Autoimmune thyroid diseases after 25 years of universal salt iodisation: an epidemiological study of Chinese adults in areas with different water iodine levels

AbstractThe present study aimed to evaluate the status of iodine nutrition and thyroid function in adults, to understand the distribution of thyroid disease in people with autoimmune thyroid disease (AITD) in different water iodine areas and to explore the relationship between serum iodine, urine iodine and thyroid function in people with AITD. A cross-sectional survey was conducted in areas of Shandong Province with different water iodine levels, and subsequently 1225 adults were enrolled from iodine-deficient (ID), iodine-adequate (IA) and iodine-excess (IE) areas. Urinary iodine, water iodine, salt iodine, serum iodine and thyroid function were measured. According to the urine iodine concentration, the ID and IA areas were defined as iodine sufficient and the IE area as iodine excessive. Urine iodine, serum iodine, free thyroxine (FT4) and thyroid-stimulating hormone (TSH) levels were comparatively higher in the IE area. The positive rate of thyroglobulin antibody (19·1 %) and the prevalence of AITD (21·8 %) were higher in the ID areas; the prevalence of subclinical hypothyroidism was lowest in the ID areas (7·3 %) and highest in the IE area (16·3 %). Among the AITD population, urinary iodine concentration, free triiodothyronine, FT4 and TSH had a non-linear correlation with serum iodine; abnormal TSH level, serum iodine concentration > 110 µg/l and goitre were risk factors for AITD in adults, especially females. Our data collectively suggest that universal salt iodisation has improved the iodine nutritional status of the population in ID areas in China. Non-step-by-step iodine fortification may induce the transformation of thyroid autoimmune diseases from recessive-to-dominant in susceptible people. Moreover, enhanced monitoring of thyroid function in people with AITD is important.

Download Full-text

Larger Thyroid Volume and Adequate Iodine Nutrition in Chinese Schoolchildren: Local Normative Reference Values Compared with WHO/IGN

International Journal of Endocrinology ◽

10.1155/2016/8079704 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

Zhe Mo ◽

Xiaoming Lou ◽

Guangming Mao ◽

Zhifang Wang ◽

Wenming Zhu ◽

...

Keyword(s):

Reference Values ◽

Urinary Iodine ◽

Thyroid Volume ◽

Reference Interval ◽

Iodine Concentration ◽

Zhejiang Province ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Local Reference ◽

Urine Iodine

Objective. Thyroid volume measured by ultrasound to define goiter needs reliable local thyroid volume reference from iodine-sufficient populations. The aim of this study is to explore the reference interval for normal thyroid volume in schoolchildren aged 8–10 years from Zhejiang Province, China.Methods. A probability-proportionate-to-size sampling method was applied to select a representative sample of 1213 children aged 8–10 years in Zhejiang Province to detect the thyroid volume, salt iodine, and urine iodine.Results. Median urinary iodine concentration in involved schoolchildren was 178.30 (125.00) μg l−1, with the percentage of samples less than 100 μg l−1as 12.69% and more than 300 μg l−1as 15.25%. Thyroid volume was significantly correlated with age and anthropometric measurements independently of each other. The 97th percentile of thyroid volume in our study was larger generally than the new international reference.Conclusions. The iodine nutritional status in Zhejiang Province was at an adequate level. Despite some limitations in this study, we initially established the reference values for thyroid volume in 8–10-year-old schoolchildren in Zhejiang Province, China, as a local reference to be used for monitoring iodine deficiency disorders.

Download Full-text

Thyroid function and thyroglobulin level in iodine deficient children of eastern Nepal

10.21203/rs.3.rs-24159/v1 ◽

2020 ◽

Author(s):

Saroj Kunwar ◽

Saroj Khatiwada ◽

Basanta Gelal ◽

Saroj Thapa ◽

Gaurishankar Shah ◽

...

Keyword(s):

Thyroid Function ◽

Urinary Iodine ◽

Iodine Concentration ◽

Ammonium Persulfate ◽

Thyroid Stimulating Hormone ◽

Overt Hypothyroidism ◽

Urinary Iodine Concentration ◽

Free Triiodothyronine ◽

Iodine Nutrition ◽

Serum Thyroglobulin

Abstract Objective: Both iodine deficiency and excess can negatively impact thyroid function. The present study was conducted to assess iodine nutrition among children and thyroid function in iodine deficient children. Results: A total of 1012 school aged children (6-14 years) from several schools of Udayapur district were enrolled initially for the assessment of urinary iodine concentration (UIC). Blood samples (n=83) were collected from a subgroup of children who had UIC<100 µg/L to measure serum thyroglobulin (Tg), thyroid stimulating hormone (TSH), free triiodothyronine (fT3) and free thyroxine (fT4). Serum UIC was measured by ammonium persulfate digestion method and Tg, TSH, fT4 and fT3 were measured by ELISA kits from Diametra Company. The prevalence of insufficient UIC (UIC<100 µg/L) was 11.1% in school children’s of Udayapur district. The median UIC was 236 µg/L. The mean fT3, fT4 and TSH among children with insufficient UIC were 2.55±0.43 pg/mL, 0.96±0.28 ng/dL and 3.60±1.44 mIU/L respectively. The Median Tg was 17.5 ng/mL. Overt hypothyroidism and subclinical hypothyroidism was seen in 6% and 3.6% cases with UIC<100 µg/L respectively.

