scholarly journals Geographical distribution of drinking-water with high iodine level and association between high iodine level in drinking-water and goitre: a Chinese national investigation

2011 ◽  
Vol 106 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Hongmei Shen ◽  
Shoujun Liu ◽  
Dianjun Sun ◽  
Shubin Zhang ◽  
Xiaohui Su ◽  
...  
Keyword(s):  
Drinking Water ◽  
Geographical Distribution ◽  
Yellow River ◽  
Urinary Iodine ◽  
Iodine Intake ◽  
High Iodine ◽  
Excessive Iodine ◽  
Iodine Level ◽  
Goitre Prevalence ◽  
The Relationship

Excessive iodine intake can cause thyroid function disorders as can be caused by iodine deficiency. There are many people residing in areas with high iodine levels in drinking-water in China. The main aim of the present study was to map the geographical distribution of drinking-water with high iodine level in China and to determine the relationship between high iodine level in drinking-water and goitre prevalence. Iodine in drinking-water was measured in 1978 towns of eleven provinces in China, with a total of 28 857 water samples. We randomly selected children of 8–10 years old, examined the presence of goitre and measured their urinary iodine in 299 towns of nine provinces. Of the 1978 towns studied, 488 had iodine levels between 150 and 300 μg/l in drinking-water, and in 246 towns, the iodine level was >300 μg/l. These towns are mainly distributed along the original Yellow River flood areas, the second largest river in China. Of the 56 751 children examined, goitre prevalence was 6·3 % in the areas with drinking-water iodine levels of 150–300 μg/l and 11·0 % in the areas with drinking-water iodine >300 μg/l. Goitre prevalence increased with water and urinary iodine levels. For children with urinary iodine >1500 μg/l, goitre prevalence was 3·69 times higher than that for those with urinary iodine levels of 100–199 μg/l. The present study suggests that drinking-water with high iodine levels is distributed in eleven provinces of China. Goitre becomes more prevalent with the increase in iodine level in drinking-water. Therefore, it becomes important to prevent goitre through stopping the provision of iodised salt and providing normal drinking-water iodine through pipelines in these areas in China.

scholarly journals Low urinary iodine is a protective factor of central lymph node metastasis in papillary thyroid cancer: a cross-sectional study

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Ziyang Zeng ◽  
Kang Li ◽  
Xianze Wang ◽  
Siwen Ouyang ◽  
Zimu Zhang ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Papillary Thyroid Cancer ◽  
Protective Factor ◽  
Urinary Iodine ◽  
Iodine Intake ◽  
Clinicopathological Features ◽  
Papillary Thyroid ◽  
Central Lymph Node ◽  
High Iodine ◽  
Central Lymph

Abstract Background An abrupt increase of thyroid cancer has been witnessed paralleling the supplemented iodine intake in formerly iodine-deficient countries. And increased iodine intake has been linked to the rising incidence rate of papillary thyroid cancer (PTC). However, the correlation between iodine and clinicopathological features of PTC has not been well-characterized. This study aimed to investigate the associations between iodine intake and the clinicopathological features of PTC patients. Methods Three hundred and fifty-nine PTC patients who received surgical treatment in Peking Union Medical College Hospital from May 2015 to November 2020 were retrospectively reviewed. The associations between urinary iodine (UI), urinary iodine/creatinine ratio (UI/U-Cr), and the clinicopathological features of PTC were analyzed. Univariate and multivariate analysis were performed to investigate the relationship between UI level and central lymph node metastasis (CLNM). Results There were no significant differences in UI in different groups according to the variables studied, except that patients with CLNM had higher UI level than CLNM(−) patients. No associations were found between UI/U-Cr and clinicopathological features except variant subtypes (classic/follicular). After dividing patients into high-iodine group and low-iodine group, more patients were found to have CLNM in the high-iodine group (p = 0.02). In addition, younger age, larger tumor size, and classic variant were positively correlated with CLNM (p < 0.05). Univariate analysis showed that insufficient iodine intake (≤ 99 μg/L) was associated with decreased CLNM risk in PTC. And after defining insufficient iodine intake as ≤ 109 μg/L and above requirements as ≥ 190 μg/L, multivariate analysis showed that lower iodine was associated with CLNM in total population of PTC (OR 0.53, 95% CI 0.31–0.91) and in PTC < 1 cm (papillary thyroid microcarcinoma, PTMC) (OR 0.43, 95% CI 0.21–0.87). Conclusions Low iodine was a protective factor for CLNM in papillary thyroid cancer, particularly in those < 1 cm. These results indicated that iodine may not only be an initiator of tumorigenesis, but also a promoter of the development of PTC.

