Excess urinary iodine concentration and thyroid dysfunction among school age children of eastern Nepal: a matter of concern

ABSTRACT Background Population iodine deficiency is indicated by >3% of the population with newborn thyroid-stimulating hormone (TSH) concentration >5 mIU/L, median urinary iodine concentration (MUIC) <100 µg/L, or >5% prevalence of goiter in school-age children. However, the agreement between these population markers has not been systematically investigated. Objective To assess the agreement between TSH, MUIC, and goiter as markers of population iodine status. Methods We performed a systematic search for studies published on PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, and PsycINFO up to 29 October, 2018. Studies assessing iodine status in the population using the TSH marker and either MUIC or goiter prevalence in school-age children were included. The agreement between markers in classifying iodine status of the population was assessed. The sensitivity and specificity of the TSH marker was determined against MUIC and goiter prevalence as the reference markers. Results Of 17,435 records identified by the search strategy, 57 eligible studies were included in the review. The agreement between markers in classifying the iodine status of populations into the same category was 65% for TSH and MUIC, and 83% for TSH and goiter prevalence. The TSH marker had a sensitivity of 0.75 and specificity of 0.53 when compared with MUIC, and 0.86 and 0.50 when compared with goiter prevalence. Conclusions The TSH marker has a better agreement with goiter prevalence than MUIC when classifying the iodine status of populations. Re-evaluation of the current criteria for classifying the iodine status of populations using the TSH marker is warranted. This systematic review was registered at PROSPERO (http://www.crd.york.ac.uk/prospero/) as CRD42018091247.

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Adequate iodine nutrition in Sweden: a cross-sectional national study of urinary iodine concentration in school-age children

European Journal of Clinical Nutrition ◽

10.1038/ejcn.2008.46 ◽

2008 ◽

Vol 63 (7) ◽

pp. 828-834 ◽

Cited By ~ 19

Author(s):

M Andersson ◽

G Berg ◽

R Eggertsen ◽

H Filipsson ◽

E Gramatkovski ◽

...

Keyword(s):

Urinary Iodine ◽

Iodine Concentration ◽

School Age Children ◽

National Study ◽

Urinary Iodine Concentration ◽

School Age ◽

Iodine Nutrition ◽

Cross Sectional

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Assessment of iodine status among school age children and pregnant women of Belarus in 2017–2018

Clinical and experimental thyroidology ◽

10.14341/ket9732 ◽

2018 ◽

Vol 14 (3) ◽

pp. 149-155

Author(s):

Tatiana V. Mokhort ◽

Sergei V. Petrenko ◽

Boris Y. Leushev ◽

Ekaterina V. Fedorenko ◽

Natalia D. Kolomiets ◽

...

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Thyroid Volume ◽

Iodine Concentration ◽

School Age Children ◽

Normative Values ◽

Urinary Iodine Concentration ◽

School Age ◽

Iodine Sufficiency

Background. Despite the measures taken by the Government of Belarus, the problem of iodine deficiency among the population remains actual. Aims. To determine iodine sufficiency in children and pregnant women living in Belarus. Materials and methods. The study included 873 schoolchildren aged 9–12 years of both sexes, of which 650 children were in regular schools, and the remaining children in boarding schools. A separate group consisted of 700 practically healthy pregnant women (during gestation from 16 to 36 weeks). Questioning, determination of urinary iodine concentration and thyroid volume with ultrasound was carried out. Results. Urine iodine median was 191 µg/L in the 873 children in 16 regions of Belarus. Thyroid volume corresponds to the normative values in children. According to the survey, 81% of households used iodized salt, constantly – 46%. Indicator of iodine sufficiency of 700 pregnant women (median urinary iodine concentration was 121 µg /l) is a non-optimal for this population group. Conclusions. Currently adequate iodine supplementation in school age children has been achieved. The prevalence of thyroid gland diseases caused by iodine deficiency in children decreased significantly. In pregnant women iodine supply is still insufficient.

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Iodine status of school age children in the two hilly districts Dhankuta and Tehrathum of Eastern Nepal

Sunsari Technical College Journal ◽

10.3126/stcj.v1i1.7986 ◽

2013 ◽

Vol 1 (1) ◽

pp. 38-41

Author(s):

AK Nepal ◽

S Gautam ◽

S Khatiwada ◽

PR Shakya ◽

B Gelal ◽

...

Keyword(s):