Download Full-text

Mild to moderate iodine deficiency in pregnancy: A matter of debate

Archive of Food and Nutritional Science ◽

10.29328/journal.afns.1001028 ◽

2021 ◽

Vol 5 (1) ◽

pp. 018-026

Author(s):

Delshad Hossein ◽

Azizi Fereidoun

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Iodine Supplementation ◽

Iodine Deficiency In Pregnancy ◽

In Pregnancy

During the last few decades painstaking efforts have been made to eliminate iodine deficiency through the world. Nowadays in regions where dietary iodine intake is adequate or borderline, the main focus is increasing dietary iodine supply in the target population during pregnancy and the first years of life. Severe iodine deficiency during pregnancy increases the risk of irreversible brain damage, intellectual disability, neurologic abnormalities, stunted growth, increased pregnancy loss, infant mortality, impairments in child development and cretinism. The potential effects of mild-to-moderate iodine deficiency are debated. Results from animal studies and observational human studies indicate that maternal mild-to-moderate iodine deficiency disturbs thyroid function in pregnancy and it also may affects fetal neurodevelopment. The effect of supplementation of iodine on thyroid function of pregnant women and their newborn, neurodevelopment of infants and cognitive performance of children have been investigated using iodine nutrition in pregnancy, based on median urinary iodine concentration. However they have found conflicting results regarding the benefits or harms of iodine supplementation in pregnancy. Although many epidemiological, interventional and clinical studies have supported the association between thyroid function in pregnant women and later psychomotor and mental development of their children, the effect of iodine supplementation in pregnant women on neurodevelopment of children is inconclusive. Even in areas with well-established universal salt iodization program, pregnancy could be at risk of having iodine deficiency and despite WHO/ICCIDD/UNICEF recommendation which believe that dietary iodine fortification during pregnancy depends primarily on the extent of pre-existing iodine deprivation, systematic dietary fortification needs to be implemented in this vulnerable group. However, iodine supplementation of mildly iodine deficient pregnant women may not have beneficial effects in their thyroid function or neurodevelopment of their children.

Download Full-text

Thyroid Function and Thyroglobulin Level in Iodine-Deficient Children of Eastern Nepal

Nepal Journal of Biotechnology ◽

10.3126/njb.v9i1.38670 ◽

2021 ◽

Vol 9 (1) ◽

pp. 75-78

Author(s):

Saroj Kunwar ◽

Saroj Khatiwada ◽

Basanta Gelal ◽

Saroj Thapa ◽

Gaurishankar Shah ◽

...

Keyword(s):

Thyroid Function ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Concentration ◽

Overt Hypothyroidism ◽

Urinary Iodine Concentration ◽

Free Triiodothyronine ◽

Iodine Nutrition ◽

Serum Thyroglobulin ◽

Cross Sectional

Iodine deficiency during childhood affects physical and mental development. Iodine deficiency or excess both can negatively impact thyroid function. We conducted this study to assess iodine nutrition and thyroid function in children with insufficient urinary iodine concentration. A community-based cross-sectional study was conducted among the selected schools of Udayapur district. Urinary iodine concentration (UIC) was measured in 1012 school children (6-14 years). Based on UIC data, 83 blood samples were collected to measure serum thyroglobulin (Tg), thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4). UIC was measured by ammonium persulfate digestion method, and Tg, TSH, fT4, and fT3 were measured using ELISA kits. The median UIE was 236 µg/L, and 11.1% of the children had insufficient UIC. The mean fT3, fT4, and TSH in children with insufficient UIC were 2.55±0.43 pg/mL, 0.96±0.28 ng/dL, and 3.60±1.44 mIU/L respectively. Among children with low UIC levels, the median Tg was 17.5 ng/mL. Overt hypothyroidism was seen in 6%, and subclinical hypothyroidism in 3.6%. The children had sufficient iodine nutrition, and the frequency of thyroid dysfunction was low among the children with insufficient UIC.

