Iodine deficiency in Europe and its consequences: an update

Iodine status and associated dietary factors among preschool children in Shanghai

Children aged 3-6 years undergo a critical stage of growth and development and are irreversibly affected by their iodine status. In order to reveal iodine status in preschool children, we detected iodine concentrations in urine samples from 1382 children aged 3-6 years based on a cross-sectional study. The median urinary iodine concentration (UIC) of children was 193.36 μg/L and was 336.96 μg/g·Cr corrected for creatinine. The study developed a link between dietary habits and iodine status, revealing that regular calcium supplement (OR: 1.79, (95% CI: 1.03, 3.12)) increased deficiency risk, while moderate seafood consumption (OR: 0.60, (95% CI: 0.38, 0.95)) decreased it. Additionally, modest intake of shellfish (OR: 0.58, (95% CI: 0.33, 1.00)), vegetables (OR: 0.61, (95% CI: 0.38, 0.97)), and eggs (OR: 0.53, (95% CI: 0.30, 0.95)) was found to protect against excess iodine. The findings underline the importance of balanced diets and various nutrients' roles in preschoolers' iodine status.

Iodine-induced thyroid dysfunction: a scientometric study and visualization analysis

Objective

Iodine is essential in thyroid hormone production. Iodine deficiency is associated with serious complications (i.e miscarriage and stillbirth), whereas excess can cause thyroid dysfunction (i.e hyperthyroidism, hypothyroidism, thyroid autoimmunity). We conducted this scientometric study to visualize hot spots and trends in iodine-induced thyroid dysfunction over past two decades. The aim of this paper was to help scholars quickly understand the development and potential trend in this field, and guide future research directions.

Methods

Articles on iodine-induced thyroid dysfunction from 2000 to 2022 were retrieved from the Web of Science Core Collection (WoSCC) using the following search terms: (((((TS=(hypothyroid*)) OR TS=(hyperthyroid*)) OR TS= ("TSH deficiency")) OR TS= ("thyroid stimulating hormone deficiency")) AND TS=(Iodine)) NOT TS=(radioiodine). Only publications in English were selected. CiteSpace, VOSviewer, Tableau, Carrot2, and R software were used to analyze the contribution and co-occurrence relationships of different countries, institutes, keywords, references, and journals.

Results

A total of 2986 publications from 115 countries and 3412 research institutions were included. From 2000 to 2022, research on iodine-induced thyroid dysfunction progressed over a three-stage development period: initial development (2000-2009), stable development (2010-2016), and rapid development (2016-2022) period. The Journal of Clinical Endocrinology and Metabolism had the most co-citations followed and China Medical University (n=76) had the most publications. The top three clusters of co-citation references were isolated maternal hypothyroxinemia, subclinical hyperthyroidism, and brain development. Various scientific methods were applied to reveal acknowledge structure, development trend and research hotspots in iodine-induced thyroid dysfunction.

Conclusion

Our scientometric analysis shows that investigations related to pregnant women, epidemiology surveys, and iodine deficiency are promising topics for future iodine-induced thyroid dysfunction research and highlights the important role of iodine on thyroid function.

Iodine Deficiency and Iodine Prophylaxis: An Overview and Update

The thyroid gland requires iodine to synthesize thyroid hormones, and iodine deficiency results in the inadequate production of thyroxine and related thyroid, metabolic, developmental, and reproductive disorders. Iodine requirements are higher in infants, children, and during pregnancy and lactation than in adult men and non-pregnant women. Iodine is available in a wide range of foods and water and is susceptible to almost complete gastric and duodenal absorption as an iodide ion. A healthy diet usually provides a daily iodine consumption not exceeding 50% of the recommended intake. Iodine supplementation is usually necessary to prevent iodine deficiency disorders (IDDs), especially in endemic areas. The community-based strategy of iodine fortification in salt has eradicated IDDs, such as endemic goiter and cretinism, in countries providing adequate measures of iodine prophylaxis over several decades in the 20th century. Iodized salt is the cornerstone of iodine prophylaxis in endemic areas, and the continuous monitoring of community iodine intake and its related clinical outcomes is essential. Despite the relevant improvement in clinical outcomes, subclinical iodine deficiency persists even in Western Europe, especially among girls and women, being an issue in certain physiological conditions, such as pregnancy and lactation, and in people consuming unbalanced vegetable-based or salt-restricted diets. Detailed strategies to implement iodine intake (supplementation) could be considered for specific population groups when iodized salt alone is insufficient to provide adequate requirements.

Iodine Bioavailability and Accumulation of Arsenic and Cadmium in Rats Fed Sugar Kelp (Saccharina latissima)

Suboptimal iodine status is a prominent public health issue in several European coun-tries. Brown algae have a high iodine content that, upon intake, may exceed the recommended dietary intake level, but iodine bioavailability has been reported to be lower than from potassium iodide (KI) and highly depends on algae species. Further, potential negative effects from other components in algae, such as cadmium (Cd) and arsenic (As), have also been addressed. In this study, we observed a lower bioavailability of iodine from farmed sugar kelp (Saccharina latissima) than from KI in female Wistar IGS rats. Urinary iodine excretion was 94-95% in rats fed KI and 73-81% in rats fed sugar kelp, followed by increased faecal iodine levels in rats fed sugar kelp. No effects on body weight, feed efficiency, or plasma markers for liver or kidney damage were detected. The highest dose of iodine reduced plasma free thyroxine (fT4) and total T4 levels, but no significant effects on circulating levels of thyroid-stimulating hormone (TSH) and free triiodo-thyronine (fT3) were detected. Faeces and urine measurements indicate that 60-80% of total As and 93% of Cd ingested were excreted in rats fed 0.5 and 5% kelp. Liver metabolomic profiling demonstrates that a high inclusion of sugar kelp in the diet for 13 weeks of feeding modulates metabolites with potential antioxidant activity and phytosterols.

Biomedical evaluation of antioxidant properties of lamb meat enriched with iodine and selenium

The article presents a study of the antioxidant properties of meat from lambs that received organic forms of iodine and selenium during growth. This meat was included in diets of laboratory animals using a model of acute toxic hepatitis. The experiments resulted in developing and testing a technique that was effective in enriching lamb with bioorganic elements of iodine and selenium and contributed to the activation metabolism in the bodies of animals consuming the meat. The purpose of the presented investigation was to compare the roles of bioorganic iodine and selenium and their combination as antioxidants in rat rations using a model of acute toxic hepatitis induced by carbon tetrachloride. The experimental studies have established a hepatoprotective effect of lamb meat enriched with selenium and iodine on rats suffering from toxic xenobiotic effects. This was confirmed by normalized hematological and biochemical measures in the blood of the experimental rats.

