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Epidemiology of thyroid nodules

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Thyroid nodules are common and are commonly benign. The reported prevalence of nodular thyroid disease depends on the population studied and the methods used to detect nodules. Nodule incidence increases with age, and is increased in women, in people with iodine deficiency, and after radiation exposure. Numerous studies suggest a prevalence of 2–6% with palpation, 19–35% with ultrasound, and 8–65% in autopsy data. With widespread use of sensitive imaging in clinical practice, incidental thyroid nodules are being discovered with increasing frequency. Ultrasonography is the most accurate and cost-effective method for evaluating and observing thyroid nodules. Current ultrasonography machines are relatively inexpensive, sensitive, and easy to operate. Most endocrinologists are now using ultrasound examination in the initial evaluation of a patient with known or suspected thyroid nodule. The management of thyroid incidentalomas is a matter of controversy.

Section snippets

Palpation

With palpation, the least sensitive method for detecting thyroid nodules, prevalence has been estimated to be about 4%.12 A sample of 4469 people from Framingham, Massachusetts, who were randomly selected from the city's total population of 10,000 (in 1948) and 740 volunteers were studied with physical examination and several laboratory tests every 2 years and observation for up to 15 years. Of the 5127 participants who were alive at last follow-up, 4% had non-toxic thyroid nodules, none of

Ultrasonography

In one study that used high-resolution ultrasound (HRUS), the prevalence of thyroid nodules was reported to be as high as 67%.18 This prospective cohort study assessed the prevalence of thyroid nodules in the community and compared findings obtained by using palpation with those obtained by using HRUS in 100 asymptomatic North American subjects without known thyroid disease. Of the participants, 21% had palpable nodules (solitary nodules, 9%; multiple nodules, 12%). With HRUS measurement, 22%

Data from autopsy studies

Autopsy data provide the gold standard for determining the true prevalence of thyroid nodules. Several autopsy studies have been performed in non-endemic and endemic goiter areas.23, 24, *25, 26, 27, 28 The prevalence of thyroid nodules in these studies was 82–650 per 1000 autopsies (Table 3).13

In addition, autopsy data from patients with no history of thyroid disease have indicated a 50% prevalence of thyroid nodules.25 Thyroid glands from 1000 consecutive subjects without previous evidence of

Dilemmas of incidentalomas

The increased sensitivity of ultrasonography has led to the detection of thyroid nodules that are too small to palpate and have indeterminate clinical significance. According to Black and Welch: ‘advances in diagnostic imaging create confusion in two crucial areas of medical decision making: establishing how much disease there is and defining how well treatment works’.29 The challenge facing the clinician is to avoid unnecessary diagnostic intervention or treatment, or both, that confers little

Summary

Thyroid nodules are common in clinical practice. Their prevalence depends largely on the screening method and the population evaluated. Increasing age, female sex, iodine deficiency, and a history of head and neck radiation seem consistently to increase the risk of thyroid nodules.*1, 2, 3 With palpation, the least sensitive method for nodule detection, prevalence has been estimated to be around 4%.12 Autopsy data from patients with no history of thyroid disease have indicated a prevalence of

Conflict of interest statement

Dr Gharib is the recipient of a research grant from Genzyme Corporation.

References (39)

  • P. Laurberg et al.

    The Danish investigation on iodine intake and thyroid disease, DanThyr: status and perspectives

    European Journal of Endocrinology

    (2006)
  • M. Imaizumi et al.

    Radiation dose-response relationships for thyroid nodules and autoimmune thyroid diseases in Hiroshima and Nagasaki atomic bomb survivors 55-58 years after radiation exposure

    JAMA: the Journal of the American Medical Association

    (2006)
  • P. Trerotoli et al.

    Prevalence of thyroid nodules in an occupationally radiation exposed group: a cross sectional study in an area with mild iodine deficiency

    BMC Public Health

    (2005)
  • J.D. Lin et al.

    Thyroid cancer in the thyroid nodules evaluated by ultrasonography and fine-needle aspiration cytology

    Thyroid

    (2005)
  • J.B. Vander et al.

    The significance of nontoxic thyroid nodules: final report of a 15-year study of the incidence of thyroid malignancy

    Annals of Internal Medicine

    (1968)
  • A. Brander et al.

    Thyroid gland: US screening in a random adult population

    Radiology

    (1991)
  • J. Matovinovic et al.

    Goiter and other thyroid diseases in Tecumseh, Michigan: studies in a total community

    JAMA: the Journal of the American Medical Association

    (1965)
  • M.L. Rallison et al.

    Thyroid nodularity in children

    JAMA: the Journal of the American Medical Association

    (1975)
  • F.L. Trowbridge et al.

    Iodine and goiter in children

    Pediatrics

    (1975)
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