title: Retrospective epidemiological study of thyroid nodules by ultrasound in asymptomatic subjects.
abstract: BACKGROUND
  The purpose of this study was to conduct thyroid ultrasound examinations on a large sample of subjects and explore the occurrence, distribution, and characteristics of thyroid nodules and thyroid cancer to provide some information on the epidemic trend of thyroid nodules and cancer.
  
  
  METHODS
  The thyroid ultrasonic examination results of 19 895 healthy physical examinees who visited the Department of Health Management, Peking Union Medical College Hospital from January 2009 to December 2011 were analyzed retrospectively to determine the detection rate and characteristics of thyroid nodules. Fine needle aspiration or surgical resection was suggested to subjects suspected of having thyroid cancer.
  
  
  RESULTS
  The detection rate of thyroid nodules was 42.6% (8 480/19 895), 40.0% (4 661/11 678) in men and 46.5% (3 819/8 217) in women. The detection rate noticeably increased with increasing age. The detection rate of thyroid nodules by palpation was obviously lower than by ultrasonic examination in various age groups. Among those with thyroid nodules, 61.3% were multiple and 38.7% were solitary; multiple nodule was the major type both in men and women. Twenty-nine cases of malignant nodules were solitary, and 30 cases of malignant nodules were multiple. There was no significant difference. The detection rate of thyroid cancer was 0.30% for the entire group of examinees, and 0.15% in men and 0.50% in women. Among all sex and age groups, 30- to 40-year-old women had the highest detection rate (0.76%). The detection rate of thyroid nodules correlated with age, systolic blood pressure, height, and weight. Increasing age and/or higher systolic blood pressure correlated with a higher detection rate, while smaller height and weight also correlated with a higher detection rate with significant differences. However, there were no significant correlations between the detection rate and diastolic blood pressure or body mass index.
  
  
  CONCLUSIONS
  The detection of thyroid cancer increased significantly, especially in women. Thus, precautions needed to be taken. Regular physical examination and timely intervention after detection of malignant nodules are critical to improve the prognosis in thyroid cancer patients.
authors.affiliation: Department of Health Management, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China.
authors.forename: Gaowa
authors.initials: G
authors.lastname: Sharen
authors.affiliation: Department of Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China. Email: zora19702006@163.com.
authors.forename: Ruina
authors.initials: R
authors.lastname: Zhao
authors.affiliation: Department of Health Management, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Health Management, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Gai
authors.affiliation: Department of Health Management, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China.
authors.forename: Huiping
authors.initials: H
authors.lastname: Lou
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000453:epidemiology*; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000453:epidemiology*; D055815:Young Adult