Iodine monitoring models contribute to avoid adverse birth outcomes related more than adequate iodine intake.

BACKGROUND: Iodine plays an important role in pregnancy. How to maintain adequate iodine intake amongst pregnant women in each trimester of pregnancy to prevent adverse birth outcomes in central China is a challenge for clinical practice. METHODS: 870 pregnant women and their infants were enrolled in the study. Urinary iodine concentration (UIC) was measured using an inductively coupled plasma mass spectrometry (ICP-MS). Maternal and newborn information were obtained during follow-up. Multinomial logistic regression models were established. RESULTS: Median UIC of pregnant women was 172 ± 135 µg/L which is currently considered to be sufficient. Multivitamin supplements containing iodine, iodized salt intake and frequent milk intake were significantly associated with higher UIC. Multivariate logistic regression analysis showed that multivitamin supplements containing iodine and milk consumption were risk factors for more than adequate iodine (UIC ≥ 250 µg/L). Iodine-rich diet was significantly related to heavier birthweight, larger head circumference and longer femur length of the newborns while more than adequate iodine intake (UIC ≥ 250 µg/L) was a risk factor for macrosomia. Logistic regression models based on potential risk factors involving iodine containing supplements and iodine-rich diet were established to predict and screen pregnant women with high risk of more than adequate iodine intake among local pregnant women in different trimesters and guide them to supplement iodine reasonably to prevent the risk. CONCLUSIONS: Multivitamin supplements containing iodine and milk consumption were risk factors for maternal UIC ≥ 250 µg/L which was a risk factor for macrosomia. Iodine monitoring models were established to provide guidance for pregnant women to reduce the risk of more than adequate iodine intake, thereby contributing to reduce the risk of having a macrosomia.

Relationship between Thyroid Status during the First Trimester of Pregnancy and Neonatal Well-Being.

Iodine is an essential micronutrient for the synthesis of thyroid hormones. The proper functioning of the thyroid axis is essential for the normal development of the nervous system, especially in the first trimester of gestation. The aim of the present study was to analyze the perinatal outcomes, anthropometry, and APGAR test scores of newborns and to relate them to maternal thyroid status. A total of 190 newborns participated in the study. No correlation was found between thyroid stimulating hormone (TSH) and maternal ioduria values in the first trimester of gestation with the weight or length of the newborn, or the APGAR score at one minute after birth. However, we found significant differences between the APGAR scores of children whose mothers had an iodine sufficiency level in the first trimester compared to the children of mothers with iodine deficiency. Similarly, the APGAR scores of children whose mothers had a TSH > 4 have significantly better APGAR scores than the children of mothers with a TSH < 4. Likewise, we found significant differences between the measurements of the newborns depending on whether their mothers smoked. The children of mothers who took iodine supplements or iodized salt obtained the highest APGAR score at one and five minutes after birth. It is essential to focus on recommending adequate consumption of iodine supplements and iodized salt prior to gestation and at least during the first trimester to achieve better fetal well-being.

Prevalence of inadequate and excessive iodine intake in a US pregnancy cohort.

