Hypothyroidism

Common causes of hypothyroidism (underactive thyroid) in older adults include:

• Hashimoto’s disease (immune system damages the thyroid). This is the most common cause of hypothyroidism in adults.
• Side effects of earlier treatment for hyperthyroidism.
• Surgery to remove some or all of the thyroid.
• Radiation treatment for neck or head cancer.
• Some medications.

Hyperthyroidism

The most common causes of hyperthyroidism (overactive thyroid) in later life include:

• Graves' disease (immune system attacks the thyroid and causes it to make too much hormone).  This is the most common cause of hyperthyroidism in older adults.
• Cancerous or non-cancerous thyroid gland tumors.
• Cancerous or non-cancerous pituitary gland tumors.
• Other diseases that cause enlargement of the thyroid gland.
• Some medications.

Thyroid Nodules

Thyroid nodules may be caused by:

• Inflammation of the thyroid due to Hashimoto's disease.
• Insufficient iodine in the diet. This is rare in the U.S. 

Thyroid Cancer Risks

People have a higher-than-average risk of developing thyroid cancer if they:

• Are male.
• Are older than age 60.
• Have had radiation treatment in the past, especially to the head or neck.
• Have a family history of thyroid or other cancers affecting the body’s glands.
• Have been exposed to radiation due to an accident.

Last Updated December 2022