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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Determination of the Elemental Iodine in Human Breast Milk by Inductively Coupled Plasma mass Spectrometry.

Adequate iodine status in lactating women is defined by a maternal median urinary iodine concentration (UIC) ≧ 100 µg/L. However, the above-mentioned criterion does not account for the secretion of iodine into breast milk and could not truly reflect the amount of iodine delivered to the infants. Measuring breast milk median iodine concentration (BMIC) is crucial, but the method to measure BMIC has not been developed and validated in Taiwan. We adopted the ammonia dilution method without prior sample digestion to measure BMIC by inductively coupled plasma mass spectrometry (ICP-MS). Samples and iodate 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. The range of intra-assay and inter-assay coefficient of variation for the four human breast milk samples with different iodine concentrations were 3.2-4.7% and 2.3-5.5%, 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 the accuracy; the bias was < 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 0.998. The limit for detection and quantification was 0.78 µg/L and 2.34 µg/L, respectively. The results of the current study confirmed that this ICP-MS method is accurate and reliable in measuring BMIC.

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.

Relationships between Dietary Patterns and Erythropoiesis-Associated Micronutrient Deficiencies (Iron, Folate, and Vitamin B12) among Pregnant Women in Taiwan.

Globally, anemia affects 56 million pregnant women, especially women with a low household income. Functional erythropoiesis requires a constant supply of micronutrients, and the demands significantly increase during fetal development. This study aims to identify dietary patterns for preventing gestational erythropoiesis-associated micronutrient deficiencies (e.g., iron, folic acid, and vitamin B12). A Nationwide Nutrition and Health Survey in Pregnant Women, Taiwan (NAHSIT-PW), was conducted between 2017 and 2019. Data on baseline information, diet, anthropometrics, and blood biochemistry were collected during a prenatal visit. Dietary patterns were identified using a reduced rank regression (RRR). Erythropoiesis-related micronutrient deficiencies were defined as single, double, and triple micronutrient deficiencies of an iron deficiency, folate depletion, and a vitamin B12 deficiency. In total, 1437 singleton pregnancies aged ≥20-48 years were included in the analysis. Prevalences of normal nutrition, and single, double, and triple erythropoiesis-related micronutrient deficiencies were 35.7%, 38.2%, 18.6%, and 7.5%, respectively. Anemic pregnant women with a low household income had the highest prevalence rates of double (32.5%) and triple (15.8%) erythropoiesis-related micronutrient deficiencies. Dietary pattern scores were positively correlated with nuts and seeds, fresh fruits, total vegetables, breakfast cereals/oats and related products, soybean products, and dairy products but negatively correlated with processed meat products and liver, organs, and blood products. After adjusting for covariates, the dietary pattern had 29% (odds ratio (OR): 0.71; 95% confidence interval (CI): 0.055-0.091, p = 0.006)) and 43% (OR: 0.57; 95% CI: 0.41-0.80, p = 0.001)) reduced odds of having double and triple erythropoiesis-related micronutrient deficiencies for those pregnant women with a low household income. For those women with anemia, dietary patterns had 54% (OR: 046, 95% CI: 0.27-0.78) and 67% (OR: 0.33; 95% CI: 0.170.64) reduced odds of double and triple erythropoiesis-related micronutrient deficiencies. In conclusion, increased consumption of breakfast cereals and oats, nuts, and seeds, fresh fruits and vegetables, soybean products, and dairy products may protect women against erythropoiesis-related micronutrient deficiencies during pregnancy.

Measurements of elemental iodine in soy sauces in Taiwan using a modified microplate method.

