Median Urinary Iodine Concentration Research Articles

Pregnant women at risk for iodine deficiency but adequate iodine intake in school-aged children of Zhejiang Province, China

The median urinary iodine concentration (UIC) of school-aged children has been commonly used as a surrogate to assess iodine status of a population including pregnant women. However, pregnant women have higher iodine requirements than children due to increased production of thyroid hormones. The aim of the study was to evaluate the iodine status of pregnant women and children as well as their household salt iodine concentration (SIC) in Quzhou, Zhejiang Province, China. Eligible pregnant women and children from all six counties of Quzhou in 2021 were recruited into the study. They were asked to complete a socio-demographic questionnaire and provide both a spot urine and a household table salt sample for the determination of UIC and SIC. A total of 629 pregnant women (mean age and gestation weeks of 29.6 years and 21.6 weeks, respectively) and 1273 school-aged children (mean age of 9 years and 49.8% of them were females) were included in the study. The overall median UIC of pregnant women and children in our sample was 127 (82, 193) μg/L and 222 (147, 327) μg/L, respectively, indicating sufficient iodine status in children but a risk of mild-to-moderate iodine deficiency in pregnant women. Distribution of iodine nutrition in children varied significantly according to their sex and age (P < 0.05). The rate of adequately household iodised salt samples (18–33 mg/kg) provided by pregnant women and children was 92.4% and 90.6%, respectively. In conclusion, our results indicated a risk of insufficient iodine status in pregnant population of China, but iodine sufficiency in school-aged children. Our data also suggested that median UIC of children may not be used as a surrogate to assess iodine status in pregnant women.

Association between maternal and cord blood thyroid hormones, and urine iodine concentration with fetal growth.

We planned to evaluate the association of fetal and maternal thyroid hormones and maternal iodine status with neonates' anthropometric parameters. In this cross-sectional study, levels of thyrotropin were measured in maternal serum in the first trimester of pregnancy, and thyrotropin (TSH) and free thyroxin (fT4) were measured in cord blood serum samples at birth. Urinary iodine concentration (UIC) levels in random urine samples of mothers were measured in the third trimester of pregnancy. The relationship between UIC and thyroid hormone levels of mothers with neonates' anthropometric birth parameters of neonates was evaluated. One hundred eighty-eight mother-newborn pairs completed the study. Mean (SD) of cord blood TSH (CB-TSH), cord blood-free thyroxin (CB-FT4) values, and maternal TSH (M-TSH) levels were 8.8 (7.3) mIU/L, 1.01 (0.2) ng/dL, and 2.2 (0.9) mIU/L, respectively. After adjusting for confounders, there was a positive significant association between female neonate length and maternal TSH and log log-transformed CB TSH (LN_CB-TSH) (p<0.05). Median UIC (Q1-Q3) was 157 (53-241) μg/L, and there was no association between birth weight, birth length, and head circumferences of neonates and mothers' UIC (p>0.05). We found a positive correlation between maternal TSH in the first trimester of pregnancy and the birth length of newborns, and a negative correlation was observed between CB-TSH and birth length in girls, but it did not provide conclusive evidence for the relationship between maternal and neonatal thyroid hormone levels and birth weight. There was no association between maternal UIC levels in the third trimester and birth anthropometric parameters.

Factors associated with inadequate urinary iodine concentration among pregnant women in Mbeya region Tanzania.

