This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science.
This page was updated on June 7, 2022.
Although the causes of thyroid cancer are still being investigated, certain factors that may increase an individual's risk of developing the disease have been identified. These factors include hereditary conditions, gender and age.
Common risk factors include:
Gender and age: Thyroid cancers occur approximately three times more frequently in women than men, although the reason for this difference is unknown. Women also tend to develop these cancers at an earlier age (40s to 50s) than men (60s to 70s).
Hereditary conditions: Certain inherited genetic abnormalities have been associated with the development of different types of thyroid cancer:
Even if no known inherited syndrome has been identified, thyroid cancer in a first-degree relative, such as a parent or sibling, raises your risk of developing thyroid cancer.
Low-iodine diet: A diet that contains very little iodine has been associated with an increased risk of follicular thyroid cancers. This may explain why these cancers are seen less frequently in the United States, where iodine is added to salt and other foods. Individuals who do not get enough iodine in their diets may also be at increased risk for papillary cancers if they are exposed to radioactivity.
Radiation exposure: Being exposed to radiation, including the kind used for certain medical treatments, as well as fallout from nuclear weapons or power plant accidents, can increase a person’s thyroid cancer risk. In particular, childhood exposure carries a greater risk of later developing thyroid cancer than exposure as an adult.
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