Iodine Nutritional Status Research Articles

Analysis of risk factors for autoimmune thyroid disease based on blood indicators and urinary iodine concentrations

ObjectiveThe aim of this study was to elucidate the relationships between thyroid hormones, lifestyle factors, biochemical markers, and autoimmune thyroid disease (AITD), thereby identifying the factors influencing the development of these diseases.MethodsThe study encompassed 517 patients with AITD and 549 patients with non-autoimmune thyroid disease. Demographic and clinical data were collected, and various laboratory indicators, including urinary iodine and thyroid hormones, were measured and compared between the groups. Lasso regression was employed to select the independent variables, while logistic regression analysis determined the factors associated with the development of AITD.ResultsThe prevalence of drinking alcohol history, median urinary iodine, and TSH concentrations proved significantly greater in the AITD group compared to the control group, while FT3 levels demonstrated lower values within the AITD group (p<0.05). Furthermore, there was a significant difference in the distribution of iodine nutrition status between the two groups (p<0.05). Both univariate and multivariate logistic regression analyses revealed significant associations among excessive iodine intake, drinking alcohol history, TSH, FT3, and the development of AITD.ConclusionsExcessive iodine intake and drinking alcohol history are implicated in an augmented risk of developing AITD. The prevention of AITD may necessitate the regular monitoring of TSH and FT3 concentrations.

Iodine nutrition status of children 3-13 years of age in areas with high groundwater iodine content in China

BackgroundAdequate iodine status is crucial for children's health and normal development. However, there is a paucity of research on the iodine status of children from areas with high groundwater iodine content. ObjectivesTo monitor the iodine status of children in Shandong, China (regions primarily characterized by high iodine concentrations in groundwater) and to describe the factors influencing children's iodine status. MethodsA cross-sectional study was conducted from 2013 to 2023 on 3,253 children aged 3-13 years. We collected drinking water, spot urine, and 24-hour urine samples from children to assess their iodine status (measuring drinking water iodine concentration (WIC), water iodine intake (WII), urine iodine concentration (UIC), 24-hour urine iodine excretion (24-h UIE), daily iodine intake (DII), etc.), and analyzed influencing factors. ResultsThe median WIC for children was 183 (IQR: 70.2, 362) μg/L, and the median spot UIC was 428 (IQR: 194, 737) μg/L, surpassing the WHO cutoff (300 μg/L). Children at risk of iodine excess numbered 1750 (61.8%). Approximately 61% of iodine intake came from drinking water. Boys had significantly higher iodine intake than girls (P < 0.001). Children's age showed positive correlations with spot UIC, 24-h UIC, and 24-h UIE. There were no significant differences in 24-h UIC and 24-h UIE among children with different BMIs. The logistic regression model revealed that the risk of iodine excess was increased by boy gender, increment in age (OR = 1.05, 95% CI: 1.02, 1.08), and every 10 μg (OR = 1.04, 95% CI: 1.03, 1.04) or 50 μg (OR = 1.19, 95% CI: 1.16, 1.22) increment in WII. ConclusionChildren in areas with high groundwater iodine content are at a risk of iodine excess. As age increases, the risk of iodine excess in children rises, with boys at a higher risk than girls.

Iodine Nutritional Status and Thyroid Autoimmunity in Chinese Children and Adolescents Aged 6-17 Years.