Background Insufficient and above WHO-recommended levels of iodine intake during pregnancy can lead to serious health outcomes. This study aimed to assess median urine iodine concentration and its associated risk factors among pregnant women in the Mbeya region, Tanzania. Method A cross sectional survey involving 420 pregnant women (n=420) aged 15-49, registered in Reproductive and Child Health Clinics was conducted. Socio-demographic and dietary factors were assessed by structured questionnaire and the urine samples were analyzed using the ammonium persulfate digestion method. Results Median urinary iodine concentration (mUIC) was 279.4μg/L and it ranged from 26.1 to 1915μg/L. Insufficient mUIC (below 150μg/L) was observed in 17.14% of participants, sufficient mUIC was 24.29% and 58.57% had mUIC above the recommended level (&gt;250μg/L). Sample women who reported consuming fish in the last 24 hours had an increased risk of insufficient mUIC [Adjusted OR= 2.60 (95%CI 1.31-5.15)] while the risk was lower for those who attended at least primary education [AOR= 0.29 (CI 0.08-0.99)]. Further, sample women resident in Mbarali district, in the oldest age group (35-49) and having a higher socio-economic status were associated with an increased risk of having MUIC above recommended level [AOR=4.09 (CI 1.85-9.010], [AOR=2.51 (CI 0.99-6.330] and, [AOR=2.08 (CI 0.91-4.71) respectively. Conclusion This study demonstrated a significant association between geographical, age and socio-economic factors and median urine iodine concentration above the WHO-recommended level. Further, this study found association between inadequate iodine in diet and insufficient median urine iodine concentration. Therefore, educational programs on iodine intake should be strengthened.

Assessment of iodine nutritional status and gestational thyroid function reference ranges during the first trimester of pregnancy in Taiwan.

Iodine nutrition is critical for fetal neurodevelopment in the first trimester of pregnancy, a period associated with dramatic changes in thyroid function. The aim of this study was to evaluate iodine nutritional status and thyroid function reference ranges in the first trimester in Taiwan. Pregnant women aged 20 years and above in the first trimester were recruited in Taipei Veterans General Hospital, Taiwan from March 2019 to July 2022. Each participant provided a spot urine sample for measurement of urinary iodine concentration (UIC) and a blood sample for check-up of thyroid function and thyroid autoantibodies. A simple food frequency questionnaire was also completed. A total of 209 women with a mean age of 32.9 ± 4.4 years were enrolled. The median UIC was 160.9 μg/L [interquartile range (IQR): 105.0-246.2 μg/L], indicating overall iodine sufficiency. The gestational thyroid function reference ranges were: TSH [median: 0.93 (0.007-2.9) µIU/mL], free T4 [1.3 (0.93-2.2) ng/dL], free T3 [3.0 (2.3-5.0) ng/dL], total T4 [9.9 (6.4-16.9) ng/dL] and total T3 [135 (88-231) ng/dL]. If the non-pregnant reference range of serum TSH was used, eight women (4.8%) would be misclassified as having subclinical hyperthyroidism, and two women (1.2%) with subclinical hypothyroidism would be missed. In multivariate analysis, nulliparous [adjusted odds ratio (OR) from model 1-3: 2.02, 2.05, 2.02; 95% confidence interval (CI): 1.08-3.77, 1.10-3.81, 1.11-3.66; p = 0.027, 0.023, 0.022, respectively] and multivitamin non-users (adjusted OR from model 1-3: 1.86, 1.85, 1.78; 95% CI: 1.04-3.34, 1.03-3.32, 1.004-3.71; p = 0.038, 0.039, 0.049, respectively) had increased odds of having lower UIC levels <150 μg/L. The iodine nutritional status in the first trimester is adequate in Taiwan; however, certain subgroups such as nulliparous and multivitamin non-users are still at risk for iodine deficiency. Gestational thyroid function reference ranges are needed for correct diagnosis of thyroid dysfunction in pregnancy.

Association Between Iodine Status and Prevalence of Hypothyroidism, Autoimmune Thyroiditis, and Thyroid Nodule: a Cross-Sectional Study in Shandong Province, China.