Download Full-text

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

Food and Nutrition Bulletin ◽

10.1177/0379572117738883 ◽

2017 ◽

Vol 39 (1) ◽

pp. 75-85 ◽

Cited By ~ 2

Author(s):

Fan-Fen Wang ◽

Kam-Tsun Tang ◽

Wen-Harn Pan ◽

Justin Ging-Shing Won ◽

Yao-Te Hsieh ◽

...

Keyword(s):

Age Groups ◽

Urinary Iodine ◽

Iodine Concentration ◽

World Health ◽

Urinary Iodine Concentration ◽

Taiwanese Population ◽

Iodine Nutrition ◽

Iodine Status ◽

Salt Iodization ◽

Health Organization

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.

Download Full-text

Association between Iodine Nutrition Status and Thyroid Disease-Related Hormone in Korean Adults: Korean National Health and Nutrition Examination Survey VI (2013–2015)

Nutrients ◽

10.3390/nu11112757 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2757 ◽

Cited By ~ 3

Author(s):

Kim ◽

Kwon ◽

Kim ◽

Hong ◽

Park

Keyword(s):

National Health ◽

Thyroid Disease ◽

Urinary Iodine ◽

Iodine Intake ◽

Thyroid Stimulating Hormone ◽

Nutrition Status ◽

Urinary Iodine Concentration ◽

Nutrition Examination Survey ◽

Iodine Nutrition ◽

Health And Nutrition

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).

Download Full-text

Two Sources of Maternal Iodine Intake and Their Effect on Maternal and Infant Iodine Status and Thyroid Function and Infant Information Processing in Southern Ethiopia (P11-007-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz048.p11-007-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

Tafere Gebreegziabher ◽

Barbara Stoecker

Keyword(s):

Information Processing ◽

Thyroid Function ◽

Visual Information ◽

Urinary Iodine ◽

Iodine Concentration ◽

Thyroid Stimulating Hormone ◽

Iodized Salt ◽

Southern Ethiopia ◽

Urinary Iodine Concentration ◽

Iodine Supplementation

Abstract Objectives The objective of this study was to assess the effects of two sources of iodine supplementation on maternal and infant thyroid function and on visual information processing (VIP) of infants in southern Ethiopia Methods A community-based, randomized, supplementation trial was conducted. Mother infant dyads (n = 106) were recruited within the first week after delivery to participate in this study. Mothers were randomly assigned either to receive a potassium iodide capsule (225 µg iodine) daily for 26 weeks or appropriately iodized salt weekly for 26 weeks for household consumption. Maternal thyroxine (T4), triiodothyronine (T3), thyroid stimulating hormone (TSH), thyroglobulin (Tg), urinary iodine concentration (UIC), breast milk iodine concentration (BMIC) and infant T4, TSH, UIC and VIP were measured as outcome variables. Results At baseline, neither mothers nor infants in the two groups (capsule and iodized salt groups) were significantly different in any of the biomarkers and anthropometry measurements. Maternal TSH and goiter rate significantly decreased following iodine supplementation but T3, T4 and Tg didn't change. Maternal UIC and BMIC and infant UIC were not different among groups. Conclusions A maternal dose of 225 µg iodine daily or adequately iodized salt initiated within a week after delivery decreased goiter and TSH but did not impact infant T4, TSH or VIP. The two treatment groups didn't differ in any of the outcome variables. Funding Sources The study was funded by Nestlé Foundation and Oklahoma State University.

Download Full-text

Endemic goitre and excessive iodine in urine and drinking water among Saharawi refugee children

Public Health Nutrition ◽

10.1017/s1368980010000650 ◽

2010 ◽

Vol 13 (9) ◽

pp. 1472-1477 ◽

Cited By ~ 41

Author(s):

Sigrun Henjum ◽

Ingrid Barikmo ◽

Anne Karine Gjerlaug ◽

Abderraháman Mohamed-Lehabib ◽

Arne Oshaug ◽

...

Keyword(s):

Drinking Water ◽

Urinary Iodine ◽

Thyroid Volume ◽

Iodine Concentration ◽

Refugee Children ◽

Urinary Iodine Concentration ◽

Endemic Goitre ◽

Cross Sectional Survey ◽

Cross Sectional ◽

Excessive Iodine

AbstractObjectiveTo assess the prevalence of enlarged thyroid volume (Tvol) in Saharawi refugee children, and their urinary iodine concentration (UIC), and to identify possible sources of excess iodine intake.DesignA cross-sectional survey was performed during January–February 2007. Tvol was measured by ultrasound and iodine concentration was analysed in casual urine samples, in household drinking water and in milk samples from household livestock.SettingThe study was undertaken in four refugee camps in the Algerian desert.SubjectsThe subjects were 421 Saharawi children, 6–14 years old.ResultsEnlarged Tvol was found in 56 % (Tvol-for-age) and 86 % (Tvol-for-body-surface-area) of the children. The median (25th percentile–75th percentile, P25–P75) UIC was 565 (357–887) μg/l. The median (P25–P75) iodine concentration in household drinking water was 108 (77–297) μg/l. None of the children had UIC below 100 μg/l, 16 % had UIC between 100 and 299 μg/l, and 84 % had UIC above 300 μg/l. There was a positive association between Tvol and whether the household possessed livestock.ConclusionsThe children are suffering from endemic goitre and high UIC caused probably by an excessive intake of iodine. The excessive iodine intakes probably originate from drinking water and milk.

