A Review of Iodine Status of Women of Reproductive Age in the USA

Adequate iodine nutrition and higher salt intake in Chinese adults aged 18-59 years recommended by international organizations

Iodine deficiency and excessive salt intake have adverse health effects. This study evaluated the iodine level and salt intake in Chinese adults aged 18-59 years after implementing the salt reduction program and compared with both the World Health Organization (WHO) and Chinese recommendations. Adults aged 18-59 years were randomly selected using multi-stage stratified random sampling in coastal urban area (CUA), non-coastal urban area (Non-CUA), coastal rural area (CRA), and non-coastal rural area (Non-CRA) of Fujian Province, China. Iodine, sodium, and creatinine concentrations in spot urine samples were measured. Knudsen equation was used to determine 24-h urinary iodine and sodium excretion. The median urinary iodine concentration (mUIC) and urinary sodium concentration (mUNaC) among adults (n = 3513) were 132.0 μg/L and 4.0 g/d, respectively. The mUIC and median daily iodine intake in CUA, Non-CUA, CRA and Non-CRA were 112.1, 127.5, 128.5, 167.5 μg/L and 189.6, 182.5, 199.4, 236.0 μg/d, respectively. The mUNaC and median daily salt intake (mDSI) in these four areas were 2.4, 2.8, 2.9, 2.9 g/L and 9.8, 10.4, 10.4, 10.6 g/d, respectively. The mUIC and DII of residents were higher in the Non-CRA than in the other three areas (P < 0.05). The UNaC and DSI of residents were lower in the CUA than in the other three areas (P < 0.05). The logistic regression demonstrated that the people living in CUA and Non-CUA consumed less salt compared with those in Non-CRA. Except for Non-CUA, the DII was lower (< 150 μg/d) among women of childbearing age in the low-salt intake group (< 5 g/d) compared with the high-salt intake group (≥ 5 g/d) (P < 0.05). Iodine nutrition in Chinese adults aged 18-59 years was sufficient, but the salt intake was substantially higher than the WHO and Chinese recommendations. Further policy implementation is needed to reduce salt intake and improve the monitoring of iodine levels in Chinese adults, especially in women of childbearing age.

Iodine Intake Trends in United States Girls and Women between 2011 and 2020

BACKGROUND

Usual intakes of iodine in United States girls and women, including pregnant and lactating women have not been adequately studied. Adequate intake of iodine is critical for neurodevelopment of girls, thyroid functions, and reproductive health of women.

OBJECTIVES

This study aimed to examine the adequacy and trends of iodine intake of United States girls and women between 2011 and 2020.

METHODS

We mapped the sources of United States girls and women's iodine intake from the 29 food groups between 2011 and 2020 using United States Department of Agriculture's iodine data release 2. The total food intakes from 2 d of dietary recall of the United States National Health and Nutritional Examination Survey and estimated iodine concentrations of the food groups were used to calculate the usual iodine intakes of female participants. Trends of usual intakes, urinary iodine concentrations (UIC), and estimated intake adequacy were calculated.

RESULTS

Median usual intakes of iodine estimated from diet and supplements and UIC of United States girls and nonpregnant, nonlactating women declined between 2011 and 2020 in all 3 age groups: ≤14 y, 15-49 y old, and ≥50 y. Median usual intakes of iodine for pregnant and lactating United States women declined as well. Inadequacy levels of usual iodine intake were 9.9% for nonpregnant, nonlactating women of reproductive age 15-49 y old, 40.3% for lactating, and 10.2% for pregnant women in the 2017-2020 period. Intake insufficiencies estimated from UIC were 48.8%, 63.2%, and 31.3% for nonpregnant, nonlactating women of reproductive age 15-49 y old, pregnant and lactating women, respectively, in the 2017-2020 period. A significant decline in milk consumption might be one of the major contributors to the dietary iodine decline in United States women.

CONCLUSIONS

Iodine intake of United States girls and women were on the decline between 2011 and 2020 and the increased inadequacy of iodine intake deserves public health attention.