The Status of Iodine Nutrition after Removing Iodized Salt in High Water Iodine Regions: a Cross-sectional Study in China

Currently, the removal of iodized salt is carried out in high water iodine regions. The present situation of iodine nutrition and the prevalence of thyroid diseases in such regions have not been clearly elucidated. This study aimed to figure out these problems to help render effective measures for cases of abnormal iodine nutrition status. A cross-sectional study was carried out in four areas of Jining and Heze, Shandong Province, China, with different water iodine concentrations (WIC). In total, 1344 adults were enrolled in this study, and data related to their iodine nutrition, thyroid function, and thyroid ultrasonography were collected. Subjects were grouped according to WIC, urine iodine concentration (UIC), serum iodine concentration (SIC), and combined UIC and SIC for analysis. Iodine levels were in excess in the 100 μg/L ≤ WIC < 300 μg/L and WIC ≥ 300 μg/L areas. Compared with the control WIC group (10-100 μg/L), the WIC ≥ 300 μg/L group had a higher prevalence of thyroid autoimmunity (TAI, 21.25% vs. 13.19%, P <0.05), subclinical hypothyroidism (SH, 20.20% vs. 11.96%, P < 0.05), thyroid nodules (TN, 31.75% vs. 18.71%, P < 0.05), and thyroid dysfunction (23.62% vs. 12.26%, P < 0.05). Compared with the UIC control group (100-300 μg/L), high UIC group (≥ 800 μg/L) had a higher prevalence of TN (33.75% vs. 21.14%, P < 0.05) and thyroid dysfunction (25% vs. 14.47%, P < 0.05). Next, compared with the control SIC group (50-110 μg/L), high SIC group (≥ 110 μg/L) had a higher prevalence of TAI (33.80% vs. 14.47%, P < 0.05), SH (23.94% vs. 14.30%, P < 0.05), and thyroid dysfunction (33.80% vs. 15.29%, P < 0.05). Finally, subjects with the highest UIC and the highest SIC also had a higher prevalence of TAI (25.92% vs. 10.97%, P < 0.05), SH (23.45% vs. 10.97%, P < 0.05), TN (34.56% vs. 15.85%, P < 0.05), and thyroid dysfunction (27.16% vs. 13.41%, P < 0.05) than subjects with middle iodine levels. The iodine nutrition of subjects in the WIC ≥ 300 μg/L areas was still in excess after removing iodized salt from their diets. High levels of iodine also increased the prevalence of TAI, SH, TN, and thyroid dysfunction in those areas. Simply removing iodized salt may not be sufficient for high water iodine regions.

OUP accepted manuscript

Context

Adequate iodine intake is essential throughout life. Key dietary sources are iodized salt and animal products, but dietary patterns in Europe are changing, for example toward lower salt intake and a more plant-based diet.

Objective

To review iodine intake (not status) in European populations (adults, children, and pregnant women) to identify at-risk groups and dietary sources.

Data sources

PubMed, Embase, and Cochrane databases, as well as European national nutrition surveys were searched for data on had iodine intake (from dietary assessment) and sources of iodine, collected after 2006.

Data selection

In total, 57 studies were included, comprising 22 national surveys and 35 sub-national studies. Iodine intake data were available from national surveys of children aged <10 years (n = 11), 11–17 years (n = 12), and adults (n = 15), but data from pregnancy were only available from sub-national studies.

Results

Iodine intake data are lacking—only 17 of 45 (38%) European countries had iodine-intake data from national surveys. Iodine intake reported from national surveys was below recommendations for: (1) children aged <10 years in 2 surveys (18%), (2) boys and girls aged 11–17 years in 6 (50%) and 8 (68%) surveys, respectively, and (3) adult men and women in 7 (47%) and 12 (80%) surveys, respectively. In pregnant women, intake was below recommendations except where women were taking iodine-containing supplements. Just 32% of national surveys (n = 7) included iodized salt when estimating iodine intake. Milk, dairy products, fish, and eggs were important contributors to intake in many countries, suggesting limited sources in plant-based diets.

Conclusion

Results are limited by the challenges of dietary assessment for measuring iodine intake. Future national surveys should include iodine intake. Policy makers should consider dietary sources alongside any iodized salt policies when considering methods for improving population iodine intake.

Systematic Review Registration

PROSPERO 2017 CRD42017075422.

Biological variation and analytical goals of four thyroid function biomarkers in healthy European volunteers

BACKGROUND

Interpretation of thyroid function tests by means of biological variation (BV) data is essential to identify significant changes between serial measurements at an individual level. Data on thyroid parameters in adults are limited.

OBJECTIVES

We aimed at determining the BV of four thyroid function test (thyroid-stimulating hormone (TSH), free thyroxin (FT4), free triiodothyronine (FT3) and thyroglobulin (Tg)) by applying recent recommendations to acquire BV data on a latest generation of immunoassay.

METHODS

Nineteen healthy volunteers (8 males and 11 females) were drawn every week during 5 consecutive weeks. Samples were analysed in duplicate on the Cobas 602 analyzer (Roche Diagnostics). After normality assessment, outlier exclusion and homogeneity of variance analysis, analytical variation (CV_A ), within-subject biological variation (CV_I ) and between-subject biological variation (CV_G ) were determined using nested ANOVA.

RESULTS

CV_A , CV_I and CV_G were 0.9%, 19.7% and 37.6% for TSH; 3.6%, 4.6% and 10.8% for FT4; 2.2%, 6.0% and 8.6% for FT3; and 0.9%, 15.4% and 84.9% for Tg. Index of individuality (II) for all parameters was between 0.2 and 0.7. The percentage above which the change between two measures is truly significant (reference change value) was 54.7% for TSH, 16.2% for FT4, 17.7% for FT3 and 42.8% for Tg.

CONCLUSION

Based on recent international recommendations, our study provides updated BV data for four thyroid function tests in European healthy volunteers. Reliable BV characteristics, and especially RCV, can facilitate the interpretation of consecutive thyroid function tests in an individual and therefore have the potential to efficiently support clinical decisions regarding thyroid diseases.

Development and validation of the quantitative determination procedure of iodine in the iodides form in the kelp thallus by the ionometry method

Introduction:

Iodine is an important compound in the kelp thallus; it should be determined to control the quality of crude herbal drugs of Laminaria sp. The ionometry method is perspective iodine (in the iodides form) determination method in the crude herbal drugs; it is characterized by the availability and relative cheapness of iodide-selective electrodes and equipment in general. This method provides an effective combination of the determination step with the fast, simple, and safe step of sample preparation.

Aim:

The current study aims to develop and validate a simple, effective procedure for the quantitative determination of iodine in the form of iodide by ionometry in the kelp thallus (Laminaria sp.).

Materials and methods:

The determination of iodides was carried out by using the “Ecotest-120” pH meter. “Ekom-I” was used as an ion-selective electrode. Silver chloride electrode “ESR 10101” was used as a reference electrode.

