Urinary Iodine Concentration Research Articles

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.

Maternal Urinary Iodine Concentration during Pregnancy and Its Impact on Child Growth and Neurodevelopment: An 11-Year Follow-Up Study.

Mild-to-moderate iodine deficiency during pregnancy is prevalent worldwide, but its consequences for maternal and child health are not clear. We aimed to investigate the impact of maternal iodine intake during pregnancy on the child's growth and neurodevelopment. This study involved a cohort of 11-year-old children (n = 70) whose mothers had participated in an iodine intake survey during pregnancy. Gestational, neonatal, anthropometric, intelligence quotient (IQ), and socioeconomic parameters were analyzed according to maternal urinary iodine concentration (UIC). There was a positive linear trend of current height Z-score, full-scale IQ, verbal IQ, family income, maternal education, and a negative trend of neonatal TSH levels with increasing maternal UIC levels. However, regression analysis indicated that maternal UIC was not an independent predictor of any gestational, neonatal, or childhood development parameter. Only maternal school education was positively associated with child height and IQ. In conclusion, we did not find any evidence of a direct effect of maternal iodine intake during pregnancy on the long-term growth and neurodevelopment of children. The results suggest that socioeconomic factors are important confounding factors that affect both maternal iodine intake and child development and must be considered when investigating the association between maternal iodine intake and child outcomes.

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.

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

FRI495 Analytical Validation Of An Inductively Coupled Plasma Mass Spectrometry Method For Measuring Iodine Content In Breast Milk

Abstract Disclosure: J. Li: None. L. Lee: None. F. Wang: None. C. Yang: None. C. Huang: None. Background: Adequate iodine status in lactating women is defined by a maternal median urinary iodine concentration above 100 μg/L. However, the current standard does not account for the secretion of iodine into breastmilk and could not truly reflect the amount of iodine delivered to the infants. Measuring breastmilk median iodine concentration (BMIC) is of crucial importance but the method to measure BMIC has not been developed and validated in Taiwan. Method: We adopted the ammonia dilution method without prior sample digestion to measure BMIC by inductively coupled plasma mass spectrometry (ICP-MS). Samples and iodine calibrators were prepared into an aqueous solution containing Triton X-100, 0.5% ammonia solution and tellurium (128Te) as the internal standard. Precision, accuracy, serial dilution, and recovery tests were performed for method validation. Results: The intra-assay and inter-assay coefficient of variation for the four human breast milk samples with different iodine concentrations ranged from 3.2% to 4.7% and 2.3% to 5.5%, respectively. The standard NIST 1549 milk powder was prepared into three different concentrations of 50 μg/L, 100 μg/L and 200 μg/L to assess accuracy and the biases were &amp;lt;5%. A recovery of 95-105% was achieved for four human breast milk samples spiked with sodium iodide solution. The serial dilution test confirmed linearity up to 500 μg/L. The limit for detection and quantification was 0.73 μg/L and 2.19 μg/L, respectively. Conclusion: The results of the current study confirmed that this ICP-MS method is accurate and reliable in measuring BMIC. Presentation: Friday, June 16, 2023

Iodized Salt May Not Be Sufficient to Guarantee an Adequate Iodine Intake in Pregnant Women.

Adequate iodine intake is of crucial importance in pregnancy to meet the thyroid hormone needs of both mother and fetus. In the present study, undertaken as a part of the surveillance actions following the introduction in Italy of a national salt iodination program in 2005, the iodine intake was investigated in 123 pregnant women and 49 control women living in the same area of central Italy. All the participants were screened for urinary iodine concentration (UIC), serum level of thyrotropin, free-thyroxine, free-triiodothyronine, and thyroid volume. Moreover, they were provided with a questionnaire on the use of iodine-containing salt or supplements. Control women had a median UIC of 102 µg/L, consistent with an iodine sufficiency, while in pregnant women the median UIC value was 108 µg/L, lower than the endorsed UIC of 150 µg/L. In addition, pregnant women showed a significantly increased median thyroid volume compared to controls. Interestingly, the median UIC did not differ between pregnant women not using iodine-containing salt or supplements and those regularly consuming iodized salt alone, while pregnant women with a daily intake of iodine-containing supplements had an adequate median UIC (168 µg/L). In conclusion, the data reported here showed that pregnant women and their fetuses are still exposed to the detrimental effects of iodine deficiency and that the consumption of iodine-containing supplements should be recommended in pregnancy.