Background: Soy sauce is widely used in a variety of Asian dishes to enhance flavor. Soybean and most soybean products, including soy sauces, are listed as prohibited foods in a low iodine diet. However, the iodine content in soy sauces is largely unknown. The aim of this study was to determine the iodine content in domestic soy sauces in Taiwan. Methods: Twenty-five different kinds of soy sauces were diluted with distilled water and with a dilution factor of fifty or above. Iodine concentrations of the diluted samples were measured colourimetrically based on the Sandell-Kolthoff reaction by a modified microplate method. All the measurements were repeated twelve times on three different days for determination of mean and standard deviation (SD), and coefficients of variance (CV). Serial dilution and recovery tests were also performed for validation. The results were confirmed by an inductively coupled plasma mass spectrometry (ICP-MS) method. Results: Among the twenty-five surveyed soy sauces, most of them (n=22) were iodine-free (<16 ug/L, and thus un-detectable). The iodine concentrations (mean ± SD) of the three iodine-containing soy sauces were 2.7 ± 0.1, 5.1 ± 0.2, and 10.8 ± 0.6 mg/L, respectively. The inter-assay, intra-assay and total CVs were all <5.3% for the modified microplate method. The results obtained by ICP-MS were consistent with those of the modified microplate method. The recovery rates in the serial dilution test and recovery test ranged from 94.7% to 118.6%. Two of the three iodine-containing soy sauces were supplemented with kelp extract, while the other one without kelp extract had the highest amount of salt among the three iodine-containing soy sauces. Therefore, we postulate that iodized salt instead of kelp extract is the source of higher iodine content in that sauce. Conclusion: The results suggest that most soy sauces are iodine-free and may be allowed during low iodine diets.

Associations of Dietary Patterns and Vitamin D Levels with Iron Status in Pregnant Women: A Cross-Sectional Study in Taiwan.

Vitamin D is involved in the pathophysiology of anemia. This cross-sectional study was conducted using the Nationwide Nutrition and Health Survey in Pregnant Women in Taiwan database. We investigated associations among dietary patterns (DPs), vitamin D, and iron-related biomarkers in pregnant women. The principal component analysis revealed four DPs. Linear and logistic regression analyses were performed to investigate the association of DPs with anemia-related biomarkers. Plant-based, carnivore, and dairy and nondairy alternatives DPs were positively associated with serum vitamin D levels. After adjusting covariates, the pregnant women consuming plant-based DPs at the mid-tertile (T2) were associated with reduced risks of low serum folate and vitamin D levels, and those consuming carnivore DPs at higher tertiles (T2 and/or T3) were correlated with an increased risk of low serum iron levels but decreased risks of low serum transferrin saturation, vitamin B12, and vitamin D levels. The pregnant women consuming dairy and nondairy alternatives DPs at the highest tertile (T3) were associated with reduced risks of low serum folate and vitamin B12 levels. However, the processed food DP was not correlated with anemia-related biomarkers. Thus, plant-based, carnivore, and dairy and nondairy alternatives DPs were associated with the risk of low-serum-anemia-related variables.

Analytical validation of an inductively coupled plasma mass spectrometry method for urinary iodine concentration measurements in Taiwan.

BACKGROUND: Urinary iodine concentration (UIC) measured by Sandell-Kolthoff spectrophotometric method has been used in the Nutrition and Health Surveys in Taiwan but this method is time consuming and produces toxic waste from arsenic trioxide. The aim of this study was to develop and validate an inductively coupled plasma mass spectrometry (ICP-MS) system to determine UIC in Taiwan. METHODS: Samples and iodine calibrators were diluted 100-fold into an aqueous solution containing Triton X-100, 0.5% ammonia solution, and tellurium (128Te) as an internal standard. Digestion prior to analysis was not necessary. Precision, accuracy, serial dilution, and recovery tests were performed. A total of 1243 urine samples covering a wide range of iodine concentrations were measured by both Sandell-Kolthoff method and ICP-MS. Passing-Bablok regression and Bland-Altman plots were used to compare values across methods. RESULTS: The limit for detection and quantification by ICP-MS was 0.95 µg/L and 2.85 µg/L, respectively. The intra-assay and inter-assay coefficients were <10%, with a recovery range of 95%-105%. The results obtained by ICP-MS and the Sandell-Kolthoff method were highly correlated (Pearson's correlation: r = 0.996, 95% confidence interval [CI]: 0.9950-0.9961, p < 0.001). For UIC between 20 and 1000 µg/L, the y-intercept for the Passing-Bablok regression was -1.9 (95% CI: -2.5599 to -1.3500) and the slope was 1.01 (95% CI: 1.0000-1.0206). CONCLUSION: This validated ICP-MS system can be used for measuring UIC.