Effects of iodine excess on serum thyrotropin-releasing hormone levels and type 2 deiodinase in the hypothalamus of Wistar rats

2021 ◽  
pp. 1-30
Author(s):  
Ying Sun ◽  
Xin Du ◽  
Zhongyan Shan ◽  
Weiping Teng ◽  
Yaqiu Jiang
Keyword(s):  
Thyroid Function ◽  
Wistar Rats ◽  
Iodine Intake ◽  
Thyrotropin Releasing Hormone ◽  
High Iodine ◽  
Releasing Hormone ◽  
Iodine Excess ◽  
Excessive Iodine ◽  
Thyroid Hormone Biosynthesis

Abstract Iodine is an important element in thyroid hormone biosynthesis. Thyroid function is regulated by the hypothalamic-pituitary-thyroid axis (HPT). Excessive iodine leads to elevated thyroid stimulating hormone (TSH) levels, but the mechanism is not yet clear. Type 2 deiodinase (Dio2) is a selenium-containing protease that plays a vital role in thyroid function. The purpose of this study was to explore the role of hypothalamus Dio2 in regulating TSH increase caused by excessive iodine and to determine the effects of iodine excess on thyrotropin-releasing hormone (TRH) levels. Male Wistar rats were randomized into five groups and administered different iodine dosages (folds of physiological dose): normal iodine (NI), 3-fold iodine (3HI), 6-fold iodine (6HI), 10-fold iodine (10HI), and 50-fold iodine (50HI). Rats were euthanized at 4, 8, 12, or 24 weeks after iodine administration. Serum TRH, TSH, total thyroxine (TT4), and total triiodothyronine (TT3) were determined. Hypothalamus tissues were frozen and sectioned to evaluate expression of Dio2, Dio2 activity, and monocarboxylate transporter 8 (MCT8). Prolonged high iodine intake significantly increased TSH expression (p < 0.05), but did not affect TT3 and TT4 levels. Prolonged high iodine intake decreased serum TRH levels in the hypothalamus (p < 0.05). Dio2 expression and activity in the hypothalamus exhibited an increasing trend compared at each time point with increasing iodine intake (p < 0.05). Hypothalamic MCT8 expression was increased in rats with prolonged high iodine intake(p < 0.05). These results indicate that iodine excess affects the levels of Dio2, TRH, and MCT8 in the hypothalamus.

scholarly journals Impact of removing iodised salt on children's goitre status in areas with excessive iodine in drinking-water

2014 ◽  
Vol 113 (1) ◽  
pp. 114-119 ◽  
Author(s):  
Shengmin Lv ◽  
Dong Xu ◽  
Yuchun Wang ◽  
Zhao Jun ◽  
Lihui Jia ◽  
...  
Keyword(s):  
Urinary Iodine ◽  
Thyroid Volume ◽  
Iodine Content ◽  
Hebei Province ◽  
Age Group ◽  
Iodised Salt ◽  
Excessive Iodine ◽  
Before And After ◽  
Goitre Prevalence ◽  
The Impact

The impact of removing iodised salt on children's goitre status in a high-iodine area (HIA) remains unclear. The aim of the present study was to explore the changes in the prevalence of goitre in children after removing iodised salt from their diet. For this purpose, three towns with the median water iodine content of 150–300 μg/l were selected randomly in Hengshui City, Hebei Province, China. A total of 452 and 459 children were randomly selected from the three towns in order to measure thyroid volume by ultrasound before and after removing iodised salt, respectively. Their goitre status was judged using the criteria of age-specific thyroid volume recommended by the WHO. After removing iodised salt, the overall median urinary iodine content (MUIC) of children decreased from 518 (interquartile range (IQR) 347–735) to 416 (IQR 274–609) μg/l. The MUIC of children across sex and age group decreased significantly except for the age group of 9 years. The overall prevalence of goitre in the three towns significantly decreased from 24·56 % (n 111/452) to 5·88 % (n 27/459) (P< 0·001). Goitre prevalence in children aged 8–10 years decreased from 33·70 % (n 31/92), 23·32 % (n 45/193) and 20·96 % (n 35/167) to 6·10 % (n 10/164), 5·52 % (n 9/163) and 6·06 % (n 8/132), respectively. Goitre prevalence in boys and girls decreased from 27·05 % (n 66/244) and 21·63 % (n 45/208) to 6·66 % (n 15/226) and 5·15 % (n 12/233), respectively. The decreases in the prevalence of goitre in children across sex and age group were all statistically significant. The present study revealed that goitre prevalence in children decreased significantly after removing iodised salt from their diet for about 1·5 years in the HIA in Hebei Province.

