Investigation and analysis of individual iodine nutrition among students aged 8 to 15 in Dongtai City, Jiangsu Province in 2021 / 中华地方病学杂志

Objective:To analyze the individual iodine nutrition status and its influencing factors among students aged 8 to 15 in Dongtai City, Jiangsu Province.Methods:From May to August 2021, a total of 905 students aged 8 to 15 were selected as survey subjects in Dongtai City based on the sampling method in the "National Monitoring Plan for Iodine Deficiency Disorders" (2016 version). Salt samples from students' homes were collected for salt iodine testing. Urine samples of students were collected for urinary iodine and creatinine testing. The creatinine correction method was used to estimate individual 24 h urinary iodine excretion and calculate iodine intake. At the same time, basic information (age, gender, height, weight, etc.) and consumption frequency of iodine rich foods (seafood, eggs, meat, milk, solid snacks) of students were collected through questionnaires and actual measurements.Results:The coverage rate of iodized salt in Dongtai City was 98.2% (889/905), the qualified rate of iodized salt was 97.9% (870/889), and the consumption rate of qualified iodized salt was 96.1% (870/905). The median estimated 24 h urinary iodine excretion was 179.7 μg/d. The median estimated iodine intake was 195.4 μg/d, the constituent ratio of estimated iodine intake < recommended nutrient intake (RNI) was 16.2% (147/905), RNI-tolerable upper intake level (UL) was 63.4% (574/905), and > UL was 20.3% (184/905). The medians estimated 24 h urinary iodine excretion of students aged 8-10, 11-13 and 14-15 were 157.4, 193.0 and 236.5 μg/d, respectively, and the difference was statistically significant ( H = 55.42, P < 0.001). The median estimated 24 h urinary iodine excretion of boys was higher than that of girls (222.6 vs 148.6 μg/d), and the median estimated 24 h urinary iodine excretion of urban students was higher than that of township students (215.6 vs 162.7 μg/d), the differences were statistically significant ( Z = - 8.41, - 5.66, P < 0.001). There were statistically significant differences in the median estimated 24 h urinary iodine excretion between students with different body mass index (weight loss, overweight, obesity, normal; H = 56.15, P < 0.001) and iodine rich foods consumption frequencies (seafood, meat, milk, eggs, solid snacks; H = 23.15, 21.20, 60.77, 20.01, 24.47, P < 0.001). Conclusion:Iodine deficiency or excess exists in students aged 8-15 in Dongtai City, and girls aged 8-10 who are physically emaciated are the focus of attention for iodine deficiency.

An investigation of iodine intake and iodine nutrition status of pregnant women in different water iodine areas of Tianjin / 中华地方病学杂志

Objective:To investigate the iodine intake and iodine nutritional status of pregnant women in different water iodine areas of Tianjin, and to provide a basis for formulating appropriate intervention measures in high water iodine areas.Methods:From January to September 2016, 90, 91 and 71 pregnant women were randomly selected as research subjects in different water iodine areas in Tianjin (water iodine ≤150, > 150 - 300 and > 300 μg/L) via the random sampling method. Samples of salt, drinking water and urine were collected from pregnant women. A semi-quantitative food frequency questionnaire was used to investigate the intake of 12 kinds of food eating by pregnant women in the past year. Salt iodine content was determined by direct titration, water iodine content was determined by ceric sulfate catalytic spectrophotometry, and urinary iodine was determined by arsenic-cerium catalytic spectrophotometry.Results:There was no statistically significant difference in salt iodine intake among pregnant women in different water iodine areas ( H = 2.29, P = 0.318); the difference in drinking water iodine intake (7.50, 282.60, 544.35 μg/d) was statistically significant ( H = 223.31, P < 0.001), and further pairwise comparison found that the differences were statistically significant ( P < 0.001); the difference in food iodine intake was not statistically significant ( H = 2.19, P = 0.334). With the increase of water iodine content in various regions, the contribution rate of drinking water iodine intake gradually increased. The medians of urinary iodine in pregnant women in different water iodine areas were 113.50, 180.55 and 268.55 μg/L, respectively, and there was a positive correlation between urine iodine content and total iodine intake ( rs = 0.31, P < 0.001). Conclusions:The iodine nutrition level of pregnant women in areas with water iodine ≤150 μg/L is insufficient (< 150 μg/L), so the consumption rate of iodized salt should be increased to prevent the occurrence of iodine deficiency disorders. The iodine nutrition level of pregnant women in areas with water iodine > 300 μg/L exceeds the appropriate amount (250 - 499 μg/L), pregnant women should control the intake of foods with high iodine content and take measures to improve water as soon as possible to reduce iodine.

