Exploration of Effects of Excessive Iodine on Children and Tolerable Upper Intake Level of Iodine for Children

NCT02915536 | Completed

• 3 other identifiers: NSFC-81273057Nestlé FoundationNSFC
• Study Type: observational
• Target: 2,229
• Locations: 0 countries
• Sites: N/A

Brief Summary

With the implementation of Universal Salt Iodization (USI) in 1995, China has successfully combated Iodine Deficiency Diseases (IDD). However, China is a country with a complicated iodine geographical environment with wide natural variation in the iodine content of drinking water. It has been reported that the water iodine of at least 11 provinces and cities in China is high, with nearly 31 million people exposed to the risks of excessive iodine intake. This has raised a new public health concern that a safe upper level of iodine intake should be established to ensure that people avoid ingesting excessive iodine intake while continuing to implement USI to control IDD. The investigators have successfully explored the tolerable upper intake level (UL) of iodine for Chinese adults by conducting a randomized double-blinded trial in 256 euthyroid volunteers. However, due to limited data on the safe upper intake level of iodine for children worldwide, current ULs of iodine for children are extrapolated from those for adults based on body weight or body surface area. As it is impossible to ethically conduct a randomized clinical trial regarding excessive iodine intake in children, the investigators plan an observational study to investigate children who have been living with different drinking water iodine levels for over 5 years, observing the changes of thyroid function in response to each iodine exposure level. Subtle changes in thyroid function and thyroid volume of children corresponding to different iodine intake levels will be determined, which will contribute to the establishment of UL of iodine for children. The aim was:

1. 1.To establish the tolerable upper intake level (UL) of iodine for children of China.
2. 2.To define the adverse effects of excess iodine on children.
3. 3.To monitor the iodine status of children living in high water iodine areas in China.

Conditions

Iodine Disorders

Keywords

iodine excess; thyroid disease; children; tolerable upper intake level

Outcome Measures

Primary Outcomes (1)

• thyroid goiter confirmed by ultrasonographic thyroid volume

  1 year

Secondary Outcomes (1)

• thyroid dysfunction confirmed by serum concentrations of FT4, FT3, and TSH with an automated chemiluminescent immunoassay by using diagnostic kits from Bayer Health Care, Siemens

  1 year

Other Outcomes (1)

• thyroid dysfunction confirmed by serum concentrations of TPOAb and TGAb with radioimmunoassay by using kits from the Beijing North Institution

  1 year

Interventions

Natural exposure of high iodine OTHER

Natural exposure of high iodine intake from drinking water

Eligibility Criteria

• Age: 7 Years - 14 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)
• Sampling Method: Probability Sample

Study Population

High water iodine areas in Shandong are far-ranging. An investigation in 2005 showed that water iodine content exceeded 150μg/L in 17 of the 20 counties, while water iodine in the other 3 exceeded 300μg/L. Regions with water iodine content in the range of 150-800µg/L were chosen as, with a corresponding UIE range of 300-800µg/L, were selected as high iodine intake (HI) areas for the study. Regions with water iodine content in the range of 10-100µg/L with a corresponding UIE range of 100-299µg/L were selected as adequate iodine intake (AI) study areas. Areas with high fluorine will be excluded. One to six primary schools were selected from each city by randomly sampling. Children were selected from these schools.

You may qualify if:

• Healthy
• Native born or residents of Shandong province for at least 5 years.

You may not qualify if:

• Previous history of thyroid diseases or medication intake (including iodine supplements)
• protein-energy malnutrition in the long term

Sponsors & Collaborators

• Wanqi Zhang: lead
• The Shandong Institute for Endemic Disease Control and Research: collaborator

Related Publications (24)

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• Chen W, Sang ZN, Liu H, Shen J, Zhao N, Tan L, Wei W, Zhang GQ, Wen SC, Zhang WQ. [Investigation of thyroid function abnormalities in children in high water iodine areas of Hebei province]. Zhonghua Yu Fang Yi Xue Za Zhi. 2012 Feb;46(2):148-51. Chinese.