In this study, the aim was to investigate the correlation between varying levels of urinary iodine concentration (UIC) in adults and the occurrence of thyroid diseases, with the additional objective of determining the optimal iodine status level for adults. A cross-sectional study was conducted on adults from six areas with different drinking water iodine concentrations (WIC) without eating iodized salt in Heze and Jining counties, Shandong Province, China. A total of 1336 adults were included in this study, and drinking water samples, blood samples, urine samples, thyroid ultrasound, and a questionnaire were collected. UIC, free triiodothyronine (FT3), free thyroid hormone (FT4), thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb) were detected. There were no significant differences in the detection rates of hypothyroidism and thyroid autoimmunity (TAI) among the different median UIC groups (UIC < 100μg/L, 100-199μg/L, 200-299μg/L, ≥ 300μg/L). However, the detection rates of hypothyroidism were higher in the UIC < 100μg/L group (16.67%) and the UIC ≥ 300μg/L group (16.51%) compared to the other groups. The detection rate of TAI increased as UIC levels increased. The detection rate of thyroid nodule (TN) in the UIC < 100μg/L group was significantly higher than that in the UIC 200-299μg/L UIC group (χ2 = 10.814, P = 0.001). After adjusting confounding factors, it was found that low UIC (< 100μg/L) was a risk factor for TN (OR 1.83, 95% CI [1.04-3.22]). Meanwhile, there no statistical difference between UIC 200 and 299μg/L and UIC 100 and199 μg/L for OR of hypothyroidism, TAI, and TN. This study identified associations between different UIC levels and the prevalence of thyroid disorders, with low UIC (< 100μg/L) posing a risk for TN, and the detection rate of TN and hypothyroidism was the lowest in UIC (200-299μg/L) group. Therefore, the acceptable UIC range of 'adequate' iodine intake among adults can be widened from 100-199µg/L to 100-299µg/L.

Association between 24-hour urinary sodium and iodine in a Beninese population

Aims: To evaluate the association between sodium concentration in 24-hour urine and iodine status in an urban and rural population of Benin. Patients and Methods: A two-center descriptive, and cross-sectional observational study was conducted. Three hundred and fifty-four apparently healthy subjects (men and women) aged 25 to 64 were selected. Adequate iodine intake was defined as an iodine/creatinine urinary ratio (I/Cr) between 32.7 and 70.0 μg/g, and deficiency and excess such as &lt; 32.7 μg/g and ≥ 70.0 μg / g respectively. Urinary sodium / creatinine (Na/Cr) ratios were classified as low (&lt; 96.0 mmol /g), intermediate (96.0 – 171.8 mmol/g), high (≥ 171.8 mmol/g). Results: The median urinary iodine concentration was 66.8 μg/L (IQI, 42 to 98) and the median urinary I/Cr ratio was 46.8 μg /g (IQI, 32.7 to 70.0). Iodine deficiency (&lt; 100 μg /L) and iodine excess (&gt; 300 μg /L) were observed in 75.1% and 2.5% of subjects, respectively. There was a statistically significant association between uncorrected UNaC and iodine status in the study population (p &lt; 0.001). Paradoxically, no statistically significant association was found between the ratio I/Cr and Na/Cr in urine (p = 0.05). The distributions of UIC, UNaC and I/Cr, urinary Na /Cr ratios varied according to age group and sex. Conclusion: No significant association was recorded between iodine status and UNaC in the Beninese study population. The recommended optimal iodine intake for eliminating disorders related to iodine deficiency has not yet been achieved in the study population; at least 50% of participants had inadequate UIC even after correction. Keywords: Iodine; Benin; sodium; urine creatinine; nutrition.

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

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

Iodine Nutrition, Thyroid-stimulating Hormone, and Related Factors of Postpartum Women from three Different Areas in China: A Cross-sectional Survey*