Pyrohydrolysis as a sample preparation method for the subsequent halogen determination: A review

The use of pyrohydrolysis as a sample preparation method for further halogen determination is extensively discussed in this review, covering studies published in the last 30 years. This method is compatible with both organic (such as cellulose, fossil fuels, carbon nanotubes, and graphite) and inorganic (such as rocks, silicates, alumina, and nuclear fuels) matrices. It has also been used for samples with different organic matter content, such as coal, mineral supplements, and soil. Sample masses vary greatly and are dependent on organic matter content in the samples, ranging from 50 mg to up to 500 mg for organic samples, and up to 4 g to inorganic samples. Different additives, such as V2O5 and cellulose, or flame retardants, such as silica, could also be used to improve analyte recovery using pyrohydrolysis. Dilute alkaline solutions or even water have been used as absorbing solutions, with mainly NaOH, NH4OH, and mixtures of NaHCO3 and Na2CO3 being applied. Furthermore, pyrohydrolysis is compatible with detection techniques such as ion chromatography, inductively coupled plasma mass spectrometry, ion selective electrode, inductively coupled plasma optical emission spectrometry, energy-dispersive X-ray fluorescence spectrometry, spectrophotometry, and isotope ratio mass spectrometry. Other advantages usually related to this method are the low residual carbon concentration of digests and the low residue generation. A critical comparison with alkaline extraction, alkaline fusion, Schöniger oxygen flask combustion, combustion bomb and microwave-induced combustion is also provided.

Adjusting the Iodine Content of Iodized Salt to Meet the Recommended Intake for Females of Reproductive Age: A Simulation Study with a Reduced Sodium Scenario

BACKGROUND

The use of iodized salt is a key strategy to increase iodine intake worldwide. In many countries, including New Zealand, females of reproductive age are still at risk of being mildly iodine deficient.

OBJECTIVE

This study aimed to determine the level of iodization of salt needed to ensure that females aged 18 to 40 y have an adequate intake of iodine in 2 scenarios: current discretionary salt intake and reduced discretionary salt intake.

METHOD

Data from nonpregnant, nonlactating females aged 18 to 40 y (n = 795) who took part in the 2008/09 New Zealand Adult Nutrition Survey and completed a 24-h dietary recall were used. Iodine intake was determined from all foods except bread and discretionary salt, which are fortified with iodine. Iodine from bread and salt was estimated at different levels of salt iodization, starting at 25 mg iodine/kg salt and increasing incrementally by 5 mg/kg, and added to calculate total iodine intake. The simulation concluded when the appropriate iodine content in salt was found using the estimated average requirement (EAR) cut-point method.

RESULTS

In the 2 scenarios, current discretionary salt intake (i.e., 400 mg/d) and reduced discretionary salt intake (i.e., 304 mg/d), the iodine concentration of salt is required to be 55 mg/kg and 70 mg/kg for no more than 2% of females to have an iodine intake below the EAR of 100 μg of iodine/d, respectively. In both scenarios and at all levels of iodine concentration, no one was above the upper level of intake of iodine of 1100 μg/d.

CONCLUSIONS

This study found that females of reproductive age need to consume iodized salt at the higher end of the legislated range of 25 to 65 mg/kg. If strategies to reduce sodium intake were adopted, the range would need to increase, or iodized salt would need to be included in a wider range of staple foods.

Dairy food consumption is beneficially linked with iodine status in US children and adults: National Health and Nutrition Examination Surveys 2001-2018

OBJECTIVES

The objective of this study was to determine the association between the consumption of dairy foods with urinary iodine concentration (UIC) and iodine deficiency risk in a nationally representative sample of the US population.

DESIGN, SETTING AND PARTICIPANTS

24-hour dietary recall data and laboratory data for UIC (μg/l) from subjects 2+ years old US population participating in National Health and Nutrition Examination Surveys 2001-2018 were used (n 26 838) for analyses after adjusting for demographic covariates. Significant associations were assessed at P < 0·05.

RESULTS

Mean intakes of total dairy were 2·21, 2·17 and 1·70 cup equivalents (cup eq) among those 2-8, 9-18 and 19+ years, respectively. Of the dairy components, intake of milk was highest followed by cheese and yogurt for all age groups. Total dairy intakes were positively associated with UIC among those 2-8 years (β = 29·9 ± 9·9 μg/l urine/cup eq dairy) and 9-18 years (β = 26·0 ± 4·8 μg/l urine/cup eq dairy) but not associated among those 19+ years. Total dairy intakes were associated with lowered risks (30 %, 21 % and 20 % for among 2-8, 9-18 and 19+ years, respectively) of being classified as iodine insufficient (UIC < 100 μg/l) or lowered risk (47 %, 30 % and 26 % among 2-8, 9-18 and 19+ years, respectively) of being classified as iodine severely deficient (UIC < 20 μg/l).

CONCLUSIONS

The results indicate that dairy foods are beneficially associated with UIC and lowered iodine deficiency risk.