BACKGROUND: US iodine intake, estimated from the median urinary iodine concentration of population representative data, has declined by half since the 1970s, which is problematic because maternal iodine intake is critical for fetal neurodevelopment. Relying on median urinary concentrations to assess iodine intake of populations is standard practice but does not describe the number of individuals with insufficient intake. Prevalence estimates of inadequate and excessive intake are better for informing public health applications but require multiple urine samples per person; such estimates have been generated in pediatric populations but not yet among pregnant women. OBJECTIVE: Our aims were as follows: (1) to assess median urinary iodine concentrations across pregnancy for comparison with national data and (2) to estimate the prevalence of inadequate and excessive iodine intake among pregnant women in mid-Michigan. STUDY DESIGN: Data were collected from 2008 to 2015 as part of a prospective pregnancy cohort in which women were enrolled at their first prenatal clinic visit. Few exclusion criteria (<18 years or non-English speaking) resulted in a sample of women generally representative of the local community, unselected for any specific health conditions. Urine specimens were obtained as close as practicable to at least 1 specimen per trimester during routine prenatal care throughout pregnancy (n=1-6 specimens per woman) and stored at -80°C until urinary iodine was measured to estimate the iodine intake (n=1014 specimens from 464 women). We assessed urinary iodine across pregnancy by each gestational week of pregnancy and by trimester. We used multiple urine specimens per woman, accounted for within-person variability, performed data transformation to approximate normality, and estimated the prevalence of inadequate and excessive iodine intake using a method commonly employed for assessment of nutrient status. RESULTS: Maternal characteristics reflected the local population in racial and ethnic diversity and socioeconomic status as follows: 53% non-Hispanic white, 22% non-Hispanic black, and 16% Hispanic; 48% had less than or equal to high school education and 71% had an annual income of <$25,000. Median urinary iodine concentrations in the first, second, and third trimester-including some women contributing more than 1 specimen per trimester-were 171 µg/L (n=305 specimens), 181 µg/L (n=366 specimens), and 179 µg/L (n=343 specimens), respectively, with no significant difference by trimester (P=.50, Kruskal-Wallis test for equality of medians). The estimated prevalence of inadequate and excessive iodine intake was 23% and <1%, respectively. CONCLUSION: Median urinary iodine concentrations in each trimester were above the World Health Organization cutoff of 150 µg/L, indicating iodine sufficiency at the group level across pregnancy. However, the estimated prevalence of inadequate iodine intake was substantial at 23%, whereas prevalence of excessive intake was <1%, indicating a need for at least some women to increase consumption of iodine during pregnancy. The American Thyroid Association, the Endocrine Society, and the American Academy of Pediatrics recommend that all pregnant and lactating women receive a daily multivitamin or mineral supplement that contains 150 µg of iodine. The data presented here should encourage the collection of similar data from additional US population samples for the purpose of informing the American College of Obstetricians and Gynecologists' own potential recommendations for prenatal iodine supplementation.

Moderate Iodine Deficiency Is Common in Pregnancy but Does Not Alter Maternal and Neonatal Thyroid Function Tests.

Introduction: An Israeli national survey found that 85% of pregnant women had urinary iodine content (UIC) levels below the adequacy range (<150 µg/L). Widespread desalinated water usage and no national fortification plan are possible causes. Studies assessing relationships between iodine status and maternal and neonatal thyroid function provided varying results. Our aims were to determine whether iodine deficiency was associated with altered maternal or neonatal thyroid function and the factors leading to iodine deficiency. Methods: A cross-sectional study including 100 healthy women without prior thyroid disease, in their first trimester of a singleton pregnancy were recruited from an HMO clinic in central Israel. The women were followed from their first trimester. All women completed a 24-h dietary recall and life habits questionnaires. We tested for UIC, maternal and neonatal thyroid function, maternal autoantibodies, and neonatal outcomes. Results: Median UIC in our cohort was 49 µg/L [25%-75% interquartile range (IQR) 16-91.5 µg/L], with 84% below adequacy range. No correlation was found between iodine deficiency and maternal or neonatal thyroid function which remained within normal ranges. Antibody status did not differ, but thyroglobulin levels were significantly higher in iodine insufficient subjects. UIC was higher in women consuming an iodine containing supplement. There was no association between UIC and dietary iodine content or water source. Conclusions: Moderate iodine deficiency is common in our healthy pregnant women population. Our data imply that moderate iodine deficiency in pregnancy seem sufficient to maintain normal maternal and neonatal thyroid function.

Impact of iodine supplementation during preconception, pregnancy and lactation on maternal thyroid homeostasis and offspring psychomotor development: protocol of the IodineMinho prospective study.