ObjectiveStudies on the relationship between iodine, vitamin A (VA), and vitamin D (VD) and thyroid function are limited. This study aimed to analyze iodine and thyroid-stimulating hormone (TSH) status and their possible relationships with VA, VD, and other factors in postpartum women. MethodsA total of 1,311 mothers (896 lactating and 415 non-lactating) from Hebei, Zhejiang, and Guangxi provinces were included in this study. The urinary iodine concentration (UIC), TSH, VA, and VD were measured. ResultsThe median UIC of total and lactating participants were 142.00 µg/L and 139.95 µg/L, respectively. The median TSH, VA, and VD levels in all the participants were 1.89 mIU/L, 0.44 µg/mL, and 24.04 ng/mL, respectively. No differences in the UIC were found between lactating and non-lactating mothers. UIC and TSH levels were significantly different among the three provinces. The rural UIC was higher than the urban UIC. Obese mothers had a higher UIC and a higher prevalence of excessive TSH. Higher UICs and TSHs levels were observed in both the VD deficiency and insufficiency groups than in the VD-sufficient group. After adjustment, no linear correlation was observed between UIC and VA/VD. No interaction was found between vitamins A/D and UIC on TSH levels. ConclusionThe mothers in the present study had no iodine deficiency. Region, area type, BMI, and VD may be related to the iodine status or TSH levels.

Relationship Between Urinary Iodine Concentration and the Prevalence of Thyroid Nodules and Subclinical Hypothyroidism.

The aim of the study was to investigate the iodine intake in the resident population in Xi'an and analyze the relationship between iodine nutritional status and the prevalence of subclinical hypothyroidism and thyroid nodules (TNs). A total of 2507 people were enrolled in Xi'an. Venous serum thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb), urinary iodine concentration (UIC), and thyroid ultrasonography were collected. Patients with abnormal TSH were checked for free thyroxine (FT4) and triiodothyronine (FT3). Adults in Xi'an had median UICs of 220.80 μg/L and 178.56 μg/l, respectively. A sum of 16.78% of people had subclinical hypothyroidism. Both iodine excess and iodine deficit increased the frequency of subclinical hypothyroidism. The lowest was around 15.09% in females with urine iodine levels between 200 and 299 μg/l. With a rate of 10.69%, the lowest prevalence range for males was 100-199 μg/l. In Xi'an, 11.37% of people have TNs. In comparison to other UIC categories, TN occurrences were higher in females (18.5%) and males (12%) when UIC were below 100 μg/l. In conclusion, iodine intake was sufficient in the Xi'an area, while the adults' UIC remains slightly higher than the criteria. Iodine excess or deficiency can lead to an increase in the prevalence of subclinical hypothyroidism. Patients with iodine deficiency are more likely to develop TNs.

Thyroid volume in Turkish school-age children living in an iodine-sufficient region.

We aimed to obtain local normative data on thyroid volume evaluated by ultrasonography and iodine status by measuring urine iodine levels in school-age children living in Aydın province. In this cross-sectional study, a sample comprising 1,553 cases was meticulously selected from a total cohort of 170,461 children aged 6-17, drawn from 21 distinct educational institutions located within the Aydın region, as participants in the investigation. Those with a known chronic disease or thyroid disease were excluded from the study. The children underwent physical examinations and ultrasonography imaging of the thyroid gland, and urine samples were collected to measure urinary iodine concentration (UIC). The median UIC was 189.5 (IQR=134.4) μg/L, which was optimal according to WHO criteria. Thyroid volume was found to be 4.6 (IQR=3.5) mL in girls and 4.2 (IQR=4.0) mL in boys (p=0.883). The thyroid volumes in our study were found to be smaller when compared to the WHO. According to WHO age and body surface area criteria, thyroid volume was over 97 % in 0.9 % (n=15) of cases. Thyroid volume was found to have a positive correlation with age, height, weight, body mass index (BMI), and body surface area (BSA) in both genders (p<0.001). However, there was no significant correlation between thyroid volume and UIC. This cross-sectional study provides normative data on thyroid volume and iodine status in school-age children in iodine-sufficient population, revealing a low prevalence of goiter and correlations between thyroid volume and anthropometric measures.

Development and validation of a food frequency questionnaire to assess habitual iodine intake among women of childbearing age.

