epidemiology

Last edited 01/2020

Incidence and prevalence

Thyroid nodules are common (1)

• prevalence can be affected by several factors, such as iodine sufficiency status and age, and detection rates differ according to the modality of imaging used and the experience of the operator

Depending on the mode of discovery, the detection rate of thyroid nodules varies widely from 4% to 67% (1):

• found by physical examination in around 4-7% of the population
• a higher detection rate of 30-67% by ultrasound
  
  
• thyroid nodules are often discovered incidentally by multiple imaging modalities
• on computed tomography, the prevalence of incidental thyroid nodules ranges from 5% to 25%

The prevalence of thyroid nodules increases with age, from approximately 42% for younger patients (<40 years) to about 76% in the older population (>61 years) when screened by ultrasound (2)

• in a Chinese centenarian cohort study of 874 people screened with ultrasound, the overall prevalence rate of thyroid nodules was 74%
(3)

Reference:

• NICE (November 2019). Thyroid disease: assessment and management
• Ospina NS et al. Thyroid nodules: diagnostic evaluation based on thyroid cancer risk assessment.BMJ 2020;368:l667.
• Yao Y, Chen X, Wu S, et al. Thyroid nodules in centenarians: prevalence and relationship to lifestyle characteristics and dietary habits. Clin Interv Aging 2018;13:515-22.