Mean Urinary Iodine Concentration Research Articles

Association of Excess Dietary Iodine Intake with Papillary Thyroid Carcinoma

Background: Papillary thyroid carcinoma (PTC) is the most common type of differentiated thyroid carcinoma and accounts for 70–80% of all thyroid carcinomas. After the global iodine fortification of salt and food, the incidence of PTC has been increasing throughout the world in recent years. Aims: To determine the relationship between excessive dietary iodine intake and PTC. Patients and methods: This cross-sectional study was carried out at the National Institute of Nuclear Medicine & Allied Sciences (NINMAS), Dhaka, from March 2020 to June 2021. A total of 111 patients were included in this study, of whom 53 were pre-operative papillary thyroid carcinoma patients and the rest, 58, were age- and sex-matched healthy individuals. Their urinary iodine concentrations were measured in the laboratory of the Bangladesh Reference Institute for Chemical Measurements (BRICM). Urinary iodine concentration is a good marker of dietary iodine intake. Statistical analysis of the results was obtained using Windows-based computer software devised with Statistical Packages for Social Sciences (SPSS) version 23.0. Results: The mean urinary iodine concentration was 223.54±55.78 microgram/liter in the PTC group and 154.29±61.83 microgram/liter in the healthy group. A remarkable number of participants in both the PTC group 42 out of 53 (79.3%) and the healthy group 18 out of 58 (31.0%) had biochemical evidence of excess iodine intake. Excess iodine intake significantly (p<0.05) increased with 8.48 times odds (95% CI 3.30-22.33) in PTC patients. Conclusion: This study revealed that a significant number of participants in the PTC group had evidence of excess iodine intake compared to that of the healthy group, which suggests that excess dietary iodine intake may be related to the occurrence of PTC. Bangladesh J. Nuclear Med. 26(1): 25-30, 2023

The prevalence of insufficient iodine intake in pregnancy in Africa: a systematic review and meta-analysis

BackgroundFortification of foodstuffs with iodine, mainly through iodization of salt, which commenced in several African countries after 1995 is the main method for mitigating iodine deficiency in Africa. We assessed the degree of iodine nutrition in pregnancy across Africa before and after the implementation of national iodine fortification programs (CRD42018099434).MethodsElectronic databases and gray literature were searched for baseline data before implementation of population-based iodine supplementation and for follow-up data up to September 2020. R-metamedian and metamean packages were used to pool country-specific median urinary iodine concentration (UIC) estimates and derived mean UIC from studies with similar features.ResultsOf 54 African countries, 23 had data on iodine nutrition in pregnancy mostly from subnational samples. Data before 1995 showed that severe iodine deficiency was prevalent in pregnancy with a pooled pregnancy median UIC of 28.6 μg/L (95% CI 7.6–49.5). By 2005, five studies revealed a trend towards improvement in iodine nutrition state in pregnancy with a pooled pregnancy median UIC of 174.1 μg/L (95% CI 90.4–257.7). Between 2005 and 2020 increased numbers of national and subnational studies revealed that few African countries had sufficient, while most had mildly inadequate, and some severely inadequate iodine nutrition in pregnancy. The pooled pregnancy median UIC was 145 μg/L (95% CI 126–172).ConclusionImprovement in iodine nutrition status in pregnancy following the introduction of fortification of foodstuffs with iodine in Africa is sub-optimal, exposing a large proportion of pregnant women to the risk of iodine deficiency and associated disorders.Systematic review registrationPROSPERO CRD42018099434

Fortification of salt with iron and iodine versus fortification of salt with iodine alone for improving iron and iodine status.

Fortification of salt with iron and iodine versus fortification of salt with iodine alone for improving iron and iodine status.