Adequate iodine status is critical for thyroid hormone synthesis, which is essential for foetal brain development. Suboptimal iodine status has been reported in young women across Europe. Although urinary iodine concentration (UIC) is a good indicator of recent exposure, it does not reflect habitual iodine intake. This study aimed to develop and validate an iodine-specific food frequency questionnaire (I-FFQ) to assess habitual intake in Irish women aged 18-50 years. A 47-item interviewer-administered I-FFQ, informed by national food consumption data on Irish women aged 18-35 years, was developed and validated in a study of 100 nonpregnant women using a 4-day weighed food diary (FD) and UIC as the reference methods. Correlation, cross-classification and Bland-Altman analyses were used to assess agreement and bias between the I-FFQ and FD. Validity coefficients were calculated using the method of triads. Median (interquartile range [IQR]) UIC was 82 (49, 139) µg/L. Median (IQR) intakes were 161 (106, 217) and 133 (98, 182) µg/day for the I-FFQ and FD, respectively (p = 0.001). Estimates were moderately correlated (r = 0.434), and the I-FFQ classified 89% of participants into the same or adjacent tertile of intake as the FD. Validity coefficients for the I-FFQ, FD and UIC were 0.542, 0.800 and 0.228, respectively. Though repeatability analyses 10 weeks later (n = 69) showed slight differences in estimates of intake (I-FFQ1: 164 (104, 210) µg/day; I-FFQ2: 132 (67, 237) µg/day), intakes were highly correlated between administrations (r = 0.627, p = 0.001). The I-FFQ provides a reasonable estimate of habitual iodine intake in young women.

Salivary iodine concentration in pregnant women and its association with iodine status and thyroid function.

There have been no reports on the application of salivary iodine concentration (SIC) in evaluating iodine nutrition in pregnant women. This study aimed to clarify the relationship between SIC and indicators of iodine nutritional status and thyroid function during pregnancy, to investigate whether salivary iodine can be applied to the evaluation of iodine nutritional status in pregnant women, and to provide a reference basis for establishing a normal range of salivary iodine values during pregnancy. Pregnant women were enrolled in the Department of Obstetrics, the people's hospital of Yuncheng Country, Shandong Province, from July 2021 to December 2022, using random cluster sampling. Saliva, urine, and blood samples were collected from pregnant women to assess iodine nutritional status, and venous blood was collected to determine thyroid function. A total of 609 pregnant women were included in this study. The median spot urinary iodine concentration (SUIC) was 261μg/L. The median SIC was 297μg/L. SIC was positively correlated with SUIC (r = 0.46, P < 0.0001), 24-h UIC (r = 0.30, P < 0.0001), 24-h urinary iodine excretion (24-h UIE) (r = 0.41, P < 0.0001), and estimated iodine intake (EII) (r = 0.52, P < 0.0001). After adjusting for confounders, there was a weak correlation between SIC and serum total iodine and serum non-protein-bound iodine (P = 0.02, P = 0.04, respectively). Pregnant women with a SIC < 176μg/L had a higher risk of insufficient iodine status (OR = 2.07, 95% CI 1.35-3.19) and thyroid dysfunction (OR = 2.71, 95% CI 1.18-6.21) compared to those with higher SIC. Those having SIC > 529μg/L were more likely to have excessive iodine status (OR = 2.82, 95% CI 1.81-4.38) and thyroid dysfunction (OR = 3.04, 95% CI 1.36-6.78) than those with lower SIC values. SIC is associated with urinary iodine concentration and thyroid function in pregnant women. SIC < 176μg/L was associated with an increased risk for iodine deficiency and hypothyroxinemia, while SIC > 529μg/L was related to excess and thyrotoxicosis. SIC can be used as a reference indicator for evaluating the iodine nutrition status of pregnant women, but it needs further investigation and verification. NCT04492657(Aug 9, 2022).

Iodineminho Study: Iodine Supplementation and Prevalence of Iodine Deficiency in Pregnant Women.