BACKGROUND: Iodine deficiency is the most common cause of preventable brain harm and cognitive impairment in children. Portuguese women of childbearing age, pregnant women and their progeny were shown to have inadequate iodine intake. Consequently, the Portuguese Health Authorities have recommended a daily supplementation with 150-200 µg iodine in preconception, pregnancy, and lactation. The IodineMinho study intends to evaluate whether (i) this recommendation impacted on the prevalence of iodine deficiency in pregnant women from the Minho region of Portugal, (ii) the time of initiation of iodine supplementation (if any) influences the serum levels of thyroid hormones at several intervals during pregnancy and (iii) there are serum thyroid-hormone parameters in the 1st trimester of pregnancy that predict psychomotor development of the child at 18 months of age. METHODS: Most Portuguese women are followed throughout pregnancy in community Family Health Units, where family physicians may choose to follow the National recommendation or other, concerning iodine sufficiency. This study will recruit women (N = 304) who intend to become pregnant or are already pregnant from 10 representative Units. Physician's approach and prescriptions, sociodemographic, nutrition and clinical information will be obtained at baseline and throughout pregnancy. To evaluate endocrine function, blood and urine samples will be collected at recruitment, once in each trimester of pregnancy, at delivery and 3 months after delivery. Breastmilk samples will be collected for iodine and energy content analysis. Children will be evaluated for psychomotor development at 18 months. Maternal thyroid volume will be evaluated by ultrasound scan at baseline, in the 3rd trimester and at 3 months after delivery. DISCUSSION: Iodine deficiency early during development precludes children from achieving full intellectual capabilities. This protocol describes a study that is innovative and unique in its detailed and comprehensive evaluation of maternal and child endocrine and psychomotor parameters. By evaluating the effectiveness of the iodine supplementation recommendation, it will contribute to the public health systems' efforts to provide excellence in maternal and infant care. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04288531 . Registered 28 February 2020-Retrospectively registered.

Comparison of the Effectiveness of Universal and Targeted Iodine Supplementation in Pregnant Women: A Randomized Controlled Trial.

OBJECTIVE: To compare the effectiveness of universal and targeted iodine supplementation strategies. METHODS: A randomized controlled trial involving low-risk Thai pregnant women was carried out. The participants were categorized into either the study group, in which iodine supplementation was varied based on median urine iodine concentration, or the control group, which received universal supplementation. Urine samples were collected before the start of treatment and at delivery. The primary outcome was iodine status after each supplementation regime. RESULTS: Two hundred and eight women were randomly categorized into 2 groups, 104 control-group participants and 104 study-group participants. Baseline iodine status in both groups was not significantly different. More than half of the pregnant women were classified as having iodine insufficiency. After supplementation, the proportions of iodine insufficiency in the control and study groups (27.9 and 33.3%, respectively; p value = 0.508) and those of excessive level (19.1 and 11.7%, respectively; p value = 0.247) were not significantly different between the 2 groups. However, iodine level above the requirement was statistically significantly higher in the control group (47.1%) compared with the study group (30.0%; p value = 0.048). CONCLUSIONS: The 2 strategies, universal and targeted supplementation, have comparable effectiveness in prevention of iodine deficiency, but the evidence suggests that targeted supplementation is better in avoiding over-supplementation.

Optimal Assessment and Quantification of Iodine Nutrition in Pregnancy and Lactation: Laboratory and Clinical Methods, Controversies and Future Directions.

Iodine intake must be boosted during pregnancy to meet the demands for increased production and placental transfer of thyroid hormone essential for optimal foetal development. Failure to meet this challenge results in irreversible brain damage, manifested in severity from neurological cretinism to minor or subtle deficits of intelligence and behavioural disorders. Attention is now being focused on explaining observational studies of an association between insufficient iodine intake during pregnancy and mild degrees of intellectual impairment in the offspring and confirming a cause and effect relationship with impaired maternal thyroid function. The current qualitative categorisation of iodine deficiency into mild, moderate and severe by the measurement of the median urinary iodine concentration (MUIC) in a population of school-age children, as a proxy measure of dietary iodine intake, is inappropriate for defining the degree or severity of gestational iodine deficiency and needs to be replaced. This review examines progress in analytical techniques for the measurement of urinary iodine concentration and the application of this technology to epidemiological studies of iodine deficiency with a focus on gestational iodine deficiency. We recommend that more precise definitions and measurements of gestational iodine deficiency, beyond a spot UIC, need to be developed. We review the evidence for hypothyroxinaemia as the cause of intrauterine foetal brain damage in gestational iodine deficiency and discuss the many unanswered questions, from which we propose that further clinical studies need to be designed to address the pathogenesis of neurodevelopmental impairments in the foetus and infant. Agreement on the testing instruments and standardization of processes and procedures for Intelligence Quotient (IQ) and psychomotor tests needs to be reached by investigators, so that valid comparisons can be made among studies of gestational iodine deficiency and neurocognitive outcomes. Finally, the timing, safety and the efficacy of prophylactic iodine supplementation for pregnant and lactating women needs to be established and confirmation that excess intake of iodine during pregnancy is to be avoided.