Polymorphisms of haptoglobin modify the relationship between dietary iron and the risk of gestational iron-deficiency anemia.

PURPOSE: To assess whether polymorphisms of haptoglobin (Hp) modify the relationship between dietary iron and the risk of gestational iron-deficiency anemia (IDA). METHODS: This study analyzed 1430 singleton pregnant women aged 20 ~ ≤ 48 years from the 2017-2019 National Nutrition and Health Survey of Pregnant Women in Taiwan. Sociodemographic, blood biochemical, Hp phenotype, and 24-h dietary recall data were collected. Erythropoiesis-related total prenatal supplementation was defined as the reported use of multivitamins and minerals, vitamin B complex, folate, and iron. RESULTS: Distributions of the Hp 1-1, Hp 2-1, and Hp 2-2 phenotypes were 13.6, 39.8, and 46.5%, respectively. Women with the Hp 1-1 phenotype had the lowest mean levels of serum ferritin (p-trend = 0.017), the highest prevalence of gestational ID (p-trend = 0.033) as well as the highest prevalence of gestational IDA (did not reach statistical differences, p-trend = 0.086). A gene-diet interaction on serum ferritin was observed between the Hp 1 and Hp 2 (2-1/2-2) alleles (p < 0.001). An adjusted multivariate logistic regression showed that compared to those with a normal blood iron status and who reported using erythropoiesis-related total prenatal supplements, those who did not had a 4.05-fold [odds ratio (OR) = 4.05 (95% confidence interval (CI) 2.63-6.24), p < 0.001] increased risk of gestational IDA. The corresponding ORs for carriers of the Hp 1 and Hp 2 alleles were 4.78 (95% CI 1.43-15.99) and 3.79 (95% CI 2.37-6.06), respectively. CONCLUSION: Pregnant women who are Hp 1 carriers are at increased risk for developing IDA if they do not meet the recommended dietary allowance for iron or use erythropoiesis-related prenatal supplements.

Associations of Food and Nutrient Intake with Serum Hepcidin and the Risk of Gestational Iron-Deficiency Anemia among Pregnant Women: A Population-Based Study.

Hepcidin is a regulator of iron metabolism. Diet affects the body's iron status, but how it influences hepcidin concentrations and the risk of gestational iron-deficiency anemia (IDA) remains unclear. We investigated relationships of food and nutrient intake with serum hepcidin levels in relation to the iron status at a population scale. A retrospective cross-sectional study was conducted based on data obtained from the Nationwide Nutrition and Health Survey in pregnant women, Taiwan (2017~2020). In total, 1430 pregnant women aged 20~45 years with a singleton pregnancy were included. Data from blood biochemistry, 24-h dietary recall, and a food frequency questionnaire were collected during a prenatal checkup. Adjusted multivariate linear and logistic regression analyses were employed to measure the beta coefficient (ß) and 95% confidence interval (CI) of serum hepcidin and the odds ratio (OR) of IDA. In IDA women, serum hepcidin levels were positively correlated with the intake frequency of Chinese dim sum and related foods (ß = 0.037 (95% CI = 0.015~0.058), p = 0.001) and dark leafy vegetables (ß = 0.013 (0.001~0.025), p = 0.040), but they were negatively correlated with noodles and related products (ß = -0.022 (-0.043~-0.001), p = 0.038). An adjusted multivariate logistic regression analysis showed that dietary protein [OR: 0.990 (0.981~1.000), p = 0.041], total fiber [OR: 0.975 (0.953~0.998), p = 0.031], and rice/rice porridge [OR: 1.007 (1.00~1.014), p = 0.041] predicted gestational IDA. Total carbohydrates [OR: 1.003 (1.000~1.006), p = 0.036], proteins [OR: 0.992 (0.985~0.999), p = 0.028], gourds/shoots/root vegetables [OR: 1.007 (0.092~1.010), p = 0.005], and to a lesser extent, savory and sweet glutinous rice products [OR: 0.069 (0.937~1.002), p = 0.067] and dark leafy vegetables [OR: 1.005 (0.999~1.011), p = 0.088] predicted IDA. The risk of IDA due to vegetable consumption decreased with an increasing vitamin C intake (p for trend = 0.024). Carbohydrates and vegetables may affect the gestational iron status through influencing hepcidin levels. Vitamin C may lower the risk of gestational IDA due to high vegetable consumption.

