Iodine status of Turkish pregnant women and their offspring: A national cross-sectional survey

BackgroundThis national cross-sectional survey aimed to assess the iodine status in pregnant women and their offspring, and also to demonstrate regional differences by measuring urinary iodine concentration (UIC). For each woman and her newborn a questionnaire was prepared with basic facts as age, parity number or birth weight and additional information regarding thyroid diseases, use of iodized salt in the household, extra iodine supplementation during pregnancy, education level and wage income.MethodsThe target population represented 1444 pregnant women who gave birth between January 1 st, 2018 and 2019, and their offspring. Iodine deficiency for pregnant women and their offspring were defined as urine iodine level <150 μg/L and <100 μg/L, respectively. Results are given as median (25th–75th percentile).ResultsThe median UIC in the group of pregnant woman was 94 (52–153) μg/L. Within the sample of 1444 pregnant women, UIC indicative of mild iodine deficiency (100−149 μg/L) was present in 21 % (n = 306), moderate deficiency (50−99 μg/L) in 30 % (n = 430), and severe deficiency (<50 μg/L) in 23 % (n = 337). This study showed a prevalence of 74 % of iodine deficiency in Turkish pregnant woman. The median UIC in the group of offspring was 96 (41−191) μg/L. Within the new-borns, UIC indicative of mild iodine deficiency (50−99 μg/L) was present in 22 % (n = 323), moderate deficiency (20−49 μg/L) in 15 % (n = 222), and severe deficiency (<20 μg/L) in 13 % (n = 192). This survey showed a prevalence of 51 % of iodine deficiency in Turkish new-borns. Pregnant women with lower socioeconomic and education level, lower access to household iodized salt, lower rates of exposure to povidone-iodine containing skin disinfectant, higher parity and higher iodine deficiency had higher rates of iodine deficiency in their offspring. Regional differences were observed both in mothers and their offspring concerning their iodine status.ConclusionsOur findings suggest that iodine deficiency is still an important public health problem in Turkey. More drastic measures should be taken to decrease these important iodine deficiencies, both in pregnant women and in their offspring.     

Oxidative Stress Increased in Pregnant Women with Iodine Deficiency

Iodine is an essential element trace for the synthesis of maternal thyroid hormones needed to support normal fetal development; it also acts as an antioxidant directly or induce antioxidant enzymes indirectly. Iodine deficiency and oxidative stress are associated with pregnancy complications. This study aimed to assess the urinary iodine concentration and its relationship with the antioxidant and oxidative stress status during gestation. Pregnant women were consecutively recruited from an obstetric clinic during all gestation trimesters, and urinary iodine concentration, antioxidant, and oxidative stress were determined. Results showed that 70 % of pregnant women have optimal iodine levels (150–200 μg/L), while approximately 30 % showed mild iodine deficiency (50–99 μg/L). Oxidative stress was significantly higher, and the antioxidant status was also compromised as evidenced by decreased total antioxidant status and superoxide dismutase (SOD) activity in pregnant women with mild iodine deficiency than pregnant women with optimal iodine levels. Significant positive correlations were noted between optimal iodine levels and total antioxidant status. Oxidative stress was significantly correlated with mild iodine deficiency. However, no significant correlation was found between iodine levels and SOD and catalase activities. In conclusion, for the first time, these data suggest a correlation between iodine levels and the antioxidant status during pregnancy.     

