Adaptation to a high iodine intake in Greenland Inuit suggested by thyroid disease pattern

Thyroid ◽  
2021 ◽  
Author(s):  
Paneeraq Noahsen ◽  
Karsten Rex ◽  
Inge Bülow Pedersen ◽  
Gert Mulvad ◽  
Hans Christian Florian Sørensen ◽  
...  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Ziyang Zeng ◽  
Kang Li ◽  
Xianze Wang ◽  
Siwen Ouyang ◽  
Zimu Zhang ◽  
...  

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.


2021 ◽  
pp. 1-30
Author(s):  
Ying Sun ◽  
Xin Du ◽  
Zhongyan Shan ◽  
Weiping Teng ◽  
Yaqiu Jiang

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.


Author(s):  
Zdeněk Peksa ◽  
Jan Trávníček ◽  
Roman Konečný ◽  
František Jelínek ◽  
Hana Dušová ◽  
...  

In 2010 and 2011 two experiments on gimmers of Šumava mountain sheep were performed. The first experiment was carried out on 12 animals (experimental period was 11 months); control group was fed with 3 mg I*kg−1 in dry matter per day and experimental group was fed with 5 mg I*kg−1 in dry matter per day. The second experiment lasted 10 months and it was carried out on 12 animals. Feed ration for control group contained 10 mg I*kg DM−1. Feed ration for experimental group contained 10 mg I*kg DM−1 too; moreover it included rapeseed meal and 1 g of sodium nitrate. The aim of the first experiment was focused on impact of high iodine intake on structure of thyroid gland. The aim of the second experiment was to discover effect of strumigens during high iodine intake on structure of thyroid gland. The animals were slaughtered after the experiment and there was executed the dissection of thyroid gland. The samples of thyroid gland were processed during classic paraffin method and dyed with haematoxylin and eosin. For finding of histometrical parameters was used program Leica IM 500 Version 4.0. The length, the width and the area of follicles were measured. The follicles were divided into three groups after this procedure (by the length); in each group were measured 20 thyreocytes. In group with intake 5 mg I*kg DM−1 (experiment from year 2010): higher weight of thyroid (p < 0.01), significant higher (p < 0.05) proportional representation of large and medium follicles, significantly (p < 0.05) higher average size of follicles, demonstrably lower (p < 0.05) height of epithelium were found. There were not found any differences in monitored parameters between the groups from experiment which was carried out during the year 2011. After comparing results from the both experiments significantly higher percentage representation of large follicles a significantly lower representation of small follicles, distinctly higher average size and higher height of epithelium in all size categories, in groups with iodine intake 10 mg I*kg DM−1was found (from second experiment – year 2011).


PEDIATRICS ◽  
1975 ◽  
Vol 56 (1) ◽  
pp. 82-90
Author(s):  
Frederick L. Trowbridge ◽  
Josip Matovinovic ◽  
Gordon D. McLaren ◽  
Milton Z. Nichaman

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.


Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2757 ◽  
Author(s):  
Kim ◽  
Kwon ◽  
Kim ◽  
Hong ◽  
Park

This study aimed to observe the relationship between iodine nutrition status (dietary iodine intake and estimated iodine intake based on urinary iodine concentration (UIC)) and thyroid disease-related hormones. This study involved 6090 subjects >19 years old with valid UIC, assessed between 2013 and 2015 by the Korean National Health and Nutrition Examination Survey, using a stratified, multistage, clustered probability-sampling design. The estimated iodine intake in participants was measured using UIC and urine creatinine. To examine the effect of iodine intake on thyroid disease, the iodine intake was divided into Korean Dietary Reference Intakes groups, and logistic regression analysis was performed via the surveylogistic procedure to obtain odds ratios (ORs) and 95% confidence intervals (CIs). The estimated iodine intake showed a significant positive correlation with dietary iodine intake (r = 0.021, p < 0.001), UIC (r = 0.918, p < 0.001), and thyroid-stimulating hormone (TSH) (r = 0.043, p < 0.001), but a significant negative correlation with free thyroxine (FT4) (r = −0.037, p < 0.001). Additionally, as the estimated iodine intake increased, age, TSH, and UIC increased, but FT4 decreased (p for trend < 0.0001). The risk of thyroid disease was higher in the “≥tolerable upper intake level (UL ≥ 2400 µg/day)” group than in the “<estimated average requirement (EAR < 150 µg/day)” group in females (OR: 2.418; 95% CI: 1.010–5.787). Also, as iodine intake increased, the risk of thyroid disease increased (p for trend < 0.038).


2010 ◽  
Vol 57 (7) ◽  
pp. 645-649 ◽  
Author(s):  
Noboru Hamada ◽  
Jaeduk Yoshimura Noh ◽  
Yasuyuki Okamoto ◽  
Miki Ueda ◽  
Toshiaki Konishi ◽  
...  

1986 ◽  
Vol 63 (2) ◽  
pp. 412-417 ◽  
Author(s):  
JUNICHI TAJIRI ◽  
KIICHIRO HIGASHI ◽  
MITSUO MORITA ◽  
TERUHISA UMEDA ◽  
TATSUO SATO
Keyword(s):  

Author(s):  
S. V. Dora ◽  
A. R. Volkova ◽  
N. E. Peykrishvili ◽  
M. B. Gudieva

Diffuse toxic goiter (DTG) is an autoimmune disease, which is based on a congenital defect in the immune system. As a result of stimulating the synthesis of antibodies directed to the TSH receptor. Goiter forms gradually and then hyperthyroidism develops. For the last decades it has been pointed out a steady increase in the number of new cases of diffuse toxic goiter and drastic reduction of likelihood of remission. To some extent the spectrum of thyroid disease and the nature of the disease depend on the level of iodine provision in the particular region. Active iodine preventive measures were implemented among the population in Saint-Petersburg for the last decades. So the median urinary iodine increased from 105 (1999) to 148 mg/l (2010). Probably the growth of the iodine intake in Saint- Petersburg reduces the incidence of DTG remission and thus optimization of the treatment in these patients seems to be relevant and requires further study.


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