Iodine Deficiency, Maternal Hypothyroxinemia and Endocrine Disrupters Affecting Fetal Brain Development: A Scoping Review

This scoping review critically discusses the publications of the last 30 years on the impact of mild to moderate iodine deficiency and the additional impact of endocrine disrupters during pregnancy on embryonal/fetal brain development. An asymptomatic mild to moderate iodine deficiency and/or isolated maternal hypothyroxinemia might affect the development of the embryonal/fetal brain. There is sufficient evidence underlining the importance of an adequate iodine supply for all women of childbearing age in order to prevent negative mental and social consequences for their children. An additional threat to the thyroid hormone system is the ubiquitous exposure to endocrine disrupters, which might exacerbate the effects of iodine deficiency in pregnant women on the neurocognitive development of their offspring. Ensuring adequate iodine intake is therefore essential not only for healthy fetal and neonatal development in general, but it might also extenuate the effects of endocrine disruptors. Individual iodine supplementation of women of childbearing age living in areas with mild to moderate iodine deficiency is mandatory as long as worldwide universal salt iodization does not guarantee an adequate iodine supply. There is an urgent need for detailed strategies to identify and reduce exposure to endocrine disrupters according to the "precautional principle".

Salt-Containing Recipes in Popular Magazines with the Highest Circulation in the United States Do Not Specify Iodized Salt in the Ingredient List

Iodine deficiency is a public health problem in the US, with the iodine status of women of reproductive age decreasing in recent years. This may be attributable to voluntary salt iodization in the US. Magazines, a common source of recipes and nutritional information, may influence salt use and iodine intake. The aim of this study is to assess whether the magazines with the highest circulation in the US include recipes that contain salt and, if so, whether they specify "iodized salt" in the recipes. Recipes in eight of the top ten magazines by circulation in the US were examined. Standardized information was collected on the presence and type of salt in recipes in the last 12 issues reviewed per magazine. About 73% of the 102 issues reviewed contained recipes. A total of 1026 recipes were surveyed for salt; 48% of the recipes listed salt as an ingredient. None of the 493 recipes containing salt specified iodized salt as the type of salt to be used. About half of the recipes in the last 12 issues of popular magazines published in the US included salt in the ingredient list; however, none recommend the use of iodized salt. There is potential for editorial changes among magazines to call for iodized salt in recipes, which may further prevent iodine deficiency in the US.

Inadequate Iodine Intake in Mothers of Young Children in Innlandet County, Norway

Background

Iodine has an essential role in child growth and brain development. Thus, sufficient iodine intake is particularly important in women of childbearing age and lactating women.

Objectives

This cross-sectional study aimed to describe iodine intake in a large random sample of mothers of young children (aged ≤2 y) living in Innlandet County, Norway.

Methods

From November 2020 to October 2021, 355 mother-child pairs were recruited from public health care centers. Dietary data were obtained using two 24-h dietary recalls (24-HRs) per woman and an electronic FFQ. The Multiple Source Method was used to estimate the usual iodine intake from the 24-HR assessment.

Results

Based on the 24-HRs, the median (P25, P75) usual iodine intake from food was 117 μg/d (88, 153) in nonlactating women and 129 μg/d (95, 176) in lactating women. The median (P25, P75) total usual iodine intake (from food combined with supplements) was 141 μg/d (97, 185) in nonlactating women and 153 μg/d (107, 227) in lactating women. Based on the 24-HRs, 62% of the women had a total iodine intake below the recommendations (150 μg/d in nonlactating women and 200 μg/d in lactating women), and 23% of them had an iodine intake below the average requirement (100 μg/d). The reported use of iodine-containing supplements was 21.4% in nonlactating women and 28.9% in lactating women. In regular users of iodine-containing supplements (n = 63), supplements contributed to an average of 172 μg/d of iodine. Among regular iodine supplement users, 81% reached the recommendations compared with 26% of nonsupplement users (n = 237). The iodine intake estimated by FFQ was substantially higher than that estimated by 24-HRs.

Conclusions

Maternal iodine intake in Innlandet County was inadequate. This study confirms the need for action to improve iodine intake in Norway, particularly among women of childbearing age.

Global, regional and national prevalence of copper, selenium and zinc deficiencies in women of childbearing age: protocol for systematic review and meta-analysis

INTRODUCTION

Micronutrient deficiencies are common in low-income and middle-income countries and are usually related to inadequate food intake, poor diet quality and low bioavailability. Copper, selenium and zinc are essential minerals in several enzymatic reactions and their deficiencies are associated with worse prognosis in pregnancy, compromising maternal health as well as her offspring. Thus, the objective of the present systematic review will be to describe the prevalence of copper, selenium and zinc deficiencies in women of childbearing age.