Background: Thyroid autoimmunity (TAI), marked by thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibodies (TgAb), affects over 10% of the general population, with children and adolescents experiencing significant impacts on growth and quality of life despite lower prevalence rates compared to adults. Methods: In the context of over 20 years of universal salt iodization (USI) in China, this study investigated the relationship between iodine nutritional status and TAI in children and adolescents aged 6-17. Results: Our findings suggest that while iodine levels are generally sufficient (median urinary iodine concentration [UIC] was 205.2 µg/L), TAI remains a significant concern due to its potential impact on growth and development. TAI was significantly associated with age, sex, and urban-rural residency (p < 0.05). Positive TPOAb and TgAb were identified as risk factors for subclinical hypothyroidism (OR = 2.274, 95% CI: 1.171-1.916). Although some literature suggests that excessive iodine may exacerbate TAI and others propose iodine deficiency as a risk factor, this study did not find a significant overall association between iodine status and TAI. Notably, a low urinary iodine-to-creatinine ratio (UI/Cr) level was linked to an increased risk of TgAb positivity in males (OR = 3.470, 95% CI: 1.200-10.036). In individuals with negative thyroid antibodies, increased BMI (OR = 1.062, 95% CI: 1.032-1.093) and high UI/Cr levels (OR = 1.510, 95% CI: 1.175-1.941) were risk factors for subclinical hypothyroidism, whereas older age (OR = 0.710, 95% CI: 0.555-0.908 for the age 9-11 group; OR = 0.681, 95% CI = 0.484-0.959 for the age 12-17 group) and high UIC levels (OR = 0.739, 95% CI: 0.554-0.985) were associated with reduced risk. No significant associations were observed in the thyroid antibody-positive group. Conclusions: These results highlight the importance of considering individual TAI status when devising iodine supplementation policies.

Salivary iodine concentrations can estimate iodine intake and diagnose abnormal thyroid function: a cross-sectional study in pregnant and lactating women in iodine-deficient areas.

Salivary iodine concentrations (SIC) and urinary iodine concentrations are correlated. This study aimed to verify the use of SIC as a biomarker for estimating iodine intake in pregnant and lactating women and to diagnose abnormal thyroid function. A cross-sectional study was conducted in northern Xinjiang, China. Participants provided venous blood, random urine, saliva and milk samples. A total of 607 pregnant and 171 lactating women volunteered to participate in the study. The average daily iodine intake was calculated for each participant. Pregnant women were divided according to trimester. The median daily iodine intake was 436·41 μg/d in the first trimester, 425·83 μg/d in the second trimester and 430·56 μg/d in the third trimester. The average daily iodine intake in lactating women was 416·16 μg/d. Different indicators were used to diagnose excessive iodine intake (> 500 μg/d). Among pregnant women, SIC had an AUC of 0·62 (P < 0·01), sensitivity of 51·75 % and specificity of 65 %. Among lactating women, SIC had an AUC of 0·63 (P = 0·03), sensitivity of 43·52 % and specificity of 85 %. SIC was an effective biomarker for diagnosing abnormal thyroid function (P = 0·03). In conclusion, this study demonstrated that SIC is a reliable biomarker for evaluating both iodine nutrition status and abnormal thyroid function in pregnant and lactating women.