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

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

Poor Iodine Knowledge, Coastal Region, and Non-Iodized Salt Consumption Linked to Low Urinary Iodine Excretion in Zhejiang Pregnant Women.

BACKGROUND: Iodine deficiency in pregnant women, defined as a median urinary iodine concentration (UIC) of less than 150 µg/L, is an important public health issue. To improve their iodine intake, it is important to understand the knowledge and practices regarding iodine. METHODS: A cross-sectional investigation was conducted on 2642 pregnant women during 2016⁻2017 in Zhejiang province, China. A 3-point Likert scale questionnaire was used to record knowledge. The UIC and iodine content in household salt were determined. RESULTS: Coastal participants were iodine deficient (median UIC 127.6 µg/L) while inland participants were iodine sufficient (median UIC 151.0 µg/L). The average knowledge scores were significantly lower for the coastal participants (24.2 points vs. 25 points for the inland participants; p < 0.001). The percentage for iodized salt consumption was significantly lower for the coastal participants (88.9% vs. 96.0% for those inland; p < 0.001). A generalized linear model analysis showed that non-iodized salt consumption, coastal region, and low knowledge scores were independently associated with a low UIC. CONCLUSIONS: Comprehensive interventional strategies are needed to develop to achieve an optimal iodine status. We recommend that coastal pregnant women should take iodine supplements based on the consumption of iodized salt, and improvement of iodine-related knowledge.

Suboptimal Iodine Status among Pregnant Women in the Oslo Area, Norway.

Norway has been considered iodine replete for decades; however, recent studies indicate reemergence of inadequate iodine status in different population groups. We assessed iodine status in pregnant women based on urinary iodine concentration (UIC), urinary iodine excretion (UIE), and iodine intake from food and supplements. In 804 pregnant women, 24-h iodine intakes from iodine-rich foods and iodine-containing supplements were calculated. In 777 women, iodine concentration was measured in spot urine samples by inductively coupled plasma/mass spectrometry (ICP-MS). In addition, 49 of the women collected a 24-h urine sample for assessment of UIE and iodine intake from food frequency questionnaire (FFQ). Median UIC was 92 µg/L. Fifty-five percent had a calculated iodine intake below estimated average requirement (EAR) (160 µg/day). Iodine intake from food alone did not provide the amount of iodine required to meet maternal and fetal needs during pregnancy. In multiple regression models, hypothyroidism, supplemental iodine and maternal age were positively associated with UIC, while gestational age and smoking were negatively associated, explaining 11% of the variance. This study clearly shows that pregnant women in the Oslo area are mild to moderate iodine deficient and public health strategies are needed to improve and secure adequate iodine status.

The effectiveness of iodine supplementation during pregnancies in geographical areas of high prevalence of iodine insufficiency.