A-051 Reference Intervals for Serum T4 and FT4 among Pregnant Women linked to the Mãe Curitibana Program

Abstract Background Thyroid diseases are frequent in women of childbearing age and can have negative maternal and fetal repercussions when not identified and properly treated. Physiological changes during pregnancy cause changes in thyroid function tests, which is why they must be carefully interpreted and, whenever possible, based on local and specific reference values for pregnant women. Determining the serum level of total (T4T) or free (FT4) T4 is fundamental for defining the diagnosis of thyroid dysfunctions between clinical (TSH and T4 altered) or subclinical (only TSH altered). This definition modifies the treatment recommendations for thyroid disorders in various published guidelines. Objectives To determine the reference intervals for FT4 and T4T of pregnant women, in the first trimester, residing in the city of Curitiba and followed by the municipal public health system. Methods Longitudinal study with a sample of 225 pregnant women aged over 18 years, linked to prenatal care in the public health system (SUS) of Curitiba city, with up to 14 weeks of gestation. Pregnant women were selected proportionally to each health district in the city, to represent the entire population of the city served by the SUS. Pregnant women who had TSH outside the reference range, positive ATPO, family history of thyroid disease, use of antithyroid drugs, use of medications that could interfere with the measurement of the markers under study were excluded. The studied population had a median urinary iodine concentration considered adequate for pregnant women (158 mcg/L). Serum FT4 and T4T were measured by chemiluminescent immunoassay on Atellica IM Analyzer. Continuous variables were expressed as mean and standard deviation and percentiles were determined and variations between 2.5 and 97.5 percentiles were considered as the normal reference interval. The results were analyzed and compared with the reference interval provided by the manufacturer for non-pregnant women. Results Of the 225 pregnant women (with mean ± standard deviation of gestational age 8 weeks ± 2.3; with mean ± standard deviation of age 27 years ± 5.9) the FT4 values of the pregnant women ranged between 0.83 and 1.68 ng/dL, with mean ± standard deviation of 1.23 ± 0.15. The 2.5th and 97.5th percentiles were 0.94 and 1.64 ng/dL. Compared with the kit manufacturer’s reference values for non-pregnant women (0.95–1.47 ng/dl), we would have 08 pregnant women with a high FT4 result. The T4T values of the pregnant women varied between 9.2 and 12.2 ng/dL, with a mean ± standard deviation of 10.9 ± 2.48. The 2.5th and 97.5th percentiles were 9.2 and 12.2 ng/dL. Compared with the kit manufacturer’s reference values for non-pregnant women (4.87 and 11.72 ng/dL), we would have 25 pregnant women with high T4T results. Conclusion The FT4 and T4T reference intervals of first trimester pregnant women are different from the non-pregnant population, however this difference is less relevant in FT4. In T4T, the lower limit of normal in pregnant women is much higher than in the normal population, which makes it less sensitive for the definition of clinical hypothyroidism in first trimester pregnant women.

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.

Bioavailability of iodine from a meal consisting of sushi and a wakame seaweed salad-A randomized crossover trial.

The consumption of seaweed is on the rise in the Western world. Seaweeds may contain substantial amounts of iodine, and some species could serve as a potential dietary iodine source. However, limited data on the iodine content and in vivo bioavailability of iodine from seaweeds exist. The objective was to assess whether iodine from a meal consisting of sushi with nori, (Porphyra spp) and a wakame seaweed salad (Undaria pinnatifida) had similar bioavailability as a potassium iodide reference supplement of similar iodine content. A randomized 2 × 2 crossover trial (AB/BA model) was conducted in 20 healthy young women. One intervention arm consisted of a meal with sushi and wakame salad (231 μg iodine), and the other of potassium iodide (KI) supplement (225 μg iodine). Urinary iodine concentration (UIC) was measured at 11 different time points for 48 h after the interventions. The UIC increased after consumption of both the sushi and wakame meal and the KI supplement, but the median UIC was higher after ingestion of the KI supplement. The estimated bioavailability of iodine during the first 24 h was 75% from sushi with wakame and 97% from the KI supplement. The bioequivalence analyses confirmed that the KI supplement had higher estimated bioavailability than the sushi and wakame meal, however, with small margins. Our findings on iodine bioavailability imply that sushi and wakame could be potential iodine sources in the diet, which may be favorable for population groups at risk for iodine deficiency. However, further research is needed to account for the variability of iodine content in seaweeds by different locations and degree of processing, to assure that the iodine levels are stable and predictable for the consumers.