6621 Iodine Nutritional Status in Different Trimesters of Pregnancy: A Prospective Observational Study in Taiwan

Abstract Disclosure: L. Pan: None. C. Yeh: None. C. Yang: None. C. Hwu: None. H. Chen: None. F. Wang: None. C. Huang: None. Pregnant women are susceptible to iodine deficiency. Iodine nutritional studies in pregnant women were mostly cross sectional evaluations of iodine status. This prospective observational study was designed to longitudinally follow the iodine status of pregnant women in different trimesters of pregnancy and to assess the clinical parameters and dietary influences on iodine status. A total of 209 pregnant women in their first trimester were enrolled in Taipei Veterans General Hospital, Taiwan from March 2019 to March 2023. Subjects provided a spot urine sample and completed a food frequency questionnaire at each trimester. Urinary iodine concentration (UIC) was measured by inductively coupled plasma mass spectrometry. The median UIC for the first, second and third trimester was 156.3 μg/L (Interquartile range [IQR]: 100.7-241.1), 146.2 μg/L (84.6-224.4), and 169.9 μg/L (94.4-283.5), respectively. Mild iodine deficiency was observed in the second trimester despite adequate iodine status in the first and third trimesters. Compared to the first trimester, intake of seaweed (p = 0.004, p &amp;lt; 0.001, respectively), fish (p &amp;lt; 0.001, p &amp;lt; 0.001, respectively), and prenatal multivitamins (p &amp;lt; 0.001, p &amp;lt; 0.001, respectively) increased in the second and third trimesters. A gradual increment in dairy product intake was also noted between each trimesters through pregnancy (p &amp;lt; 0.001, p = 0.004, respectively). Multivariate analysis indicated a positive association between multiparity and increased UIC in the second trimesters (multiparity vs. uniparity; adjusted odds ratio [OR]: 2.273, 95% confidence interval [CI]: 1.202-4.310). Additionally, increased prenatal multivitamin intake elevated the odds of adequate UIC in the third trimester (≥ 3 days/week vs. ≤ 1 day/week; adjusted OR: 2.890, 95% CI: 1.351-6.173). This study revealed the longitudinal changes in iodine status during pregnancy and suggested that women who regularly took prenatal multivitamins and were multiparous were more likely to have adequate iodine nutrition. Presentation: 6/2/2024

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 checkup 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: thyroid stimulating hormone (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 nonpregnant 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% CI, 1.08-3.77, 1.10-3.81, 1.11-3.66; p = 0.027, 0.023, 0.022, respectively) and multivitamin nonusers (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 nonusers are still at risk for iodine deficiency. Gestational thyroid function reference ranges are needed for correct diagnosis of thyroid dysfunction in pregnancy.

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.

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).

Study of iodine transport and thyroid hormone levels in the human placenta under different iodine nutritional status.

Iodine and thyroid hormones (TH) transport in the placenta are essential for fetal growth and development, but there is little research focus on the human placenta. The research aimed to investigate iodine and TH transport mechanisms in the human placenta. The placenta was collected from sixty healthy pregnant women. Urinary iodine concentration (UIC), serum iodine concentration (SIC), placenta iodine storage (PIS) and the concentration of serum and placenta TH were examined. Five pregnant women were selected as insufficient intake (II), adequate intake (AI) and above requirements intake (ARI) groups. Localisation/expression of placental sodium/iodide symporter (NIS) and Pendrin were also studied. Results showed that PIS positively correlated with the UIC (R = 0·58, P < 0·001) and SIC (R = 0·55, P < 0·001), and PIS was higher in the ARI group than that in the AI group (P = 0·017). NIS in the ARI group was higher than that in the AI group on the maternal side of the placenta (P < 0·05). NIS in the II group was higher than that in the AI group on the fetal side (P < 0·05). In the II group, NIS on the fetal side was higher than on the maternal side (P < 0·05). Pendrin was higher in the II group than in the AI group on the maternal side (P < 0·05). Free triiodothyronine (r = 0·44, P = 0·0067) and thyroid-stimulating hormone (r = 0·75, P < 0·001) between maternal and fetal side is positively correlated. This study suggests that maternal iodine intake changes the expression of NIS and Pendrin, thereby affecting PIS. Serum TH levels were not correlated with placental TH levels.

Analysis of iodine nutritional status of children aged 8-10 years in Zhejiang Province from 2016 to 2021