Download Full-text

Thyroid stimulating hormone isn’t a sensitive indicator of iodine nutritional status in schoolchildren

Revista de Ciências Médicas e Biológicas ◽

10.9771/cmbio.v14i3.14990 ◽

2016 ◽

Vol 14 (3) ◽

pp. 350

Author(s):

Renata De Oliveira Campos ◽

Joaquim Custódio Silva Júnior ◽

Elton Estrela Ramos

Keyword(s):

Public Schools ◽

Nutritional Status ◽

Filter Paper ◽

Urinary Iodine ◽

Iodine Concentration ◽

Thyroid Stimulating Hormone ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Cross Sectional ◽

Stimulating Hormone

Introduction: iodine deficiency disorders (IDD) are most common cause of preventable brain damage, mental retardation and stunted growth in children worldwide. Several indicators are complementary to urinary iodine concentration (UIC) for assessing iodine nutritional status, as thyroid size, thyroglobulin (Tg) and thyroid stimulating hormone (TSH) concentrations in the blood. Objective: analyze TSH in filter paper blood values and correlate with UIC in schoolchildren from public school at state of Bahia, Brazil. Methodology: cross-sectional study was conducted in 880 schoolchildren aged 6-14 years, randomly selected, of public schools in five cities of four micro-regions of Bahia between October 2013 and September 2014. TSH was analyzed in filter-paper blood and UIC were measured by adapted Sandell-Kolthoff reaction. Results: 880 blood samples on filter-paper were analyzed for TSH. The reference range previously established is 0.72 to 6.0 μUI/mL. Results of this research TSH dosage ranged from 0.24 μIU/L to 7.71 μIU/L, with a mean of 1.01±0.55 μUI/L and median 0.89 μUI/L. Only one child presented TSH greater than 6.0 (7.71 μIU/L); however, results of urinary iodine were consistent with a more than adequate nutrition iodine (243.70μg/L). There’ no correlation between TSH and UIC (r= 0.115; p= 0.002). Conclusion: in the present study, schoolchildren showed low values of TSH, but the mean UIC was indicative of adequate iodine nutrition.

Download Full-text

Thyroid dysfunction in region of excess iodine intake of Eastern Nepal

International Journal of Scientific Reports ◽

10.18203/issn.2454-2156.intjscirep20181848 ◽

2018 ◽

Vol 4 (5) ◽

pp. 114

Author(s):

Saroj Thapa ◽

Madhab Lamsal ◽

Rajendra K. Chaudhari ◽

Basanta Gelal ◽

Saroj Kunwar ◽

...

Keyword(s):

Primary School ◽

Subclinical Hypothyroidism ◽

Thyroid Dysfunction ◽

Urinary Iodine ◽

Iodine Concentration ◽

Primary School Children ◽

Nutrition Status ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Excess Iodine

Background: Iodine deficiency as well as iodine excess can result in an increased prevalence of thyroid disorders. The prevalence of excess iodine nutrition is increasing all over the world. The aim of the present study was to find the occurrence of iodine nutrition status in primary school children of Eastern Nepal and find the prevalence of associated thyroid dysfunction among those with excess urinary iodine concentration.Methods: A community based cross sectional study was conducted in Udayapur district which is located in Eastern part of Nepal. Primary school aged children (6 years to 12 years) were enrolled in this study from three schools. Blood and urine samples were collected and assayed for urinary iodine concentration (UIC), free thyroid hormones (fT3 and fT4), and thyroid stimulating hormone (TSH). Results: The median UIC was 232.27 µg/L. The iodine status showed that 15.5% (n=31) had low UIC, 21% (n=42) had above requirement and 36% (n=72) had excessive iodine nutrition status. The mean concentration of fT3 and fT4 was 2.87 pg/ml and 1.21 ng/dl respectively, while the median TSH concentration was 3.03 mIU/L. The prevalence of thyroid dysfunction was 10% (n=20) with subclinical hypothyroidism being the most common. Majority of participants with subclinical hypothyroidism had excess UIC.Conclusions: Above requirement and excess iodine nutrition is more common in region where there is unregulated consumption and improper monitoring of iodized salt. Subclinical hypothyroidism is common in regions of excess iodine nutrition.

Download Full-text