Association between TSH status and prevalence of miscarriages and stillbirth

Thyroid hormones play a significant role in normal human body growth. Abnormalities in thyroid stimulating hormone (TSH) levels can result in pregnancy loss due to miscarriages and intrauterine death (IUD). The objective of the study was to assess the levels of association of thyroid stimulating hormone with miscarriages and IUD. The descriptive study involving 110 samples between 18-40 years of age fulfilling inclusion criteria were sampled for TSH testing (2ml blood) after attaining their written informed consent. The mean age of participants was 29.49±4.26 year. The prevalence of hypothyroidism and hyperthyroidism was 3.64% and 2.73%, respectively. Complications like gestational hypertension, depression and oligomenorrhea were found prevalent in these females. Majority of females were taking high/low iodine than recommended iodine level (150mcg). This work shows that there is a significant association between pregnancy loss and disturbed TSH levels among pregnant females.

Effects of Maternal Iodine Status during Pregnancy and Lactation on Maternal Thyroid Function and Offspring Growth and Development: A Prospective Study Protocol for the Ideal Breast Milk Cohort

BACKGROUND: Iodine is an intrinsic element of thyroid hormone, which is essential for childhood growth and development. The Ideal Breast Milk (IBM) cohort study aims to evaluate the effects of maternal iodine status during pregnancy and lactation on maternal thyroid function, offspring growth and development, and offspring thyroid function. METHODS: The IBM cohort study recruited pregnant women from Seoul National University Hospital between June 2016 and August 2017, followed by enrollment of their offspring after delivery. For the maternal participants, iodine status is evaluated by urinary iodine concentration (UIC) and dietary records in the third trimester and at 3 to 4 weeks and 12 to 15 months postpartum. For the child participants, cord blood sampling and UIC measurements are performed at birth. At 3 to 4 weeks of age, UIC and breastmilk iodine concentrations are measured. At 12 to 15 months of age, growth and development are assessed and measurements of UIC, a thyroid function test, and ultrasonography are performed. RESULTS: A total of 198 pregnant women in their third trimester were recruited. Their mean age was 35.1±3.5 years, and 78 (39.4%) of them were pregnant with twins. Thirty-three (16.7%) of them had a previous history of thyroid disease. CONCLUSION: Korea is an iodine-replete area. In particular, lactating women in Korea are commonly exposed to excess iodine due to the traditional practice of consuming brown seaweed soup postpartum. The study of the IBM cohort is expected to contribute to developing guidelines for optimal iodine nutrition in pregnant or lactating women.

Encuesta de ioduria como control de la ingesta de iodo / Survey on urinary iodine as iodine intake control / Pesquisa de iodúria como um controle da ingestão de iodo

Desde 1964, año en que se incorporó iodo a la sal de mesa, ha disminuido notoriamente el bocio endémico en Uruguay. Por haberse modificado con posteridad, en dos oportunidades la proporción del iodo en la misma, se tornó imprescindible reevaluar los niveles de la ingesta poblacional siguiendo las recomendaciones de la OMS. Los objetivos de este estudio fueron evaluar los niveles de iodo en la población a través de las iodurias, seleccionar la mejor forma de expresar su excreción y estudiar la relación de las mismas con el sodio urinario. Se analizaron 491 muestras de orina de niños en edad escolar, de nueve departamentos del Uruguay y se determinó iodo, sodio y creatinina. Se observó una mediana de 0,248 mg/L de iodo, valor adecuado según las recomendaciones de la OMS (0,100-0,300 mg/L), una distribución no paramétrica de la ioduria expresada como cociente de Iodo/ creatinina en mg/g que discrimina mejor los valores atípicos respecto de la expresión de iodurias en mg/L, una pobre relación entre la excreción de iodo y el sodio, (r2=0,199) lo que indica que su aporte no es exclusivo de la sal de mesa y un predominio de excreción más elevado en los niños de menor edad respecto de los mayores.

