Dietary iodine intake and the association with subclinical thyroid dysfunction in male workers

Kim, Eun Hye; Choi, Tae-in; Park, Yoo Kyoung

doi:10.4163/kjn.2012.45.3.218

Korean J Nutr. 2012 Jun;45(3):218-228. Korean.
Published online Jun 28, 2012.
https://doi.org/10.4163/kjn.2012.45.3.218

Original Article

Dietary iodine intake and the association with subclinical thyroid dysfunction in male workers

Eun Hye Kim,¹ Tae-in Choi,² and Yoo Kyoung Park¹^,³

Author information

Author notes

Copyright and License

- ¹Deparment of Medical Nutrition, Kyunghee University, Yongin 446-701, Korea.
- ²Radiation Health Research Institute, Korea & Hydro Nuclear Power Co., Ltd, Seoul 132-884, Korea.
- ³Research Institute of Medical Nutrition, Kyunghee University, Seoul 130-784, Korea.
To whom correspondence should be addressed. (Email: ypark@khu.ac.kr )

Received December 19, 2011; Revised January 27, 2012; Accepted March 01, 2012.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The prevalence rate of thyroid dysfunction (hypothyroidism and hyperthyroidism) has increased within the Korean population and seems to be affected by iodine dietary habits. Some studies reported that the prevalence of thyroid dysfunction increase both in the area of iodine deficiency and excess. In this study, we tried to discover the difference in iodine intake, anthropometric measurements, and blood parameters between male subjects with or without subclinical thyroid dysfunction. A total of 5,249 subjects (Euthyroid: 4706, SubHypo: 454, SubHyper: 89) were used in this study. There were no significant differences in BMI, body fat, visceral fat, waist circumference, SBP, DBP, total cholesterol, HDL-cholesterol, LDL-cholesterol, TG, fasting serum glucose, HbA1c, alcohol intake, however significant differences were noticed in both age and smoking status. Through a food frequency questionnaire (FFQ), iodine intake per day was estimated. The average iodine intake was similar (SubHypo 392.9 ± 279.0 µg, Euthyroid 376.5 ± 281.7 µg, SubHyper 357.3 ± 253.8 µg) among groups. The main source of iodine intake was eggs (52.8%, 54.2%, 52.4%) followed by milk (16.3%, 15.8%, 17.8%), then sea mustard & sea tangle (12.4%, 11.9%, 11.6%). The prevalence of subclinical hypothyroidism and subclinical hyperthyroidism was higher in subjects whose intake was higher than the recommended nutrient intake (RNI). These results suggest that the excess consumption of iodine intake may act as one of the risk factors regarding thyroid dysfunction in Korea. Therefore, an adequate amount of iodine intake is necessary in order to prevent subclinical thyroid dysfunction and clinical thyroid dysfunction.

Keywords

subclinical hypothyroidism; subclinical hyperthyroidism; iodine content food; iodine

Figures

Fig. 1
Difference of free thyroxine hormone according to iodine intake.

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Fig. 2
Difference of thyroid stimulating hormone according to iodine intake.

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Tables

Table 1
Diagnosis by thyroid function tests

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Table 2
Anthropometric parameter and characteristics of the subjects

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Table 3
Serum biochemical parameter of the subjects

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Table 4
Iodine intake and distribution in SubHypo, Euthyroid, SubHyper group

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Table 5
Contribution of food sources to the total iodine intake

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Table 6
Differences according to DRI of iodine intake in subclinical hypothyroidism

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Table 7
Differences according to DRI of iodine intake in euthyroid

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Table 8
Differences according to DRI of iodine intake in subclinical hyperthyroidism

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Notes

This work was supported by Radiation Health Research Institute, Korea & Hydro Nuclear Power Co., Ltd.

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