The objective of this study was to determine the effectiveness of routine iodine supplementation among pregnant women in areas of high prevalence of an iodine insufficiency, using WHO criteria to determine the iodine status. A longitudinal study was conducted on pregnant women attending antenatal care at a tertiary hospital. The urine iodine concentration was measured in the first trimester and after 150 µg of iodine supplementation in the third trimester. A total of 327 pregnant women met the inclusion criteria with a complete follow-up. The prevalence of an iodine insufficiency was significantly lower in the third trimester, when compared to the first trimester (21.41% vs 55.35%, p < .001). However, 21.4% of cases still had an iodine insufficiency and 35.17% had an 'above-requirement' in the third trimester. In the areas of high prevalence of iodine insufficiency, an iodine supplementation significantly reduces the number of women with insufficiency; however, it was associated with unnecessarily high UICs, leading to the risk of excess iodine. Impact statement What is already known on this subject: Iodine insufficiency is highly prevalent in many geographical areas. Half of the pregnant women in the northern part of Thailand had an iodine insufficiency in the first trimester. What do the results of this study add: Iodine supplementation (daily 150-mcg of potassium iodide) could significantly reduce the number of women with the insufficiency. About one-fifth of women still had an iodine insufficiency in spite of iodine supplementation. Universal supplementation could be associated with unnecessarily high UICs, potentially at risk of iodine excess. What are the implications of these findings for clinical practice and/or further research: Physicians should guard against the occurrence of adverse effect from an iodine excess when there is routine iodine supplementation for pregnant women. Further study is required to establish the best strategy for an iodine supplementation in pregnancy.

Thyroglobulin level at week 16 of pregnancy is superior to urinary iodine concentration in revealing preconceptual and first trimester iodine supply.

Pregnant women are prone to iodine deficiency due to the increased need for iodine during gestation. Progress has recently occurred in establishing serum thyroglobulin (Tg) as an iodine status biomarker, but there is no accepted reference range for iodine sufficiency during pregnancy. An observational study was conducted in 164 pregnant women. At week 16 of gestation urinary iodine concentration (UIC), serum Tg, and thyroid functions were measured, and information on the type of iodine supplementation and smoking were recorded. The parameters of those who started iodine supplementation (≥150 µg/day) at least 4 weeks before pregnancy (n = 27), who started at the detection of pregnancy (n = 51), and who had no iodine supplementation (n = 74) were compared. Sufficient iodine supply was found in the studied population based on median UIC (162 µg/L). Iodine supplementation ≥150 µg/day resulted in higher median UIC regardless of its duration (nonusers: 130 µg/L vs. prepregnancy iodine starters: 240 µg/L, and pregnancy iodine starters: 205 µg/L, p < .001, and p = .023, respectively). Median Tg value of pregnancy starters was identical to that of nonusers (14.5 vs. 14.6 µg/L), whereas prepregnancy starters had lower median Tg (9.1 µg/L, p = .018). Serum Tg concentration at week 16 of pregnancy showed negative relationship (p = .010) with duration of iodine supplementation and positive relationship (p = .008) with smoking, a known interfering factor of iodine metabolism, by multiple regression analysis. Serum Tg at week 16 of pregnancy may be a promising biomarker of preconceptual and first trimester maternal iodine status, the critical early phase of foetal brain development.

Calcium intake in winter pregnancy attenuates impact of vitamin D inadequacy on urine NTX, a marker of bone resorption.

PURPOSE: Pregnancy is characterised by increased bone turnover, but high bone turnover with resorption exceeding formation may lead to negative maternal bone remodelling. Recent studies are conflicting regarding the effect of calcium on skeletal health in pregnancy. The aim of this study was to examine the seasonal effect of serum 25-hydroxyvitamin D (25OHD) and dietary calcium on a marker of bone resorption. METHODS: This was prospective study of 205 pregnant women [two cohorts; early pregnancy at 13 weeks (n = 96), and late pregnancy at 28 weeks (n = 109)]. Serum 25OHD and urine cross-linked N-telopeptides of type I collagen (uNTX) were measured at both time points. Intakes of vitamin D and calcium were recorded using 3-day food diaries at each trimester. RESULTS: Compared to summer pregnancies, winter pregnancies had significantly lower 25OHD and significantly higher uNTX. Higher calcium intakes were negatively correlated with uNTX in winter, but not summer. In late pregnancy, compared to those reporting calcium intakes ≥1000 mg/day, intakes of <1000 mg/day were associated with a greater increase in uNTX in winter pregnancies than in summer (41.8 vs. 0.9%). Increasing calcium intake in winter by 200 mg/day predicted a 13.3% reduction in late pregnancy uNTX. CONCLUSIONS: In late pregnancy, during winter months when 25OHD is inadequate, intakes of dietary calcium <1000 mg/day were associated with significantly increased bone resorption (uNTX). Additional dietary calcium is associated with reduced bone resorption in late pregnancy, with greater effect observed in winter. Further research regarding optimal dietary calcium and 25OHD in pregnancy is required, particularly for women gestating through winter.

