Prevalence of Thyrotoxicosis and Hypothyroidism in the Subjects for Health Check-Up / 대한내분비학회지

ABSTRACT

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 14301~313, 1999)