Plasma 25(OH)D Concentrations and Gestational Diabetes Mellitus among Pregnant Women in Taiwan.

Vitamin D's function in the development of gestational diabetes mellitus (GDM) is not consistent in the literature. We examined the association between maternal plasma 25(OH)D concentration and GDM risk. A national cross-sectional study (1497 pregnant women) was conducted between 2017 and 2019 across Taiwan. Blood samples were drawn at recruitment to assess 25(OH)D concentrations, including vitamin D deficiency (VDD) (<20 ng/mL), insufficiency (<32 ng/mL), and sufficiency (≥32 ng/mL). GDM was detected from 24 to 28 weeks of gestation with the results extracted from the antenatal visit records. The prevalence of GDM was 2.9%. Logistic model analysis showed that 25(OH)D concentrations were not significantly associated with the risk of GDM (adjusted odds ratio (AOR) = 0.97, p = 0.144). However, subjects with VDD had a significantly greater risk of GDM (AOR = 2.26, p = 0.041), but not in those with vitamin D insufficiency (AOR = 1.20, p = 0.655). Furthermore, cubic piecewise spline regression was used to explore the relationship between five-unit intervals of 25(OH)D and the predicted probability of GDM. As the proportion of GDM increased for low 25(OH)D concentrations, it decreased at moderate concentrations and increased again at higher concentrations. These findings revealed a nonlinear relationship between 25(OH)D and GDM risk. VDD would be risky for GDM occurrence.

Associations of the pre-pregnancy weight status with anaemia and the erythropoiesis-related micronutrient status.

OBJECTIVE: The coexistence of underweight (UW) and overweight (OW)/obese (OB) at the population level is known to affect iron deficiency (ID) anaemia (IDA), but how the weight status affects erythropoiesis during pregnancy is less clear at a population scale. This study investigated associations between the pre-pregnancy BMI (pBMI) and erythropoiesis-related nutritional deficiencies. DESIGN: Anthropometry, blood biochemistry and 24-h dietary recall data were collected during prenatal care visits. The weight status was defined based on the pBMI. Mild nutrition deficiency-related erythropoiesis was defined if individuals had an ID, folate depletion or a vitamin B12 deficiency. SETTING: The Nationwide Nutrition and Health Survey in Taiwan (Pregnant NAHSIT 2017-2019). PARTICIPANTS: We included 1456 women aged 20 to 45 years with singleton pregnancies. RESULTS: Among these pregnant women, 9·6 % were UW, and 29·2 % were either OW (15·8 %) or OB (13·4 %). A U-shaped association between the pBMI and IDA was observed, with decreased odds (OR; 95 % CI) for OW subjects (0·6; 95 % CI (0·4, 0·9)) but increased odds for UW (1·2; 95 % CI (0·8, 2·0)) and OB subjects (1·2; 95 % CI (0·8, 1·8)). The pBMI was positively correlated with the prevalence of a mild nutritional deficiency. Compared to normal weight, OB pregnant women had 3·4-fold (3·4; 95 % CI (1·4, 8·1)) higher odds for multiple mild nutritional deficiencies, while UW individuals had lowest odds (0·3; 95 % CI (0·1, 1·2)). A dietary analysis showed negative relationships of pBMI with energy, carbohydrates, protein, Fe and folate intakes, but positive relationship with fat intakes. CONCLUSION: The pre-pregnancy weight status can possibly serve as a good nutritional screening tool for preventing IDA during pregnancy.