The presence of endemic goiter in Uruguay has decreased markedly since the addition of iodine to table salt in 1964. It was essential to evaluate the population levels of iodine intake accordingly to WHO specifications, since iodine support to the table salt has been modified twice. The aims of this study were to evaluate the levels of iodine in the population through the urinary iodine levels, select the best way to express their excretion and study the relationship thereof with urinary sodium. Four hundred ninety- one urine samples were analyzed from school children from nine states of Uruguay and sodium, creatinine and iodine were measured. The iodine median was 0.248 mg/L, an adequate value according to WHO specifications (0.100-0.300 mg/L). The expression of urinary iodine as the ratio between urinary iodine and urinary creatinine (mg/g) had a non-parametric distribution that discriminate the atypical values better than the urinary iodine (mg/L). The relationship between iodine excretion and sodium was poor (r2=0.199), indicating that the input of iodine does not come exclusively from table salt. Younger children had a greater excretion than older ones.

Desde 1964, quando o iodo foi adicionado ao sal de mesa, diminuiu acentuadamente o bócio endêmico no Uruguai. Por ter sido modificada posteriormente, em duas oportunidades, a proporção do iodo no mesmo, tornou-se essencial reavaliar os níveis de ingestão da população seguindo as recomendações da OMS. Os objetivos deste estudo foram avaliar os níveis de iodo na população através das iodúrias, selecionar a melhor maneira de expressar sua excreção e estudar a relação das mesmas com o sódio urinário. 491 amostras de urina de crianças em idade escolar, de nove departamentos do Uruguay foram analisadas, determinando-se iodo, sódio e creatinina. Foi observada uma mediana de 0.248 mg/L de iodo, valor apropriado de acordo com as recomendações da OMS (0.100-0.300 mg/L), também uma distribuição não paramétrica expressa como quociente de iodo/creatinina em mg/g que discrimina de uma maneira melhor os valores atípicos para a expressão de iodúrias em mg/L, uma pobre relação entre a excreção de iodo e de sódio, (r2=0,199 ), indicando que a sua contribuição não é exclusiva do sal de mesa e uma predominância de excreção maior nas crianças mais novas em relação às maiores.

Relationship between maternal iodine intake and congenital hypothyroidism in newborns / 国际儿科学杂志

Iodine is an essential trace element for human body,and it is a basic raw material for the synthesis of thyroid hormones.Congenital hypothyroidism is a disease caused by inadequate thyroid hormone synthesis.As iodized salt has been widely consumed in our country,the epidemic goiter plunged in iodine deficiency areas.However,the incidence of congenital hypothyroidism in China has not decreased significantly.It was found that either insufficient or excessive intake of iodine during pregnancy had adverse effects on neonatal congenital hypothyroidism,and the proper iodine intake during pregnancy will be helpful to reduce the mobility of congenital hypothyroidism.

Dietary evaluation of a low-iodine diet in Korean thyroid cancer patients preparing for radioactive iodine therapy in an iodine-rich region

BACKGROUND/OBJECTIVES: Despite the importance of a low-iodine diet (LID) for thyroid cancer patients preparing for radioactive iodine (RAI) therapy, few studies have evaluated dietary intake during LID. This study evaluated the amount of dietary iodine intake and its major food sources during a typical diet and during LID periods for thyroid cancer patients preparing for RAI therapy, and examined how the type of nutrition education of LID affects iodine intake. SUBJECTS/METHODS: A total of 92 differentiated thyroid cancer patients with total thyroidectomy were enrolled from Seoul National University Hospital. All subjects completed three days of dietary records during usual and low-iodine diets before 131I administration. RESULTS: The median iodine intake was 290 µg/day on the usual diet and 63.2 µg/day on the LID. The major food groups during the usual diet were seaweed, salted vegetables, fish, milk, and dairy products and the consumption of these foods decreased significantly during LID. The mean energy intake on the LID was 1,325 kcal, which was 446 kcal lower than on the usual diet (1,771 kcal). By avoiding iodine, the intake of most other nutrients, including sodium, was significantly reduced during LID (P < 0.005). Regarding nutritional education, intensive education was more effective than a simple education at reducing iodine intake. CONCLUSION: Iodine intake for thyroid cancer patients was significantly reduced during LID and was within the recommended amount. However, the intake of most other nutrients and calories was also reduced. Future studies are needed to develop a practical dietary protocol for a LID in Korean patients.

