**8. Novel strategies for the vulnerable group**

In the Iodine Global Network newsletter published on its website, Prof. Dr. Zimmermann had laid out the strategies needed for the vulnerable groups, i.e., the newborns, infants and the children. He had suggested that these tests should be done on these groups respectively: blood thyroid-stimulating hormone, urinary iodine and blood spot thyroglobulin (http://www.ign.org/zimmermanncalls-for-new-strategies-against-idd.htm). He also suggested using the TSH measurement in the newborn screening for iodine assessment. Commonly, iodinedeficient newborns present with elevated TSH. The WHO reported that if the TSH level is greater than 5 mIU/L from the whole blood of 3% of the newborns measured after 3–4 days post-birth, this would indicate that the population is iodine deficient. Another suggestion made by him was to use the newborns' urinary iodine as a marker of IDD in addition to the current practise of measuring the median urinary iodine of the schoolchildren. Using a non-invasive system, urine was collected from infants, and study had shown that in 1200 infants, the baseline TSH of 77 μg/L had increased to 100 μg/L after 4 days post-birth. In addition to that, a system for collecting young children blood spot was done to measure their TG concentration, and a reference range of 4–40 μg/L had been determined. Noteworthy, there are challenges in order to establish a specific international reference range among newborns as there will be differences between the population from the USI areas and the non-USI areas.

### **9. Conclusion**

Excess urinary iodine is generally well tolerated, but individuals with underlying thyroid disease or other risk factors may be susceptible to iodine-induced thyroid dysfunction following acute or chronic exposure. Increased iodine exposure including the global public health efforts of iodine supplementation, the escalating use of iodinated contrast radiologic studies, amiodarone administration in vulnerable patients, excess seaweed consumption and various miscellaneous sources should be looked for.

Iodine-induced thyroid dysfunction may be subclinical or overt. Recognition of the association between iodine excess and iodine-induced hypothyroidism or hyperthyroidism is important in the differential diagnosis of patients who present without a known cause of thyroid dysfunction.

## **Conflict of interest**

It is declared that there is no conflict of interest involved in the publication of this book chapter.

**25**

**Author details**

Husniza Hussain1

Putrajaya, Malaysia

Kuala Lumpur, Malaysia

Malaysia

and Muhammad Yazid Jalaludin5

\*, Rusidah Selamat<sup>2</sup>

Ministry of Health Malaysia, Kuala Lumpur, Malaysia

provided the original work is properly cited.

*Urinary Iodine: Biomarker for Population Iodine Nutrition*

*DOI: http://dx.doi.org/10.5772/intechopen.84969*

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

, Lim Kuang Kuay3

1 Nutrition Unit, Cardiovascular, Diabetes and Nutrition Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Kuala Lumpur,

2 Nutrition Division, Ministry of Health Malaysia, Putrajaya, Malaysia

3 Centre for Occupational Health Research, Institute for Public Health,

4 Paediatrics Department, Putrajaya Hospital, Ministry of Health Malaysia,

5 Faculty of Medicine, Department of Paediatrics, University of Malaya,

\*Address all correspondence to: husnizah9thesis@gmail.com

, Fuziah Md Zain4

*Urinary Iodine: Biomarker for Population Iodine Nutrition DOI: http://dx.doi.org/10.5772/intechopen.84969*
