Prevalence of Ultrasonographically-Detected Thyroid Nodules in Adults without Previous History of Thyroid Disease

Abstract

Background: The prevalence of palpable thyroid nodules in the general population is about 5%, and is 3~5 times higher in women than in men. However, much higher prevalence, up to 50%, was reported from autopsy data. Recently, the use of high resolution ultrasonography for routine check-up has resulted in much more detection of non-palpable thyroid nodules. We studied the prevalence of thyroid nodules in healthy adults without history of thyroid disease, and compared the prevalence in relation to palpability, age and gender. Methods: The prevalence of thyroid nodules was studied in adults aged f rom 20 to 79 years who had visited the health promotion center at Asan Medical Center, Seoul, Korea, from Jan 2002 to Dec 2003. Subjects with previous thyroid disease were excluded. 7,440 subjects (6,168 female, 1,272 men) were included in this study. Thyroid palpation was performed and followed by ultrasonography using a 12-MHz real-time scanner. Results: Thyroid nodules were detected in 3,040 of the 7,440 subjects (41%). Palpable nodules were present in 213 (3%), and non-palpable, but ultrasonographically detected thyroid nodules were present in 2,827 (38%). Thyroid nodules were present in 2,602 women (42.2%) and 370 men (29%). Among them, 159 women (2.6%) and 54 men (4.2%) had palpable thyroid nodules and 2,443 women (39.6%) and 316 men (24.8%) had non-palpable but ultrasonographically detected nodules. A significant linear trend was found between age and the prevalence of thyroid nodules. Conclusions: The prevalence of ultrasonographically detected thyroid nodules in adults with no previous history of thyroid disease was 41%. The prevalence of palpable nodules and non-palpable, but ultrasonographically detected nodules were 3% and 38%, respectively. Thyroid nodules were detected in 42.2% of women and 29% of men, showing that thyroid nodules are very common in healthy adults, even in men. (J Kor Endocrinol Soc 21:389~393, 2006)