- Prevalence of Thyrotoxicosis and Hypothyroidism in the Subjects for Health Check-Up.
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Jae Hoon Chung, Byoung Joon Kim, Yun Ho Choi, Myung Hee Shin, Sung Hoon Kim, Yong Ki Min, Myung Sik Lee, Moon Gyu Lee, Kwang Won Kim
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J Korean Endocr Soc. 1999;14(2):301-313. Published online January 1, 2001
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Abstract
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- BACKGROUND
The prevalence of ovat hyperthyroidism ar hypothyroidism has been estimated up to 5% in the general populatian. Subclinical hyperthyroidism and subclinical hypothyroidism have pevalences of approximately 1% and 6%, ectively. The prevalence of hypothyroidism may be associated with excessive intake of iodine in iodine sufficient areas. Therefore, we assumed the prevalence of thyroid dysfunction in Karea might be different from those af Western cauntries. However, thete have been no surveys to examine the prevalence of thyroid dysfunction in Karea. We performed the study to investigate the prevalence of thyrotoxicosis and hypothyroidism in Korean adults. METHODS: This study was performed in 15019 subjects (8275 men, 6744 women; between 17 and 87 years of age) visited in health promotion center of Samsung Medical Center for 12 months in 1996. Serum T3, T4, and TSH concentrations were measured with RIA or IRMA using commercial kits. History of thyroid dysfunction and current medication were obtained from medical records. The criteria for thyrotoxicosis were TSH level below than 0.30 mU/L and increased T3 or T4 levels (T3 > 3.1 nmol/L or T4 > 152 nmol/L). Patients who had TSH level above than 5.0 mU/L and T4 level below than 77 nmol/L met the criteria for hypothyroidism. RESULTS: The prevalence of thyrotoxicosis was 5.5/1000 population (men 3.6/1000, women 7.7/1000) with peak prevalence in fifth decade. The prevalence of previously undiagnosed thyrotoxicosis was 4.0/1000 (men 2.9/1000, women 5.3/1000). The prevalence of hypothyroidism was 2.8/1000 population (men 1.1/1000, women 4.9/1000) with peak prevalence in seventh decade. The prevalence of previously undiagnosed hypothyroidism was 1.6/1000 (men 0.6/1000, women 2.S/1000). The prevalence of subclinical thyrotoxicosis was 12.4/1000 population (men 11.8/1000, women 13.0/1000). The prevalence of subclinical hypothyroidism was 18.2/1000 population (men 11.2/1000, women 26.7/1000) which frequency was increased with age. CONCLUSION: Although the prevalence of thyrotoxicosis and hypothyroidism was not significantly different from those of other countries, it was lower than expected and female preponderance is not significant. The prevalence of subclinical thyrotoxicosis and subclinical hypothyroidism was lower than those of other countries. The prevalence of subclinical hypothyroidism was higher in women and old ages. (J Kor Soc Endecrinol 14:301~313, 1999)
- A Frequency of Hypothyroidism in a Population of Hypercholesterolemin Subjects.
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Jae Hoon Chung, Kwang Won Kim, Byoung Joon Kim, Sung Hoon Kim, Kyung Ah Kim, Myung Sik Lee, Moon Gyu Lee, Yong Ki Min, Yun Ho Choi, Myung Hee Shin
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J Korean Endocr Soc. 1998;13(3):351-358. Published online January 1, 2001
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Abstract
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- BACKGROUND
Hypothyroidism is a treatable cause of secondary hyperlipidemia. The lipid profile usually seen is an increased total and low density lipoprotein(LDL) cholesterol, and the plasma triglyceride may also be increased. Hypercholesterolemia associated with hypothyroidism is an important factor in the pathogenesis of coronary artery disease(CAD). And the hyperchole-sterolemia caused by hypothyroidism is potentially reversible by thyroid hormone replacement therapy. Hypothyroidism should be ruled out by routine laboratory screening as a treatable cause of secondary hyperlipidemia and increased CAD risk. We carried out this study aimed at evaluating the frequency of hypothyroidism and its relationship with serum cholesterol concentration in Koreans. METHODS: We investigated 15028(men 8273, women 6755) Korean subjects who visited our hospital center for health promotion during an one year period(from January 1, 1996, to December 31, 1996). Among them, we analyzed 6756 hypercholesterolemic subjects whose serum cholesterol levels were greater than 200 mg/dL. They performed thyroid function tests(total T, T4, and TSH) and lipid profiles(total cholesterol, triglyceride and HDL-cholesterol) were measured by enzyme assay. We defined hypothyroidism by serum thyrotropin values greater than 5 U/mL. RESULTS: The observed prevalence of hypothyroidism was 2.4%(163/6756). Among those with high TSH levels, 17(10.4%) had overt hypothyroidism with a low T4 (below 6 g/dL) level. As we analyzed the frequency of hypothyroidism according to cholesterol range by 20 mg/dL, the frequency was significantly increased in the group whose serum cholesterol levels were greater than 300 mg/dL, especially in women over 50 years of age. Analysis of lipid parameters showed that hypertriglyceridemia was frequent and hyperHDLaemia was observed in hypothyroidic populations. CONCLUSION: Screening for hypothyroidism by measurement of thyrotropin values is of particular importance in patients with hypercholesterolemia. And the frequency of hypothyroidism was more significantly increased in whose serum cholesterol levels were greater than 300 mg/dL, especially in the group of women over 50 years of age.
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