Iodine and Goiter in Children

PEDIATRICS ◽  
1975 ◽  
Vol 56 (1) ◽  
pp. 82-90
Author(s):  
Frederick L. Trowbridge ◽  
Josip Matovinovic ◽  
Gordon D. McLaren ◽  
Milton Z. Nichaman
Keyword(s):  
United States ◽  
Urinary Iodine ◽  
The United States ◽  
Iodine Intake ◽  
Urinary Iodine Excretion ◽  
High Iodine ◽  
Goiter Prevalence ◽  
Iodine Excretion ◽  
American Children

Goiter examination was performed on 7,785 children aged 9 to 16 years in four areas of the United States—Michigan, Kentucky, Texas, and Georgia. Urinary iodine and creatinine, thyroxine, protein-bound iodine, and plasma inorganic iodide determinations were made on 377 matched pairs of goitrous and nongoitrous control children. The overall prevalence of goiter was 6.8%. Most children with goiter had palpably but not visibly enlarged thyroids and showed no evidence of clinical or biochemical thyroid abnormality. Mean urinary iodine excretion was 452µg/gm of creatinine, many times the 50µg/gm of creatinine level used to define deficiency. Children with goiter and areas with high goiter prevalence tended to have higher rather than lower iodine excretion. These findings are consistent with other data indicating high iodine intakes in the United States and suggest that goiter in American children cannot be assumed to be related to iodine deficiency. The possible role of high iodine intake in the causation of goiter is discussed.

scholarly journals Chronic iodine excess does not increase the incidence of hyperthyroidism: a prospective community-based epidemiological survey in China

2007 ◽  
Vol 156 (4) ◽  
pp. 403-408 ◽  
Author(s):  
Fan Yang ◽  
Zhongyan Shan ◽  
Xiaochun Teng ◽  
Yushu Li ◽  
Haixia Guan ◽  
...  
Keyword(s):  
Urinary Iodine ◽  
Iodine Intake ◽  
Urinary Iodine Excretion ◽  
Thyroid Peroxidase ◽  
Community Based ◽  
Iodine Excess ◽  
Iodine Supplementation ◽  
Excessive Iodine ◽  
Iodine Excretion ◽  
Excessive Iodine Intake

Objective: An increasing incidence of hyperthyroidism has been observed when iodine supplementation has been introduced to an iodine-deficient population. Moreover, the influence of chronic more than adequate or excessive iodine intake on the epidemiological features of hyperthyroidism has not been widely and thoroughly described. To investigate the influences of different iodine intake levels on the incidence of hyperthyroidism, we conducted a prospective community-based survey in three communities with mild-deficient, more than adequate (previously mild deficient iodine intake), and excessive iodine intake. Subjects and methods: In three rural Chinese communities, a total of 3761 unselected inhabitants aged above 13 years participated in the original investigation and 3018 of them received identical examinations after 5 years. Thyroid function, levels of thyroid peroxidase antibody (TPOAb), thyroglobulin antibody and urinary iodine excretion were measured and thyroid ultrasound examination was also performed. Results: In three communities, median urinary iodine excretion was 88, 214, and 634 μg/l (P<0.05) respectively. The cumulative incidence of hyperthyroidism was 1.4, 0.9, and 0.8% (P>0.05) respectively. Autoimmune hyperthyroidism was predominant in thyroid hyperfunction in all the three cohorts. Either positive TPOAb (>50 U/ml) or goiter in original healthy participants was associated with the occurrence of unsuspected hyperthyroidism in 5 years (logistic regression, OR=4.2 (95% CI 1.7–8.8) for positive TPOAb, OR=3.1 (95% CI 1.4–6.8) for goiter). Conclusion: Iodine supplementation may not induce an increase in hyperthyroidism in a previously mildly iodine-deficient population. Chronic iodine excess does not apparently increase the risk of autoimmune hyperthyroidism, suggesting that excessive iodine intake may not be an environmental factor involved in the occurrence of autoimmune hyperthyroidism.

scholarly journals Urinary iodine concentration: a biochemical parameter for assessing the iodine status

Mediscope ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 30-35
Author(s):  
GM Molla
Keyword(s):  
Iodine Deficiency ◽  
Urinary Iodine ◽  
Iodine Concentration ◽  
Iodine Intake ◽  
Urinary Iodine Concentration ◽  
Lactating Women ◽  
Iodine Status ◽  
Excessive Iodine ◽  
Pregnancy And Lactation ◽  
Neonates And Infants