Current status of iodine intake in Croatia--the results of 2009 survey

In 1996, due to persistence of mild to moderate iodine deficiency, new law on obligatory salt iodination with 25 mg of potassium iodide (KI) per kg of salt was implemented in Croatia. Along with a new law, a new program for monitoring of iodine prophylaxis was implemented. Investigations of goiter and iodine intake performed in 2002, demonstrated sufficient iodine intake in Croatia with overall median of urinary iodine concentration (UIC) for schoolchildren in Croatia of 140 microg/L. In 2002, thyroid volumes (TV) measured by ultrasound in schoolchildren from all four geographic regions of Croatia were for the first time within the normal range according to ICCIDD reference values. Nowadays, Croatia is internationally recognized as iodine sufficient country. The aim of the present study was to assess current status of iodine intake in Croatia. The investigation was carried out in 2009. A total of 386 schoolchildren aged 7-10 years from all four major geographic regions of Croatia, 103 euthyroid pregnant women and 36 women of child-bearing age from Zagreb, the capital, were included in the survey. Urinary iodine concentration (UIC) was measured in all participants. Thyroid volumes were measured by ultrasound in schoolchildren from the capital of Zagreb (N = 101) and the village of Rude (N = 56). In the time period 2002-2009, the content of KI was analyzed in 384 salt samples from Croatian salt plants and samples of imported salt. An overall median UIC for schoolchildren in Croatia was 248 microg/L. Median UIC in pregnant women was 159 microg/L, with 50% of samples below and under 150 microg/L. Median UIC in women of child-bearing age was 136 microg/L. Thyroid volumes in schoolchildren were within the normal range according to the new reference values. Mean value of KI/kg of salt in samples from Croatian salt plants was 25.5 mg/kg and 24.9 mg/kg in samples of imported salt. A total of 72/384 (18.8%) of salt samples didn't corresponded to the Croatian law on obligatory salt iodination. Presented data indicate sufficient iodine intake of the Croatian population. Current medians of UIC in schoolchildren in Croatia are significantly higher than medians measured in 2002. This indicates that other potential sources of iodine are present in Croatian diet that may contribute to overall iodine intake. Due to rising medians of UIC in schoolchildren in Croatia, it is important to conduct nutrition studies to identify potential sources of "silent prophylaxis" in order to avoid iodine excess.     

Urinary iodine and sodium concentration and thyroid status in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

ObjectivesTo evaluate urinary iodine concentration (UIC) in civil servants aged 35-74 years of the Brazilian Study of Adults Health (ELSA-Brasil) to analyze its relationship with sociodemographic, clinical risk factors, lifestyle, urinary Na and thyroid status.DesignCross-sectional study in six Brazilian cities.MethodsThis analysis included 792 participants with information about urinary iodine concentration (UIC). Thyroid status was defined by serum levels of TSH/FT4 and the current use of antithyroid drugs for treatment of overt hyperthyroidism or levothyroxine to treat overt hypothyroidism. The determination of UIC was carried out with an inductively coupled plasma mass spectrometer (ICP-MS) and was expressed as median with Interquartile Range (IQR).ResultsIn 792 participants, thereof 52% women, mean age was 51.9 (9.0) years. The median UIC was 219 (IQR, 166-291) for all persons studied, thereof 211 (IQR, 157-276) for women and 231 (IQR, 178-304) for men. According to the WHO classification, for all persons studied, 60% had more than adequate iodine-supply (UIC ≥200 μg/L), 37% were adequately supplied (UIC 100-199 μg/L) and <3% had a deficient iodine status (<100 μg/L). In the 35-44-year age strata, which includes women of childbearing age, 23.2% of women presented less than 150 μg/L of UIC. No differences in UIC were detected according to thyroid status. (P = 0.39) The correlation between Ur-Na and UIC showed a Spearman coefficient of 0.52 (P < 0.0001) and it was also found an association of Ur-Na with UIC: Beta of 1.76 (95% Confidence Interval (95% CI): 1.01 to 2.51. The urinary Na concentration showed a synergy with the UIC, that means medians of 57, 72, 107 and 141 mmol Na/L urine (P < 0.001) in the groups with the four UIC classes according to the WHO grading mentioned above. The very low Na content in the persons exhibiting <100 μg/L UIC seems to reflect also a higher urine volume due to the frequent use of diuretics. The strong relationship between the urinary Na concentration and the UIC points to a dependence of the UIC on the individual consumption of iodized salt, which should be more considered in future studies. The strong relationship between the urinary Na concentration and the UIC points to a dependence of the UIC on the individual consumption of iodized salt, which should be more considered in future studies.ConclusionsEuthyroid persons were dominating by more than four fifths and no significant association was found between UIC and thyroid status. Although most of the persons studied present more than adequate iodine intake it was observed that nearly a quarter of women in childbearing age are iodine deficient.     