Iodine Nutrition in Children ≤2 years of Age in Norway

BackgroundAs a component of the thyroid hormones (THs), iodine is vital for normal neurodevelopment during early life. However, both deficient and excess iodine may affect TH production, and data on iodine status in young children are scarce. ObjectivesTo describe iodine nutrition (iodine status and intake) in children ≤2 y of age in Innlandet County (Norway) and to describe the associations with maternal iodine nutrition. MethodsA cross-sectional study was performed in a representative sample of mother–child pairs selected from 30 municipalities from November 2020 until October 2021. Iodine status [child urinary iodine concentration (UIC), maternal UIC, and breast milk iodine concentration (BMIC)] was measured. Child’s iodine intake was estimated using 2 24-h dietary recalls (24-HR) and a food frequency questionnaire. The Multiple Source Method was used to estimate the usual iodine intake distributions from the 24-HR assessments. ResultsThe median UIC in 333 children was 145 μg/L, indicating adequate iodine status according to the WHO cutoff (100 μg/L). The median usual iodine intake was 83 μg/d. Furthermore, 35% had suboptimal usual iodine intakes [below the proposed Estimated average requirement (72 μg/d)], whereas <1% had excessive usual iodine intakes [above the Upper intake level (200 μg/d)]. There was a positive correlation between children’s iodine intake and BMIC (Spearman rank correlation coefficient r = 0.67, P < 0.001), and between children’s UIC and BMIC (r = 0.43, P < 0.001), maternal UIC (r = 0.23, P = 0.001), and maternal iodine intake (r = 0.20, P = 0.004). ConclusionDespite a median UIC above the cutoff for iodine sufficiency, more than a third of the children had suboptimal usual iodine intakes. Our findings suggest that many children will benefit from iodine fortification and that risk of iodine excess in this age group is low.

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.

The relationship between dietary inflammatory index values and thyroid function in the US adult population: An analysis of the NHANES 2007-2012 cohort.

Researchers have developed the Dietary Inflammatory Index (DII) as a tool to quantify the inflammatory potential of a given diet. Higher DII scores indicated a more proinflammatory diet. While inflammation is known to have a strong impact on thyroid function, the precise nature of the association between DII scores and thyroid function has yet to be clarified. This study was conducted with the goal of exploring this relationship in a representative population of adults from the United States. For this study, we used data from the National Health and Nutrition Examination Survey (NHANES). Standardized questionnaires were used to collect demographic and dietary data from the participants, and laboratory tests were used to collect data on the participants' thyroid parameters and other relevant data. Linear regression models and smoothed curve fitting were used to assess the relationship between DII scores and thyroid function, with weighted data analyses and subgroup analyses being conducted as appropriate. In total, 7712 subjects were recruited from the NHANES 2007-2012 cohort. Their weighted mean age was 44.87 (0.47) years, mean DII score was 1.41 (0.05). Mean FT3 was 3.20 (0.01) pg/mL and mean TT4 was 7.81 (0.03) µg/dL. In adjusted analyses, higher DII values were related to increases in FT3 (β = .007; p = .027) and TT4 (β = .050; p = .005) levels. Subgroup analyses showed a negative correlation between FT3 levels and DII scores in a population with high urinary iodine concentrations. These data indicate that the consumption of a more proinflammatory diet, as evidenced by elevated DII scores, is correlated with significant increases in FT3 and TT4 levels. However, for people with high urinary iodine concentrations, a more proinflammatory diet was associated with lower FT3 levels. Additional research will be vital to clarify the mechanistic basis for these findings.

Association between iodine nutrition and cervical lymph node metastasis of papillary thyroid microcarcinoma.

We aimed to investigate the association between iodine intake and nodal metastasis stratified by central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM) of papillary thyroid microcarcinoma (PTMC). Urinary iodine concentration (UIC) and clinicopathological characteristics were used to identify factors associated with CLNM and LLNM using logistic regression analysis. A sum of 3,858 PTMC patients were enrolled. The median UIC (MUI) of patients with CLNM or LLNM was not statistically different from those without nodal metastasis. Male patients had a higher MUI than females (183.4 μg/L vs. 173.6 μg/L). Female patients with extracapsular extension had a higher MUI than those without it (210.0 μg/L vs. 172.1 μg/L). Male patients with LLNM had a significantly lower MUI than those without LLNM (134.7 μg/L vs. 187.9 μg/L). Female patients with more than adequate iodine intake were more likely to present with CLNM and extrathyroidal extension than those with adequate iodine intake with an odds ratio (95% confidence interval) of 1.23 (1.01-1.51) and 1.59 (1.09-2.32) after adjustment. Iodine nutrition was not found to be associated with LLNM. In addition, patients with a younger age, larger tumors, extrathyroidal extension, and intrathyroidal spread were more likely to be CLNM, whereas nodular goiter presented with a protective factor; CLNM was the only factor associated with LLNM of PTMC in both genders. In conclusion, iodine nutrition has a much closer association with female than male patients, and high iodine intake may be associated with CLNM and extrathyroidal extension in female PTMC patients.