METHODS AND ANALYSIS

The search will be performed by independent reviewers. The bases used will be PubMed/MEDLINE, Science direct, Lilacs, Adolec, Scopus, EMBASE, CINAHL, Web of Science, CENTRAL, IMSEAR, PAHOS, WPRIM, IMEMR, AIM for grey literature OpenGrey and OVID. National data will be searched in BDTD. A first search will be performed and a second search will be performed just before submission. Risk of bias assessment will be performed using the Joanna Briggs group prevalence study checklist. Combinable studies will be performed meta-analysis. Heterogeneity will be tested using Cochran's Q test and quantified by the inconsistency test (I²). In the presence of high heterogeneity, meta-analysis will be performed using the random effects model with Stata metaprop. Summary prevalence will be generated for each outcome, presented in Forest plot figures.

ETHICS AND DISSEMINATION

This systematic review will be solely based on published and retrievable literature, no ethics approval will be obtained. Our dissemination strategy will involve the presentation in scientific meetings, as well as the publication of article(s), posters and presentations in congresses.

PROSPERO REGISTRATION NUMBER

CRD42020165352.

Sustained Elimination of Iodine Deficiency Within the Third Decade After Compulsory Iodine Supplementation Policy in the South of Iran: A Population-Based Cross-Sectional Study

Objectives

Recently, some studies in Iran have shown mild to moderate iodine concentrations in adult and pregnant women populations despite iodine sufficiency in children. This study aimed to evaluate the urine iodine status and salt intake among adult households in the city of Sadra, Fars province in southern Iran, and to assess its possible influencing factors.

Method

Participant households for this cross-sectional study were selected using randomized cluster sampling in the city of Sadra, Fars province, southern Iran from 1 February, 2021 to 30 November, 2021. Two subjects >18 y of age from each household were invited. Ninety-two subjects (24 men, 68 women) were enrolled. The participants were asked to collect their 24 h urine. They were then examined for thyroid disorders and subjected to thyroid ultrasonography and thyroid function tests. Urine samples were tested for iodine, sodium, and creatinine concentrations. Household salt intake was also estimated.

Results

Median urine iodine content (UIC) in the participants was 175 (IQR: 117, 250) μg/L, whereas the median salt consumption per person per day was 9.6 (IQR, 7.3-14.5) g. Sex, methods of salt storage, presence of goiter or thyroid nodules, the addition of salt in the cooking stage, and subclinical hypothyroidism had no effect on UIC, whereas individuals with hypertension and lower education had significantly lower iodine concentrations. UIC had a significant positive correlation with urine sodium and thyroid stimulating hormones (TSH) concentrations (P < 0.001, 0.046) and a negative correlation with thyroid volume and T4 (P = 0.029, 0.018).

Conclusion

Iodine status in the adult population of Sadra city was categorized as sufficient, although the iodine concentrations reported in Tehran were insufficient. The contributing factor can be higher salt consumption or possible higher environmental iodine concentrations in Sadra city than Tehran.

W-Compound can be used as a Biomarker for Fetal Thyroid Function and a Potential Tool for Screening Congenital Hypothyroidism

Sulfoconjugation is the major pathway for thyroid hormone (TH) metabolism, converting T4 to inactive metabolites, T4S, rT3S, and T3S in fetus, via sulfotransferases (SULT) and type 3 deiodinase in gestation. Consistent with high production rate of T4S and rT3S, there are high serum sulfated iodothyronine analogs, including T4S, T3S, rT3S, and 3,3'-T2S (T2S), in ovine and human fetal and preterm infants. Fetal TH metabolic pathways predict T2S as the major TH metabolite in the fetus. Since maternal T2S appears to be quantitatively derived from fetal T3 (the active TH), the amount of T2S in the maternal compartment correlates with fetal thyroid function in sheep. In humans, maternal serum contains high levels of radioimmunoassayable T2S; however, it displays as a peak adjacent to but unidentical to synthetic T2S on HLPC and we named it the W-Compound. Levels of W-Compound increase during pregnancy and peak as high as 20-fold to that of nonpregnant women. Maternal serum levels of W-Compound significantly correlate with fetal T4 and W-compound concentrations but not maternal serum T4 in euthyroid or hyperthyroid women, showing a distinct difference between fetal and maternal in TH metabolism. Fetal T2S is actively transferred to the mother via placenta and the quantity of T2S or its metabolite (W-Compound) in maternal compartment reflects fetal thyroid function. Thus, maternal serum W-Compound may be a biomarker for monitoring fetal thyroid function in utero, although more investigations are needed to determine if it can be used as an alternative strategy for screening/managing congenital hypothyroidism due to dysregulated thyroid hormone metabolism.