Iodine is necessary for the proper brain development. The prevalence of iodine deficiency in Portuguese pregnant women led the health authorities, in 2013, to recommend iodine supplementation for women in preconception, throughout pregnancy and during lactation. To assess the impact of iodine supplementation initiated in the preconception or the first trimester of pregnancy on the prevalence of iodine deficiency and maternal thyroid status. An observational prospective cohort study that follows thyroid function and iodine status of women recruited in preconception or in the first trimester of pregnancy. The median urinary iodine concentration (UIC) was significantly higher among women taking iodine supplements (no-supplement group UIC=63µg/L; supplement group UIC =100µg/L, p = 0.002) but still below the levels recommended by the World Health Organization. Only 15% of pregnant women had adequate iodine status and 17% showed UIC < 50 µg/l. There was no influence of whether iodine supplementation started in preconception or in the 1st trimester of gestation (UIC preconception group: 112µg/L vs UIC pregnancy group: 91µg/L, p = 0.569). In the 1st trimester of pregnancy, total thyroxine levels were lower and free triiodothyronine levels were higher in non-supplemented women. Thyroglobulin levels were lower in women who started iodine supplementation in preconception compared to non-supplemented women and women who started iodine supplementation during gestation. In the Minho region of Portugal, fertile women have insufficient iodine intake. Additional public health measures are needed since the current recommendations for iodine supplementation for pregnancy are unsatisfactory to achieve an adequate iodine status.

Dietary Iodine Intake and Pattern of Thyroid Disorders among the Ethnic Population of Eastern Himalayan Ranges of India

Background and Aim: In the present study, dietary iodine intake and thyroid functioning were assessed among the ethnic adolescent group of Eastern Himalayan range with the hypothesis that insufficient iodine intake negatively affects normal thyroid functions. The aim of the study was to see the prevalence and relation between iodine deficiency and thyroid functioning. Materials and Methods: It is a hospital-based study conducted in the health care facilities of Dima Hasao district, Assam, from April 2021 to March 2022. The study included 821 subjects including both male and female of adolescent age group (10–19 years). The thyroid profiling, anti-Thyroid peroxidase antibody (anti-TPO Ab), and urinary iodine content (UIC) were carried out. Thyroid hormone analysis was carried out by chemiluminescence assay. The anti-TPO Ab was determined using the electrochemiluminescence immunoassay analyzer. The dietary iodine intake was measured on the basis of UIC and was determined by arsenic cerium catalytic spectrophotometry method by the Sandell-Kolthoff reaction. Results: The prevalence of thyroid disorder among the studied population was found to be 13.8%. Among different conditions of thyroid disorders, hypothyroidism was present in 10.6% and hyperthyroidism in 3.13%. 4.18% had elevated anti-TPO Ab. Among the euthyroid subjects with different thyroid disorders, 1.48% and 21% had anti-TPO Ab positivity, respectively. The median UIC was 99.97 µg/l. 25.78% of the population had iodine deficiency. Thyroid disorders were common in subjects with iodine deficiency (61.34%) than iodine sufficient subjects (20%). Conclusion: The work was an attempt to demonstrate how the dietary iodine intake influences thyroid functioning among the adolescent ethnic population of Eastern Himalayas which is manifested as high prevalence of subclinical hypothyroidism with iodine deficiency. The work underscores region specific recommendation on iodine supplementation for populations living in geographically remote locations.

Iodine intake in the Swiss population 100years after the introduction of iodised salt: a cross-sectional national study in children and pregnant women.

The Swiss voluntary salt iodisation programme has successfully prevented iodine deficiency for 100years, but dietary habits are changing and todayonly one-third of processed foods contain iodised salt. We aimed to monitor the current iodine status in childrenand pregnant women. We conducted a nationwide cross-sectional study in children (6-12years) and pregnant women and measured the urinary iodine concentration (UIC) in spot urine samples. We estimated the iodine intake using UIC and urinary creatinine concentration (UCC) and determined the prevalence of intakes below the average requirement (AR) using the SPADE method. We measured dried blood spot (DBS) thyroglobulin (Tg), TSH and total T4 in pregnant women. The median UIC was 127μg/L (bootstrapped 95% CI 119, 140, n = 362) in children and 97μg/L (bootstrapped 95% CI 90, 106, n = 473) in pregnant women. The estimated prevalence of inadequate iodine intake (< 65μg/day) was 5.4% (bootstrapped 95% CI 0.0, 14.6) in children. Half (47%) of the women consumed iodine-containing multivitamin and mineral supplements (≥ 150μg/day). Compared to non-users, users had higher median UIC (129 vs. 81μg/L, P < 0.001), lower prevalence of inadequacy (< 160μg/day; 0.2 vs. 31%) and lower DBS-Tg (23 vs. 29μg/L, P < 0.001). All women were euthyroid. The Swiss diet and current salt fortification provides adequate iodine intake in children, but not in all pregnant women. Iodine supplements cover the dietary gap in pregnancy but are not universally consumed. Therefore, improved use of iodised salt in processed foods is desired to ensure adequate iodine intake in all population groups. This trial was registered at clinicaltrials.gov as NCT04524013.