Urinary iodine as an important indicator for preeclampsia: a Polish perspective

Abstract Preeclampsia (PE) is one of the leading causes of perinatal and maternal morbidity. Although subclinical hypothyroidism in pregnancy is one of the established risk factors for PE, the link between iodine deficiency and PE is not fully understood. The aim of our study was to assess urinary iodine concentration (UIC), serum thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) levels in Polish women with PE (PE group, n=78) compared with healthy non-pregnant women (CNP group, n=30), and healthy pregnant women (CP group, n=46). The UIC was determined by inductively coupled plasma mass spectrometry (ICP-MS). Both the mean UIC of 144.6±36.4 μg/L in the CP group and the mean of 125.8±33.6 μg/L in the PE group, respectively, were lower compared to non-pregnant women (149.8±28.8 μg/L), and the difference between the PE and CNP groups was statistically significant. TSH values were the highest in the PE group, while the lowest average level was for the CNP group. The fT3 and fT4 values in the PE group were significantly lower compared to the CNP and CP groups. Despite iodine supplementation during pregnancy, the UIC was lower compared to non-pregnant women, while in women with PE it was at a significantly lower level. To reduce the incidence of possible health complications, proper iodine supplementation and monitoring of the UIC is recommended for pregnant women suffering from PE or at risk of developing PE.

Association of Salt Iodization and Urine Iodine Concentration in Schoolchildren from Public Schools in Northeast of Brazil.

Iodine deficiency (ID) is recognized as a leading risk factor for child development. Universal salt iodization (USI) is an effective and well-established intervention strategy for the prevention of iodine deficiency disorders (IDD). To evaluate the levels of iodine in household salt samples and the urinary iodine concentration (UIC) in schoolchildren aged 6 to 14years in public schools in Bahia, Brazil. A cross-sectional study was conducted with 1231 students (6 to 14years old) from 17 public schools in Bahia. The iodine concentration was evaluated in salt and UIC samples. The adapted Sandell-Kolthoff reaction was used to determine urinary iodine levels. A spectrophotometer (UV-Vis) was used to examine the reduction of ceric ammonium sulfate. A standard iodine solution using a potassium iodate was used to extrapolate the iodine concentrations. The total of 665 salt samples had a median iodine concentration of 24mg/kg (25th-75th percentile 17.0 to 28.5mg/kg). The largest proportion (79.6%) of salt samples had iodine concentration in the recommended range, 17.6% of the samples presented iodine at a salt concentration below the established level (<15mg/kg) and a small proportion was above it (2.8%). The general mean urinary iodine concentration (MUIC) was 217.53 ± 28.30μg/L and median was 205.50μg/L. The students evaluated and the salt samples analyzed showed satisfactory results, as recommended by Brazilian legislation and nutritional recommendations of the World Health Organization (WHO).

Iodine concentration and prevalence of thyroid disease in older people after salt iodization in Turkey.

Iodine uptake is a main factor affecting thyroid disease. In Turkey, mandatory salt iodization began in 1999-2000. This study in 2009 determined the prevalence of thyroid diseases in older people in Mamak district, Ankara after iodization to ascertain if salt iodization alone is sufficient to reach adequate iodine levels in the older population. All Mamak residents ≥ 65 years were eligible for inclusion in the study. Demographic data and medical history were recorded. All participants had a thyroid ultrasound. Blood samples were taken to assess thyroid function and autoantibodies, and urine samples to assess iodine concentration. Participants with low levels of thyroid stimulating hormone underwent scintigraphy to assess thyroid uptake. Fine-needle aspiration biopsy was done of nodules ≥ 1.5 cm where thyroid stimulating hormone was not suppressed. Of 1200 eligible residents, 979 were included. Their mean age was 70.9 (standard deviation (SD) 5.7) years; 49.7% were women. Mean urinary iodine concentration was 98 (SD 81.29) μg/L. Goitre was found in 18.2% (89/487) of women and 6.7% (33/492) of men (P < 0.001) and 43.8% (428/979) had nodules. Subclinical hypothyroidism was found in 5.8% (57/979) of the participants, overt hyperthyroidism in 0.8% (8/979), subclinical hyperthyroidism in 2.2% (22/979) and T3 thyrotoxicosis in 0.3% (3/979). Toxic multinodular goitre and toxic adenoma caused 80% of hyperthyroidism cases. Biopsy detected no malignant pathology. After salt iodization, iodine levels have not yet reached favourable levels in older people. Iodization of salt seems insufficient to achieve these levels in older people; alternative iodine supplementation should be considered.