Assessing iodine intakes in pregnancy and strategies for improvement

An adequate intake of iodine in the diet of pregnant women is important to ensure normal growth and development of the fetus. It is difficult, however, to accurately determine iodine intakes using traditional methods of dietary assessment, primarily because the contribution of iodised salt use, at the table and in cooking, to total iodine intake is difficult to quantify. Given the limitations of dietary assessment, biochemical indices in blood and urine are typically used to assess iodine status in children and adults. Although reference ranges exist for thyroid hormones, there has been no consensus on the cut-offs needed in pregnancy to diagnose iodine deficiency. In contrast, a median urinary iodine concentration (UIC) of 150-249 μg/L has been established to determine the adequate iodine status of a group of pregnant women. However, the large intra-individual variation in UIC from either spot or 24h urine samples means that UIC cannot be used to assess iodine status in an individual pregnant woman. The difficulty in determining if an individual pregnant woman is iodine deficient is problematic for cross-sectional studies examining associations between iodine status in pregnancy and developmental outcomes in the child.     

Evaluation of endemic goiter prevalence in Bulgarian schoolchildren

Iodine deficiency is a major health problem worldwide. The environment of the Balkan countries, including Bulgaria, is distinguished for its low iodine content. In 1994, the strategies for the prevention and control of iodine-deficiency disorders were actualized in Bulgaria and universal salt iodization and supplementation for the risk population groups (schoolchildren, pregnant women) were introduced. The aim of this study was to assess the effectiveness of the iodine prophylaxis in schoolchildren, living in an endemic for goiter area after the introduction of salt iodization in Bulgaria. For this purpose, the goiter prevalence and iodine status in 483 schoolchildren (274 boys and 209 girls) aged between 8 and 15 yr, living in an endemic for goiter area in Bulgaria were evaluated. Despite the normalization of iodine supply, mild iodine deficiency on the basis of goiter prevalence (16.15%) and urinary iodine excretion was found. These data indicate the need for reevaluation of the national strategy for prevention of iodine deficiency.     

Urine Iodine Levels in Preeclamptic and Normal Pregnant Women

The aim of this study was to investigate the urine iodine concentration in women with severe preeclampsia and in healthy women in Erzurum, Turkey. Urine specimens were obtained from 40 severe preeclampsia and 18 healthy pregnant women. Urinary iodine levels were determined by the Foss method based on the Sandell–Kolthoff reaction. The urinary iodine level for women with severe preeclampsia was 4.25 ± 2.7 μg/dL, lower than 20.89 ± 6.4 μg/dL of urinary iodine for healthy pregnant women (p < 0.001). Blood magnesium concentration was found to be 1.63 ± 0.05 mg/dL for women with severe preeclampsia, which is lower than that of healthy pregnant women (1.87 ± 0.05 mg/dL; p < 0.001). There was a positive correlation between urinary iodine level and blood magnesium level in pregnant women with preeclampsia (Pearson correlation coefficient = 0.43; p < 0.01). However, there was no correlation between urinary iodine level and blood magnesium level in healthy pregnant women. There was no difference in thyroid hormone levels (T4, TSH, FT4) between women with severe preeclampsia and healthy pregnant women. However, there was a difference in T3 thyroid hormone levels between women with severe preeclampsia (1.86 ± 0.4 μg/dL) and healthy pregnant women (1.45 ± 0.3 μg/dL; p < 0.001). There was also a difference in FT3 between women with severe preeclampsia (2.77 ± 0.4 pg/mL) and healthy pregnant women (2.41 ± 0.5 μg/dL; p < 0.01). Urinary iodine excretion is currently the most convenient laboratory marker of iodine deficiency. The method is useful for the rapid and low-cost assessment of iodine deficiency. Our results suggested that urinary iodine concentration might be a useful marker for prediagnosing preeclamptic women. In addition, iodine supplementation may also be considered for preeclamptic therapy.     