Results and Discussion:

The developed procedure has a suitable level of linearity (correlation coefficient = 0.9995%), correctness (variation coefficient = 1.58%), repeatability (variation coefficient = 6.67%), and analytical area (0.03–209.4 μg/mL analyte in the test solution). The procedure allows us to determine iodine in the form of iodides with an accuracy comparable to the accuracy of neutron activation analysis and can be recommended as an alternative to titrimetric methods existing in the world-leading pharmacopoeias.

Iodine, Thyroglobulin and Thyroid Gland

Iodine is essential in the biosynthesis of thyroid hormones that affect metabolic processes in the organism from the prenatal state to the elderly. The immediate indicator of iodine intake is the concentration of iodine in urine, but the indicator of iodine intake in the longer term of several months is thyroglobulin (Tg). Tg negatively correlated with increasing intake of iodine in population that do not suffer from thyroid disease, while a more than adequate to excessive iodine intake leads to an increase in Tg. The dependence of Tg on iodine can be described by a U-shaped curve. Thyroglobulin in serum is elevated in thyroid disease mainly in hyperthyroidism (diagnosis E05 of WHO ICD-10 codes) and in goiter (diagnosis E04 of WHO ICD-10 codes). Tg values decrease below 20 µg/l after effective treatment of patients with thyroid disease. Thyroglobulin may thus be an indicator of thyroid stabilization and the success of the thyroid gland treatment.

SCIENTIFIC SUBSTANTIATION OF TECHNOLOGY OF PASTA BASED ON FRESHWATER MUSSELS ENRICHED WITH SELENIUM

The possibility of using dietary selenium-protein additive "Neoselen" for enrichment of pastes based on mussels with organic selenium has been investigated. The formulation of the pastes involved the use of the soft body of the freshwater mmussels of the genus Anodonta. The influence of the introduction of different percentage of the additive "Neoselen" on the organoleptic properties of the developed pastes based on freshwater mussels was investigated. It is found that the addition of additive "Neoselen" even more than 5% does not impair the taste and color of the developed pastes. Moisture content, moisture retention, fat-holding capacity and active acidity of the developed pastes were investigated. The moisture-holding and fat-holding capacity of the developed paste is determined. The difference in the consistency of pastes based on freshwater mussels with different percentage of unpowered additives was investigated by determining the values of plastic viscosity and modulus of elasticity. The regularities of the influence of the additive "Neoselen" on the general chemical and mineral composition of pastes based on freshwater mussels have been established. It is established that the addition of 1%, 3% or 5% in the paste of additive "Neoselen" can enrich it by 7.8, 23.4 and 39 mkg of selenium, respectively. Studies have shown that in the composition of both the control and experimental samples of pastes in the amount of protein, minerals and water content. With the increase of the content of the additive "Neoselen" in the formulation of pastes, the content of protein and minerals increases. The complex of qualitative characteristics of the developed pastes is investigated. The regularities of the influence of the component composition on the organoleptic and physicochemical and functional-technological characteristics of the minced systems based on freshwater mussels and the additive "Neoselen" have been established. It is established that the optimal doses of the use of additive "Neoselen" in the formulation of pastes ranges from 3-5%.

Evaluation of the effectiveness of iodine prophylaxis in Poland based on over 20 years of observations of iodine supply in school-aged children in the central region of the country

INTRODUCTION

Due to the mild-to-moderate iodine deficiency in Poland, in 1997 iodine prophylaxis based on obligatory salt iodization was introduced. We attempted to evaluate the effectiveness of such prophylaxis, based on over 20 years of observations of iodine supply in school-aged children in Opoczno district (Central Poland).

MATERIAL AND METHODS

A group of 603 children (316 girls and 287 boys), aged 6-14, was examined at 4 time points: in the years 1994, 1999, 2010 and 2016. The children were tested for urine iodine concentration (UIC) and in each child the thyroid volume was measured ultrasonographically.

RESULTS

The median UIC in 1994 (45.5 μg/l) indicated moderate iodine deficiency, while after introducing prophylaxis it corresponded to adequate values (1999 - 101.1 μg/l, 2010 - 100.6 μg/l, 2016 - 288.3 μg/l); however, the last value was higher than the previous two. The thyroid size, assessed by ultrasonography and presented as volume/body surface area (V/BSA), in 1994 was 6.55 × 10^-6 m; this value was higher than at other time points (2.73 × 10^-6 m in 1999, 2.73 × 10^-6 m in 2010, and 2.70 × 10^-6 m in 2016).

CONCLUSIONS

Iodine prophylaxis has proved effective in eliminating iodine deficiency. In recent years, the diversification of iodine sources, despite the reduction of salt consumption, has led to an increase in median UIC to values close to the upper limit of UIC, accepted as normal. Further increase in iodine supply may be unfavourable for health; therefore constant monitoring of iodine prophylaxis is required.

Iodine nutrition status in Spain Needs for the future

Although iodine nutrition in Spain has improved in recent years, the problem is not completely resolved. It is necessary that health institutions establish measures to ensure an adequate iodine nutrition of the population, especially among the highest risk groups (children and adolescents, women of childbearing age, pregnant women and nursing mothers). A low salt intake should be advised, but it should be iodized. It is also imperative that food control agencies establish effective control over adequate iodization of salt. Indicators on iodine nutrition should be included in future health surveys. The EUthyroid study and the Krakow Declaration on iodine nutrition provide an opportunity to set up a pan-European plan for the prevention of iodine deficiency that should be considered and used by health authorities.

Inadequacies of micronutrient intake in normal weight and overweight young adults aged 18-25 years: a cross-sectional study

OBJECTIVES

This study aims to assess adequacy in micronutrient intake in comparison with reference nutrient intakes (RNI) and to identify differences in intakes between normal weight and overweight individuals.

STUDY DESIGN

A sample of 542 university students (18-25 years), normal weight (N = 369) and overweight (N = 173), were included in a cross-sectional study.

METHODS

A three-day diet diary was used to assess energy and nutrient intake. Body mass index (BMI) and waist circumference were measured.

RESULTS

Mean dietary vitamin D intake was lower than RNI in both men (4.44 μg) and women (5.04 μg). Mean intakes of calcium (597.44 mg), iron (8.62 mg) and folate (171.29 mg) were also lower than recommendations in women. Weight status (normal weight versus overweight) was significantly associated with micronutrient intake, and a trend towards a decrease in vitamin and mineral intake with increasing weight was noted.

CONCLUSIONS

Results suggest the need to increase the intake of some micronutrients to meet the RNI, to ensure optimal health. This study provides a helpful tool to reinforce recommendations and potential health promotion and intervention strategies in university settings and could influence manufacturers involved in new food product development targeted to this young population.