Intensifying Iodine Deficiency Throughout Trimesters of Pregnancy in a Borderline Iodine-Sufficient Urban Area, Ankara, Turkey

Iodine has long been recognized as an essential micronutrient for maternal thyroid function, as well as fetal growth and development during pregnancy. The current study aimed to evaluate thyroid hormone status, urinary iodine concentration (UIC), thyroid volume, and nodularity in pregnant women, throughout trimesters, in a borderline iodine sufficient, urban area with mandatory table salt iodization. Two-hundred-sixty-five pregnant women ranging from 17 to 45 years participated in this prospective longitudinal study. Thyroid function tests, thyroid volume, nodule growth, and UIC were recorded throughout the first, second, and third trimesters with no intervention. Median UIC was 96, 78, and 60 µg/L in the first, second, and third trimester of pregnancy, respectively (p < 0.001). Mean TSH values increased significantly (i.e. 0.65 mIU/ml, 1.1 mIU/ml, and 1.3 mIU/ml in the first, second, and third trimesters, respectively) (p < 0.001). Mean ± s.d. thyroid volume was significantly higher in the third trimester (14.72 ± 6.8 ml) compared with the first trimester (13.69 ± 5.31 ml) (p < 0.001). An intensifying iodine deficiency (ID) was reported throughout trimesters in this cohort of pregnant women from Ankara. A significant percentage of pregnant women from a borderline iodine sufficient, urban area in Turkey were iodine deficient during all trimesters, and the deficiency increased throughout the pregnancy. Pregnant women should receive iodine supplementation, besides consuming iodized salt in borderline iodine sufficient areas.

Lithium from breast-milk inhibits thyroid iodine uptake and hormone production, which are remedied by maternal iodine supplementation

BACKGROUND

Lithium is especially taken as a maintenance medication for Bipolar Disorder. In women with bipolar disorder, lithium is often effective during postpartum period, but breast-feeding for medicated mothers is controversial because of harmful effects for her child. At present, the biological mechanisms of lithium are not well-understood, affecting its usage and overall health implications.

PROCEDURE

We developed a rat lithium and breast-feeding model at human therapeutic levels to study the effects of lithium exposure through breast-milk on pups' thyroid function. Novel laser analytical spectroscopy, along with traditional blood and immunohistochemical tests, were applied to further investigate the mechanisms behind the thyroid dysfunction. Maternal iodine supplementation was evaluated as a therapeutic method to address the pups' thyroid dysfunction.

RESULTS

Pups exposed to lithium via breastmilk, even with the dam on a sub-therapeutic level, experienced weight gain, reduced blood thyroxine (T₄ ), and elevated blood urea nitrogen, indicating effects on thyroid and kidney function. We show that lithium inhibited iodine uptake by thyroid follicles, initiating a mechanism that reduced iodination of tyrosine, thyroglobulin cleavage, and thyroid hormone production. Importantly, infant thyroid function can be significantly improved by administering supplementary iodine to the medicated dam's diet during breast-feeding.

CONCLUSION

These results elucidate the mechanisms of lithium in thyroid function, provide valuable information on use postpartum, and suggest a clinically applicable remedy to side-effects. The results are particularly important for patients (and their infants) who respond well to lithium and need, or choose, to breast-feed.

Reflection of Dietary Iodine in the 24 h Urinary Iodine Concentration, Serum Iodine and Thyroglobulin as Biomarkers of Iodine Status: A Pilot Study

BACKGROUND

The iodine status of the US population is considered adequate, but subpopulations remain at risk for iodine deficiency and a biomarker of individual iodine status has yet to be determined. The purpose of this study was to determine whether a 3 day titration diet, providing known quantities of iodized salt, is reflected in 24 h urinary iodine concentration (UIC), serum iodine, and thyroglobulin (Tg).

METHODS

A total of 10 participants (31.3 ± 4.0 years, 76.1 ± 6.3 kg) completed three, 3 day iodine titration diets (minimal iodine, US RDA, (United States Recommended Daily Allowance), and 3× RDA). The 24 h UIC, serum iodine, and Tg were measured following each diet. The 24 h UIC and an iodine-specific food frequency questionnaire (FFQ) were completed at baseline.

RESULTS

UIC increased an average of 19.3 μg/L for every gram of iodized salt consumed and was different from minimal to RDA (p = 0.001) and RDA to 3× RDA diets (p = 0.04). Serum iodine was different from RDA to 3× RDA (p = 0.006) whereas Tg was not responsive to diet. Baseline UIC was associated with iodine intake from milk (r = 0.688, p = 0.028) and fish/seafood (r = 0.646, p = 0.043).

CONCLUSION

These results suggest that 24 h UIC and serum iodine may be reflective of individual iodine status and may serve as biomarkers of iodine status.