Incidence of thyroid diseases in Zhejiang Province,China, after 15 years of salt iodization

Thyroid diseases(TD) can be induced by either deficient or excessive iodine intake. Universal Salt Iodization(USI) program has been implemented in China since 1995, to prevent iodine deficiency disorders (IDD). To evaluate the current conditions of TD and the role of USI, a multi-stage stratified random sampling scheme was used to perform a cross-sectional survey on the incidence of TD among participants in 6600 households in Zhejiang Province, a coastal area in China. Iodine nutrition status of the population was assessed by dietary iodine intake recall and urinary iodine concentration (UIC) of the participants, and TD were diagnosed by thyroid ultrasonography for 15122 participants and for 5873 participants by serum criteria for thyroid function(fT3, fT4, TSH, TRAb, TgAb, TPOAb; see Introduction for abbreviations). The median UIC of the surveyed population was 163 μg iodine/L. From the participants 23.2% had UIC < 100 μg/L which is moderately iodine-deficient according to WHO classification. Diffuse goiter was present in 2.3% of the population and thyroid nodule in 20.9%. The incidence of hyperthyroidism, subclinical hyperthyroidism, hypothyroidism, subclinical hypothyroidism, Graves’ disease and chronic lymphocytic thyroiditis was 0.5%, 0.6%, 0.6%, 7.8%, 0.2% and 0.3%, respectively. The proportion of several TD for participants with non-iodized salt intake was higher than that for participants with iodized salt intake.     

Relationship between mild iodine deficiency in pregnant women and thyroid function: A meta-analysis

BackgroundPregnant women are among the key groups in iodine nutrition evaluation. The purpose of the present study was to summarize the evidence supporting the relationship between mild iodine deficiency (UIC: 100–150 μg/L) in pregnant women and levels of thyroid function tests.MethodsThis review follows the guidelines for systematic reviews (PRISMA 2020). Three electronic databases (PubMed, Medline, and Embase) were searched for relevant publications in English on the association between mild iodine deficiency in pregnant women and thyroid function. Articles published in Chinese were searched in China’s electronic databases (CNKI, WanFang, CBM, and WeiPu). Pooled effects were presented as standardized mean differences (SMDs) and odds ratios (ORs) with 95% confidence intervals (CIs) using fixed or random effect models, respectively. This meta-analysis was registered at www.crd.york.ac.uk/prospero as CRD42019128120.ResultsWe summarized the results from 7 articles with 8261 participants. The overall pooled results showed that the levels of FT₃, FT4, and abnormal TgAb (the antibody levels exceeded the upper limit of the reference range) were significantly increased in pregnant women with mild iodine deficiency compared to pregnant women with adequate iodine status (FT₃: SMD=0.854, 95% CI: 0.188, 1.520; FT₄: SMD=0.550, 95% CI: 0.050, 1.051; TgAb: OR=1.292, 95% CI: 1.095; 1.524). Subgroup analysis was carried out on the sample size, ethnicity, country, and gestation of FT₃, FT_4, and TSH, but no plausible factor was found. Egger’s tests indicated no publication bias.The increase in FT₃ and FT_4, as well as TgAb levels, in pregnant women is associated with mild iodine deficiency.ConclusionMild iodine deficiency is associated with an increase in FT_3,FT₄ and TgAb levels in pregnant women. Mild iodine deficiency may increase the risk of thyroid dysfunction in pregnant women.     

