Excretion ◽

Metabolic Demand ◽

Cross Sectional ◽

Iodine Status ◽

Iodine Excretion

Background: Due to excess metabolic demand of iodine in pregnancy, pregnant women and lactating mother and their neonates are most vulnerable of iodine deficiency disorder. Urinary iodine excretion is a good marker of recent dietary iodine intake. Thus, present study was conducted to assess the iodine status and median urinary iodine excretion (UIE μg/lit) among pregnant and non-pregnant women of Tripura.Methods: Tribal and Bengali pregnant and non-pregnant women from Bokafa and Jolaibari Block of South Tripura district were included in the study. Urinary iodine excretion was done using simple micro plate method. Salt iodine was estimated using iodometric titration. All the tests were performed at CNRT Lab, ICMR, India.Results: Total number of subjects included in this study was 1071. Total number of urine samples collected from pregnant and non-pregnant women was 538 and 533 respectively. Median value of UIE in pregnant and non-pregnant women of Tripura was 155.0µg/L and 130.0µg/L. In pregnant women percentage prevalence of severe (<20µg/L), moderate (20-49µg/L) and mild iodine deficiency (50-149µg/L) was found in 4.1%, 15.1% and 29.6% subjects. In case of non-pregnant women severe (<20µg/L), moderate (20-49µg/L) and mild iodine deficiency (50-99µg/L) was found in 0.6%, 9.6%, 27.8% subjects respectively. The overall prevalence of iodine deficiency was found in 48.8% pregnant women, compared to 38.0% non-pregnant subjects.Conclusions: Efforts towards universal salt iodization need to be stepped-up in Sub-Himalayan region (NE part of India) and pregnant and lactating mothers may be targeted with alternate iodine supplements (Colloidal Iodine).

Download Full-text

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.

Download Full-text

THE SITUATION OF URINARY IODINE CONCENTRATION (UIC) AMONG SCHOOL AGE CHILDREN, WOMEN AT REPRODUCTIVE AGE AND PREGNANT WOMEN IN INDONESIA: THE ANALYSIS OF RISKESDAS 2013

GIZI INDONESIA ◽

10.36457/gizindo.v39i1.207 ◽

2017 ◽

Vol 39 (1) ◽

pp. 49

Author(s):

Djoko Kartono ◽

Atmarita Atmarita ◽

Abas B Jahari ◽

Soekirman Soekirman ◽

Doddy Izwardy

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Iodized Salt ◽

Reproductive Age ◽

School Age Children ◽

Urinary Iodine Concentration ◽

Iodine Status ◽

Iodine Level

Iodine Deficiency Disorders (IDD) are the leading cause of goiter, cretinism, developmental delays and other health problems. Iodine deficiency is an important public health issue as it is a preventable cause of intellectual disability. While elimination of iodine deficiency is imperative, it should be noted that excessive intake of iodine can also lead to adverse health effects. This paper analyzed the iodine status using median urinary iodine concentration (MUIC) of school age children (SAC), women of reproductive age (WRA), and pregnant women (PW) who live in the same household from Riskesdas 2013. The total number of households included in the analysis was 13,811 households, from which 6,149 SAC (aged 6 – 12 years), 13,218 WRA (aged 15-49 years), and 578 PW (aged 15-49 years) were enumerated. The national MUIC of SAC, WRA and PWwas in the normal range indicated that the iodine status was adequate using WHO epidemiological criteria. Iodine status in some sub-populations indicated deficiency, however, in terms of geographic characteristics people who live in the urban has better iodine status compared to rural areas. Similarly, populations in richer economic quintiles had better iodine status. Only pregnant women in the 1st and 2nd quintile were deficient. Almost all regions in Indonesia showed the MUIC was in the normal adequate range, except NTT-NTB, Maluku-Papua, and East Java for pregnant women who tend to have lower MUIC (<150 µg/L). The status of iodized salt at the household was detected using both Rapid Test Kit/RTK as well as Titration. The result demonstrated a strong association between salt iodine level and iodine status. The MUIC for all three groups were lower when the iodine level in salt was lower, then increased when the levels of iodine content in salt increased. The iodine status of pregnant women consuming non-iodized salt was inadequate. The detrimental effect of iodine deficiency on the mental and physical development of children as well as on the women of reproductive age has been recognized. Indonesia still needs the salt iodization program to keep the iodine status in the normal range. In particular coverage with adequately iodized salt needs to be improved in order to improve the iodine status of pregnant women. For the prevention of Iodine disorders (insufficient), monitoring should be undertaken in regular basis to assess the MUIC, especially for pregnant women.