Ultrasound Measurements of Thyroid Gland Volume at 36 Weeks' Corrected Gestational Age in Extremely Preterm Infants Born before 28 Weeks' Gestation

BACKGROUND

Thyroid ultrasound is a non-invasive imaging tool and provides good evaluation of thyroid anatomy, location, vascularisation, and echogenicity. The aim of this study was to assess thyroid function and thyroid volume in extremely preterm infants born before 28 weeks' gestation evaluated at 36 weeks' corrected gestational age (CGA) compared to term infants' normative data in the literature.

DESIGN

In this largest prospective UK study of extremely premature infants born at less than 28 weeks' gestation, thyroid volume measurement was assessed at 36 weeks' CGA. Fifty-five extremely preterm infants (28 males) who were born before 28 weeks' gestation were recruited to the study. All infants had ultrasound assessment of the thyroid gland at 36 weeks' CGA. We also prospectively measured thyroid stimulating hormone (TSH) and free thyroxine (FT4) in all infants at the time of recruitment (within 5 days of birth), at days 14, 21, and 28, and at 36 weeks' CGA.

RESULTS

The mean thyroid volume was measured at 0.57 mL (SD ±0.18). There was no association between mean thyroid volume and thyroid function (TSH or FT4). No associations were found between mean thyroid volume and gestation or birth weight in these infants.

CONCLUSIONS

Our findings provide a reference range with a mean thyroid volume of 0.57 mL (SD ±0.18) in this extremely preterm age group if less than 28 weeks' gestation. Thyroid volume at birth can vary from country to country due to variations in iodine intake as well as gestational age.

Active Site Binding Is Not Sufficient for Reductive Deiodination by Iodotyrosine Deiodinase

The minimal requirements for substrate recognition and turnover by iodotyrosine deiodinase were examined to learn the basis for its catalytic specificity. This enzyme is crucial for iodide homeostasis and the generation of thyroid hormone in chordates. 2-Iodophenol binds only very weakly to the human enzyme and is dehalogenated with a k_cat/K_m that is more than 4 orders of magnitude lower than that for iodotyrosine. This discrimination likely protects against a futile cycle of iodinating and deiodinating precursors of thyroid hormone biosynthesis. Surprisingly, a very similar catalytic selectivity was expressed by a bacterial homologue from Haliscomenobacter hydrossis. In this example, discrimination was not based on affinity since 4-cyano-2-iodophenol bound to the bacterial deiodinase with a K_d lower than that of iodotyrosine and yet was not detectably deiodinated. Other phenols including 2-iodophenol were deiodinated but only very inefficiently. Crystal structures of the bacterial enzyme with and without bound iodotyrosine are nearly superimposable and quite similar to the corresponding structures of the human enzyme. Likewise, the bacterial enzyme is activated for single electron transfer after binding to the substrate analogue fluorotyrosine as previously observed with the human enzyme. A cocrystal structure of bacterial deiodinase and 2-iodophenol indicates that this ligand stacks on the active site flavin mononucleotide (FMN) in a orientation analogous to that of bound iodotyrosine. However, 2-iodophenol association is not sufficient to activate the FMN chemistry required for catalysis, and thus the bacterial enzyme appears to share a similar specificity for halotyrosines even though their physiological roles are likely very different from those in humans.

Correlation of manganese with thyroid function in females having hypo- and hyperthyroid disorders

The aim of present study was to compare the level of manganese (Mn) with thyroid functions, thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxin (FT4) of females having hyper- (HPRT) and hypothyroid (HPOT) disorder. For comparative study, females of the same age group (16-30 years) having no thyroid disorders were selected as referents. The serum samples were acid digested prior to analysis by electrothermal atomic absorption spectrometry. The validity and accuracy of the methodology was checked by a certified sample. The resulted data indicated that the mean values of Mn in serum samples of females have hyperthyroidism was significantly higher than referent subjects (p < 0.01), while lower values of Mn was observed in serum samples of hypothyroid patients. The mean values of FT3 and FT4 were found to be lower while TSH higher is in HPRT patients than age-matched healthy control females (p = <0.01). The reverse resulted data of these thyroid hormones was observed in HPOT patients (0.003).

The importance of iodine in public health

Iodine (I) deficiency has been known for more than a century and is known to cause cretinism at the extreme end of the spectrum but also, importantly, impaired development and neurocognition in areas of mild deficiency. The WHO has indicated that median urinary iodine of 100-199 μg/l in a population is regarded as indicative of an adequate iodine intake. The understanding of the spectrum of iodine deficiency disorders led to the formation of The International Council for the Control of Iodine Deficiency Disorders which has promulgated the use of household iodized salt and the use of such salt in food processing and manufacture. Iodine deficiency is particularly important in pregnancy as the fetus relies on maternal thyroxine (T4) exclusively during the first 14 weeks and also throughout gestation. As this hormone is critical to brain and nervous system maturation, low maternal T4 results in low child intelligence quotient. The recommendation for I intake in pregnancy is 250 μg/day to prevent fetal and child brain function impairment. During the past 25 years, the number of countries with I deficiency has reduced to 32; these still include many European developed countries. Sustainability of adequate iodine status must be achieved by continuous monitoring and where this has not been performed I deficiency has often recurred. More randomized controlled trials of iodine supplementation in pregnancy are required in mild iodine-deficient areas to inform public health strategy and subsequent government action on suitable provision of iodine to the population at risk.

Global perspectives on trace element requirements

Trace elements are inorganic constituents of the human body present in concentrations less than 50mg/kg body weight. An exception is iron that is found in slightly higher amounts, 60 mg/kg body weight, but it is classified within this category due to its physiological roles. Requirements of trace elements can vary according to age, gender, growth, body composition, genetics, pregnancy, lactation, wound healing and burns, alcohol abuse, infections, and diseases (anemia, coronary artery, Keshan, Kashin-Beck). Additionally, interactions may occur with dietary factors, such as other minerals (iron versus copper), phytates (zinc), oxalates (iron), fiber (manganese), and polyphenolic compounds (molybdenum). On a global basis, requirements can vary according to soil and geographical location, food preparation and processing, food accessibility, cultural practices (geophagia) and pollution. Furthermore, global differences exist in body composition, ethnicity, and age of menarche.