Nutritional Iodine Status in Pregnant Women from Health Area IV in Asturias (Spain): Iodised Salt Is Enough

Background: Iodine deficiency during pregnancy may have adverse effects on the neurodevelopment of the foetus. Recent studies of pregnant women in Asturias (Spain) indicate that nutritional iodine levels are sufficient. The objective of this study was to confirm the appropriate nutritional iodine status and to analyse the influence of the ingestion of iodine on maternal urinary iodine concentration (UIC) and thyroid function. Methods: An observational study was carried out between May and June 2017 on women in the first trimester of pregnancy from Health Area IV in Asturias. The women completed a questionnaire related to their consumption of iodine and samples were taken to analyse UIC and thyroid function. Results: Three hundred and eighteen pregnant women were involved. Of these, 51.10% used iodised salt, 48.90% consumed ≥ 2 servings of dairy products daily and 87.08% took iodine supplements. The median UIC was 171.5 μg/L (116–265 μg/L) and 60.41% of women had UIC ≥ 150 μg/L. Multivariate logistic regression analysis demonstrated that iodised salt had a protective effect on UIC < 150 μg/L (odds ratio (OR) 0.404 (0.237–0.683), p = 0.001), but not iodine supplements (OR 0.512 (0.240–1.085), p = 0.080). The average level of thyroid stimulating hormone (TSH) was 2.26 ± 0.94 mIU/L; 68.40% of pregnant women taking iodine supplements had TSH < 2.5 mIU/L compared to 30.00% of those who were not taking supplements (p = 0.031). Conclusions: The pregnant women in our health area are maintaining appropriate nutritional iodine levels. The consumption of iodised salt protects against iodine deficiency; thus, iodine supplements should be taken on an individualised basis.

Factors Associated with Thyroid Disorders and Iodine Adequacy in Pregnant Saudi Women

Little is known about iodine adequacy and gestational thyroid disorders (GTDs) in Saudi Arabia. This study measured the rates of GTDs and iodine adequacy in 810 healthy Saudi women. Concentrations of serum thyroid hormones and 24-h urine iodine (24-h UIC), and GTDs were diagnosed according to the American Thyroid Association guidelines. Dietary and socioeconomic data to determine factors associated with GTDs and iodine insufficiency were collected. GTDs were detected in 265 women (32.7%) as follows: subclinical (SCH; 20.2%) and overt (OH; 5.8%) hypothyroidism, isolated hypothyroxinemia (ISH; 4.7%) and hyperthyroidism (2%). The SCH (109.2 μg/L; IQR: 77.2-149.7), OH (95.3 μg/L; IQR: 74.3-130.5) and ISH (107.3 μg/L; IQR: 65.5-133.1) groups had median 24-h UIC below the WHO recommended limit, whereas the euthyroid (191.4 μg/L; IQR: 170.03-219.8) and hyperthyroid (159.5 μg/L; IQR: 152.9-238.3) groups were iodine sufficient. Numbers of pregnancies, less education, not consuming iodized salt and not using iodine supplements increased risk of hypothyroidism and ISH. Contrariwise, interval ≥ 3 years from last pregnancy and higher 24-h UIC decreased odds of hypothyroidism and ISH. Moreover, dairy products and egg consumption were markedly lower in all GTD groups. Dairy products and seafood consumption correlated independently with 24-h UIC of the study participants, whereas consuming yogurt, eggs, redfish and shellfish protected against GTDs. In conclusion, GTDs appear to be prevalent in pregnant Saudi women and the hypothyroid and hypothyroxinemia groups had iodine insufficiency. However, consuming iodized salt, iodine supplements, dairy products, seafoods and eggs may protect against GTDs.

Is There an Ideal Diet to Protect against Iodine Deficiency?

Iodine deficiency is a global issue and affects around 2 billion people worldwide, with pregnant women as a high-risk group. Iodine-deficiency prevention began in the 20th century and started with global salt iodination programmes, which aimed to improve the iodine intake status globally. Although it resulted in the effective eradication of the endemic goitre, it seems that salt iodination did not resolve all the issues. Currently, it is recommended to limit the consumption of salt, which is the main source of iodine, as a preventive measure of non-communicable diseases, such as hypertension or cancer the prevalence of which is increasing. In spite of the fact that there are other sources of iodine, such as fish, seafood, dairy products, water, and vegetables, the high consumption of processed food with a high content of unionised salt, alternative diets or limited salt intake can still lead to iodine deficiency. Thus, iodine deficiency remains a relevant issue, with new, preventive solutions necessary. However, it appears that there is no diet which would fully cover the iodine requirements, and iodine food supplementation is still required.