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• Chen W, Wu Y, Lin L, Tan L, Shen J, Pearce EN, Guo X, Wang W, Bian J, Jiang W, Zhang W. 24-Hour Urine Samples Are More Reproducible Than Spot Urine Samples for Evaluation of Iodine Status in School-Age Children. J Nutr. 2016 Jan;146(1):142-6. doi: 10.3945/jn.115.215806. Epub 2015 Nov 25.

  PMID: 26609173 RESULT

• Cui T, Wang W, Chen W, Pan Z, Gao S, Tan L, Pearce EN, Zimmermann MB, Shen J, Zhang W. Serum Iodine Is Correlated with Iodine Intake and Thyroid Function in School-Age Children from a Sufficient-to-Excessive Iodine Intake Area. J Nutr. 2019 Jun 1;149(6):1012-1018. doi: 10.1093/jn/nxy325.

  PMID: 31070733 DERIVED

• Chen W, Zhang Q, Wu Y, Wang W, Wang X, Pearce EN, Tan L, Shen J, Zhang W. Shift of Reference Values for Thyroid Volume by Ultrasound in 8- to 13-Year-Olds with Sufficient Iodine Intake in China. Thyroid. 2019 Mar;29(3):405-411. doi: 10.1089/thy.2018.0412.

  PMID: 30696370 DERIVED

• Chen W, Zhang Y, Hao Y, Wang W, Tan L, Bian J, Pearce EN, Zimmermann MB, Shen J, Zhang W. Adverse effects on thyroid of Chinese children exposed to long-term iodine excess: optimal and safe Tolerable Upper Intake Levels of iodine for 7- to 14-y-old children. Am J Clin Nutr. 2018 May 1;107(5):780-788. doi: 10.1093/ajcn/nqy011.

  PMID: 29722836 DERIVED

• Chen W, Li X, Wu Y, Bian J, Shen J, Jiang W, Tan L, Wang X, Wang W, Pearce EN, Zimmermann MB, Carriquiry AL, Zhang W. Associations between iodine intake, thyroid volume, and goiter rate in school-aged Chinese children from areas with high iodine drinking water concentrations. Am J Clin Nutr. 2017 Jan;105(1):228-233. doi: 10.3945/ajcn.116.139725. Epub 2016 Dec 7.

  PMID: 27927635 DERIVED

Biospecimen

Retention: SAMPLES WITH DNA

* whole blood * 24-h urine samples * spot urine samples

MeSH Terms

Conditions

Thyroid Diseases

Condition Hierarchy (Ancestors)

Endocrine System Diseases

Study Officials

• Wanqi Zhang, Doctor

  Tianjin Medical University

  STUDY CHAIR

• Jianchao Bian

  The Shandong Institute for Endemic Disease Control and Research

  PRINCIPAL INVESTIGATOR

• Zuoliang Dong, Master

  Tianjin Medical University

  PRINCIPAL INVESTIGATOR

• Laixiang Lin, Doctor

  Tianjin Medical University

  PRINCIPAL INVESTIGATOR

• Jun Shen, Master

  Tianjin Medical University

  PRINCIPAL INVESTIGATOR

• Jinbiao Wang

  The Shandong Institute for Endemic Disease Control and Research

  PRINCIPAL INVESTIGATOR

• Wen Jiang, Master

  The Shandong Institute for Endemic Disease Control and Research

  PRINCIPAL INVESTIGATOR

• Zhongna Sang, Doctor

  Tianjin Medical University

  PRINCIPAL INVESTIGATOR

• Long Tan, Doctor

  Tianjin Medical University

  PRINCIPAL INVESTIGATOR

• Wen Chen, Master

  Tianjin Medical University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Vice Dean of School of Public Health, Tianjin Medical University

Study Record Dates

• First Submitted: September 20, 2016
• First Posted: September 27, 2016
• Study Start: January 1, 2013
• Primary Completion: September 1, 2015
• Study Completion: March 1, 2016
• Last Updated: September 29, 2016

Record last verified: 2016-09