Effect of various sources and levels of iodine, as well as the kind of diet, on the performance of young laying hens, iodine accumulation in eggs, egg characteristics, and morphotic and biochemical indices in blood

Young hens were fed over a period of 150 d with 2 kinds of diets including corn and soybean meal or corn, soybean, and rapeseed meal. Diets were enriched with potassium iodide (KI) or potassium iodate (KIO3) as an I source in amounts equal to 1, 3, or 5 mg of supplemented I/kg of feed. The hen performance, egg quality, hematological and morphotic indices in blood, hepatic enzyme activity, lipid indices in blood serum as well as I accumulation in wet egg content were determined. Introduction of 00-variety rapeseed meal into the diet improved the laying rate and feed conversion (P < 0.05); however, better egg weight was noted by feeding the hens with a diet without rapeseed meal. Use of KI as an I source enhanced the egg weight. The increased I level in the diet had an equivocal influence on egg weight, improved the feed conversion per 1 kg of eggs, and decreased the proportion of damaged eggs. The use of corn, soybean, and rapeseed meal in hen diets significantly improved yolk color; similar results were noted after an increase in I levels in the diets after 3 mo of feeding. Hematological indices of hen blood demonstrated significantly higher red blood cells numbers and hemoglobin concentrations with the use of KI. The use of a diet containing rapeseed meal led to an enhancement of hepatic enzyme activity, especially of alkaline phosphatase (P = 0.007). Lipid metabolism indices were not influenced by the kind of diet or the I source or level. The accumulation of I in wet egg content was negatively influenced by the use of a diet containing rapeseed meal (P = 0.000). The application of KI as an I source enhanced (P = 0.003) the accretion of I in eggs after 5 mo of treatment. Enhanced I supply significantly increased accumulation of I in eggs (P = 0.000) after 3 and 5 mo of the experiment from 260 and 310 to 1,011 and 1,256 µg/kg of wet egg content, respectively.

Nutrient intake of European adolescents: results of the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study

OBJECTIVE

An adequate nutritional intake in childhood and adolescence is crucial for growth and the prevention of youth and adult obesity and nutrition-related morbidities. Improving nutrient intake in children and adolescents is of public health importance. The purpose of the present study was to describe and evaluate the nutrient intake in a European sample using the D-A-CH nutrient intake recommendations and the Nutritional Quality Index (NQI).

DESIGN

The HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study is a cross-sectional study, the main objective of which is to obtain comparable data on a variety of nutritional and health-related parameters in adolescents aged 12·5-17·5 years.

SETTING

Eight cities in Europe.

SUBJECTS

The initial sample consisted of 3528 European adolescents. Among these, 1590 adolescents (54% female) had sufficient and plausible dietary data on energy and nutrient intakes from two 24 h recalls using the HELENA-DIAT software.

RESULTS

The intakes of most macronutrients, vitamins and minerals were in line with the D-A-CH recommendations. While the intakes of SFA and salt were too high, the intake of PUFA was too low. Furthermore, the intakes of vitamin D, folate, iodine and F were less than about 55% of the recommendations. The median NQI was about 71 (of a maximum of 100).

CONCLUSIONS

The intakes of most nutrients were adequate. However, further studies using suitable criteria to assess nutrient status are needed. Public health initiatives should educate children and adolescents regarding balanced food choices.

Correlation analysis of genotypes, auditory function, and vestibular size in Chinese children with enlarged vestibular aqueduct syndrome

CONCLUSION

In children with enlarged vestibular aqueduct syndrome (EVAS), their hearing was more related to genotype than VA size, and VA size was related to genotype.

OBJECTIVE

To study genotypes of the SLC26A4 gene, types and levels of hearing loss, and vestibular aqueduct (VA) size in children with EVAS.

METHODS

A total of 271 children with nonsyndromic sensorineural hearing loss and EVA underwent SLC26A4 gene screening. According to genotype typing, the phenotypes including pure tone average (PTA), distribution of subjects, and diameters of the external aperture and middle portion of the VA, were compared by t test or Pearson's χ(2) tests. Further, divided by the dilated level of the VA, subject distribution in different hearing loss levels was compared by Pearson's χ(2) test.

RESULTS

In all, 66 types of mutations were identified and 2 were novel (c.665G >T and c.1639G >A). Biallelic genotype was found in 207 subjects, monoallelic in 56, and no mutation in 8. The hearing loss was more stable in the subjects with monoallelic mutation than in other genotype groups. An air-bone gap was more frequently found in subjects with biallelic missense mutations than in other groups. The patients with no mutation had the most slightly enlarged VA. There was no dominant correlation between hearing loss level and VA size, and between VA size and different genotypes.

Very high prevalence of ultrasound thyroid scan abnormalities in healthy volunteers in Modena, Italy

BACKGROUND

Italy is characterized by high prevalence of goiter. To date, only limited data about the prevalence of goiter in the Italian adult population are available.

AIM

To investigate the prevalence of thyroid ultrasound abnormalities in adults unaware of any thyroid disease and evaluate the rate of differentiated thyroid cancer (DTC) obtained by this intervention.

METHODS

Ultrasound (US) thyroid scan was performed in adult volunteers recruited by advertisement in Modena, Italy. One hundred and thirty-five women and 66 men (no.= 201), unaware of any thyroid disease (mean age of 46 ± 10.7 yr) underwent their first thyroid US scan.

RESULTS

US thyroid abnormalities were found in 101 subjects (50.3%): 91 nodular goiters (45.2%) and 13 US-thyroiditis (6.5%) associated with positive auto-antibodies in 11 of them. Seventeen subjects (18%) with nodules underwent US-fine needle aspiration biopsy with the following cytological class (C) outcome: 14 patients C2 (82%), 1 patient C3 (6%), 2 patients had C4 (12%), the latter received histological confirmation.

CONCLUSIONS

The prevalence of thyroid abnormalities is very high in subjects unaware of any thyroid disease. DTC was found in 1% of subjects and in 2% of those affected by nodular goiter. Compared to the detection rate of the well-established screening programs for breast (0.45%) and colorectal (0.27%) cancer, the prevalence of DTC seems to be much higher. Thyroid US screening could allow the detection of DTC in asymptomatic subjects and this diagnosis often includes DTC at an advanced stage. Thus, US screening not necessarily results in the over-diagnosis of clinically not relevant thyroid diseases.

Mild iodine deficiency in pregnancy in Europe and its consequences for cognitive and psychomotor development of children: a review

Despite the introduction of salt iodization programmes as national measures to control iodine deficiency, several European countries are still suffering from mild iodine deficiency (MID). In iodine sufficient or mildly iodine deficient areas, iodine deficiency during pregnancy frequently appears in case the maternal thyroid gland cannot meet the demand for increasing production of thyroid hormones (TH) and its effect may be damaging for the neurodevelopment of the foetus. MID during pregnancy may lead to hypothyroxinaemia in the mother and/or elevated thyroid-stimulating hormone (TSH) levels in the foetus, and these conditions have been found to be related to mild and subclinical cognitive and psychomotor deficits in neonates, infants and children. The consequences depend upon the timing and severity of the hypothyroxinaemia. However, it needs to be noted that it is difficult to establish a direct link between maternal iodine deficiency and maternal hypothyroxinaemia, as well as between maternal iodine deficiency and elevated neonatal TSH levels at birth. Finally, some studies suggest that iodine supplementation from the first trimester until the end of pregnancy may decrease the risk of cognitive and psychomotor developmental delay in the offspring.