Iodine nutritional status of lactating women in northern Taiwan in 2019.

BACKGROUND: Pregnant and lactating women are vulnerable to iodine deficiency. This study was conducted to evaluate the iodine nutritional status of lactating women in northern Taiwan. METHODS: Women recruited from Taipei Veterans General Hospital (TVGH) in 2019 provided a spot urine sample and completed a Food Frequency Questionnaire. The urinary iodine concentration (UIC) was measured by inductively coupled plasma mass spectrometry. RESULTS: The overall median UIC in 198 women was 120.4 µg/L, indicating a sufficient iodine status. Univariate analysis revealed a lower median UIC in women of younger age (p = 0.004), who were not taking multivitamins (p = 0.004), not on a postpartum nourishment diet (p = 0.04), and whose infant received more breast milk (p = 0.004). The median UIC was <100 µg/L in the group aged 20 to 29 years (UIC: 74.4 µg/L) and in women whose infants' diet was composed of >50% breast milk (UIC: 86.1 µg/L). A postpartum nourishment diet was followed by 73.7% (n = 146) of the women. Nevertheless, a significant decrease in the intake frequency of iodine-containing foods, including seaweeds (p < 0.001), seafood (p < 0.001), dairy products (p = 0.009), and multivitamins (p < 0.001) was observed compared with the intake noted in a previous survey of pregnant women in TVGH. Following multivariate analysis, only younger age (20-29 vs ≥30 years; odds ratio [OR]: 3.38; 95% confidence interval [CI]: 1.49-7.65), no use of multivitamin (OR: 1.89; 95% CI: 1.03-3.48), and infant diet composition (>50% breast milk vs <50% breast milk; OR: 2.93; 95% CI: 1.37-6.25) were independently associated with UIC < 100 µg/L. CONCLUSION: The results suggest that the iodine status in lactating women in northern Taiwan is adequate. However, iodine deficiency may continue to be present in certain subgroups, such as women of younger age and those who do not take multivitamins.

Iodine nutritional status of pregnant women in an urban area of northern Taiwan in 2018.

Pregnant women are considered as one of the most vulnerable groups for iodine deficiency. The Nutrition and Health Survey in Taiwan 2013 revealed that the median urinary iodine concentration (UIC) of non-pregnant women of child-bearing age of 15-44 years was 124 µg/L, which was adequate in general, but insufficient according to pregnancy criteria. The aim of this study was to determine the iodine nutritional status of pregnant women in an urban area of Northern Taiwan. A hospital-based cross-sectional survey was conducted in Taipei Veterans General Hospital. Random spot urine samples were collected from January to October, 2018 and UIC was determined by inductively coupled plasma mass-spectrometry. A food frequency questionnaire was also delivered to the participants. The overall median UIC was 225.3 µg/L (IQR: 109.1-514.2 µg/L) for 257 pregnant women ranging from 21-47 years-old. The distribution of UIC was as follows: 35.4% with UIC <150 µg/L, 17.1% with UIC within 150-249 µg/L, 21.8% with UIC within 250-499 µg/L, and 25.7% with UIC ≥500 µg/L. The use of prenatal multivitamin was very common among the participants: 79.4% (n = 204) took multivitamin either every day or less frequently, with 52.5% (n = 135) taking one pill every day, and only 20.6% (n = 53) never took multivitamin during their pregnancy. Other commonly consumed iodine-containing foods were dairy products and fish. Our results indicate that the iodine status in the studied women is adequate. However, efforts are still needed to avoid iodine deficiency as well as iodine excess.

Iodine Status of Taiwanese Population in 2013: 10 Years After Changing From Mandatory to Voluntary Salt Iodization.