Iodine is a micronutrient, which is essential for the synthesis of thyroid hormones. Thyroid hormones play a major role in the development of different functional components in different stages of life. The relationship between iodine intake level of a population and occurrences of thyroid disorders U-shaped with an increase from both low and high iodine intake. Iodine deficiency disorders (IDDs) are a major health problem worldwide in all age groups, but infants, school children, and pregnant and lactating women are vulnerable. During pregnancy and lactation, the fetus and infants are sensitive to maternal iodine intake. Even mild iodine deficiency may lead to irreversible brain damage during this period. A main cause of IDDs of neonates and infants is maternal iodine deficiency. Universal salt iodization strategy has been initiated by the World Health Organization and United Nation International Children Emergency Fund by the year 1993 for correction and prevention of iodine deficiency. Excessive iodine causes hypothyroidism, iodine-induced hyperthyroidism and autoimmune thyroid diseases. Iodine deficiency and excessive iodine, both cause goiter. There are many indicators for assessing the IDDs, such as measurement of thyroid size by palpation or ultrasonography, serum thyroid stimulating hormone, and thyroglobulin but these are less sensitive, costly and sometimes interpretation is difficult. Urinary iodine concentration (UIC) is a well-accepted, cost-efficient, and easily obtainable indicator of iodine status. Since the majority of iodine absorbed by the body is excreted in the urine, it is considered a sensitive marker of current iodine intake and can reflect recent changes in iodine status. Iodine requirements are greatly increased during pregnancy and lactation, owing to metabolic changes. During intrauterine life, maternal iodine is the only source of iodine for a fetus. UIC determines the iodine status of pregnant and lactating women. Breast milk is the only source of iodine for exclusively breastfed neonates and infants. Breast milk iodine concentration can be determined by UIC. UIC predicts the adverse health consequences of excessive iodine intake such as goiter, hypothyroidism, and hyperthyroidism. This review presents that iodine status in different groups of a population can be determined by UIC which will be helpful in assessing the iodine status in a community, finding out the cause of thyroid disorders, to predict the risk of adverse health effects of iodine deficiency and excessive iodine, and in making plan for iodine supplementation.Mediscope Vol. 5, No. 2: Jul 2018, Page 30-35

scholarly journals Goitre prevalence and epidemiological features in children living in areas with mildly excessive iodine in drinking-water

2013 ◽  
Vol 111 (1) ◽  
pp. 86-92 ◽  
Author(s):  
Shengmin Lv ◽  
Dong Xu ◽  
Yuchun Wang ◽  
Zhenshui Chong ◽  
Yonggui Du ◽  
...  
Keyword(s):  
Drinking Water ◽  
Thyroid Volume ◽  
Hebei Province ◽  
Age Group ◽  
Who Criteria ◽  
Epidemiological Features ◽  
Excessive Iodine ◽  
High Prevalence ◽  
Goitre Prevalence ◽  
Epidemiological Characteristics

The prevalence of goitre in areas with mildly excessive iodine in drinking-water is still under debate. The aim of the present study was to explore the prevalence of goitre and its epidemiological characteristics in these areas using WHO criteria. To this end, three towns with a median water iodine (MWI) of 150–300 μg/l were selected randomly in Hengshui City of Hebei Province of China, and one town with a MWI of 105 μg/l was chosen as a control. A total of 452 children in the three towns and 120 children in the control town were randomly selected to measure thyroid volume (Tvol) by ultrasound. The goitre status of these children was judged using the criteria recommended by the WHO. The overall goitre prevalences in the three towns were 24·6 % (111/452) by age-specific Tvol and 33·0 % (149/452) by body surface area (BSA)-adjusted Tvol, which were significantly higher than that in the control town by both age-specific Tvol (14·0 % (17/120), P= 0·015) and BSA-adjusted Tvol (17·5 % (21/120), P= 0·001). Significant differences were found neither in goitre prevalences across sex by both age-specific Tvol (P= 0·078) and BSA-adjusted Tvol (P= 0·692) nor in that across age group by both BSA-adjusted Tvol (P= 0·461) and age-specific Tvol (P= 0·183). The present study found a high prevalence of goitre in children living in areas with mildly excessive iodine in drinking-water in Hebei Province. No significant differences were found in goitre prevalences across sex and age group. These results suggest that the Tvol reference values recommended by the WHO could be too low for Chinese children.

scholarly journals Drinking water contributes to excessive iodine intake among children in Hebei, China

2013 ◽  
Vol 67 (9) ◽  
pp. 961-965 ◽  
Author(s):  
S Lv ◽  
Y Wang ◽  
D Xu ◽  
S Rutherford ◽  
Z Chong ◽  
...  
Keyword(s):  
Drinking Water ◽  
Iodine Intake ◽  
Excessive Iodine ◽  
Excessive Iodine Intake
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