Download Full-text

Iodine levels are associated with oxidative stress and antioxidant status in pregnant women with hypertensive disease

Nutrición Hospitalaria ◽

10.20960/nh.460 ◽

2017 ◽

Vol 34 (3) ◽

pp. 661 ◽

Cited By ~ 9

Author(s):

Sergio Cuellar-Rufino ◽

Mónica Navarro-Meza ◽

Pablo García-Solís ◽

Irene Xochihua-Rosas ◽

Omar Arroyo-Helguera

Keyword(s):

Oxidative Stress ◽

Pregnant Women ◽

Iodine Deficiency ◽

Antioxidant Status ◽

Urinary Iodine ◽

Positive Association ◽

Urinary Iodine Concentration ◽

Hypertensive Disease ◽

Free T4 ◽

Sod Activity

Background: Previously has been reported the antioxidant function of iodine, and iodine deficiency as a risk factor of preeclampsia.Aim: We analyze the association between iodine deficiency, oxidative stress and antioxidant status with hypertensive disease of pregnancy (HPD).Method: 57 pregnant women were recruited in the last trimester of pregnancy, 20 diagnosed with hypertensive disease of pregnancy and 37 normotensive pregnant women. Urinary iodine concentration (UIC), TSH, free T4 (fT4), total antioxidant status (FRP), Superoxide dismutase (SOD), Catalase (CAT), and oxidative stress (TBARS) were evaluated by colorimetric methods.Results: UIC median for all pregnant women was of 151.9 µg / L. The UIC median for pregnant women with HPD was between 50-149 µg/L compared to 150-249 µg/L in normotensive women. No significant changes were found in levels of TSH and fT4 in normotensive pregnant compared with HPD women. Pregnant women with HPD had significant high levels of TBARS, and significant low levels of FRP, SOD, CAT and UIC compared to normotensive pregnant. In addition, pregnant women with optimal levels of UIC had a higher SOD activity (R = 0.354, P = 0.011), while iodine deficiency was associated with HPD (R = -0,281, p = 0.039). Similarly, pregnant with HPD had a significant negative association with SOD activity (R = -0,702, p = 0.005), CAT (R = -0,409, p = 0.002), and FRP (R = -0,624, p = 0.003), and a positive association with TBARS (R = 0.744, p = 0.001).Conclusion: iodine contributes to REDOX balance during pregnancy; its deficiency is associated with HPD. This study shows the importance of iodine during pregnancy.

Download Full-text

A systematic review of iodine deficiency among women in the UK

Public Health Nutrition ◽

10.1017/s1368980018003506 ◽

2018 ◽

Vol 22 (06) ◽

pp. 1138-1147 ◽

Cited By ~ 1

Author(s):

Huiqing Jiang ◽

Hilary J Powers ◽

Giulia S Rossetto

Keyword(s):

Systematic Review ◽

Pregnant Women ◽

Iodine Deficiency ◽

Large Scale ◽

Urinary Iodine ◽

Women Of Childbearing Age ◽

Childbearing Age ◽

Female Population ◽

Iodine Status ◽

The Uk

AbstractObjectiveThe present study reviewed the literature on iodine status among women of childbearing age and pregnant women in the UK. Particular attention was given to study quality and methods used to assess iodine status.DesignA systematic review was conducted to examine the literature and critically evaluate study design.SettingStudies were identified in PubMed, Web of Science, Scopus and Ovid MEDLINE databases, as well as from secondary references.ParticipantsWomen of childbearing age or pregnant, living in the UK.ResultsFifty-seven articles were identified and twelve articles were selected, including a total of 5283 women. Nine studies conducted urinary iodine assessments, three studies conducted dietary assessments only, and seven studies classified their target population as iodine deficient according to WHO criteria.ConclusionsNo single study from the selected articles could produce nationally representative results regarding the prevalence of iodine deficiency among the female population in the UK. Consideration of the evidence as a whole suggests that women of childbearing age and pregnant women in the UK are generally iodine insufficient. Further large-scale research is required for more accurate and reliable evidence on iodine status in the UK.

Download Full-text