Iodine intake from supplements and diet during pregnancy and child cognitive and motor development: the INMA Mother and Child Cohort Study.

BACKGROUND: The effect of mild-to-moderate maternal iodine deficiency on the neuropsychological development of their offspring is uncertain. We aimed to assess the association between iodine status during pregnancy and the cognitive and motor development of children at 4-5 years. METHODS: We conducted a prospective cohort study in four Spanish regions with recruitment of pregnant women between 2003 and 2008 and follow-up of their children up to 4-5 years (mean (SD)=4.8 (0.6)). Cognitive and motor function was assessed in 1803 children using the McCarthy Scales of Children's Abilities. Dietary iodine and supplementation were measured through questionnaires twice during pregnancy. Urinary iodine concentration (UIC) was measured in spot samples. The residuals of a regression of UIC against creatinine were used to define a variable corrected for creatinine (UIC~Cr). RESULTS: Neither iodine supplements nor iodised salt consumption or maternal UIC were associated with cognitive or motor function. After adjusting for creatinine, children of women with UIC~Cr <100 µg/L had 3.93 (95% CI -6.18 to -1.69) general cognitive scores lower than the reference (150-249 µg/L). Dietary iodine was inversely associated with motor scores and milk but not other dairy products or seafood consumption accounted for this association (beta: -1.36; 95% CI -2.12 to -0.61; per one daily milk serving). CONCLUSIONS: We found an association between low maternal urinary iodine and lower cognitive scores in childhood, although only when corrected for creatinine, adding to the evidence that iodine deficiency may have potential harmful effects on neurodevelopment. Iodine supplementation does not appear to improve child's neurodevelopment at 4-5 years.

Moderate iodine deficiency among pregnant women in Hong Kong: revisit the problem after two decades.

INTRODUCTION: A survey conducted during 2005 to 2007 by the Centre for Food Safety in Hong Kong suggested that only 5% of the local population had a sufficient dietary intake of iodine. The study, however, was limited as biochemical data (ie urinary iodine concentration) were lacking. Pregnant women are vulnerable to iodine deficiency because of their increased requirement. Recent studies have shown that iodine deficiency in early pregnancy is associated with poorer cognitive development in early childhood. This study reports the iodine status of women during early gestation at an obstetric unit in Hong Kong. METHODS: Healthy pregnant women with no history of hyperemesis gravidarum were enrolled into a study when they first made a booking in an antenatal clinic of a public hospital to investigate their iodine status during early pregnancy. All subjects were asked to collect their morning urine for measurement of iodine and creatinine levels. Daily dietary intake of iodine was assessed in a subgroup of participants by structured interview using a standard food frequency questionnaire. RESULTS: A total of 600 pregnant women were enrolled at a median of 7.0 weeks of gestation. The median urinary iodine concentration and urinary iodine-to-creatinine ratio were 100 µg/L and 98 µg/g, respectively; 429 (71.5%) participants had iodine insufficiency according to the World Health Organization classification. Daily dietary intake of iodine was assessed in 146 participants. The median daily intake of iodine was 69.5 µg and 122 (83.6%) participants had an intake below the 250 µg recommended during pregnancy by the World Health Organization. CONCLUSIONS: Local pregnant women continue to have an inadequate dietary intake of iodine and remain iodine-deficient.

First Israeli National Iodine Survey Demonstrates Iodine Deficiency Among School-Aged Children and Pregnant Women.