Objective: To analyze the iodine nutrition status of children aged 8 to 10 years in Zhejiang Province from 2016 to 2021. Methods: A multi-stage stratified sampling method was used to select non-residential children aged 8 to 10 years from 90 counties in Zhejiang Province. A total of 114 103 children were included in the study from 2016 to 2021. Direct titration method and arsenic-cerium catalytic spectrophotometry were used to detect salt iodine content and urinary iodine level, respectively, to evaluate the iodine nutritional status of children. Ultrasound was used to detect thyroid volume and analyze the current prevalence of goiter in school-age children. Results: The age of 114 103 children was (9.04 ± 0.81) years old, with 50.0% of (57 083) boys. The median of iodine content M (Q1, Q3) in children's household salt was 23.00 (19.80, 25.20) mg/kg, including 17 242 non-iodized salt, 6 173 unqualified iodized salt, and 90 688 qualified iodized salt. The coverage rate of iodized salt was 84.89%, and the coverage rate of qualified iodized salt was 79.48%. The proportion of non-iodized salt increased from 11.85% in 2016 to 16.04% in 2021 (χ2trend=111.427, P<0.001). The median of urinary iodine concentration M (Q1, Q3) in children was 182.50 (121.00, 261.00) μg/L, among which the proportions of iodine deficiency, iodine suitability, iodine over suitability, and iodine excess were 17.25% (19 686 cases), 39.21% (44 745 cases), 26.85% (30 638 cases), and 16.68% (19 034 cases), respectively. The median of urinary iodine concentration in children in inland areas [M (Q1, Q3): 190.90 (128.80, 269.00) μg/L] was significantly higher than that in children in coastal areas [M (Q1, Q3): 173.00 (113.00, 250.30) μg/L] (P<0.001). From 2016 to 2021, a total of 39 134 ultrasound examinations were conducted, and 1 229 cases of thyroid enlargement were detected. The goiter rate was 3.14% (95%CI: 2.97%-3.32%). The incidence of goiter in children in coastal areas [3.45% (95%CI: 3.19%-3.72%), 641/18 604] was higher than that in children in inland areas [2.86% (95%CI: 2.64%-3.10%), 588/20 530] (P=0.001). Conclusion: From 2016 to 2021, the iodine nutrition level of children aged 8-10 years in Zhejiang Province is generally suitable, and the rate of goiter in children meets the limit of iodine deficiency disease elimination standards.

Mechanism of multi-organ compensation under different iodine intake in pregnant rats: results from a repeated-measures study of iodine metabolism.

This study aimed to explore the differences in iodine metabolism and expression of NIS and Pendrin in pregnant rats under different iodine nutritional status. Female Wistar rats were divided into four groups: low iodine (LI), normal iodine (NI), tenfold high iodine (10HI), and fifty fold high iodine (50HI). The intervention began after one week of adaptive feeding. Iodine metabolism experiments were performed beginning on the 15th day of pregnancy. 24-h iodine intake and excretion were calculated. The concentrations of iodine in urine, fecal, thyroid, and placenta were measured by ICP-MS. PCR and Western Blot were used to detect the mRNA levels and cell membrane protein of sodium/iodide symporter (NIS) and Pendrin in the small intestine, thyroid, kidney, and placenta. Fecal iodine excretion (FIE) and urinary iodine excretion (UIE) in the 50HI group were significantly higher than those in the NI group (P < 0.05). The NIS protein and mRNA in the kidney and small intestine have an upward trend in iodine deficiency and a downward trend in iodine excess. Thyroid and placental iodine storage in the 50HI group were significantly higher than those in the NI group (P < 0.05). NIS, Pendrin protein, and mRNA in the thyroid and placenta tend to increase when iodine is deficient and decrease when there is excess. Iodine excretion and iodine stores in the placenta and thyroid gland are positively correlated with iodine intake. NIS and Pendrin are also regulated by iodine intake.

Iodine nutritional status and its associations with thyroid function of pregnant women and neonatal TSH.