24 h urinary creatinine excretion during pregnancy and its application in appropriate estimation of 24 h urinary iodine excretion

BackgroundUrinary creatinine can be used to adjust urinary iodine to evaluate iodine nutritional status during pregnancy. However, the reference intervals and impact factors of urinary creatinine are unknown.Methods24 h urine creatinine concentration (24 hUCr) and spot UCr at four different time periods of the day of pregnant women from Part 1 (n = 743) were measured. Linear regression analysis was performed to identify the impact factors of 24 h urinary creatinine excretion (24 hUCrE) and obtain the estimated 24 h urinary creatinine excretion (24 hUCrE_est). Then measured urinary iodine concentration (UIC) of 24 h and at fasting of pregnant women from Part 2 (n = 325), used spot urinary iodine to creatinine concentration ratio (UIC/UCr) and 24 hUCrE_est to calculate the estimated 24 h urinary iodine excretion (24 hUIE_est), finally checked the consistency and correlation of 24 hUIE_est and 24 h urinary iodine excretion (24 hUIE).ResultsIn Part 1, the median 24 hUCrE was 1.24(IQR0.98–1.76)g, and the reference interval was 0.61−2.93 g. The median 24 hUCr was 0.76 (IQR0.57−1.01)g/L, and the reference interval was 0.36−1.88 g/L. Multiple linear regression results showed that pregnancy weight was an influencing factor to 24 hUCrE after adjusting by gestational weeks, age, pre-pregnancy BMI, and percentage of body fat (F = 45.029, p＜0.001). In Part 2, there was no statistically significant difference between 24 hUIE_est and 24 hUIE (Z =−0.767, p = 0.443). Using 24hUIE as the gold standard, the relative average difference in 24hUIE_est was 4.2 %, the relative average differences for UIC and UIC/UCr were 32.4 % and 37.2 %. The reference interval of 24 hUIE and 24 hUIE_est were 88.43–585.90 μg and 50.97–700.39 μg, respectively.ConclusionsThe reference intervals of 24 hUCrE, spot UCr, 24 hUIE, and 24 hUIE_est during pregnancy were established. 24 hUCrE has important application value in iodine nutrition evaluation to gain more lead time for pregnant women with iodine nutrition-related diseases.     

Iodine supplementation in pregnancy and its effect on child cognition

Maternal hypothyroidism and hypothyroxenemia due to iodine deficiency have been shown to affect development of the newborn negatively. Maternal iodine supplementation may therefore improve cognitive performance of the offspring, even in areas of mild-to-moderate iodine deficiency (ID). Several iodine supplementation studies have been performed in mildly ID pregnant women in Europe. These studies have shown that iodine supplementation increases maternal urinary iodine (UI) excretion and reduces thyroid volume, as well as prevents increases in infant thyroid volume and thyroglobuline. However, randomized controlled studies with long-term outcomes are lacking. Therefore, two trials were started in 2008 in areas of low iodine status; one in Bangalore, India (n=325), and another in Bangkok, Thailand (n=514). Pregnant women were recruited <14 weeks gestational age and randomized to either receive a daily dose of 200 μg I (as KI) or an identical placebo throughout pregnancy. Both trials are ongoing, and women are followed up during pregnancy and at delivery. UI, thyroid hormones, and thyroid size are measured. Birth outcomes are recorded, such as gestational age at delivery, height, weight, and APGAR scores, and cord blood and heel stick blood (<72 h) is collected from the child. Child development is assessed at 6 weeks of age using the Neonatal Behavioral Assessment Scale (NBAS), and at 12 and 24 months of age using the Bayley Scales of Infant Development. The outcomes of these trials will contribute importantly to the evidence base for iodine supplementation of pregnant women living in areas of mild iodine deficiency.     

Nutrición de yodo en mujeres embarazadas del área de Oviedo. ¿Es necesaria la suplementación con yodo?

