What is a risk factor?

A risk factor is anything that may increase your chance of having a disease. Risk factors for a certain type of cancer might include tobacco use, unhealthy diet, excess weight, decreased physical activity, family history, or many other things. The exact cause of someone’s cancer may not be known. But risk factors can make it more likely for a person to have cancer.

Things you should know about risk factors for cancer:

• Risk factors can increase your risk, but they don't always cause the disease.

• Some people with 1 or more risk factors never get cancer. Other people with cancer have no known risk factors.

• Some risk factors are very well-known. But experts are studying risk factors for many types of cancer.

Some risk factors may not be in your control. This includes your family history, age, or gender. But others may be things you can change. Knowing about risk factors can help you make choices that might lower your risk. For instance, if an unhealthy diet is a risk factor, you may choose to eat healthy foods. If excess weight is a risk factor, your healthcare provider may help you lose weight.

Who is at risk for thyroid cancer?

Risk factors for thyroid cancer include:

• Gender. People assigned female at birth are 3 times more likely to have thyroid cancer.

• Age. Thyroid cancer can happen at any age. But it's more common in people assigned female at birth in their 40s and 50s. It's more common in people assigned male at birth in their 60s and 70s.

• History of radiation exposure. Your risk is higher if you had radiation treatments to your head, neck, or throat as a child. Exposure to low doses of radiation in medical diagnostic tests as a child may increase your risk of developing thyroid cancer, too. It’s also higher if you were exposed to nuclear fallout from power plant accidents or nuclear weapons.

• Iodine deficiency. A diet low in the mineral iodine raises your risk.

• Family history. People with certain inherited genetic diseases that are passed down in families are at higher risk. These include familial medullary thyroid cancer (FMTC), familial non-medullary thyroid cancer (FNMTC), Cowden disease, Carney complex, type 1, multiple endocrine neoplasia type 2A syndrome (MEN2A), and multiple endocrine neoplasia type 2B syndrome (MEN2B).

• Goiter. A goiter is an enlarged thyroid. If you have had a goiter or a family history of thyroid disease, you may be at an increased risk for thyroid cancer.

What are your risk factors?

Talk with your healthcare provider about your risk factors for thyroid cancer. Find out what you can do about them.