Insufficient iodine nutrition status and the risk of pre-eclampsia: a systemic review and meta-analysis

BackgroundAlthough subclinical hypothyroidism in pregnancy is one of the established risk factors for pre-eclampsia, the link between iodine deficiency, the main cause of hypothyroidism, and pre-eclampsia remains uncertain. We conducted...

Evaluation of iodine salt intake, salt storage, and urinary iodine among the households in Markazi Province, Iran

BACKGROUND: Iodine deficiency is known as a major nutritional health problem in Iran. The aim of this study was to evaluate iodine salt intake, salt storage, and urinary iodine in households of Markazi Province, Iran, in 2014. METHODS: In this cross-sectional analytical study, 440 households of 11 cities in Markazi Province in 2014 were selected through a multistage random sampling. A structured questionnaire was used to collect information about the type of salt used and awareness about salt storage. Parameters of salts were measured by taking the samples from household salt. Simultaneously, urinary iodine was measured via samples from the elementary students in the household. Data were analyzed using SPSS software. RESULTS: Of 440 households, 225 households (58.0%) used iodized refined salt. Approximately, 60.0% of households were aware of the correct way of salt storage. The mean urinary iodine concentration (UIC) of children was 19.2 ± 18.3 μg/l. The average iodine concentration in household salts was 29.3 ± 3.8 ppm and only half of the salt-producing companies had iodine levels above 30 ppm. The average of salt heavy metals at the level of production and consumption was at a standard level. CONCLUSION: The average iodine concentration of salts was less than the standard level. Therefore, in the absence of proper monitoring of the cycle of production and supply of iodized salt, there is a possibility of recurrent iodine deficiency complications in Markazi Province. Enhancing public awareness about salt storage for maintaining the quantity and quality of iodine is recommended.

Change over time in the iodine nutritional status of pregnant women from the Pamplona healthcare region

IntroductionAdequate iodine intake is essential during pregnancy. A previous study of pregnant women from the Pamplona healthcare region showed mild iodine deficiency (mean urinary iodine level, 125mcg/L). This study was intended to ascertain the iodine intake of pregnant women in our region and to analyze the change over time in their iodine nutritional status. MethodsAn observational study of 400 women in their first trimester of pregnancy. An iodine intake questionnaire was administered. To assess iodine status, urinary iodine concentration (UIC) was measured in a simple urine sample, and serum thyroglobulin levels were determined. In addition, thyroid volume was measured by cervical ultrasound examination. ResultsIodized salt was used by 70.5% of all participants (55.3% since the pre-gestational period) and 98.5% of them received iodine-containing supplements (mean dose, 202.6±30.1mcg/day). Mean urinary iodine concentration was 242mcg/L (138.5–415.5mcg/L) and the mean serum thyroglobulin level was 12.3mcg/L (8.3–9mcg/L). Iodized salt intake was associated with higher UICs and lower thyroid volume. No differences were found in any of the tested parameters regarding the intake of dairy products, fish, or eggs. ConclusionsIodine intake by pregnant women in Pamplona has increased due to a greater use of iodized salt and to higher doses of iodine supplements. As a result of this, an adequate iodine status has been achieved in the last decade.

Consumption of multiple micronutrients or small-quantity lipid-based nutrient supplements containing iodine at the recommended dose during pregnancy, compared with iron and folic acid, does not affect women's urinary iodine concentration in rural Malawi: a secondary outcome analysis of the iLiNS DYAD trial.