Iodine Deficiency as Assessed by Neonatal TSH in a Sample of Mother-and-Newborn Pairs in Jiangsu Province, China

China has eliminated iodine deficiency disorders since 2011 via the implementation of universal salt iodisation. Following this, a new revised salt iodisation policy was introduced to reduce iodine content in table salt. Since maternal iodine deficiency can lead to cognitive impairment and cretinism in infants, the aim of our study was to assess if the iodine status of pregnant women and neonates was affected by the introduction of new salt iodisation policy. The medical records of the pregnant women and their neonates in the Northern Jiangsu People's Hospital, Yangzhou, Jiangsu Province, China, between January 2018 and May 2018 were reviewed and obtained. Our study included 374 mother-and-newborn pairs. Mean age of the participants was 28 ± 4 years. TSH, FT3 and FT4 of the participants remained within the reference range. The prevalence of thyroid dysfunction was 4.3%. The overall mean neonatal TSH, birth weight and prevalence of low birth weight (LBW) was 2.56 ± 1.59 mIU/L, 3348 ± 465 g and 2.4%, respectively. The prevalence of neonatal TSH values > 5 mIU/L was 8.3%, which suggested the emergence of mild iodine deficiency (i.e. 3.0-19.9%) in our province. In conclusion, although our study reported an improvement of iodine status to mild iodine deficiency in 2017, our pregnant women remained to be iodine deficient. We recommended an ongoing monitoring of iodine status and advocate for the routine iodine supplementation together with iodised salt in Chinese pregnant women.

Iodine concentration and content measured by dual-source computed tomography are correlated to thyroid hormone levels in euthyroid patients: a cross-sectional study in China

Background

The aim of this study was to investigate the correlation of the dual energy CT measured iodine concentration and total iodine content with blood measured thyroid parameters.

Methods

Forty-three patients with normal thyroid function at our hospital from August 2017 to October 2019 were included in this retrospective study. Dual energy CT was used to scan the neck of thyroid patients. The mean iodine concentration and thyroid tissue volume were measured to calculate the total iodine content of the thyroid. Relevant tests of triiodothyronine (FT3), total triiodothyronine (TT3), total thyroxine (TT4), free thyroxine (FT4), and thyroid hormone (TSH) were conducted. The correlation of the thyroid mean iodine concentration and total iodine content with blood-measured thyroid function was analysed.

Result

The total iodine content in the thyroid was positively correlated with FT3 but negatively correlated with TSH. The mean iodine concentration of the thyroid was positively correlated with both FT3 and TT3.

Conclusion

The thyroid iodine content measured by dual energy CT can be used to determine the human iodine nutritional status and evaluate thyroid function, which will facilitate the diagnosis and treatment of thyroid diseases.

Vegans, Vegetarians and Pescatarians Are at Risk of Iodine Deficiency in Norway

Low iodine intakes have been documented in different population groups in Norway. We aimed to assess iodine status, dietary intake, supplement and macroalgae use, and iodine knowledge in vegans, vegetarians and pescatarians. In this study, 115 vegans, 55 vegetarians and 35 pescatarians from the Oslo region of Norway, aged 18-60 years, participated. A spot urine sample was collected along with a dietary assessment of iodine intake, supplement and macroalgae use. The median urinary iodine concentration (MUIC) in vegans was 43 µg/L (moderate iodine deficiency), in vegetarians 67 µg/L and in pescatarians 96 µg/L (mild iodine deficiency). In multiple linear regression analysis, use of iodine supplements was one of the strongest predictors of UIC. About half of the participants had median 24-h iodine intakes below estimated average requirement (EAR) of 100 µg/day. Fifty percent had low knowledge score, while 27% had very low knowledge score. Vegans, vegetarians and possibly pescatarians in Norway, are unable to reach the recommended iodine intake merely from food and are dependent on iodine supplements. There is an urgent need for dietary guidance targeting vegans, vegetarians and pescatarians to avoid inadequate iodine intake in non-supplement users, as well as avoiding excess iodine intake in macroalgae users.

Iodine Status of Women and Infants in Russia: A Systematic Review

This systematic review presents a critical synthesis of the available information on the iodine status among women and infants in Russia. Literature search was performed in accordance with PRISMA guidelines using PubMed, Scopus Web of Science databases as well as eLIBRARY-the Russian national source. Altogether, 277 papers were identified and 19 of them were eligible for the review. The data on median urinary iodine concentration (UIC) in women and infants from 25 Russian regions were presented. A substantial variability in UIC across the country with no clear geographical pattern was observed. Despite substantial heterogeneity in research methodology and data presentation the results suggest that the iodine status among pregnant women and infants in Russia is below the recommended levels. Our findings demonstrate that iodine deficiency is a re-emerging public health problem in Russia. Urgent public health measures on national, regional and individual levels are warranted.