National monitoring of iodine, sodium, and vitamin D status in toddlers and women of childbearing age - results and lessons learned from a pilot study in Norway.

Norway is lacking a population-based national monitoring program for iodine, sodium, and vitamin D status. The aim of this study was to pilot-test a study design for collecting biological samples from a country-representative sample of 2-year-old children and their mothers and to report results for iodine, salt, and vitamin D at baseline, before initiation of salt iodization in Norway. In a cross-sectional study, we recruited 2-year-old children and their mothers during the routine 2-year check-up through 38 randomly selected health clinics in 2021. Spot urine samples were analyzed for iodine, creatinine, and sodium, and dried blood spots from the mothers were analyzed for thyroglobulin (Tg) and 25-hydroxyvitamin D (25(OH)D). We aimed at including 400 mother-child pairs but recruited only 55 pairs. Major challenges were closed health clinics due to the COVID-19 pandemic, lack of motivation of the health personnel to prioritize recruiting, missing information about non-participation, and high workload for participants. The median urinary iodine concentration (UIC) was 123 (95% CI: 76, 228) µg/L in the toddlers and 83 (95% CI: 72, 99) µg/L in the mothers. The median urinary sodium concentration (UNaC) was 62 (95% CI: 37, 91) mmol/L in the toddlers and 93 (95% CI: 77, 107) mmol/L in the mothers. Of the mothers, 18% had levels of 25(OH)D <50 nmol/L (suboptimal status). Lessons learned from the pilot study will be used to design a national monitoring program for toddlers and women of childbearing age in Norway. The results indicate that 2-year-old children and women of childbearing age in Norway may have inadequate iodine intakes at the group level, while for vitamin D, most of the mothers had adequate status.

The problem of iodine deficiency in the Chechen republic: assessment of the current state and ways of solution

To conduct a comprehensive study to assess the current iodine security of the population of the Chechen Republic, to analyze the prevalence of thyroid pathology and compare it with official statistics, to formulate conclusions about the necessary preventive measures. In the Chechen Republic, a total of 1239 people were examined, of which 921 were schoolchildren of pre-pubertal age (8-10 years) and 318 were adults. The survey of the adult population was carried out at medical organizations in four districts of the republic (Nadterechny, Shalinsky, Vedensky, Grozny) and included a questionnaire survey, a clinical examination by an endocrinologist with palpation of the thyroid gland, thyroid ultrasound, and a study by a qualitative method of samples of table salt used in households for the presence of iodine.Children's examinations were carried out by the cluster method on the basis of secondary schools in 9 out of 15 districts of the republic and included an examination by an endocrinologist and measurement of anthropometric parameters (height, weight), thyroid ultrasound to evaluate volume, determination of iodine concentration in single portions of urine and qualitative analysis of samples of table salt used in children's nutrition in families for the presence of iodine.The incidence and prevalence of thyroid disease among the population of the Chechen Republic were analyzed using data from official state statistics - form No. 12 «Information on the number of diseases registered in patients living in the area served by the medical institution» (ROSSTAT data as of 01.01.2021). According to the results of a survey of 921 pre-pubertal children, the median urinary iodine concentration was 71.3 µg/L (frequency of values below 50μg/L - 17,7%) and varies from 48.9 to 179.2 µg/L in the surveyed areas. According to thyroid ultrasound data, diffuse goiter was detected in 16.4% of the examined children, with goiter frequency ranging from 11.3% to 23.5%. The proportion of iodized salt consumed in schoolchildren's families was 4.2% in all study areas (range of values from 1.3% to 8%), which indicates an extremely low level of using iodized salt by household.According to the results of the examination of the adult population (n=318), structural changes in thyroid tissue were detected in 79.9% (n=254), while the proportion of nodular thyroid pathology being 83% (n=205), with a range of values across different districts of 52.5-80%. Based on the obtained data, according to WHO criteria, it can be stated that, overall, the degree of severity of iodine deficiency disorders in the Chechen Republic corresponds to mild severity with a tendency towards moderate severity in several districts of the foothills. The results of the examination of the adult population indicate a high prevalence of thyroid pathology, predominantly nodular, in the Chechen Republic. The data obtained in the course of large-scale research made it possible to initiate the development of necessary medical and organizational measures in the region - a program for the prevention of IDD.