Comparison of Thyroglobulin and Thyroid Function in Pregnant Women between Counties with a Median Urinary Iodine Concentration of 100–149 μg/L and 150–249 μg/L

ObjectiveThis study explored whether thyroglobulin and thyroid disease prevalence rates were higher in pregnant Chinese women with a median urinary iodine concentration of 100–149 μg/L, compared with those with a median urinary iodine concentration of 150–249 μg/L maintained through sustainable universal salt iodization. MethodsThis was a cross-sectional study in which 812 healthy pregnant women were enrolled to collect samples of their household edible salt, urine, and blood during their routine antenatal care in the 18 counties in Fujian Province, China. The levels of salt iodine concentration, urinary iodine concentration (UIC), free triiodothyronine (FT3), free thyroid hormone (FT4), thyroid-stimulating hormone (TSH), thyroglobulin (Tg), thyroid peroxidase antibody and thyroglobulin antibody were assessed during the routine antenatal care visits. ResultsThe median UIC (mUIC) in pregnant women was 130.8 μg/L (interquartile range = 91.5–198.1 μg/L) in the counties with an mUIC of 100–149 μg/L (Group I), and 172.0 μg/L (interquartile range = 123.5–244.4 μg/L) in the counties with an mUIC of 150–249 μg/L (Group II). Goiter prevalence and thyroid nodule detection rates showed no difference between Group I and Group II (P > 0.05). Except for FT4 values, the TSH, FT4, FT3, Tg and Tg values > 40 (μg/L) and the thyroid diseases prevalence rate (TDR) showed no significant differences between Group I and Group II (P > 0.05), whether or not iodine supplementation measures were taken. ConclusionCompared with an mUIC of 150–249 μg/L, not only there was no difference in thyroid morphology, but also the Tg value, rate of Tg values > 40 μg/L, and TDR were not higher in pregnant women in the counties with an mUIC of 100–149 μg/L achieved through sustainable universal salt iodization in Fujian Province, China.

Iodine Status of School Children Aged 6 to 12 Years in Rural and Urban Communities in Imo State, Southeast Nigeria

Background: Iodine is a trace element essential for the synthesis of thyroid hormones, thyroxine and triiodothyronine, which in turn play a crucial role in the growth and development of most organs, especially the brain. Iodine deficiency is therefore a serious medical condition fraught with dire consequences. Median urinary iodine concentrations of 100–199 mcg/L in children and adults, 150–249 mcg/L in pregnant women and &gt;100 mcg/L in lactating women indicate iodine intakes are adequate. Objective: This study set to determine the Iodine status of children aged 6-12 years using MUIC in selected urban and rural communities of Imo state, South East Nigeria. Methods: It was cross sectional in nature and was carried out between July 2018 and January 2019. It involved 386 children aged 6-12 years who were selected from primary schools in both urban and rural local areas within the three educational zones of Imo State. Their urinary Iodine concentration was assayed using Ammonium persulphate technique of the Sandell- Koltkoff reaction method. Results: The median urine iodine concentration (MUIC) in the study participants ranged from 65 – 490 mcg/l with a median of 160mcg/l. While median urine iodine concentrations (MUIC) of 160 mcg/L and 156mcg/L, respectively, were observed in urban-dwelling and rural-dwelling school children respectively. Of the 386 participants, 30 had a MUIC of &lt; 100\(\mu\)g/L therefore giving an iodine deficiency prevalence of 7.8%. They consisted of 14 participants from the urban areas and 16 from the rural areas. The difference between MUIC of children in rural and urban areas of Imo state was not statistically significant . (χ2 = 0.10: p = 0.75). Conclusion: While there was Iodine deficiency prevalence of 7.8%, there was no statistically significant difference between the Iodine status of pupils in urban and rural areas of Imo state.