Inadequate iodine intake during pregnancy increases the risk of neonatal morbidity and mortality. We aimed to evaluate whether prenatal supplements containing iodine affect urinary iodine concentrations (UIC) of pregnant women in Malawi. A randomised controlled trial. Pregnant women (n 1391) were assigned to consume 60 mg/d Fe and 400 µg/d folic acid (IFA) or 18 vitamins and minerals including 250 µg/d iodine (MMN) or 20 g/d small-quantity lipid-based nutrient supplements (SQ-LNS) with similar nutrient contents as MMN group, plus macronutrients (LNS) until childbirth. In a sub-study (n 317), we evaluated group geometric mean urinary iodine concentration (UIC) (µg/L) at 36 weeks of gestation controlling for baseline UIC and compared median (baseline) and geometric mean (36 weeks) UIC with WHO cut-offs: UIC < 150, 150-249, 250-499 and ≥500 reflecting insufficient, adequate, above requirements and excessive iodine intakes, respectively. Mangochi District, Malawi. Women ≤20 weeks pregnant. Groups had comparable background characteristics. At baseline, overall median (Q1, Q3) UIC (319 (167, 559)) suggested iodine intakes above requirements. At 36 weeks, the geometric mean (95 % CI) UIC of the IFA (197 (171, 226)), MMN (212 (185, 243)) and LNS (220 (192, 253)) groups did not differ (P = 0·53) and reflected adequate intakes. In this setting, provision of supplements containing iodine at the recommended dose to pregnant women with relatively high iodine intakes at baseline, presumably from iodised salt, has no impact on the women's UIC. Regular monitoring of the iodine status of pregnant women in such settings is advisable. Clinicaltrials.gov identifier: NCT01239693.

Standardized Map of Iodine Status in Europe.

Background: Knowledge about the population's iodine status is important, because it allows adjustment of iodine supply and prevention of iodine deficiency. The validity and comparability of iodine-related population studies can be improved by standardization, which was one of the goals of the EUthyroid project. The aim of this study was to establish the first standardized map of iodine status in Europe by using standardized urinary iodine concentration (UIC) data. Materials and Methods: We established a gold-standard laboratory in Helsinki measuring UIC by inductively coupled plasma mass spectrometry. A total of 40 studies from 23 European countries provided 75 urine samples covering the whole range of concentrations. Conversion formulas for UIC derived from the gold-standard values were established by linear regression models and were used to postharmonize the studies by standardizing the UIC data of the individual studies. Results: In comparison with the EUthyroid gold-standard, mean UIC measurements were higher in 11 laboratories and lower in 10 laboratories. The mean differences ranged from -36.6% to 49.5%. Of the 40 postharmonized studies providing data for the standardization, 16 were conducted in schoolchildren, 13 in adults, and 11 in pregnant women. Median standardized UIC was <100 μg/L in 1 out of 16 (6.3%) studies in schoolchildren, while in adults 7 out of 13 (53.8%) studies had a median standardized UIC <100 μg/L. Seven out of 11 (63.6%) studies in pregnant women revealed a median UIC <150 μg/L. Conclusions: We demonstrate that iodine deficiency is still present in Europe, using standardized data from a large number of studies. Adults and pregnant women, particularly, are at risk for iodine deficiency, which calls for action. For instance, a more uniform European legislation on iodine fortification is warranted to ensure that noniodized salt is replaced by iodized salt more often. In addition, further efforts should be put on harmonizing iodine-related studies and iodine measurements to improve the validity and comparability of results.

Is It Necessary to Recommend Iodine Supplement to Pregnant Women Living in Areas with Adequate Iodine Intake?

Background: Iodine need is increased during pregnancy and its deficiency can lead to complications in mother and fetus. The latest international guidelines have recommended a higher intake of iodine. Iran has implemented a national salt iodization program since 25 years ago, and the general population is iodine-sufficient. However, recent studies have shown that a significant proportion of pregnant women have urinary iodine concentration (UIC) below the recommended range of 150 - 250 µg/L. Based on the results of these studies, iodine supplement during pregnancy is widely used, but this practice is controversial. Objectives: The aim of this study was to evaluate the necessity for iodine supplementation in pregnant women living in Shiraz, an iodine-replete area. Methods: In this cross-sectional case-control study, UIC and thyroid-stimulating hormone of 174 pregnant women taking 150 µg/day iodine (group 1) were compared with 124 pregnant women not taking the supplement (group 2). The proportion of women with UIC below the recommended level in each group was also determined. UIC of the women in different trimesters in each group was also investigated and compared. Results: Mean UIC in groups 1 and 2 was 175.71 ± 56.43 µg/L and 122.5 ± 44.37 µg/L and this difference was significant (P = 0.006). Also, 56% of women in group 2 and 24 % in group 1 had UIC below the recommended value (P &lt; 0.01). Mean UIC in both groups decreased with advancing gestational age. In group 1, mean UIC remained in the recommended range, whereas in group 2, it decreased to less than 100 µg/L. Conclusions: In areas covered by the national salt iodine implementation program, it is necessary to recommend iodine supplement to pregnant women to prevent iodine insufficiency.