Iodine intake and thyroid disease / 中华地方病学杂志

Iodine is a micronutrient that is essential for the production of thyroid hormones.Either iodine deficiency or excess will not only affect the synthesis and secretion of thyroid hormone but also be related to the occurrence and development of thyroid diseases.Iodine deficiency can cause endemic goiter,cretinism,hypothyroidism and thyroid cancer;high incidence of hyperthyroidism,hypothyroidism,autoimmune thyroid disease,goiter,and thyroid cancer are associated with excessive iodine intake.It is essential to assess iodine nutritional status for the populations,particularly those with thyroid diseases.

Urinary iodine excretion in healthy Mexican adults / Excreción urinaria de yodo en adultos sanos mexicanos

The iodine nutritional status of a population is mainly measured by urinary iodine excretion (UI) and thyroid volume determined by ultrasound (US). The surveillance of nutritional iodine levels in the Mexican population has been insufficient. Our aim was to determine the UI in random samples from adults living in an urban area. We selected a sample of healthy individuals over the age of 18 that were students, physicians or administrative personnel at our Institution and had no known thyroid disease. Thyroid volume was determined by ultrasound in all volunteers as well as thyroid hormones and antithyroid antibodies and a urine sample was obtained. One hundred and two volunteers with a median age of 29, participated in the study. The group’s median UI was 221 μg/L,interquartile range (IQR)(135.0 to 356.8) and no differences were observed between genders: women had a UI of 218.0 μg/L IQR (129.0 a 351.0) vs. 223.0 μg/L IQR (138.0 to 374.0) in males, p 0.941. Excessive dietary iodine intake was established in 31.4% of all volunteers according to their UI, placing them at risk of thyroid dysfunction. It is fundamental to evaluate the national iodine nutritional status in Mexico. We discuss the current status of the nutritional state in the Americas, emphasizing that in Latin America and the observed tendency in the region to ingest a diet high in iodine.

El estatus nutricional del yodo en una población, principalmente es medido por la excreción del yodo urinario (UI) y el cálculo del volumen tiroideo por ultrasonido (US). La vigilancia nutricional del yodo en la población en México ha sido escasa. El objetivo fue determinar la UI en una muestra casual en adultos sanos que habitan en un área urbana. Se seleccionó una muestra de individuos mayores de 18 años, entre estudiantes, médicos y trabajadores administrativos de nuestra institución, sanos, sin enfermedad tiroidea conocida. A todos los voluntarios se les determinó el volumen tiroideo por US, hormonas y anticuerpos antitiroideos y se les solicitó una muestra de orina. Participaron 102 voluntarios, mediana de 29 años. La mediana de la UI del grupo fue 221 μg/L, rango intercuartílico (RIQ) (135.0 a 356.8), no hubo diferencias entre géneros, las mujeres tuvieron una UI de, 218.0 μg/L RIQ (129.0 a 351.0) vs 223.0 μg/L RIQ (138.0 a 374.0) p 0.941. El 31.4% de los voluntarios mostraron una ingestión excesiva de yodo en la dieta de acuerdo a la UI, lo cual los coloca en riesgo de sufrir disfunción tiroidea. Es necesario considerar la evaluación Nacional del estatus nutricional del yodo, en México. En el artículo se discute la situación actual del estatus nutricional en las Américas, haciendo énfasis en Latinoamérica y a la tendencia de la región a la dieta excedida en yodo.

