Prevalence of thyroid diseases among adult for health check-up in a Youngdong area of Kwangwon province

ABSTRACT

BACKGROUND: Thyroid diseases is common in adult and frequently has significant clinical consequences. But, Prevalence have not been accurately estimated before performance of sensitive TSH and high resolution ultrasound devices on thyroid gland in practice. The objective of the study was to obstain prevalance rate of thyroid dysfunction and structural abnormality by sensitive TSH, Free T4 and high resolution ultrasound. METHODS: The subjects were 10,543(5,638 male and 4,815 female) individuals who visited a health care center of a general hospital in Kangnung city during the period of Jan. 1st, 1997 through May 31st, 2000. For thyroid dysfunction, serum TSH(Thyroid Stimulation Hormone) and Free T4 concentration of those were measured by RIA or IRMA. During the period of Dec. 1st, 1997 through May 25th, 1998, 1,316 individuals were examined by radiology specialists using high resolution ultrasonography with 7.5 MHz linear array. Consequently 21 patients who showed thyroid nodule were performed ultrasound-guided fine needle aspiration. Accordingly medical records containing results of physical examination made by 3 specialists in family medicine before thyroid ultrasonography were investigated in association with other diagnostic modalities. RESULTS: The measurements of thyroid function revealed that 10,090(96.5%) were normal, 240(2.3%) low(below 0.39 mU/L) and 123(1.2%) high(above 5.1 mU/L) in TSH. In terms of prevalence rate per 1,000 population, 15.2 cases were with subclinical hyperthyroidism, and 9.0 cases with subclinical hypothyroidism, 7.7 cases with hyperthyroidism and 3.3 cases with hypothyroidism. Among 94 individuals(7.1%) with structural abnormality on thyroid gland by ultrasonography, 60(4.6%) showed solitary solid nodule, 12(0.9%) multiple solid nodules, 18(1.4%) cystic nodules and 3(0.3%) diffuse parenchymal lesions. Physical examination found only 13.3% of 91 nodules found by high-resolution ultrasonography, and nodules as large as above 1.0 cm in size were palpable only in 22.2%. 21 Of 91 thyroid nodules was received ultrasound-guided FNA and 4(19%) were found to have malignant nodules. CONCLUSION: The study results showed the relatively high rate of thyroid diseases among general population, with the prevalence rate of thyroid dysfunction 3.6%, thyroid nodule 6.9%, malignant incidentaloma among thyroid nodules 4.4%. Physical examination was relative ineffective in detection for thyroid nodules in routine health examinations.