Evolución del estado de nutrición de yodo en gestantes del area sanitaria de Pamplona

IntroductionAdequate iodine intake is essential during pregnancy. A previous study of pregnant women from the Pamplona healthcare region showed mild iodine deficiency (mean urinary iodine level, 125 mcg/L). This study was intended to ascertain the iodine intake of pregnant women in our region and to analyze the change over time in their iodine nutritional status. MethodsAn observational study of 400 women in their first trimester of pregnancy. An iodine intake questionnaire was administered. To assess iodine status, urinary iodine concentration (UIC) was measured in a simple urine sample, and serum thyroglobulin levels were determined. In addition, thyroid volume was measured by cervical ultrasound examination. ResultsIodized salt was used by 70.5% of all participants (55.3% since the pre-gestational period) and 98.5% of them received iodine-containing supplements (mean dose, 202.6±30.1 mcg/day). Mean urinary iodine concentration was 242 mcg/L (138.5-415.5 mcg/L) and the mean serum thyroglobulin level was 12.3 mcg/L (8.3-9 mcg/L). Iodized salt intake was associated with higher UICs and lower thyroid volume. No differences were found in any of the tested parameters regarding the intake of dairy products, fish, or eggs. ConclusionsIodine intake by pregnant women in Pamplona has increased due to a greater use of iodized salt and to higher doses of iodine supplements. As a result of this, an adequate iodine status has been achieved in the last decade.

Assessing Cassava Flour Consumption Impact on Iodine Nutritional Status in Schoolchildren from Public Schools in Brazil.

Cassava (Manihot esculenta Crantz) is an important food source in many developing countries. This root contains cyanoglucosides, which can aggravate iodine deficiency disorders (IDDs). To analyze the impact of cassava flour consumption (CFC) on urinary iodine concentration (UIC) among schoolchildren from public schools in Bahia, Brazil. Cross-sectional study was conducted on 1231 schoolchildren (ages 6-14years old). Anthropometric parameters, household food insecurity, UIC, and CFC were evaluated. CFC prevalence was 90.8%. The mean UIC indicated adequate iodine nutrition in group A (CFC positive) and group B (CFC negative) (203.29 ± 81.08μg/L versus 225.98 ± 76.59μg/L, respectively). We found that daily cassava flour intake did not significantly raise the risk of iodine deficiency (ID) (odds ratio [OR] = 1.43 [confidence interval (CI) 0.72-2.82]; p = 0.29), nor did it significantly protect against excessive iodine intake (EII) (OR = 0.70[CI 0.39-1.26]; p = 0.24). The prevalence of iodine deficiency (ID) (12.6% versus 8.9%) and EII (9.6% versus 15%) did not significantly differ between both groups. The results of this study suggest that the cyanides present in cassava flour have very little influence on iodine metabolism, which is probably justified by cassava processing methods.

Iodine nutrition status in Graves' disease: A single-center study from Bangladesh

Context: An increase in occurrence of Graves' disease (GD) has been reported in many countries after the introduction of the salt iodization program. Aims: To observe iodine nutrition status in GD. Settings and Design: Cross-sectional observational study conducted in the Department of Endocrinology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from May 2013 to September 2014. Methods and Material: This study included 140 GD patients (55 newly detected, 85 already under treatment). Urinary iodine concentration (UIC) was measured in spot urine sample following wet digestion method. The iodine nutrition status was categorized according to the internationally recommended cutoffs of UIC (excessive: ≥300 μg/L, more than optimal: 200-299 μg/L, optimal: 100-199 μg/L, deficiency: Results: The median UIC in subjects with Graves' disease was 96.69 μg/L. 21.2% of the study subjects had iodine status to be considered as more than optimal or excessive, 25.7% had optimal iodine level, and more than half (51.4%) had iodine deficiency. The mean UIC were similar in newly diagnosed and treated groups, and among subjects with different thyroid functional status. UIC did not differ among male and female subjects and among subjects from different socioeconomic groups. UIC showed no correlations with age, socioeconomic condition, the family history of thyroid disease, TSH, FT4, and thyroid function status of the study participants. Conclusions: Effective monitoring of salt iodization program is needed to prevent iodine-excess related increase in the prevalence of Graves' disease.