Background and objectiveIn Asturias, where iodine deficiency was eradicated in school children by the year 2000, iodine deficiency persisted in pregnant women, who were recommended to use of iodine supplementation. The aim of this study was to determine the iodine nutrition of pregnant women in our area and whether or not iodine supplements are needed.Material and methodsThroughout May and June 2013 we studied the iodine nutrition and thyroid function during the first trimester of pregnancy in 173 women in the health area of Oviedo.ResultsThe median urinary iodine was 197 μg/L. Iodinated supplements were used by 47% of women, which had a yoduria median higher than those not taking iodinated supplements (247 vs. 138 μg/L; p < .001), and also a higher TSH (2.30 vs 1.94 mU/L) although not significantly different. Yoduria was also higher in women who took more than 2 servings of dairy products (median: 230 μg/L) than those who took less (median: 191 μg/L). Within the group of women who were not taking iodine supplements, those regularly using iodized salt in the kitchen (47%) had a median urinary iodine concentration of 190 μg/L indicating iodine sufficiency.ConclusionsIodinated supplements seem unnecessary nowadays in pregnant women of Oviedo who regularly take iodized salt and our recommendation in these cases should be to continue the use of iodized salt in the recommended amounts during pregnancy and consume at least two daily servings of milk or dairy products.     

Teratology public affairs committee position paper: Iodine deficiency in pregnancy

Iodine deficiency is an important nutritional deficiency, with more than 2 billion people worldwide estimated to be at risk. The developing fetus and young children are particularly at risk. During pregnancy and lactation, iodine requirements increase, whether in iodine-poor or iodine-sufficient countries, making the mother and the developing fetus vulnerable. The American Thyroid Association (ATA) recommends 250 micrograms per day of iodine intake for pregnant and lactating women. The thyroid gland is able to adapt to the changes associated with pregnancy as long as sufficient iodine is present. Dietary intake is the sole source of iodine, which is essential to the synthesis of thyroid hormones. Iodine is found in multiple dietary sources including iodized salt, dairy products, seaweed, and fish. Prenatal vitamins containing iodine are a good source of iodine, but iodine content in multivitamin supplements is highly variable. Congenital hypothyroidism is associated with cretinism. Clinical hypothyroidism has been associated with increased risk of poor perinatal outcome including prematurity, low birth weight, miscarriage, preeclampsia, fetal death, and impaired fetal neurocognitive development. Subclinical hypothyroidism is also associated with poor pregnancy outcomes and potential fetal neurocognitive deficits, but the data are more variable than those for clinical hypothyroidism. We concur with the ATA recommendation that all pregnant and lactating women should ingest (through diet and supplements) 250 micrograms of iodine daily. To achieve this goal, we recommend that all pregnant and lactating women take daily iodine supplementation of 150 micrograms. Birth Defects Research (Part A) 94:677-682, 2012. ? 2012 Wiley Periodicals, Inc.     

Assessment of Iodine Status in Children,Adults, Pregnant Women and Lactating Women in Iodine-Replete Areas of China

Background

Iodine deficiency disorders (IDD) are widespread in China. Presently, IDD have been put under control by Universal Salt Iodisation (USI) in China; however, there is a lack of evidence on whether the iodine status in adults, pregnant women and lactating women is optimal. This study was therefore conducted to assess the iodine nutrition and thyroid function of children, adults, pregnant women and lactating women residing in areas where the USI program is fully established.

Design

Six areas were selected according to the geographical regions in China. In each of these areas, we selected 4 distinct groups of subjects (children, adults, pregnant women and lactating women) in regions where the coverage rate of iodised salt was more than 95% and the levels of iodine and fluoride in drinking water were less than or equal to 10 µg/L and 1 mg/L, respectively. We tested the iodine content of salt, urinary iodine (UI), free thyroxin (FT4), thyrotropin (TSH), thyroglobulin (Tg), thyroglobulin antibody (Tg-Ab) and antimicrosomal antibody (TM-Ab) in the 4 groups, and examined the thyroid volume in children.