BACKGROUND: In 2003, Taiwan's iodine policy changed from mandatory to voluntary. The Nutrition and Health Survey in Taiwan (NAHSIT) 2001-2002 for schoolchildren showed adequate iodine nutrition, while NAHSIT 2005-2008 for adults showed the iodine status was at borderline adequacy. OBJECTIVE: To investigate the iodine status of the Taiwanese population from schoolchildren to adulthood 10 years after the change of the salt iodization policy. METHOD: Urinary iodine was measured in samples from subjects in NAHSIT 2013. RESULTS: The median urinary iodine concentration (UIC) of the Taiwanese population aged 6 years and above in 2013 was 96 µg/L, indicating mild iodine deficiency. The median UIC of 6- to 12-year-old schoolchildren was 124 µg/L (interquartile range [IQR]: 92-213 µg/L), and 115 µg/L (IQR: 80-166 µg/L), 125 µg/L (IQR: 74-161 µg/L), 73 µg/L (IQR: 52-131 µg/L), and 78 µg/L (IQR: 52-132 µg/L) in populations aged 13 to 18 years, 19 to 44 years, 45 to 64 years, and ≥65 years, respectively. Declining iodine nutrition in age groups ≥45 years old was noted that the median UIC of populations aged 45 to 64 years and ≥65 years was 99 and 88 µg/L, respectively, in NAHSIT 2005-2008. The median UIC of schoolchildren was not lower than that during the mandatory salt fortification period, but the distribution of urinary iodine levels signified a dietary pattern change. CONCLUSION: Wide-ranging variation in iodine nutrition levels was observed in different age groups. Universal salt iodization, as suggested by the World Health Organization, should be the best strategy to achieve adequate iodine nutrition.

Iodine Nutritional Status of School Children in Nauru 2015.

Little is known about iodine nutritional status in island countries in the Pacific Ocean. The primary objective of this study was to report for the first time the iodine nutritional status of people in Nauru. In addition, sources of iodine nutrition (i.e., water and salt) were investigated. A school-based cross-sectional survey of children aged 6-12 years was conducted in three primary schools of Nauru. Urinary iodine concentration (UIC) was determined by spot urine samples. Available water and salt samples in Nauru were collected for the measurement of iodine content. A food frequency questionnaire was conducted. The median UIC was 142 µg/L, and 25.2% and 7.4% of the population had median UIC below 100 µg/L and 50 µg/L, respectively. Natural iodine-containing foods such as seaweeds and agar were rare. Iodine was undetectable in Nauruan tank water, filtered tap water, and raindrops. Of the analyzed salt products, five kinds were non-iodized, and three were iodized (iodine content: 15 ppm, 65 ppm, and 68 ppm, respectively). The results indicate that the iodine status in Nauruan school children is adequate. Iodized salt may serve as an important source of iodine nutrition in Nauru.

Iodine status of adults in Taiwan 2005-2008, 5 years after the cessation of mandatory salt iodization.

BACKGROUND/PURPOSE: Iodine deficiency causes a broad spectrum of disorders across all ages. Mandatory salt iodization in Taiwan successfully reduced the goiter rate from 21.6% to 4.3% in schoolchildren surveyed in 1971. The program continued until 2003 when salt iodization was changed from mandatory to voluntary. The purpose of this study was to investigate the iodine status of Taiwanese individuals after the change in the iodine policy. METHODS: Urinary iodine (UI) was measured in samples from adults in the Nutrition and Health Survey in Taiwan 2005-2008. RESULTS: The median UI level was 100 µg/L, and the percentage of populations with UI levels below 100 µg/L and 50 µg/L was 50.1% and 15.1%, respectively, indicating that the iodine status was borderline adequate. Men had a higher UI level than women (102 µg/L vs. 98 µg/L, p = 0.003), and older individuals (age > 60 years) had a lower UI level than younger people, particularly in women. The iodine status of the population < 50 years was sufficient, but it was insufficient in older groups. Mild iodine insufficiency was noted in all areas of Taiwan except the Southern area and Penghu islands, with the lowest UI level of 79 µg/L in the Mountain area. Although the UI level of women of childbearing age (19-44 years) was 103 µg/L, there may be a risk of iodine deficiency during pregnancy. CONCLUSION: The iodine nutrition of the Taiwanese population in 2005-2008 was borderline adequate, with insufficiency in some subgroups. Further monitoring of the iodine status is necessary.