BACKGROUND: National data on iodine status in Israel are lacking. Reliance on iodine-depleted desalinated water, the absence of a salt iodization program, and reports of increased use of thyroid medication in Israel suggest that the population's iodine intake is likely inadequate. The aims of this study were therefore to determine the iodine status of Israeli school-age children (SAC) and pregnant women (PW) in a nationally representative sample obtained by a novel approach of using pre-discard urinalysis samples collected from a centralized national laboratory. METHODS: Spot urine samples from 1023 SAC and 1074 PW, representing all regions and major sectors in Israel, were collected during 2016 at the Maccabi Healthcare Services central laboratory. Urinary iodine concentration (UIC) was measured, and the results were analyzed by trimester, sex, region, and sector. RESULTS: SAC were iodine deficient, with a median (interquartile range [IQR]) UIC of 83 µg/L (52-127 µg/L); 62% of SAC UICs were below the World Health Organization adequacy range for SAC (100-199 µg/L). PW were also iodine deficient, with a median (IQR) UIC of 61 µg/L (36-97 µg/L); 85% of PW UICs were below the adequacy range for PW (150-249 µg/L). For both SAC and PW, the median UIC was below the World Health Organization's adequacy range across all sectors, sexes, and districts. Among SAC, the median (IQR) UIC was lower among females (75 µg/L; 48-119 µg/L) than males (92 µg/L; 59-133 µg/L; p < 0.05). Median UIC values of PW correlated significantly with the median UIC for SAC by sub-district (R2 = 0.3, p < 0.05). CONCLUSIONS: Urine sampling via a centralized national laboratory was efficient and cost-saving. Iodine deficiency in Israeli SAC and PW is a serious public-health concern. A national program of salt iodization and iodine supplementation of PW should be urgently considered.

Selenium metabolism to the trimethylselenonium ion (TMSe) varies markedly because of polymorphisms in the indolethylamine N-methyltransferase gene.

BACKGROUND: Selenium is an essential element, but its metabolism in humans is not well characterized. A few small studies indicate that the trimethylselenonium ion (TMSe) is a common selenium metabolite in humans. OBJECTIVE: This study aimed to elucidate the human metabolism of selenium to TMSe. DESIGN: Study individuals constituted subsamples of 2 cohorts: 1) pregnant women (n = 228) and their 5-y-old children (n = 205) in rural Bangladesh with poor selenium status [median urinary selenium (U-Se): 6.4 µg/L in mothers, 14 µg/L in children] and 2) women in the Argentinian Andes (n = 83) with adequate selenium status (median U-Se: 24 µg/L). Total U-Se and blood selenium were measured by inductively coupled plasma mass spectrometry (ICPMS), and urinary concentrations of TMSe were measured by high-performance liquid chromatography/vapor generation/ICPMS. A genomewide association study (GWAS) was performed for 1,629,299 (after filtration) single nucleotide polymorphisms (SNPs) in the Bangladeshi women (n = 72) by using Illumina Omni5M, and results were validated by using real-time polymerase chain reaction. RESULTS: TMSe "producers" were prevalent (approximately one-third) among the Bangladeshi women and their children, in whom TMSe constituted ∼10-70% of U-Se, whereas "nonproducers" had, on average, 0.59% TMSe. The TMSe-producing women had, on average, 2-µg U-Se/L higher concentrations than did the nonproducers. In contrast, only 3 of the 83 Andean women were TMSe producers (6-15% TMSe in the urine); the average percentage among the nonproducers was 0.35%. Comparison of the percentage of urinary TMSe in mothers and children indicated a strong genetic influence. The GWAS identified 3 SNPs in the indolethylamine N-methyltransferase gene (INMT) that were strongly associated with percentage of TMSe (P < 0.001, false-discovery rate corrected) in both cohorts. CONCLUSIONS: There are remarkable population and individual variations in the formation of TMSe, which could largely be explained by SNPs in INMT. The TMSe-producing women had higher U-Se concentrations than did nonproducers, but further elucidation of the metabolic pathways of selenium is essential for the understanding of its role in human health. The MINIMat trial was registered at isrctn.org as ISRCTN16581394.