Results

The median urinary iodine (MUI) concentrations were 271.4 μg/L, 260.2 μg/L, 205.9 μg/L and 193.9 μg/L in children, adults, pregnant women and lactating women, respectively; MUI in children and adults were more than adequate. The goitre prevalence (GP) in children was 6.70%. The odds ratios (OR) of subclinical hypothyroidism in the Tg-Ab- or TM-Ab-positive groups were 3.80, 7.65, 2.01 and 7.47 for children, adults, pregnant women and lactating women, respectively, compared with the negative groups.

Conclusions

The iodine status in children and adults is above the requirement, we should reduce their iodine intake. Subclinical hypothyroidism easily occurs in the Tg-Ab or TM-Ab positive groups.     

Effect of Iodine Nutrition on Pregnancy Outcomes in an Iodine-Sufficient Area in China

Many studies focused on the association between thyroid disease and pregnancy outcomes. The present study explored the effect of iodine nutrition during the first trimester on pregnancy outcomes. One thousand five hundred sixty-nine pregnant, euthyroid women at ≤12 weeks of gestation in an iodine-sufficient area in China were recruited. According to the World Health Organization (WHO) criteria for iodine nutrition during pregnancy, participants were divided into four groups: adequate iodine (median urinary iodine concentration (UIC), 150–249 μg/L), mild deficiency (UIC, 100–150 μg/L), moderate and severe deficiency (UIC, <100 μg/L), and more than adequate and excessive (UIC, ≥250 μg/L) groups. Pregnancy outcomes, including abortion, gestational hypertension, pre-eclampsia, gestational diabetes mellitus (GDM), placenta previa, placental abruption, preterm labor, low birth weight infants, macrosomia, breech presentation, and cord entanglement, were obtained during follow-up. The results showed that there was no significant difference in general characteristics, including age, body mass index, abdominal circumference, systolic blood pressure, diastolic blood pressure, heart rate, smoking rate, and drinking rate, among the four groups. In the more than adequate and excessive group, thyroid-stimulating hormone (TSH) was greater and free thyroxine (FT4) was lower than any other groups but still within normal range. The thyroglobulin (Tg) level was greater in the moderate and severe deficiency group. The incidence of GDM was significantly greater in women with mild iodine deficiency than in women with adequate iodine nutriture (18.38 vs. 13.70%, p < 0.05). Compared with the adequate group, incidence of macrosomia was significantly greater in the more than adequate and excessive group (12.42 vs. 9.79%, p < 0.05). Mild iodine deficiency was an independent risk factor for GDM (odds ratio = 1.566, 95% confidence interval = 1.060–2.313, p = 0.024); more than adequate and excessive iodine was an independent risk factor for macrosomia (OR = 1.917, CI = 1.128–3.256, p = 0.016). In summary, during 1st trimester, both mild iodine deficiency and excessive iodine intake had adverse impacts on pregnancy outcomes in an iodine-sufficient area.     

Iodine in plant-based dairy products is not sufficient in the UK: A market survey

BackgroundFollowing a well-balanced diet ensures that a person gets all the essential elements for health sustenance. However, in the United Kingdom an increasing proportion of people are transiting to become vegans who exclude animal-based products in their diets. Consequently, people may have a deficit of essential elements such as iodine which is not present in most plant-based meals, additionally iodide fortified table salt is not commonly used in the UK. Without iodine people consuming a vegan diet risk developing iodine deficiency and diseases like goiter.MethodsThe objective of this study is to determine the difference in iodine content and iodine speciation between plant-based and dairy products. More than 100 market samples of plant-based and dairy milk products were collected in Scotland, UK.ResultsIodine concentrations in dairy milk is ten times higher compared to plant-based milks. Similar differences were also apparent for butter, yogurt and cheese. A total of 20% of plant-based milk products were fortified with iodine, however these products had lower iodine concentrations compare to the equivalent dairy products. In this study we calculated that people with average diet have an iodine intake of 226 + /- 103 μg day⁻¹ from dairy products which satisfies the WHO recommended intake of adults and 90% of the recommend intake for pregnant and breast-feeding women. A diet from substituted dairy products gives only 21.8 µg day⁻¹ for the respective WHO guideline intake values, which accounts only 15% of the iodine intake for adults and 9% for pregnant and lactating women. Iodine fortified diet could increase the iodine intake to 55% or 33% of the WHO recommended daily intake respectively.ConclusionPlant-based dairy consumers are encouraged to use iodine fortified dairy products or use of iodized salt in the UK for home cooking, otherwise there are at risk to get iodine deficient.     