Iodine serves as a crucial precursor for the synthesis of thyroid hormones and plays an import role in both pregnant women and their offspring. The relationships between iodine nutritional status and maternal thyroid function and neonatal outcomes remain inconclusive in areas with adequate iodine nutrition. This study aims to investigate their correlations. Blood, morning urine and 24-hour urine were collected from the pregnant women to measure thyroid functions, serum iodine concentration (SIC), morning urine iodine concentration (UIC) and 24-hour urine iodine excretion (24-hour UIE). Indicators of their offspring's neonatal indexes were recorded. A total of 559 pregnant women were enrolled in this study. The iodine indicators including Tg, 24-hour UIE and morning UIC were significantly different among the euthyroid pregnant women and those with different thyroid disorders. The levels of FT3, FT4, and SIC exhibited a gradual decline and the concentration of TSH exhibited a gradual increase trend throughout the progression of pregnancy in euthyroid pregnant women. There were no significant differences in neonatal outcomes and neonatal TSH values among euthyroid pregnant women and thyroid disorders pregnant women. SIC had a significant impact on maternal FT4 levels throughout all three trimesters, with varying degrees of importance observed in each trimester. TSH level emerged as the primary determinant of FT4 during the first trimester, while SIC exerted a predominant influence on FT4 levels in the second and third trimesters. The prevalence of thyroid disorders in pregnant women was the lowest when the SIC of pregnant women was probable in the range of 60~70 μg/L, 24-hours UIE was in the range of 250~450 μg, and Tg was in the range of 9~21 μg/L. Maternal TSH exhibited a notable influence on neonatal TSH levels, particularly at the 50th and 75th quantiles. Among the iodine nutritional indicators, SIC and morning UIC demonstrated higher AUC values for abnormal FT4 and TSH, respectively. The iodine nutrition status of pregnant women exerts an impact on their thyroid function and prevalence of thyroid disorders, and neonatal TSH was affected by maternal TSH. SIC may be a better indicator for iodine nutritional assessment than other indexes.

Iodine nutritional status in women of reproductive age in algeria

Iodine nutritional status in women of reproductive age in algeria

Serum iodine concentration and its associations with thyroid function and dietary iodine in pregnant women in the southeast coast of China: a cross-sectional study.

Iodine deficiency is a major public health problem in pregnant women. Serum iodine (SI) may represent a useful biomarker for iodine nutrition evaluation. We aimed to assess the relationship between serum iodine concentration (SIC) and urinary iodine concentration (UIC), dietary iodine, thyroid function, and thyroid diseases in pregnant women in the southeast coast of China, and to provide a normal reference range of SIC for pregnant women. A multistage random sampling method was used to select the study population. We collected urine and blood samples from pregnant women and determined UIC and SIC as well as thyroid function using Arsenic-Cerium Catalytic Spectrophotometry, inductively coupled plasma mass spectrometry, and Beckman Coulter Access2 chemiluminescent immunoanalyzer and kit, respectively, and administered a questionnaire on dietary iodine intake in pregnant women. There was a significant negative correlation between SI and thyroid-stimulating hormone (TSH) (r = -0.141) and a significant positive correlation between SI and free triiodothyronine (FT3) (r = 0.106), free thyroxine (FT4) (r = 0.236), triiodothyronine (TT3) (r = 0.229), total thyroxine (TT4) (r = 0.433), and dietary iodine intake (r = 0.068). There was a significant difference in SI levels of pregnancy between the second (78.13 μg/L) and third trimester (75.37 μg/L) (p = 0.018). SI levels between inadequate intake (74.58 μg/L) and appropriate intake (77.92 μg/L) groups were statistically different (p = 0.036). Low SIC was a risk factor for the development of hypothyroxinemia (adjusted OR = 3.14, 95% confidence interval: 1.75-5.66). The reference range for SIC in normal pregnant women is 45.03-112.44 μg/L. SI may be a composite indicator of iodine nutritional status and thyroid function.

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.

Fifteen Years of Iodine Prophylaxis in Italy: Results of a Nationwide Surveillance (Period 2015-2019).