School Children ◽

Urinary Iodine ◽

Iodine Concentration ◽

Cross Sectional Study ◽

School Age Children ◽

Urinary Iodine Concentration ◽

Population Parameter ◽

School Age ◽

Cross Sectional ◽

Iodine Status

Background: Iodine deficiency remains a significant health problem in developing countries, including Nepal. Objective: This study was conducted to measure the iodine status of school children in two districts Dhankuta and Tehrathum of Eastern Nepal by estimating median urinary iodine concentration (UIC) as a population parameter in the school children. Materials and Methods: This cross-sectional study was conducted from August 2010 to July 2011 in school children (6-12 years of age) of two hilly districts of Eastern Nepal, Dhankuta and Tehrathum. A total of 154 school age children from the two districts were chosen for the study after obtaining written consent from their guardians and school authority. UIC was estimated in these school children by ammonium persulphate digestion microplate method. Results: Among the school age children selected for the study median inter-quartile range (IQR) of urinary iodine in Dhankuta (n=63) and Tehrathum (n=91) districts were 214.04 (126.44; 323.0) μg/L and 252.34 (161.81; 301.63) μg/L. No significant differences were observed between the median UIC of these two districts (p=0.235). Among the school children in Dhankuta districts 2(3.2%) were severely deficient, 4(6.3%) were moderately deficient and 6(9.5%) were mildly deficient. In Tehrathum district 2(2.2%) were moderately deficient and 5(5.5%) were mildly deficient. Conclusion: The present study showed improved iodine status with optimal levels of median urinary iodine concentration in the two districts, Dhankuta and Tehrathum of Eastern Nepal. Regular monitoring of population median urinary iodine concentration is recommended for sustainable optimal iodine nutrition.DOI: http://dx.doi.org/10.3126/stcj.v1i1.7986 Sunsari Technical College Journal Vol.1(1) 2012 38-41

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Excessive intake of iodine and low prevalence of goiter in school age children five years after implementation of national salt iodization in Shebedino woreda, southern Ethiopia

BMC Public Health ◽

10.1186/s12889-021-10215-y ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Elilta Elias ◽

Workneh Tsegaye ◽

Barbara J. Stoecker ◽

Tafere Gebreegziabher

Keyword(s):

Iodine Deficiency ◽

Primary Schools ◽

Urinary Iodine ◽

Public Health Problem ◽

Iodine Concentration ◽

School Age Children ◽

Southern Ethiopia ◽

Urinary Iodine Concentration ◽

School Age ◽

Salt Iodization

Abstract Background Iodine is a trace element required for the synthesis of thyroid hormones. The multiple effects of iodine deficiency on human health are called iodine deficiency disorders (IDDs). IDDs have been common nutritional problems in Ethiopia. In 2012, Ethiopia launched a national salt iodization program to address IDDs. The objective of this study was to assess the effects of this program after 5 years by measuring urinary iodine concentration (UIC) and prevalence of goiter in school age children as well as household salt iodine concentration (SIC). Methods A school-based cross-sectional design was employed. After ethical approval, 408 children from eight randomly selected primary schools provided urine samples. UIC was analyzed by inductively coupled plasma mass spectrophotometry (ICP-MS). A 10 g salt sample was collected from each household of a sampled child. SIC was analyzed with a digital electronic iodine checker (WYD, UNICEF) and goiter was assessed by palpation. Results The mean (±SD) age of the children was 9 ± 2 years. The prevalence of goiter was 4.2% and no child had grade 2 goiter. The median (IQR) UIC was 518 (327, 704) μg/L and UIC ranged from 3.1 to 2530 μg/L. Of the salt samples, 15.6% were not adequately iodized (< 15 ppm), 39.3% were adequately iodized (≥15 to ≤40 ppm), and 45.1% were > 40 ppm. SIC ranged from 4.2 to 195 ppm. Of the mothers, 92% said iodized salt prevents goiter and 8% mentioned prevents mental retardation. Conclusions In 2017 iodine deficiency was no longer a public health problem in the study area. However, the high variability in UIC and SIC and excessive iodine intake are of great concern. It is vital to ensure that salt is homogenously iodized at the production site before being distributed to consumers.

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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.

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Iodine Nutritional Status and Related Factors among Chinese School-Age Children in Three Different Areas: A Cross-Sectional Study

Nutrients ◽

10.3390/nu13051404 ◽

2021 ◽

Vol 13 (5) ◽

pp. 1404

Author(s):

Xiaoyun Shan ◽

Changqing Liu ◽

Xiaoyan Luo ◽

Yan Zou ◽

Lichun Huang ◽

...

Keyword(s):

Vitamin A ◽

Nutritional Status ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Thyroid Stimulating Hormone ◽

School Age Children ◽

Urinary Iodine Concentration ◽

School Age ◽

Related Factors ◽

Cross Sectional

We evaluated the iodine nutritional status and related factors among school-age children based on the 2016 National Nutrition and Health Surveillance of Children and Lactating Women; 3808 children from Hebei, Guangxi, and Zhejiang province were included in the study. Urinary iodine concentration (UIC), thyroid-stimulating hormone (TSH), body mass index (BMI), vitamin A (VA), and vitamin D (VD) were measured. The abnormal rate of UIC and TSH were assessed. Relationships between UIC/TSH and the possible factors were analyzed. The overall median UIC was 185.14 µg/L, and the median UIC of children aged 8–10 was 164.60 µg/L. Prevalence of iodine deficiency and excess was 13.84% and 14.36%, respectively, and 12.87% of children showed TSH excess. UIC, as well as the abnormal rates of iodine deficiency (ID) and TSH, were significantly different among the three provinces. The median UICs and excess rates increased with age, reaching 211.45 µg/L and 21.35% at age of 14~, while TSH showed the opposite trend. Overweight children tended to have lower UIC and higher TSH. Higher UIC and TSH were found in VA sufficient group (p < 0.01). Further, the VD deficient group had a higher TSH compared to the sufficient group (p < 0.01). Moreover, UI and TSH distribution was obviously different among different vitamin A/D status (p < 0.05). Although the median UIC of school-age children was optimal, there were pockets of inadequate and excessive UI in the three provinces. Compared to the national IDD monitoring results in 2014, the iodine nutritional status of children was greatly improved. Considerations of region, age, BMI, VA, or VD are needed in the future iodine evaluation and surveillance.

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