Risk of suboptimal iodine intake in pregnant Norwegian women

Pregnant women and infants are exceptionally vulnerable to iodine deficiency. The aims of the present study were to estimate iodine intake, to investigate sources of iodine, to identify predictors of low or suboptimal iodine intake (defined as intakes below 100 μg/day and 150 μg/day) in a large population of pregnant Norwegian women and to evaluate iodine status in a sub-population. Iodine intake was calculated based on a validated Food Frequency Questionnaire in the Norwegian Mother and Child Cohort. The median iodine intake was 141 μg/day from food and 166 μg/day from food and supplements. Use of iodine-containing supplements was reported by 31.6%. The main source of iodine from food was dairy products, contributing 67% and 43% in non-supplement and iodine-supplement users, respectively. Of 61,904 women, 16.1% had iodine intake below 100 μg/day, 42.0% had iodine intake below 150 μg/day and only 21.7% reached the WHO/UNICEF/ICCIDD recommendation of 250 μg/day. Dietary behaviors associated with increased risk of low and suboptimal iodine intake were: no use of iodine-containing supplements and low intake of milk/yogurt, seafood and eggs. The median urinary iodine concentration measured in 119 participants (69 μg/L) confirmed insufficient iodine intake. Public health strategies are needed to improve and secure the iodine status of pregnant women in Norway.

The DIAGONALE study: a survey designed to analyze the diagnosis and management of goiter in France

OBJECTIVE

Euthyroid goiter is frequent for general practitioners (GPs) and endocrinologists (ENDOs). It may induce complications especially in elderly subjects when it becomes nodular and hyperfunctional whereas in young subjects prevention of iodine deficiency may prevent this evolution. The primary objective of the observational study diagnosis of iodine deficiency induced goiter and national medical practices (DIAGONALE) was to determine the circumstances of diagnosis of euthyroid goiter, its incidence, the patient characteristics and the management.

METHODS

A representative sample of GPs and ENDOs working in a private medical practice (exclusively or not) was randomly drawn from a national file without changing the physician-patient relationship.

RESULTS

Four hundred and sixty-nine GPs and 195 ENDOs participated in the study. Goiter was diagnosed in 0.86% of patients seen by GPs and 15.7% of patients seen by ENDOs. Pregnant women were mainly and teenagers exclusively seen by ENDOs. The interview and clinical examination were an important time in the management of euthyroid goiter. TSH level was systematically assayed as well as an ultrasonography; 22.6% of GPs did not perform a scintigraphy versus 63.1% of ENDOs. Levothyroxine treatment was frequently prescribed and the objective of TSH levels was 2mU/L for GPs and 1mU/L for ENDOs.

CONCLUSION

This observational study showed differences in the management of euthyroid goiter between GPs and ENDOs but also many common practices. It also highlighted a higher incidence rate of goiter in pregnant women and teenagers seen by ENDOs.

The changing epidemiology of iodine deficiency

Globally, about 2 thousand million people are affected by iodine deficiency. Although endemic goitre is the most visible sign of iodine deficiency, its most devastating consequence is brain damage causing mental retardation in children. The relationship between iodine deficiency and brain damage was not clearly established until the 1980s when the term iodine deficiency disorders (IDDs), which encompass a spectrum of conditions caused by iodine deficiency, was introduced. This paradigm shift in the understanding of the clinical consequences of iodine deficiency led to a change in iodine deficiency assessment. The median urinary iodine excretion level has been recommended as the preferred indicator for monitoring population iodine deficiency status since 2001. The 2007 WHO urinary iodine data in schoolchildren from 130 countries revealed that iodine intake is still insufficient in 47 countries. Furthermore, about one-third of countries lack national estimates of the prevalence of iodine deficiency. The picture that has emerged from available data worldwide over the past two decades is that IDDs are not confined to remote, mountainous areas in developing countries, but are a global public health problem that affects most countries, including developed countries and island nations. The recognition of the universality of iodine deficiency highlights the need to develop and apply new strategies to establish and maintain sustainable IDD elimination and strengthen regular monitoring programmes.

Excessive iodine intake during pregnancy in Somali refugees

Iodine deficiency and excess are both associated with adverse health consequences, with fetuses, children and pregnant women being most vulnerable to the devastating effects of severe deficiency. It is often assumed that the iodine status of a population if displaced or in a remote or emergency situation is low. However, there is little evidence available to support this assumption, especially among long-term food-aid-dependent pregnant women. An effectiveness trial of a prenatal multiple-micronutrient supplement that contained 150 µg day(-1) iodine was conducted in two refugee camps in the North Eastern Province of Kenya in 2002. Urinary iodine concentration (UIC) was measured in a subsample of pregnant women attending antenatal care in Dagahaley (control camp) (n = 74) and Ifo (intervention camp) (n = 63). There was no significant difference in median UIC between the two camps (P = 0.118). The combined median UIC was 730 µg L(-1) (interquartile range, 780) (5.77 µmol L(-1)) and exceeded the upper safe limit of 500 µg L(-1) (3.95 µmol L(-1)) for pregnant women (P < 0.001), indicating excessive iodine intake. About 20% of the study subjects had 'more than adequate' urinary iodine, while over 71% had excessive UIC. Salt iodine content varied between 5.1 and 80.1 ppm in the five market salt samples analysed. In conclusion, excessive iodine intake was evident in the Dadaab refugee camps. Further research needs to be conducted to investigate the source of excess iodine, to determine the measures needed to address excessive iodine intake and to reconsider the World Health Organization/World Food Programme/United Nations Children's Fund guidance on supplementation of vulnerable groups in emergencies.

Maternal thyroid function in different conditions of iodine nutrition in pregnant women exposed to mild-moderate iodine deficiency: an observational study

OBJECTIVE

We examined the effect of different conditions of nutritional iodine intake on maternal thyroid function throughout gestation in a cohort of healthy, anti-thyroid antibody-negative women from a mild-moderately iodine-deficient (ID) area.

DESIGN

Observational cohort study.

PATIENTS

The study included 168 women receiving prenatal preparations containing 150 μg of iodine from early pregnancy (150-I group); 105 women who had regularly used (>2 years) iodized salt prior to becoming pregnant (I-salt group); 160 women neither taking iodine supplements nor using iodized salt (no-I group).

MEASUREMENTS

Maternal TSH, FT3 and FT4 were determined throughout gestation.

RESULTS

Mean TSH concentrations were higher among the 150-I women than in the remaining two groups, and in a high proportion of them, TSH values were found to exceed the upper limit for gestational age. Conversely, the prevalence of low free-thyroxine levels in the 150-I women was similar to that observed in the I-salt women and markedly lower than that recorded for the no-I group.

CONCLUSIONS

The regular use of iodine-containing supplements proved effective in reducing the risk of inappropriately low FT4 levels during pregnancy. The observed TSH increase in 150-I women may be because of a transient stunning effect on the thyroid gland, occurring as a result of the abrupt increase in daily iodine intake. Whilst the importance of gestational iodine supplementation is undisputed, we believe that in mild-moderately ID areas, women considering conception should be advised to take iodine supplementation for several months prior to pregnancy.