Iodine status and associated dietary factors among preschool children in Shanghai.

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

Iodine status of school-aged children in the changing context of universal salt iodization program during 1997–2018 in Chongqing, China

ObjectiveTo illustrate the changes of iodized salt usage, goiter rate of school-aged children and median urinary iodine concentration (MUIC) of school-aged children in Chongqing for the last 21 years. This study aims to estimate the variational provincial status of iodine nutrition and provide scientific evidence for fine-tuning and adaptation of the current program. MethodsDifferent number of families and school children aged 8–10 years from Chongqing during 1997–2018 participated in the study. UIC and iodine content in table salt were measured. Thyroid volumes of students were examined and goiter prevalence was calculated across years. ResultsThe median iodine content of table salt was negatively associated with years(r = −0.727, P < 0.01). The MUIC were decreased annually (ranged between 200 and 300 μg/L) and was negatively associated with year(r = −0.831, P < 0.01). Goiter of school-aged children in Chongqing was decreased from the highest rate of 23.58% in 1999 to 1.62% in 2018(Cochran-Armitage Trend Test: χ2=-30.695, P < 0.01). Thyroid volume were negatively associated with years(r = −0.962, P < 0.01) and had a positive relationship with MUIC 1997–2018 (r = 0.862, P < 0.01). ConclusionsThe consumption of adequately iodized salt can eliminate Iodine deficiency disorders (IDD) in children, but possible excessive iodine intake from salt could result in high urinary iodine excretion and even goiter. A systematic, well-designed and continual program monitoring is essential to ensure the adequacy of iodine fortification levels and to regularly change the iodine concentration in household table salt.

Iodine status, including breastmilk iodine content, of lactating mothers and their infants aged 0 to 6 months in Vhembe and Mopani districts of the Limpopo province, South Africa.

Background. Both iodine deficiency and excess may affect lactating women and their infants. In Limpopo Province, South Africa (SA), there are no data on the iodine status of individuals in these vulnerable groups.Objective. To determine the iodine status, including breastmilk iodine content, of lactating mothers and their infants aged 0 - 6 months in Vhembe and Mopani districts, Limpopo, SA.Methods. A cross-sectional descriptive study in the quantitative domain was undertaken in Vhembe and Mopani districts. Mother-infant pairs were randomly selected. Breastmilk iodine content (BMIC), urinary iodine content (UIC) of infants, UIC of mothers, household (HH) salt iodine content (SIC) and water iodine content (WIC). The iodine nutrition knowledge of mothers was determined.Results. The median (interquartile range (IQR)) of BMIC among lactating mothers in Vhembe and Mopani was 102 (62 - 179.7) μg/Land 150.4 (89.4 - 201.7) μg/L, respectively. The median (IQR) UIC of mothers in Vhembe and Mopani was 96.3 (54.8 - 154.8) μg/L and137.9 (72 - 212.4) μg/L, respectively. The median UIC of infants was 217.7 (107.1 - 409.9) and 339.8 (162.9 - 490.3) μg/L in Vhembe andMopani, respectively. There was a significant difference between SIC of coarse and fine salt in both districts. Lactating mothers in both areas had limited iodine nutrition knowledge.Conclusion. The results suggest that iodised salt is a major contributor to iodine status in lactating mothers and their infants. Our results also show that the salt iodisation programme in SA supplies sufficient iodine for children, women of reproductive age, lactating mothers and breastfed infants.