The iodine status in Hangzhou, Zhejiang province 2010 / 中华流行病学杂志

Objective To explore the iodine level in the environment and the iodine status among the general population as well as the prevalence of thyroid nodules in Hangzhou city.Relationship between the prevalence of thyroid nodules and the policy of universal salt iodization in Hangzhou was also analyzed.Methods Questionnaire,a 3- day weighed dietary record method,and 3 days' 24- hour dietary recall method were used to understand the iodine nutrition status and dietary intake of iodine among the general population in the city.Drinking water,edible salt and morning urine were collected to determine iodine content.All objects under survey underwent the thyroid B ultrasonic examination.Statistical analysis was done by SPSS 13.0 and SAS 9.1.Results (1)In total,12 620 effective questionnaires were available,with 221 water samples,12 730 urine samples,and 3593 salt samples collected.12 515 objects underwent B ultrasonic examination,and 1848received dietary investigation.(2)Water iodine level of Hangzhou was in the range of 0.20-5.99 μg/L,with the median level as 2.58 μg/L.(3) Average daily dietary intake of iodine for adult males in Hangzhou was 289.2 lμg/d.The contribution of iodine intake from iodized salt was 74.4％.(4) The median of Hangzhou residents' urinary iodine was 178.80 μg/L,with the urinary iodine levels at 100 μg/L-,200 μg/L-,＜100 μg/L,and ≥300 μg/L groups were 37.14％,23.11％,21.05％,and 18.69％ respectively.Urinary iodine of pregnant women was 141.0 tg/L.(5) Incidence of thyroid nodules in females(28.6％ ) was higher than that of males(20.1％ ).The detection rate increased with age (6.4％ at group 6-,10.9％ at 12-,12.0％ at 18-,24.4％ at 40-,and 38.8％ at 65-) ; with the highest in urban area (29.8％),followed by suburbs (23.3％) and in rural area it showed the least (20.3％).Urinary iodine level was found lower among the population who had been detected with thyroid nodules (160.36 μ g/L) than those among the undetected population (182.00 μg/L).Conclusion Hangzhou appeared to be an area where the environmental was iodine deficient.Iodized salt was the major source of iodine intake.The iodine status among the general population seemed to be safe and suitable,but the iodine level for pregnant women was not sufficient.There was still no evidence indicating that the universal salt iodization policy in Hangzhou was associated with the prevalence of thyroid nodules.

The prevalence of thyroid dysfunction in elderly cardiology patients with mild excessive iodine intake in the urban area of São Paulo

OBJECTIVES: To evaluate the prevalence of thyroid dysfunction in elderly cardiac patients in an outpatient setting. SUBJECTS AND METHODS: A total of 399 consecutive patients (268 women, age range 60-92 years) who were followed at Heart Institute were evaluated for thyroid dysfunction with serum free T4, TSH, anti-Peroxidase antibodies, urinary iodine excretion measurements and thyroid ultrasound. RESULTS: Hyperthyroidism (overt and subclinical) was present in 29 patients (6.5 percent), whereas hypothyroidism (overt and subclinical) was found in 32 individuals (8.1 percent). Cysts were detected in 11 patients (2.8 percent), single nodules were detected in 102 (25.6 percent), and multinodular goiters were detected in 34 (8.5 percent). Hashimoto's thyroiditis was present in 16.8 percent patients, most of whom were women (83.6 percent). The serum TSH increased with age and was significantly higher (p= <0.01) in patients, compared to the normal control group. No significant differences in serum TSH and free T4 values were observed when patients with atrial fibrillation (AF) where compared with those without arrhythmia. The median urinary iodine levels were 210 µg/L (40-856 µg/L), and iodine levels were higher in men than in women (p<0.01). Excessive iodine intake (urinary iodine >300 µg/L) was observed in one-third of patients (30.8 percent). CONCLUSIONS: Elderly patients have a higher prevalence of both hypo- and hyperthyroidism as well as thyroid nodules when compared with the general population. About one-third of the older patients had elevated urinary secretion of iodine and a higher prevalence of chronic Hashimoto's thyroiditis. It is recommended that ultrasonographic studies, tests for thyroid function and autoimmunity should be evaluated in elderly patients.

A method in field measurement of urinary iodine.