In 2005, a nationwide program of iodine prophylaxis on a voluntary basis was implemented in Italy by law. However, recent data on iodine status are lacking. The aim of this study was to evaluate efficiency, effectiveness, and possible adverse effects (increased occurrence of thyroid autoimmunity and hyperthyroidism) of the Italian iodine prophylaxis program. From 2015 to 2019, a nationwide survey was performed. The use of iodized salt was evaluated in a sample of 164 593 adults and in 998 school canteens. A sample of 4233 schoolchildren (aged 11-13 years) was recruited to assess urinary iodine concentration, prevalence of goiter, and thyroid hypoechogenicity on ultrasound, with the latter being an indirect indicator of thyroid autoimmunity. Neonatal TSH values of 197 677 infants screened in regions representative of Northern, Central, and Southern Italy were analyzed to investigate the percentage of TSH values >5.0 mIU/L. Data on methimazole prescriptions were analyzed as indirect indicators of new cases of hyperthyroidism. The prevalence of the use of iodized salt was 71.5% in adult population and 78% in school canteens. A median urinary iodine concentration of 124 μg/L, a prevalence of goiter of 2.2%, and a prevalence of thyroid hypoechogenicity of 5.7% were observed in schoolchildren. The percentage of neonatal TSH values >5.0 mIU/L resulted still higher (5.1%) than the World Health Organization threshold of 3.0%, whereas the prescriptions of methimazole showed a reduction of 13.5%. Fifteen years of iodine prophylaxis have led to iodine sufficiency in Italy, although there still is concern about iodine nutritional status during pregnancy.

FRI484 Assessment Of Early-trimester Maternal Thyroid Function And Iodine Nutritional Status Of Pregnant Women In Northern Taiwan

Abstract Disclosure: G. Su: None. C. Yeh: None. C. Yang: None. C. Hwu: None. H. Chen: None. F. Wang: None. C. Huang: None. Background: The American Thyroid Association (ATA) has proposed to lower the early-trimester upper limit of the TSH reference interval to become 0.5 mIU/L less than the non-pregnant value. The local-regional reference intervals in Taiwan is unknown. The aim of the study is to evaluate the early-trimester thyroid function and iodine nutritional status of pregnant women in Taiwan. Methods: Women aged ≥20 years-old and in gestation 8 to 15 weeks were recruited in Taipei Veterans General Hospital from March 2019 to July 2022. Thyroid function and antibodies, including TSH, free T4, free T3, total T4, total T3, anti-thyroglobulin antibody (aTG) and anti-thyroidperoxidase antibody (aTPO), TSH receptor antibody, were measured. The gestation-specific thyroid function reference range was derived from the 2.5th and 97.5th percentiles of the studied women. Random spot urine sample was collected and urinary iodine concentration was checked by inductively coupled plasma mass spectrometry. A simple food frequency questionnaire was also completed. Results: A total of 211 women were enrolled and the derived early-trimester upper limit of serum TSH (median: 0.92 [0.007-3.08] uIU/mL) was lower than the value provided by the manufacturer (0.27-4.2 uIU/mL), while the upper limit of free T4 (median: 1.28 [0.93-2.15] ng/dL) and free T3 (3.00 [2.30-5.10]ng/dL) were both higher than the non-pregnant value (0.93-1.7 ng/dL and 2.0-4.4 ng/dL, respectively). The range of total T4 (median: 9.90 [6.39-15.36] ng/dL) and total T3 (median: 136 [89.50-223.20] ng/dL) in the studied women were similar to the non-pregnant range (5.1-14.1 ng/dL and 80-200 ng/dL, respectively). The positivity rate of aTG &amp; aTPO were 8.6%. Two patients with mild Graves’ disease and three patients with subclinical hypothyroidism were incidentally detected and treated. The positive predictive value for detecting thyroid dysfunction using the non-pregnant reference interval was only 15.9% because subclinical hyperthyroidism (18.2%, n=37) would be over-diagnosed and subclinical hypothyroidism (1.0%, n=2) would be under-diagnosed. The overall median UIC was 160.9 μg/L, indicating a sufficient iodine status. Dairy products were the most commonly consumed iodine-containing food type with 71.8% of the pregnant women ingesting dairy products ≥3 days/week. The median intake frequency for seaweed, fish, and seafood were one day per week. Approximately 34.0% of the women took multivitamin every day, but 58.4% of the women never took multivitamin. Conclusion: Our results indicate that the iodine nutritional status in the early trimester of pregnancy is adequate and that the upper limit of serum TSH was approximately 1.12 uIU/mL lower than the upper limit provided by the manufacturer. Gestation-specific thyroid function reference intervals are needed for correct diagnosis of thyroid dysfunction in pregnancy. Presentation: Friday, June 16, 2023