Intervalos de referencia de hormonas tiroideas en mujeres gestantes mediante 2 inmunoanálisis diferentes: la importancia del método por encima de valores únicos universales, en consonancia con las recomendaciones internacionales 2017

Background and objectivesThyroid dysfunction during pregnancy affects maternal and foetal health, which may influence the child's neurocognitive development. The thyroid physiology changes during pregnancy, requiring reference values (RV) to be established for each population and method. The objectives were to determine these thyroid hormone (TH) RV using 2 immunoassays and to estimate the nutritional status of iodine and the prevalence of thyroid autoimmunity in our population. Patients and methodsA total of 378 pregnant women from the health sectors of Zaragoza and Huesca, whose urinary iodine, antithyroid antibody and TH levels were assessed by 2different immunoassays (Beckman and Siemens), were enrolled. ResultsThe mean urinary iodine concentration was 187μg/l, with a median concentration of 146μg/l. From them, 78% took potassium iodide supplements and their consumption was related to higher levels of urinary iodine; 10.8% were positive for antithyroid peroxidase antibodies, 4.4% for anti-thyroglobulin antibodies, 2.4% for both and 4.1% for anti-TSHr. There was no association between urinary iodine and TSH or T4L. The reference values of TSH in the first trimester were Beckman: 0.2-4 and Siemens 0.2-3.4 mIU/l. ConclusionThe thyroid hormone reference values were markedly different from those proposed by the ATA-2011 guidelines but practically identical to those described in the Spanish population using the same immunoassays, as proposed by the ATA-2017 guidelines. Thyroid autoimmunity was similar to that published nationally and internationally. The mean and median urinary iodine levels are among the highest published in Spain to date and depend mainly on supplementation with potassium iodide to reach the WHO objectives, supporting the recommendations for supplementation with at least 150μg of iodine.

Daily Consumption of Lipid-Based Nutrient Supplements Containing 250 μg Iodine Does Not Increase Urinary Iodine Concentrations in Pregnant and Postpartum Women in Bangladesh

Background: Maternal iodine deficiency during pregnancy and lactation is common in Bangladesh.Objective: We evaluated the effect of lipid-based nutrient supplements for pregnant and lactating women (LNS-PL) on urinary iodine concentration (UIC).Methods: We conducted a cluster-randomized controlled effectiveness trial in which we enrolled 4011 pregnant women at ≤20 gestational weeks. Women in 48 clusters received iron and folic acid (IFA; 60 mg Fe/d + 400 μg folic acid/d) and women in 16 clusters received LNS-PL (20 g/d, 118 kcal) containing 22 vitamins and minerals (including 250 μg I). We randomly selected a subsample of 1159 women for repeated urine sample collection, i.e., at enrollment, at 36 wk of gestation, and at 6 mo postpartum, for UIC analysis, a secondary outcome of the trial.Results: The geometric mean UIC at 36 wk of gestation and at 6 mo postpartum did not differ significantly between the IFA and LNS-PL groups. The median (quartile 1, quartile 3) UIC at 36 wk was 27.4 μg/L (16.9, 52.7 μg/L) in the IFA group and 30.2 μg/L (17.7, 56.6 μg/L) in the LNS-PL group; at 6 mo, these were 23.0 μg/L (10.0, 45.9 μg/L) in the IFA group and 22.2 μg/L (9.1, 50.4 μg/L) in the LNS-PL group.Conclusion: Daily consumption of LNS-PL containing 250 μg I did not increase the UICs of pregnant and lactating women in Bangladesh. Iodine from lipid-based nutrient supplements may have been stored in the thyroid gland or secreted in breast milk instead of being excreted in urine. Additional research that uses other biomarkers of iodine status is needed to determine how to meet the iodine requirements of pregnant and lactating women in Bangladesh and similar settings. This trial was registered at clinicaltrials.gov as NCT01715038.