Iodine status of Taiwanese children before the change in national salt iodization policy: a retrospective study of the nutrition and health survey in Taiwan 2001-2002.

Taiwan was an iodine deficiency area and endemic goiter was common in 1940's. Mandatory salt iodization started in 1967, and a 1971 survey indicated that goiter rates in children decreased from 21.6% to 4.3%. To understand iodine status before the change of national salt iodization program in 2003, from mandatory to voluntary salt iodization, we retrospectively measured urinary iodine concentrations of samples collected from children in the Nutrition and Health Survey in Taiwan 2001-2002. The median UI level for children aged 6-12 years was 123 µg/L (no differences between males and females). Females aged 10-12 years had the lowest urinary iodine levels. The percentages of this population with urinary iodine levels below 100, 50, and 20 µg/L were 35.2% ± 1.0%, 4.4% ± 0.4%, and 0.2% ± 0.1%, respectively. Older children were more likely to have low urinary iodine levels. People living in different areas of Taiwan had a median urinary iodine levels ranged from 113 µg/L to 164 µg/L (males: 113-153 µg/L; females: 105-174 µg/L), with the highest level in Penghu islands, and the lowest level in the eastern and southern (Southern area 2) areas. According to international criteria, iodine status in 2001-2002 was adequate, comparable to the surveyed goiter rates (4.3%, classified as iodine sufficiency) in 1971, inferring that iodine nutrition remained adequate and stable during this period. The present study is of great importance in documenting the iodine status of Taiwan before the change from mandatory to voluntary salt iodization to serve as a baseline data for future trend analysis in iodine nutrition.

Plasma corticotrophin response to desmopressin in patients with Cushing's disease correlates with the expression of vasopressin receptor 2, but not with that of vasopressin receptor 1 or 3, in their pituitary tumours.

OBJECTIVES: Most patients with Cushing's disease (CD) respond to corticotrophin-releasing hormone (CRH) or desmopressin with increased corticotrophin (ACTH) and cortisol levels. Although the vasopressin receptor subtype located on normal corticotrophs is the V3 receptor (V3R), desmopressin is a selective V2 receptor (V2R) agonist and it is unclear whether corticotrophinomas exhibit aberrant V2R expression. Furthermore, no studies have determined the relationship between the in vivo response of CD patients to desmopressin and vasopressin receptor expression, or between the response to CRH and CRH receptor (CRHR) expression. Therefore, the aim of this study was to investigate the expression of vasopressin receptors (V1R, V2R, and V3R) and CRHR on corticotroph tumours and its possible relation to the in vivo response. DESIGNS: A prospective study of 29 patients with CD. METHODS: Patients underwent desmopressin and CRH stimulation tests before surgery. The expression of vasopressin receptors and CRHR on corticotrophinomas was determined by immunocytochemistry. RESULTS: Most of the corticotrophinomas exhibited abundant expression of V1R, V3R, and CRHR, whereas the expression of V2R varied greatly and was lower in macroadenomas than in microadenomas. Both the percentage increment of ACTH and net area under the curve (AUC) of ACTH in the desmopressin stimulation test were found to be correlated with tumour volume. After adjustment for tumour volume, a positive correlation was found between the percentage increment of ACTH and the degree of V2R expression, but not between that of V1R or V3R. No relationship between the level of expression of CRHR on tumour tissues and the percentage increment or netAUC of ACTH to CRH was observed in CD patients. CONCLUSIONS: We concluded that V2R was expressed on corticotrophinomas and that the level of its expression correlated well with the ACTH response to desmopressin in CD patients, although abundant expression of V1R and V3R was also found in almost all corticotroph tumours. Further studies are needed to elucidate the role of these receptors in the pathogenesis of CD.