Iodine distribution in the environment as a limiting factor for roe deer antler development

The iodine-containing hormones produced by the thyroid gland play a role in the complex neuro-hormonal regulation of antler development. The proper function of the thyroid depends on the adequate iodine supply of the organism, which is directly related to the iodine content of food and drinking water. The purpose of this study was to explore the connection between the iodine content of the water base, which has a strong correlation with the iodine concentration of environmental components available to animals, and the antler weight of roe deer (Capreolus capreolus) shot in Hungarian hunting areas. Using a general linear model, controlling for the collective effects of other environmental factors (deer population density, harvest rate, land use, and soil fertility information), the iodine content of the water base explained 51.4% of the total variance of antler weights. The results suggest that antler weights increase with increasing iodine concentration regardless of other factors; thus, the environmental iodine distribution can be a limiting factor suppressing roe deer performance assessed here as antler weight. Further experimental studies of controlled iodine uptake are needed to define the exact physiological iodine requirements of roe deer bucks.

Evaluation of iodine, iron, and selenium in biological samples of thyroid mother and their newly born babies

BACKGROUND

There is accumulating facts that the metabolism of essential trace elements is altered in thyroid patients.

AIM

The aim of present study was to compare the status of essential trace elements, iodine, iron (Fe), and selenium (Se) in biological samples (serum and urine) of goitrous mothers (age ranged 30-40) and their newly born infants (n=76). An age matched 68 non-goitrous mothers and their infants, residing in the same locality, were selected as referents. For a comparative study, the biological samples of non-goitrous and goitrous pregnant and non pregnant female subjects of the same age group and socio-economic status were also analyzed.

METHODS

The Fe and Se concentrations in biological samples were determined by a flame and hydride generation atomic absorption spectrometry respectively, while iodine was measured by iodide-ion selective electrode, prior to microwave assisted acid digestion. The validity and accuracy of the methodology was checked by certified reference materials.

RESULTS

The mean values of iodine, Fe and Se in serum and urine samples of thyroid mothers and their infants were significantly lower as compared to the referent mothers-infants pairs (p<0.01).

CONCLUSIONS

The deficiencies of essential trace elements may adversely affect the health of women and their neonates.

Cord blood thyroid-stimulating hormone and free T4 levels in Turkish neonates: is iodine deficiency still a continuing problem?

BACKGROUND

The objectives of this study were to determine the cord blood thyroid-stimulating hormone (TSH) and free T(4) (FT(4) ) levels in Turkish neonates and to determine whether these variables reveal iodine deficiency.

METHODS

We collected 818 cords from healthy mothers at parturition and measured levels of FT(4) and TSH. We also measured cord blood FT(4) and TSH levels in different stages of gestation and gender. We grouped the neonates according to cord serum TSH levels, either being less (Group A) or greater (Group B) than 10 mIU/L. Group A included 589 neonates (300 girls [51%] and 289 boys [49%]) and Group B included 229 neonates (105 girls [45%] and 124 boys [55%]).

RESULTS

The percentage of subjects with cord blood TSH < 10 mIU/L and >10 mIU/L was 72% and 28%, respectively. Although cord TSH levels in Group B were greater than those in Group A (P < 0.001), cord blood FT(4) levels in Group B were lower than those in Group A (P < 0.05). There was no difference between both sex in terms of birthweight and maternal age. TSH and FT(4) levels did not vary according to neonate sex during gestation, except for from week 37 to 41. TSH levels of male neonates at the 41st week of gestation were higher than those of female neonates (P < 0.05). There were no effects of birthweight on TSH and FT(4) levels if the neonate was lighter than 2500 g at birth. TSH levels of male neonates were higher than those of female neonates when their birthweights were <2500 g (P < 0.05). There was no significant difference in TSH levels according to birthweights in male neonates.

CONCLUSION

Our data provide the normative data for cord blood TSH and FT(4) levels in Turkish neonates and show that iodine deficiency is a still a public health problem in Turkey. These measurements can be useful for detection and verification of hypothyroidism in a screening program for congenital hypothyroidism as well as evaluation of the success of the iodination program.

Lack of consistent association of thyrotropin receptor mutations in vitro activity with the clinical course of patients with sporadic non-autoimmune hyperthyroidism

BACKGROUND

Up to date, 14 patients with sporadic non-autoimmune hyperthyroidism (SNAH) caused by sporadic germline mutations in the TSH receptor (TSHR) gene have been reported. Despite considerable differences in the activity of hyperthyroidism, all SNAH case reports concluded that the demonstrated constitutive activity explains the phenotype.

AIM

Recently, linear regression analysis (LRA) of constitutive activity as a function of TSHR expression determined by 125I-bTSH binding or fluorescence activated cell sorting analysis was described as a more reliable way of characterizing the in vitro activity (IVA) of a constitutively activating TSHR mutation. Therefore, we analyzed a possible genotype-phenotype correlation in a systematic review of the case reports and investigated the TSHR mutation's LRA in selected cases.

MATERIAL AND METHODS

We determined the LRA for all sporadic germline mutations which had not previously been reported. Moreover, we systematically evaluated all case reports of SNAH for evidence of an association of the clinical course (CC) with the IVA of the mutated TSHR.

RESULTS

The LRA determined were: M453T (5.2+/-0.8), L512Q (4.5+/-0.7), I568T (25.6+/-6.3), F631L (45.9+/-9.4), T632I (14.5+/-2.7), D633Y (16.4+/-6.4). None of the 10 examined clinical signs showed a significant association with the LRA. Moreover, the comparison of the CC of patients harboring the same mutation (S281N, M453T, I568T, S505N) also showed no relation of the clinical activity with a high LRA.

CONCLUSION

Considering the different diagnostic circumstances, therapeutic strategies and the limitations of a systematic analysis of case reports due to the restricted number of case reports and limited follow-up we found no consistent relation of the TSHR mutation's IVA determined by LRA with the CC of patients with SNAH. This may also be due to the action of genetic, epigenetic, and environmental modifiers.

Iodine sources and iodine levels in pregnant women from an area without known iodine deficiency

OBJECTIVE

An adequate iodine intake during pregnancy is essential for normal development of the foetus. The World Health Organization (WHO) recommends that the median urinary iodine concentration (UIC) in a population of pregnant women should range between 150 and 249 microg/l. The aim of this study was to evaluate iodine status and to examine the main sources of iodine in pregnant women from an apparently iodine-sufficient area.

METHODS

Six hundred pregnant women in the third trimester completed a food frequency questionnaire, and iodine was measured in urine samples. Urinary iodine concentrations were described in the whole population and in subgroups according to their frequency of intake of milk, fish, eggs, bread and iodized salt, as iodine supplements.