Iodine adequacy in reproductive age and pregnant women living in the Western region of Saudi Arabia

BACKGROUND

Despite the serious maternal and foetal complications associated with iodine deficiency during pregnancy, surveys related to pregnant women in the Kingdom of Saudi Arabia (KSA) are lacking. This study, therefore, measured urine iodine concentrations (UIC) alongside the potential socioeconomic factors contributing towards iodine inadequacy in reproductive age and pregnant Saudi women from the Western province of KSA.

METHODS

Spot urine samples were collected from 1222 pregnant and 400 age-matched non-pregnant/non-lactating reproductive age women. The socioeconomic characteristics were obtained through a structured questionnaire. The WHO criteria for iodine sufficiency in non-pregnant (100-199 μg/L) and pregnant (150-249 μg/L) women were applied.

RESULTS

The median UIC in the non-pregnant women (101.64 μg/L; IQR: 69.83-143.55) was at the lowermost WHO recommended cut-off, whereas the pregnant group was iodine deficient (112.99 μg/L; IQR: 81.01-185.57). Moreover, the median UIC was below adequacy across the different trimesters. The use of non-iodised salt significantly increased the risk of iodine deficiency in the non-pregnant (OR = 2.052; 95%CI: 1.118-3.766) and pregnant women (OR = 3.813; 95%CI: 1.992-7.297), whereas taking iodine supplements significantly lowered the risk in both groups (OR = 0.364; 95%CI: 0.172-0.771 and OR = 0.002; 95%CI: 0.001-0.005, respectively). Passive smoking was also an independent risk factor for iodine deficiency in the non-pregnant (OR = 1.818; 95%CI: 1.097-3.014) and pregnant (OR = 1.653; 95%CI: 1.043-2.618) groups. Additionally, BMI correlated independently and significantly with median UIC in the non-pregnant and pregnant populations. However, multiparity (OR = 3.091; 95%CI: 1.707-5.598) and earning below the minimum wage (2.520; 95%CI: 1.038-6.119) significantly increased the risk of iodine deficiency only in the non-pregnant women.

CONCLUSIONS

This study is the first to show borderline iodine sufficiency in reproductive age Saudi women from the Western province, whereas mild iodine deficiency was observed in the pregnant population and could represent a serious public health problem. This study also advocates the necessity to establish routine iodine dietary advice services by the health authorities to foster adequate iodine intake in pregnant women to avoid the perilous consequences of iodine deficiency on maternal-foetal health.

Simultaneous Biofortification of Rice With Zinc, Iodine, Iron and Selenium Through Foliar Treatment of a Micronutrient Cocktail in Five Countries

Widespread malnutrition of zinc (Zn), iodine (I), iron (Fe) and selenium (Se), known as hidden hunger, represents a predominant cause of several health complications in human populations where rice (Oryza sativa L.) is the major staple food. Therefore, increasing concentrations of these micronutrients in rice grain represents a sustainable solution to hidden hunger. This study aimed at enhancing concentration of Zn, I, Fe and Se in rice grains by agronomic biofortification. We evaluated effects of foliar application of Zn, I, Fe and Se on grain yield and grain concentration of these micronutrients in rice grown at 21 field sites during 2015 to 2017 in Brazil, China, India, Pakistan and Thailand. Experimental treatments were: (i) local control (LC); (ii) foliar Zn; (iii) foliar I; and (iv) foliar micronutrient cocktail (i.e., Zn + I + Fe + Se). Foliar-applied Zn, I, Fe or Se did not affect rice grain yield. However, brown rice Zn increased with foliar Zn and micronutrient cocktail treatments at all except three field sites. On average, brown rice Zn increased from 21.4 mg kg^-1 to 28.1 mg kg^-1 with the application of Zn alone and to 26.8 mg kg^-1 with the micronutrient cocktail solution. Brown rice I showed particular enhancements and increased from 11 μg kg^-1 to 204 μg kg^-1 with the application of I alone and to 181 μg kg^-1 with the cocktail. Grain Se also responded very positively to foliar spray of micronutrients and increased from 95 to 380 μg kg^-1. By contrast, grain Fe was increased by the same cocktail spray at only two sites. There was no relationship between soil extractable concentrations of these micronutrients with their grain concentrations. The results demonstrate that irrespective of the rice cultivars used and the diverse soil conditions existing in five major rice-producing countries, the foliar application of the micronutrient cocktail solution was highly effective in increasing grain Zn, I and Se. Adoption of this agronomic practice in the target countries would contribute significantly to the daily micronutrient intake and alleviation of micronutrient malnutrition in human populations.