Iodine Concentration in the Breast Milk and Urine as Biomarkers of Iodine Nutritional Status of Lactating Women and Breastfed Infants in Taiwan.

Breast milk iodine concentration (BMIC) can be different when median urinary iodine concentration (UIC) is similar. The BMIC, UIC/creatinine (Cr), estimated 24-h urinary iodine excretion (24-h UIE) of lactating women in Taiwan is unknown. This study enrolled lactating women from Taipei Veterans General Hospital (August 2021-February 2023). Each participant provided a random spot urine sample, two breast milk samples, a blood sample, and completed a food frequency questionnaire on the same day. Iodine measurement was performed by inductively coupled plasma mass spectrometry. The median UIC of the enrolled 71 women was 91.1 μg/L, indicating insufficient iodine status; however, the median BMIC was 166.6 μg/L and this suggested that the amount of iodine delivered through breast milk was adequate for the breastfed infants. BMIC was correlated with UIC/Cr and 24-h UIE (both rs = 0.49) but not with UIC (rs = 0.18) or thyroid stimulating hormone (rs = 0.07). Women who did not consume dairy products (adjusted odds ratio: 24.41, 95% confidence interval: 1.26-471.2) and multivitamins (adjusted odds ratio: 8.26, 95% confidence interval: 1.76-38.79) were at increased odds for having lower BMIC. The results suggest that measuring maternal UIC alone may not be sufficient, as BMIC, UIC/Cr, and 24-h UIE are all important biomarkers. Ingestion of dairy products and multivitamins were independently associated with BMIC.

Thyroid peroxidase antibody titers, thyroid function, and iodine nutrition status of pregnant normotensive and preeclamptic women in Eastern Cape South Africa

Autoimmune thyroid disease, one of the main risk factors for hypothyroidism, is associated with adverse pregnancy outcomes. The burden of autoimmune thyroid disease in pregnancy and its association with thyroid function among normotensive pregnant women and pregnant women with hypertension in South Africa are not known. This study aimed to establish the magnitude of thyroid peroxidase autoantibodies in pregnancy in the Eastern Cape of South Africa and its relationship with iodine nutrition status and preeclampsia. Overall, 60 randomly selected normotensive pregnant controls at term and 120 pregnant participants with preeclampsia in the third trimester of pregnancy going to the Mthatha Regional Hospital and the Nelson Mandela Academic Hospital in the Eastern Cape Province who had complete data on thyroid peroxidase antibody titers, urinary iodine concentrations, serum thyroid-stimulating hormones, and free triiodothyronine, free thyroxine, and thyroglobulin levels were enrolled in this unmatched case-control study. The cases and controls had similar mean chronological age (23.8 vs 24.0 years), body mass index (29.4 vs 28.8 kg/m2), and median parity (both 1) (P>.05). The controls had a higher mean gestational age than participants with preeclampsia (38.5 vs 33.7 weeks, respectively; P<.001). Both participants with preeclampsia and normotensive participants had median thyroid peroxidase antibody levels consistent with a negative thyroid autoimmune status. Participants with preeclampsia had higher but nonstatistically significant median thyroid peroxidase antibody (2.14 vs 1.77 IU/L), thyroglobulin (25.9 vs 21.3 µg/L), and thyroid-stimulating hormone (2.4 vs 2.3 mIU/L) levels (P>.05) and significantly lower median urinary iodine concentration (123.4 vs 188.6 µg/L), free thyroxine (13.2 vs 14.1 pmol/L), and free triiodothyronine (4.3 vs 4.6 pmol/L) levels (P<.05) than normotensive controls. Thyroid peroxidase antibodies were positively correlated with thyroglobulin, urinary iodine concentration, and thyroid-stimulating hormone. In the rural Eastern Cape of South Africa, pregnant women in the third trimester of pregnancy have thyroid peroxidase antibody titers that show negative thyroid autoimmune status. Insufficient iodine intake, other than thyroid autoimmune disease, seems to be the underlying cause of the lower free triiodothyronine and free thyroxine levels observed among women with preeclampsia.