The objective of this study is to determine a very cheap, reliable, relatively rapid portable field unit for quantitative urinary iodine measurements. As Individual Urine Excretion (IUE) approximate those of Daily Iodine Intake (DII), iodine deficiency can be measured in casual urine samples of individual. Using the criteria, the frying pot method has been introduced and modified from the long and tedious Zak’s method after Pino et al, and Robbins and Dunn et al. This modified method has many advantages. Such the assay takes 84 tubes of urine per pot in100o C paraffin oil bath and changes into water. It has been shortened from one hour to 25 minutes. Change of color to intermediate violet is observed by adding ferroine as the indicator, resulting in a standard curve reading the concentration of iodine being, in micrograms per liter. The results of 255 subjects from Mukdaharn Province indicated the reliability of the method as the results of which are the same as those using in the heating block and spectrophotometespectrophotomete. This has been confirmed by the results of 1,007 samples. This new technique provides good results; between oil and water, the results on using water are even better. This saves much money modification reduces significantly by lowering the cost of equipment. It is rapid, simple and reliable. The method is portable and valuable for measuring and monitoring iodine deficiency studies and for epidemiological studies of iodine deficiency its control in developing countries.

The Effect of Iodine Restriction on Thyroid Function in Patients with Hypothyroidism Due to Hashimoto's Thyroiditis

Lifelong thyroid hormone replacement is indicated in patients with hypothyroidism as a result of Hashimoto's thyroiditis. However, previous reports have shown that excess iodine induces hypothyroidism in Hashimoto's thyroiditis. This study investigated the effects of iodine restriction on the thyroid function and the predictable factors for recovery in patients with hypothyroidism due to Hashimoto's thyroiditis. The subject group consisted of 45 patients who had initially been diagnosed with hypothyroidism due to Hashimoto's thyroiditis. The subjects were divided randomly into two groups. One group was an iodine intake restriction group (group 1) (iodine intake: less than 100 microgram/day) and the other group was an iodine intake non-restriction group (group 2). The thyroid-related hormones and the urinary excretion of iodine were measured at the baseline state and after 3 months. After 3 months, a recovery to the euthyroid state was found in 78.3 % of group 1 (18 out of 23 patients), which is higher than the 45.5% from group 2 (10 out of 22 patients). In group 1, mean serum fT4 level (0.80 +/- 0.27 ng/dL at the baseline, 0.98 +/- 0.21 ng/dL after 3 months) and the TSH level (37.95 +/- 81.76 microIU/mL at the baseline, 25.66 +/- 70.79 microIU/mL after 3 months) changed significantly during this period (p < 0.05). In group 2, the mean serum fT4 level decreased (0.98 +/- 0.17 ng/dL at baseline, 0.92 +/- 0.28 ng/dL after 3 months, p < 0.05). In the iodine restriction group, the urinary iodine excretion values were higher in the recovered patients than in non-recovered patients (3.51 +/- 1.62 mg/L vs. 1.21 +/- 0.39 mg/ L, p=0.006) and the initial serum TSH values were lower in the recovered patients than in the non-recovered patients (14.28 +/- 12.63 microIU/mL vs. 123.14 +/- 156.51 microIU/mL, p=0.005). In conclusion, 78.3% of patients with hypothyroidism due to Hashimoto's thyroiditis regained an euthyroid state iodine restriction alone. Both a low initial serum TSH and a high initial urinary iodine concentration can be predictable factors for a recovery from hypothyroidism due to Hashimoto's thyroiditis after restricting their iodine intake.

Advances on the treatment of Hashimoto thyroiditis / 中国实用内科杂志

Hashimoto thyroiditis(HT) is the most common autoimmune thyroid disease,which can present as euthyroidism,hypothyroidism or hyperthyroidism.Currently,there are still disputes on the treatment of such diseases.This paper summarizes the researches on the HT treatment at home and abroad in recent years,introduces the latest developments of iodine restriction,thyroid hormone replacement therapy,systemic immune regulation therapy,local immune regulation therapy,statins and surgical treatment.It elaborates the international consensus on recommended iodine intake and the importance of the individualized principle of thyroid hormone replacement therapy.