Neonatal thyrotropin concentration and iodine nutrition status of mothers: a systematic review and meta-analysis

Background: Low maternal iodine intake disturbs the thyroid function of neonates transiently or permanently.Objective: To our knowledge, we conducted one of the first systematic reviews and meta-analyses aimed at exploring the association of neonatal thyrotropin concentrations and iodine status of mothers during pregnancy and early postpartum periods.Design: Data were collected through literature searches for studies published between 1969 and 2015 with the use of electronic databases. Mean or median maternal urinary iodine and neonatal thyrotropin concentrations, along with other relevant data, were extracted from eligible studies. The quality and risk of bias of each study was assessed.Results: A random-effects model was used for the analysis. Of 110 studies identified, 25 trials were shown to be eligible for inclusion in the meta-analysis. Mean (95% CI) thyrotropin concentrations of neonates born to mothers with iodine deficiency were higher than in neonates born to mothers with iodine sufficiency during pregnancy in both heel blood samples [1.79 mIU/L (95% CI: 1.61, 1.97 mIU/L) compared with 1.75 mIU/L (95% CI: 1.68, 1.82 mIU/L), respectively] and cord blood samples [11.91 mIU/L (95% CI: 6.67, 17.14 mIU/L) compared with 6.15 mIU/L (95% CI: 4.30, 8.01 mIU/L), respectively]. There were no significant differences in neonatal thyrotropin concentrations of heel samples between mothers with iodine deficiency and those with sufficiency during the early postpartum period; however, the values of thyrotropin in cord samples of neonates born to mothers with iodine deficiency were significantly higher than in neonates born to mothers with iodine sufficiency [11.62 mIU/L (95% CI: 10.47, 12.77 mIU/L) compared with 7.40 mIU/L (95% CI: 6.21, 8.59 mIU/L)].Conclusion: Our findings reveal that, compared with heel blood samples, neonatal thyrotropin in samples collected from the cord are more sensitive to the iodine status of mothers; however, further investigations are required in this regard.

Iodine Nutritional Status in Schoolchildren from Public Schools in Brazil: A Cross-Sectional Study Exposes Association with Socioeconomic Factors and Food Insecurity.

National programs of salt iodization were implemented in Brazil to combat iodine deficiency (ID) in children of school age. Currently, there are limited data in Brazil on those still vulnerable to this deficiency and the state of nutritional iodine status in the northeast region of Brazil, where children are vulnerable to malnutrition. The aim of this study was to analyze the iodine nutritional status, household food insecurity, socioeconomic and demographic characteristics among schoolchildren from the public school system living in state the state of Bahia, Brazil. A cross-sectional study was conducted on 1419 schoolchildren in Bahia between the ages of 6 and 14 years old. Anthropometric parameters, urinary iodine concentrations (UIC), and thyrotropin (TSH) measurements were evaluated from blood spots on filter paper. The mean UIC was 206.4 ± 80.5 μg/L, with a median of 221.6 μg/L, indicating sufficient iodine intake in the region. Low urinary iodide concentration (<100 μg/L) was detected in 12.3% of the schoolchildren (n = 174), with 6.2% with mild (<100 μg/L), 3.0% with moderate (20-49 μg/L), and 3.1% with severe ID (<20 μg/L). Moreover, 9.4% (n = 134) had a urinary iodide concentration of >300 μg/L, indicating the coexistence of excessive iodine intake (EII). The mean TSH was 1.0 ± 0.6 mIU/L. The body mass index category "overweight/obesity" was a protective factor against EII (odds ratio [OR] = 0.64 [confidence interval (CI) 0.4-1.0]; p = 0.07). Urban areas (73%) had a mean UIC of 213.1 ± 80 μg/L compared with 176.8 ± 76.1 μg/L in rural areas. The risk for EII increased in children living in a house with more than six people (OR = 1.62 [CI 0.9-2.6]; p < 0.05) and water consumption from shallow wells (OR = 1.70 [CI 0.9-3.1]; p = 0.09). The risk of ID was increased by 70% in schoolchildren who had moderate or severe food insecurity (OR = 1.70 [CI 0.9-3.0]; p > 0.05). A significant proportion of schoolchildren still have ID or EII in the northeast region of Brazil, emphasizing the importance of committed public policies to address this problem. Socioeconomic factors and the lack of education about nutritional importance of iodine were important influencing factors in the presence of ID in schoolchildren.

