Non-immune-related hypothyroidism and its relationship with excess iodine

  • Hye In Kim
  • Hyun-Kyung Oh
  • So Young Park
  • Hye Won Jang
  • Myung-Hee Shin
  • Ji Min Han
  • Ji Cheol Bae
  • Sun Wook Kim
  • Tae Hyuk KimEmail author
  • Jae Hoon ChungEmail author
Original Contribution



In iodine-sufficient areas, autoimmune hypothyroidism has been regarded as the major subtype of hypothyroidism. Non-immune-related hypothyroidism has received little attention because it is considered to be rare. The aim of this study was to evaluate the prevalence of non-immune-related hypothyroidism in Korea and to identify its associating factors.


A total of 6434 participants in the Korea National Health and Nutrition Examination Survey VI (2013–2015) without known thyroid disease who were examined for thyroid stimulating hormone, free thyroxine, TPO Ab, and urine iodine concentration (UIC) were enrolled. The weighted proportions, demographic variables, and severity of immune-related and non-immune-related hypothyroidism were compared. To assess the effect of iodine on hypothyroidism in TPO Ab positive or negative populations, the weighted prevalence of hypothyroidism was assessed in each population according to UIC or estimated iodine intake subgroups.


The prevalence of undetected hypothyroidism in Korea was 3.8% (n = 233). Of these 233 cases, 171 (71.8%) were non-immune-related. In the TPO Ab negative population, the prevalence of hypothyroidism was increased significantly in the subgroup with UIC between 250 and 749 µg/L (HR 2.12 [1.17, 3.83]) and ≥ 750 µg/L (HR 3.42 [1.93, 6.04]) or the subgroups with estimated iodine intake ≥ 750 µg/day (HR 2.81 [1.64, 4.80]).


This nationwide study demonstrated that most cases of hypothyroidism in iodine-sufficient areas are non-immune-related and are associated with excess iodine above a certain level. More attention to this unrecognized but widespread potential health risk is needed.


Iodine-sufficient area Non-immune-related hypothyroidism Excess iodine 



The authors thank the Korea National Health and Nutrition Examination Survey for providing public access to its data.

Compliance with ethical standards

Conflict of interest

The authors have no conflicts of interest to disclose.

Supplementary material

394_2018_1837_MOESM1_ESM.docx (26 kb)
Supplementary material 1 (DOCX 25 KB)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Hye In Kim
    • 1
  • Hyun-Kyung Oh
    • 2
  • So Young Park
    • 3
  • Hye Won Jang
    • 4
  • Myung-Hee Shin
    • 2
  • Ji Min Han
    • 1
  • Ji Cheol Bae
    • 1
  • Sun Wook Kim
    • 3
  • Tae Hyuk Kim
    • 3
    Email author
  • Jae Hoon Chung
    • 3
    Email author
  1. 1.Division of Endocrinology and Metabolism, Department of Medicine, Samsung Changwon HospitalSungkyunkwan University School of MedicineChangwonKorea
  2. 2.Department of Social and Preventive MedicineSungkyunkwan University School of MedicineSeoulKorea
  3. 3.Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical CenterSungkyunkwan University School of MedicineSeoulKorea
  4. 4.Department of Medical EducationSungkyunkwan University School of MedicineSeoulKorea

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