Iodine deficiency during pregnancy: a national cross-sectional survey in Latvia.

OBJECTIVE: Low iodine intake during pregnancy may cause thyroid dysfunction, which results in inadequate fetal brain development. In the absence of a universal salt iodization programme, we conducted a nationwide survey of iodine deficiency in pregnant women in Latvia. DESIGN: A countrywide twenty-cluster survey, with at least twenty women per cluster. Participants completed a questionnaire on dietary habits concerning iodine intake (n 739). Thyroid function (thyroid-stimulating hormone, free thyroxine and thyroperoxidase antibodies) was measured (n 550). Urinary iodine was measured using the ammonium persulfate method (n 696). SETTING: The survey was performed in all regions of Latvia during the spring and autumn seasons in 2013. SUBJECTS: Pregnant women (n 829). RESULTS: The median creatinine (Cr)-standardized urinary iodine concentration (UIC) was 80·8 (interquartile range (IQR) 46·1-130·6) µg/g Cr or 69·4 (IQR 53·9-92·6) µg/l during pregnancy, and 81% of pregnant women had UIC levels below the WHO recommended range of 150-250 µg/g Cr. The UIC was lowest during the first trimester of pregnancy, 56·0 (IQR 36·4-100·6) µg/g Cr, reaching higher concentrations of 87·5 (IQR 46·4-141·7) µg/g Cr and 86·9 (IQR 53·8-140·6) µg/g Cr in the second and third trimesters, respectively. Women taking supplements containing ≥150 µg iodine (6·8% of respondents) had non-significantly higher UIC than did women without supplementation (96·2 v. 80·3 µg/g Cr, respectively, P=NS). Thyroperoxidase antibody concentration did not correlate significantly with UIC: Spearman's ρ=-0·012, P=0·78. CONCLUSIONS: The median UIC indicates iodine deficiency in pregnant women in Latvia. Iodine supplementation (150 µg daily) and regular UIC monitoring should be suggested to overcome iodine deficiency and to reach the recommended levels without inducing autoimmune processes.

Iodine deficiency in pregnant women in Austria.

BACKGROUND/OBJECTIVES: In Austria, iodine deficiency has been considered to be eliminated owing to table salt fortification with iodine, but whether this also applies to pregnant women is unclear. Even mild iodine deficiency during gestation may lead to neurocognitive sequelae in the offspring. SUBJECTS/METHODS: This is a cross-sectional investigation of urinary iodine excretion in 246 pregnant women (first trimester n=2, second trimester n=53, third trimester n=191, gestational diabetes mellitus n=115, no gestational diabetes mellitus n=131). The iodine content of morning spot urine samples was determined using inductively coupled plasma mass spectrometry. RESULTS: Pregnant women in the Vienna area had a median urinary iodine concentration (UIC) of 87 µg/l. Only 13.8% of the cohort were in the recommended range of 150-249 µg/l, whereas 21.5% had a UIC of 0-49 µg/l, 40.2% had a UIC of 50-99 µg/l and 19.5% had a UIC of 100-149 µg/l. In all, 4.9% had a UIC over 250 µg/l. A total of 137 women of foreign origin had a significantly higher iodine excretion compared with Austrian-born women. Maternal or gestational age had no influence on UIC. Although 79 women on iodine supplementation had a significantly higher iodine concentration compared with women without iodine supplementation (97.3 vs 80.1 µg/l, P=0,006), their UIC was below the recommended range, indicating that doses of 100-150 µg per day are not sufficient to normalize iodine excretion. Sodium and iodine concentrations in the urine were tightly correlated (R=0.539, n=61), suggesting that low intake of iodized salt might contribute to insufficient iodine supply. CONCLUSIONS: This study shows that pregnant women in the Vienna area have a potentially clinically significant iodine deficiency and that currently recommended doses of iodine supplementation may not be sufficient.