Dietary iodine intake and urinary iodine excretion in patients with thyroid diseases

This study was conducted to examine the usual iodine intake in patients with thyroid diseases and to compare iodine status with normal subjects. The dietary iodine intake was assessed using a semi-quantitative food frequency questionnaire, and urinary iodine excretion was measured in 184 patients diagnosed with thyroid diseases and 207 normal subjects. The average usual iodine intake of patients with thyroid diseases was 673.8 +/- 794.9 ug/day and that of normal subjects was 468.9 +/- 481.9 ug/day. Among the patients with thyroid diseases, higher values were found in the patients with thyroid cancer (1460.6 +/- 1044.8 ug/day) and lower values were found in patients with simple goiter (443.5 +/- 470.4 ug/day). The urinary iodine excretions of patients and normal subjects were 4.33 +/- 5.70 mg/L and 2.11 +/- 0.69 mg/L, respectively. The iodine intake and urinary iodine excretion of patients with thyroid diseases were significantly higher than those of normal subjects (p < 0.05). The dietary iodine intake and urinary excretion of patients with thyroid cancer were significantly higher than other patients with thyroid diseases and normal subjects because of the use of seaweed or seaweed-containing dietary supplements (p < 0.01). This study suggests that the habitual ingestion of seaweed-containing dietary supplements in addition to dietary iodine intake will have adverse effects due to its excessive iodine intake.

Iodine supplementation had better be conducted by localization and Individualization / 中华内分泌代谢杂志

For the first time,the iodine-induced thyroid diseases group of China Medical University has finished a five-year prospective epidemiological study on the incidences of thyroid diseases in the three communities with various levels of iodine intake.The results indicated that increased incidences of subclinical hypothyroidism and autoimmune thyroiditis in the communities with more than adequate and excessive iodine intake.The individuals with positive thyroid autoantibodies at baseline more likely became hypothyroid due to more than adequate and excessive iodine intake.These adverse effects are mainly involved in the susceptible populations for thyroid diseases.Hence it appears to be reasonable that iodine supplementation should be conducted by localization and individualization.

Dietary iodine intake and urinary iodine excretion in normal Korean adults

Korea is a region abundant in foods containing iodine such as seaweed and fish. An adequate amount of iodine consumption is extremely important as both a deficiency and excess of iodine can result in health problems. This study was undertaken to assess the iodine nutritional status of normal Korean adults who consume seaweed and fish, and to determine the relationship between the dietary iodine intake and the urinary excretion of iodine. The dietary assessment of iodine using a food frequency questionnaire and a urinary iodine excretion examination were carried out in 278 healthy adults. The iodide selective electrode (ISE) method was used to determine urinary iodine excretion. The average usual iodine intake of Korean adults was 479 micrograms per day (ranging from 61 micrograms to 4086 micrograms). There was no significant difference in sex or age. The major food sources of dietary iodine included seaweed (66%), milk and dairy products (11%), and fish (9%). The contribution of seaweed to the total iodine intake tended to increase with age while the contribution of milk decreased. The average urinary excretion of iodine was 674 micrograms/g creatinine and there was no significant difference in sex or age. The dietary iodine intake was positively correlated with the urinary excretion of iodine (gamma = 0.60, p < 0.01). The study data indicated that the iodine intake and excretion of Koreans depends mostly on the amount of seaweed consumption like sea tangle and sea mustard. As well, the current iodine intake and urinary iodine excretion by Koreans seems to be higher than in other countries.

The Incidence of Postpartum Thyroiditis and Effect of High Iodine Intake on it in Korean Women / 대한내분비학회지