Thyroid stimulating hormone isn’t a sensitive indicator of iodine nutritional status in schoolchildren

&lt;p&gt;&lt;strong&gt;&lt;em&gt;Introduction:&lt;/em&gt;&lt;/strong&gt;&lt;em&gt; iodine deficiency &lt;/em&gt;&lt;em&gt;disorders (IDD)&lt;/em&gt;&lt;em&gt; &lt;/em&gt;&lt;em&gt;are most common cause of preventable brain damage, mental retardation and stunted growth in children&lt;/em&gt;&lt;em&gt; worldwide. Several indicators are complementary to urinary iodine concentration (UIC) for assessing iodine nutritional status, as thyroid size, thyroglobulin (Tg) and thyroid stimulating hormone (TSH) concentrations in the blood.&lt;/em&gt;&lt;strong&gt;&lt;em&gt; Objective:&lt;/em&gt;&lt;/strong&gt;&lt;em&gt; &lt;/em&gt;&lt;em&gt;analyze TSH in filter paper blood values and correlate with UIC in schoolchildren from public school at state of Bahia, Brazil&lt;/em&gt;&lt;em&gt;. &lt;strong&gt;Methodology: &lt;/strong&gt;&lt;/em&gt;&lt;em&gt;cross-sectional study was conducted in 880 schoolchildren aged 6-14 years, randomly selected, of public schools in five cities of four micro-regions of Bahia between October 2013 and September 2014. TSH was analyzed in filter-paper blood and UIC were measured by adapted Sandell-Kolthoff reaction. &lt;/em&gt;&lt;strong&gt;&lt;em&gt;Results:&lt;/em&gt;&lt;/strong&gt;&lt;em&gt; 880 blood samples on filter-paper were analyzed for TSH. The reference range previously established is 0.72 to 6.0 &lt;/em&gt;&lt;em&gt;μ&lt;/em&gt;&lt;em&gt;UI/mL&lt;/em&gt;&lt;em&gt;. Results of this research TSH dosage ranged from 0.24 &lt;/em&gt;&lt;em&gt;μ&lt;/em&gt;&lt;em&gt;IU/L to&lt;/em&gt;&lt;em&gt; 7.71 &lt;/em&gt;&lt;em&gt;μ&lt;/em&gt;&lt;em&gt;IU/L,&lt;/em&gt;&lt;em&gt; with a mean of 1.01±0.55 &lt;/em&gt;&lt;em&gt;μ&lt;/em&gt;&lt;em&gt;UI/L&lt;/em&gt;&lt;em&gt; and median 0.89 &lt;/em&gt;&lt;em&gt;μ&lt;/em&gt;&lt;em&gt;UI/L&lt;/em&gt;&lt;em&gt;. Only one child presented TSH greater than 6.0 (7.71 &lt;/em&gt;&lt;em&gt;μ&lt;/em&gt;&lt;em&gt;IU/L); however, results of urinary iodine were consistent with a more than adequate nutrition iodine (243.70&lt;/em&gt;&lt;em&gt;μ&lt;/em&gt;&lt;em&gt;g/L). There’ no correlation between TSH and UIC (r= 0.115; p= 0.002)&lt;/em&gt;&lt;em&gt;.&lt;/em&gt;&lt;em&gt; &lt;/em&gt;&lt;strong&gt;&lt;em&gt;Conclusion:&lt;/em&gt;&lt;/strong&gt;&lt;em&gt; in the present study, schoolchildren showed low values of TSH, but the mean UIC was indicative of adequate iodine nutrition&lt;/em&gt;&lt;em&gt;.&lt;/em&gt;&lt;em&gt;&lt;/em&gt;&lt;/p&gt;