The use of breast milk iodine concentration in the first week of lactation as a biomarker of iodine status in breast-feeding women.

Breast milk iodine concentration (BMIC) is a promising indicator of iodine status in lactating women. However, there are limited data on its usefulness to reflect maternal iodine deficiency. Therefore, the aim of our study was to assess iodine concentration in breast milk and urine samples in exclusively breast-feeding women. Eligible pregnant women undergoing routine antenatal care in a large hospital in Shaanxi Province, China, were followed up from the third trimester of pregnancy until the first week of lactation. Urine samples (20 ml) were collected during pregnancy and lactation. Iodine concentration in samples was measured based on Sandell-Kolthoff reaction. Breast milk samples (5 ml) were provided during lactation. A receiver operating curve (ROC) was constructed to determine the diagnostic performance of BMIC. An iodine-specific FFQ was completed twice during pregnancy and lactation. A total of 200 women completed the study. The overall median BMIC was 89 μg/l, indicating iodine sufficiency (i.e. BMIC reference range between 60 and 465 μg/l). Women reported similar median urinary iodine concentration (UIC) during pregnancy and lactation (112 and 113 μg/l, respectively), but their iodine status differed - mild-to-moderate iodine deficiency during pregnancy and iodine sufficiency during lactation. The ROC for BMIC using UIC as a reference standard was 0·755 (95 % CI: 0·644, 0·866). In conclusion, this study demonstrated that women were iodine sufficient in the first week of lactation as assessed by UIC, which was consistent with BMIC. These findings suggested that BMIC is a useful biomarker to assess iodine status in lactating women.

Iodine nutrition in greenland: urinary iodine concentration during a 20-year period

Iodine nutrition in greenland: urinary iodine concentration during a 20-year period

Thyroid function and urinary concentrations of iodine, selenium, and arsenic in vegans, lacto-ovo vegetarians and pescatarians

PurposePopulations following a plant-based diet may be at particular risk of thyroid dysfunction due to low iodine and selenium intakes. The main purpose was to assess thyroid function and urinary concentration of iodine, selenium, and arsenic, in subjects following a vegan, lacto-ovo vegetarian, or pescatarian diet.MethodsIn Norway, a country without mandatory dietary iodine fortification, 205 adults, following vegan (n = 115), lacto-ovo vegetarian (n = 55) and pescatarian diet (n = 35) were included. Thyroglobulin (Tg), thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), and serum anti-TPO (S-anti-TPO) were measured in a venous blood sample and concentrations of iodine (UIC), creatinine (UCC), selenium, and arsenic were measured from single spot urine samples.ResultsSubclinical hypothyroidism (TSH > 4.0 mU/L) was observed in 3% of subjects. The overall median (p25, p75) Tg was 17 (9, 30) µg/L and vegans had higher Tg compared to pescatarians. Vegans not consuming iodine-containing supplements (n = 43) had higher Tg, than supplement users (n = 72), 27 (11, 44) vs. 16 (8, 25) µg/L and higher fT4, 16 (15, 17) vs. 15 (14, 17) pmol/L, respectively. The overall median UIC was 57 (28, 130) µg/L, all dietary groups had median UIC below WHO thresholds. Median urinary selenium and arsenic concentration was 13 (6, 22) and 3 (2, 8) µg/L, respectively.ConclusionThe prevalence of subclinical hypothyroidism was low and fT4 and fT3 were within the normal range for all dietary groups. Vegans had significantly increased Tg compared to pescatarians.

Methods for determining iodine in urine

Iodine deficiency remains a serious threat to public health worldwide, especially in children and pregnant women. Despite the apparent ease of iodine deficiency elimination with the help of a simple and highly effective strategy of compulsory salt iodization, the problem of iodine deficiency and iodine deficiency disorders remains urgent for public health in the Russian Federation. The most effective and informative way to study iodine status at population level is determination of iodine concentration in urine in epidemiological studies. This article presents a review of urinary iodine determination methods, as well as methodological recommendations for iodine determination, developed and adopted in National Medical Research Center for Endocrinology.