BACKGROUND: Postpartum thyroiditis(PPT) is one of syndromes of thyroid dysfunction that occurs in the first year after parturition. Reported incidence of PPT is 3.9-8.2% of postpartum women in several studies from different countries. The fact that 52-100% of patients with PPT have thyroid autoantibodies, and that lymphocytic infiltration of thyroid gland is the characteristic pathological feature of PPT suggest that PPT is an autoimmune disease. High iodine intake in short term period is known to aggrevate the experimental autoimmune thyroiditis. This study was performed to investigate the incidence and clinical features of PPT in Korean postpartum women who usually ingest excessive amount of idine in immediate postpartum period and to investigate the predictive value of thyroid autoantibodies in the development of PPT in them. METHOD: Between March 1996 and February 1997, 99 women without previous history of any thyroid disease who delivered babies at Boramae hospital were enrolled. Thyroid function parameters(T3, T4, free T4, TSH), thyroid autoantibodies(anti-microsomal antibody, anti-thyroglobulin antibody) and urinary iodine excretion were measured prospectively before and 1, 3 months after delivery. Dietary iodine intake during postpartum period was evaluated by questionnaire, and clinical parameters were followed up. RESULTS: During 3 months of observation, PPT developed in 8.1%(8/99) of postpartum women. Five cases had typical course having thyrotoxic phase and the other 3 cases had hypothyroid phase without toxic phase. However, only one of those required thyroid hormone replacement therapy in the latter group. There were no differences in age, baseline thyroid function parameters, parity, percent cases with family history of thyroid disease between those developed PPT (n=8) and those did not develop PPT(n=91). Duration of high iodine intake(3.8 +- 0.5 wk. vs. 3.7 +- 0.8 wk., p>0.05), total ingested amount of high iodine diet(77 +- 28 vs. 79 +- 24 bowels of miyokguk, p)0.05), and the urinary iodine excretion(1.9 +- 1.4 mg/g creatinine vs. 3.7 +- 3.7mg/g creatinine, p0.05) at 1 month postpartum were not different between two groups. Of 99 total subjects, anti-microsomal antibody(AMA) was present in 13.1%(13/99) before delivery in their sera. Positive predictive value of the presence of AMA before delivery in predicting the development of PPT was 30.8%. CONCLUSION: The fact that incidence of PPT in normal Korean postpartum women who usually have high iodine intake in immediate postpartum period is not higher than those of other countries, and that there was no difference in the amount of iodine intake between those developed PPT and those did not suggest that high iodine intake in immediate postpartum period do not influence on the incidence of PPT. The presence of AMA before delivery had low specificity in prediction of development of PPT, so the measurement of AMA seems not to be a useful screening test.

Urinary Iodine Content of Children Aged 8—10 years in Qiandongnan, Guizhou Province in 2006 / 环境与健康杂志

Objective To understand the iodine nutrition of children in Qiandongnan and to provide the scientific evidence for prevention and control of iodine deficiency disorders (IDD). Methods The 3200 urinary samples of pupils aged 8-10 were collected from 80 primary schools in 16 county and city in Qiandongnan in 2006. The urinary iodine content was tested by colorimetric ceric-arsenic assay and vitriolic ammonium assimilation. Results The median of urinary iodine content in children samples was 362.9?g/L, the percentage of urinary iodine( ≥100?g/L) was 98.00%, in which ≥300?g/L was 65.31%, the percentage of urinary iodine(

A comparative epidemiologic survey of hyperthyroidism in areas with different iodine intake / 中华内分泌代谢杂志

Objective To investigate the epidemiology of hyperthyroidism in three rural communities with different iodine intake after universal salt iodization (USI) since 1996 as well as the influence of USI on the incidence of hyperthyroidism. Methods Inhabitants in Panshan community did not take iodized salt whereas inhabitants in Zhangwu and Huanghua communities have taken iodized salt since 1996. The thyroid function, thyroid autoantibodies, urinary iodine concentration and thyroid B ultrasound were performed in 1103, 1584 and 1074 subjects respectively in the three communities and the number of hyperthyroidism patients between 1991 and 1999 was collected to calculate the yearly average incidence of hyperthyroidism. Results The median urinary iodine concentrations in Panshan, Zhangwu and Huanghua were 103 ?g/L, 375 ?g/L and 615 ?g/L, respectively (P0.05) andtheprevalenceofsubclinicalhyperthyroidism was 3.7%, 3.9% and 1.1%, respectively. Comparing the yearly average incidence of hyperthyroidism of 1996～1999 with that of 1991～1995, a significant increased incidence in Panshan, while a slight but insignificant elevated one in Zhangwu and a fixed one in Huanghua were found. Conclusion USI can not result in a raise of the prevalence of active hyperthyroidism as well as subclinical hyperthyroidism. The increase of iodine intake is not the only explanation for the raising of the incidence of hyperthyroidism.