Relation between iodine nutrition and thyroid diseases in Qinghai, China.

To investigate the adult iodine nutrition and the prevalence of thyroid diseases in Qinghai Province, and analyze the correlation between iodine and thyroid diseases, so as to provide a basis for adjusting the salt iodization plan in Qinghai Province. Using cluster and stratified sampling method to select 2628 permanent residents over 18 years old in Qinghai Province for questionnaire survey, physical examination, thyroid color ultrasound, and laboratory index detection. 1. The coverage of iodized salt in adults is 99.71%. 2. The detection rates of thyroid disorders in adults were as follows: Clinical hyperthyroidism was 1.20%, subclinical hyperthyroidism was 0.20%, clinical hypothyroidism was 1.00%, subclinical hypothyroidism was 29.20%, and the goiter was 2.10%. The percentages positivity of TPO Ab, TG Ab, goiter was 9.80%, 9.20%, 2.10%, respectively. Among them single thyroid nodule was 6.40%, multi-nodule thyroid gland was 1.80%. 3. The percentages of mild iodine deficiency, moderate iodine deficiency, Severe iodine deficiency, adequate iodine intake (AI), more than adequate iodine intake (MAI)and excessive iodine intake (EI)were 8.41%, 2.17%, 0.26%, 33.22%, 28.35%, and 27.59%, respectively. The percentages of mild, moderate and severe iodine deficiency in urban populations (7.13%, 0.87%, 0.0%) were significantly lower than those in rural populations (9.81%, 3.59%, 0.56%) (P < 0.05), and the rates of adequate, more than adequate iodine intake in urban populations (36.03%, 30.93%) were significantly higher than that in rural populations (30.14%, 25.52%). The rate of excess iodine intake was higher in rural areas (30.38%) than in urban areas (25.04%). 4. The positive rates of subclinical hypothyroidism, goiter, TPO Ab and TG Ab in female adults (35.28%, 3.39%, 13.54%, 13.94%) were higher than those in male adults (23.58%, 0.96%, 6.266%, 4.79%). The detection rate of single thyroid nodules was higher in urban (8.01%) than rural populations (4.70%), while the detection rate of hypothyroidism, subclinical hypothyroidism, and goiter (0.58%, 25.84%, 1.38%) was lower than that in rural populations (1.52%, 32.96%, 2.96%) (P<0.05). 5. There was no statistical significance in the detection rates of clinical hyperthyroidism, subclinical hypothyroidism, subclinical hypothyroidism, goiter, thyroid nodules, TPO Ab and TG Ab positive rates in different iodine nutritional status (P>0.05). The positive rate of hypothyroidism in the iodine deficiency group is higher than in other iodine nutrition groups. The nutritional status of iodine in Qinghai Province is iodine excess. Subclinical hypothyroidism was detected at a high rate. Subclinical hypothyroidism, goiter, TPO Ab, and TG Ab were more common in female than in male. The proportion of mild, moderate, and severe iodine deficiency was higher in urban areas than in rural areas. The detection rate of thyroid nodules was higher in urban than in rural areas, and that of hypothyroidism, subclinical hypothyroidism, and goiter was lower than that in rural populations. The detection rate of clinical hypothyroidism was statistically significant in different iodine nutritional states (P< 0.05).