title: Thyroid Stimulating Hormone Reference Range and Prevalence of Thyroid Dysfunction in the Korean Population: Korea National Health and Nutrition Examination Survey 2013 to 2015.
abstract: BACKGROUND
  No nationwide epidemiological study evaluating the prevalence of subclinical and overt forms of hypothyroidism and hyperthyroidism has yet been conducted in Korea. This study aimed to evaluate the reference range of serum thyroid stimulating hormone (TSH) and the national prevalence of thyroid dysfunctions in Korea.
  
  
  METHODS
  Nation-wide cross-sectional data were analyzed from a representative sample of the civilian, non-institutionalized Korean population (n=6,564) who underwent blood testing for thyroid function and anti-thyroid peroxidase antibody (TPOAb) as part of the Korea National Health and Nutrition Examination Survey VI (2013 to 2015).
  
  
  RESULTS
  The reference interval of serum TSH in the Korean reference population was 0.62 to 6.68 mIU/L. Based on this reference interval, the prevalence of overt and subclinical hypothyroidism was 0.73% (males 0.40%, females 1.10%) and 3.10% (males 2.26%, females 4.04%), respectively. The prevalence of hypothyroidism increased with age until the age group between 50 to 59 years. Positive TPOAb were found in 7.30% of subjects (males 4.33%, females 10.62%). The prevalence of overt and subclinical hypothyroidism TPOAb-positive subjects was 5.16% and 10.88%, respectively. The prevalence of overt and subclinical hyperthyroidism was 0.54% (males 0.30%, females 0.81%) and 2.98% (males 2.43%, females, 3.59%), respectively.
  
  
  CONCLUSIONS
  The Serum TSH reference levels in the Korean population were higher than the corresponding levels in Western countries. Differences were found in the prevalence of hypothyroidism and hyperthyroidism according to age, sex, and TPOAb positivity. This study provides important baseline information for understanding patterns of thyroid dysfunction and diseases in Korea.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Won Gu
authors.identifier: http://orcid.org/0000-0002-8404-7759
authors.initials: WG
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Won Bae
authors.identifier: http://orcid.org/0000-0003-4544-1750
authors.initials: WB
authors.lastname: Kim
authors.affiliation: Division of Health and Nutrition Survey, Korea Centers for Disease Control and Prevention, Cheongju, Korea.
authors.forename: Gyeongji
authors.identifier: http://orcid.org/0000-0001-7741-6539
authors.initials: G
authors.lastname: Woo
authors.affiliation: Division of Health and Nutrition Survey, Korea Centers for Disease Control and Prevention, Cheongju, Korea.
authors.forename: Hyejin
authors.identifier: http://orcid.org/0000-0001-8859-2095
authors.initials: H
authors.lastname: Kim
authors.affiliation: Division of Health and Nutrition Survey, Korea Centers for Disease Control and Prevention, Cheongju, Korea.
authors.forename: Yumi
authors.identifier: http://orcid.org/0000-0003-3296-5619
authors.initials: Y
authors.lastname: Cho
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Tae Yong
authors.identifier: http://orcid.org/0000-0003-4982-4441
authors.initials: TY
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sun Wook
authors.identifier: http://orcid.org/0000-0002-6858-3439
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Social and Preventive Medicine, Sungkyunkwan University School of Medicine, Suwon, Korea.
authors.forename: Myung Hee
authors.identifier: http://orcid.org/0000-0002-0509-286X
authors.initials: MH
authors.lastname: Shin
authors.affiliation: Department of Surgery, Chungbuk National University College of Medicine, Cheongju, Korea.
authors.forename: Jin Woo
authors.identifier: http://orcid.org/0000-0001-8651-4464
authors.initials: JW
authors.lastname: Park
authors.affiliation: Department of Surgery, CHA Gangnam Medical Center, CHA University, Seoul, Korea.
authors.forename: Hai Lin
authors.identifier: http://orcid.org/0000-0003-4229-5700
authors.initials: HL
authors.lastname: Park
authors.affiliation: Division of Health and Nutrition Survey, Korea Centers for Disease Control and Prevention, Cheongju, Korea. kwoh27@korea.kr.
authors.forename: Kyungwon
authors.identifier: http://orcid.org/0000-0001-8097-6078
authors.initials: K
authors.lastname: Oh
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. thyroid@skku.edu.
authors.forename: Jae Hoon
authors.identifier: http://orcid.org/0000-0002-9563-5046
authors.initials: JH
authors.lastname: Chung
keywords: Hyperthyroidism; Hypothyroidism; Prevalence; Thyroid gland; Thyrotropin