RESULTS

The median UIC was 104 microg/l (n = 600), however, the median was higher among women who had a high milk intake (117 microg/l), used iodized salt (117 microg/l) or who were supplemented with iodine (141 microg/l). Women receiving iodine supplementation who also consumed more than one cup of milk per day had median UIC higher than 150 microg/l. In multivariate models, women with moderate and high milk intake had lower risk of having UIC below 150 microg/l [OR (95% CI): 0.42 (0.22-0.82) and 0.29 (0.15-0.55) respectively], after adjustment for potential confounders.

CONCLUSIONS

On the basis of WHO criteria, the iodine status of pregnant women was inadequate in this area. Milk was the most important dietary source of iodine, and iodine supplementation was also an important source of iodine, although not enough to reach the current recommendations.

Neonatal thyroid function in Seveso 25 years after maternal exposure to dioxin

BACKGROUND

Neonatal hypothyroidism has been associated in animal models with maternal exposure to several environmental contaminants; however, evidence for such an association in humans is inconsistent. We evaluated whether maternal exposure to 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a persistent and widespread toxic environmental contaminant, is associated with modified neonatal thyroid function in a large, highly exposed population in Seveso, Italy.

METHODS AND FINDINGS

Between 1994 and 2005, in individuals exposed to TCDD after the 1976 Seveso accident we conducted: (i) a residence-based population study on 1,014 children born to the 1,772 women of reproductive age in the most contaminated zones (A, very high contamination; B, high contamination), and 1,772 age-matched women from the surrounding noncontaminated area (reference); (ii) a biomarker study on 51 mother-child pairs for whom recent maternal plasma dioxin measurements were available. Neonatal blood thyroid-stimulating hormone (b-TSH) was measured on all children. We performed crude and multivariate analyses adjusting for gender, birth weight, birth order, maternal age, hospital, and type of delivery. Mean neonatal b-TSH was 0.98 microU/ml (95% confidence interval [CI] 0.90-1.08) in the reference area (n = 533), 1.35 microU/ml (95% CI 1.22-1.49) in zone B (n = 425), and 1.66 microU/ml (95% CI 1.19-2.31) in zone A (n = 56) (p < 0.001). The proportion of children with b-TSH > 5 microU/ml was 2.8% in the reference area, 4.9% in zone B, and 16.1% in zone A (p < 0.001). Neonatal b-TSH was correlated with current maternal plasma TCDD (n = 51, beta = 0.47, p < 0.001) and plasma toxic equivalents of coplanar dioxin-like compounds (n = 51, beta = 0.45, p = 0.005).

CONCLUSIONS

Our data indicate that environmental contaminants such as dioxins have a long-lasting capability to modify neonatal thyroid function after the initial exposure.

Dietary supplements contribute substantially to the total nutrient intake in pregnant Norwegian women

BACKGROUND

Use of dietary supplements during pregnancy may give an important contribution to nutrient intake, and for nutrients like folate and vitamin D supplements are recommended. Our objective was to study use and contribution of dietary supplement to nutrient intake among women participating in the Norwegian Mother and Child Cohort Study (MoBa).

METHODS

This study is based on 40,108 women participating in MoBa which is conducted by the Norwegian Institute of Public Health. The women had filled inversion 2 of the food frequency questionnaire in MoBa between February 2002 and February 2005.

RESULTS

81% reported use of one or more dietary supplements. The most commonly used category was cod liver oil/fish oil supplements (59%) followed by singular folic acid supplements (36%) and multivitamin/multimineral supplements (31%). The nutrient contribution of the dietary supplements varied from 65% for folate and vitamin D to 1% for potassium among supplement users. The dietary intake of vitamin D, folate, iodine and iron did not reach the Nordic Recommendations for pregnant women.

CONCLUSIONS

Use of supplements improved the intake of folate, iron and vitamin D, but not sufficiently to reach the recommended amounts.

Reference values for neonatal thyroid volumes in a moderately iodine-deficient area

BACKGROUND

The reference ranges of thyroid volumes in neonates vary according to the iodine status of a specific region. In different studies, it ranged between 0.47 and 1.62 ml. It has been previously shown that Bursa city was a moderately iodine-deficient area. We therefore aimed at determining normal reference ranges of neonatal thyroid volumes in our moderately iodine-deficient area.

METHODS

In this cross-sectional study, thyroid volumes of 100 healthy fullterm neonates (51 boys and 49 girls; mean gestational age 38.9+/-1.1 weeks; and mean birth-weight 3370+/-446 g) were measured during the first week of life using thyroid ultrasonography. These data were compared with the gestational age, birth weight, gender, and TSH values of neonates as well as with maternal factors such as gestational diabetes, preeclampsia, smoking, medication use, and heart disease.

RESULTS

All blood samples for TSH were taken during the first 5 days (mean 1.09+/-0.9 days). The mean TSH levels in all male and female neonates were 3.77+/-3.71, 4.57+/-3.61, and 2.93+/-3.66 mIU/l, respectively. This difference was statistically significant (p=0.006). Mean thyroid volumes for all male and female neonates were calculated as 0.82+/-0.18 (range 0.51-2.04), 0.84+/-0.21 (range 0.51-2.04), and 0.80+/-0.14 ml (range 0.58-1.30), respectively. There were no statistically significant differences in thyroid volumes with respect to gestational age, birth weight, gender, TSH values of neonates and maternal factors.

CONCLUSION

Normal thyroid volumes in neonates vary between different regions. Local reference values should be used in thyroid volume assessment. Our results are in concordance with the literature and can be used as reference values for our region.

Amniotic fluid iodine concentrations do not vary in pregnant women with varying iodine intake

Iodine deficiency is an important clinical and public health problem. Its prevention begins with an adequate intake of iodine during pregnancy. International agencies recommend at least 200 μg iodine per d for pregnant women. We assessed whether iodine concentrations in the amniotic fluid of healthy pregnant women are independent of iodine intake. This cross-sectional, non-interventional study included 365 consecutive women who underwent amniocentesis to determine the fetal karyotype. The amniocentesis was performed with abdominal antisepsis using chlorhexidine. The iodine concentration was measured in urine and amniotic fluid. The study variables were the intake of iodized salt and multivitamin supplements or the prescription of a KI supplement. The mean level of urinary iodine was 139·0 (sd94·5) μg/l and of amniotic fluid 15·81 (sd7·09) μg/l. The women who consumed iodized salt and those who took a KI supplement had significantly higher levels of urinary iodine than those who did not (P = 0·01 andP = 0·004, respectively). The urinary iodine levels were not significantly different in the women who took a multivitamin supplement compared with those who did not take this supplement, independently of iodine concentration or multivitamin supplement. The concentrations of iodine in the amniotic fluid were similar, independent of the dietary iodine intake. Urine and amniotic fluid iodine concentrations were weakly correlated, although the amniotic fluid values were no higher in those women taking a KI supplement. KI prescription at recommended doses increases the iodine levels in the mother without influencing the iodine levels in the amniotic fluid.