Suplementación con yodo durante el embarazo y la lactancia. Toma de posición del Grupo de Trabajo de Trastornos relacionados con la Deficiencia de Yodo y Disfunción Tiroidea de la Sociedad Española de Endocrinología y Nutrición

Severe and mild iodine deficiency during pregnancy and lactation affects thyroid function of the mother and neonate as well as the infant's neuropsychological development. Studies performed in Spain confirm that most women are iodine deficient during pregnancy and lactation. Pregnant and breast feeding women and women planning to become pregnant should take iodine supplements.     

Serum selenium and selenoprotein P status in adult Danes – 8-year followup

Selenium is an essential micronutrient important to human health. The main objective of this study is to describe serum selenium and selenoprotein P status in two samples of the Danish population. In addition, the influence of various factors potentially associated with selenium status was investigated.Blood samples from a total of 817 randomly selected subjects from two cities in Denmark were analyzed. Half of the samples were collected in 1997–1998 and the other half in 2004–2005. Samples from women aged 18–22, 40–45 and 60–65 years, and men aged 60–65 years were selected for this study. All subjects had filled in a food frequency questionnaire (FFQ) and a questionnaire with information about smoking habits, alcohol consumption and exercise habits.Mean serum selenium level was 98.7±19.8 μg/L and median selenoprotein P level was 2.72 (2.18–3.49) mg/L. Serum selenium and selenoprotein P increased with age, and selenoprotein P was higher in men than in women. Serum selenium levels decreased by 5% on average from 1997–98 to 2004–05 (P<0.001), whereas selenoprotein P level increased (P<0.001). The intake of fish correlated weakly with serum selenium level (r=0.14, P<0.001) but not with selenoprotein P level. Smoking status, alcohol intake, exercise habits, BMI and medicine use did not influence selenium status.It is concluded that selenium status in this Danish population is at an acceptable level. No major groups with regard to age, sex or lifestyle factors could be identified as being in risk for selenium deficiency.     

Excessive iodine intake and thyroid dysfunction among lactating Saharawi women

ObjectivesExcessive iodine intake may lead to thyroid dysfunction, which may be particularly harmful during pregnancy and lactation. The main objective was to describe iodine status and the prevalence of thyroid dysfunction among lactating women in areas with high iodine (HI) and very high iodine (VHI) concentrations in drinking water.Design and methodsA cross-sectional survey was performed among 111 lactating women in the Saharawi refugee camps, Algeria. Breast milk iodine concentration (BMIC), urinary iodine concentration (UIC) and the iodine concentration in the most commonly consumed foods/drinks were measured. A 24-h dietary recall was used to estimate iodine intake. Thyroid hormones and antibodies were measured in serum.ResultsMedian UIC, BMIC and iodine intake across both areas was 350 μg/L, 479 μg/L and 407 μg/day, respectively. In multiple regression analyses, we discovered that being from VHI area was associated with higher UIC and BMIC. BMIC was also positively associated with iodine intake. Thyroid dysfunction and/or positive thyroid antibodies were found in 33.3% of the women, of which 18.9% had hypothyroidism and 8.1% had hyperthyroidism and 6.3% had positive antibodies with normal thyroid function. Elevated thyroid antibodies were in total found in 17.1%. We found no difference in distribution of thyroid dysfunction or positive antibodies between HI and VHI areas. BMI, BMIC and elevated thyroglobulin (Tg) predicted abnormal thyroid function tests.ConclusionsThe high prevalence of thyroid dysfunction may be caused by excessive iodine intake over several years.