Common causes of hypothyroidism in later life include:
- Hashimoto’s disease, a disease where your immune system attacks and damages your thyroid gland. The reasons for this aren’t clear. Hashimoto’s disease is the most common cause of hypothyroidism in adults in the United States.
- Side effects of earlier treatment for hyperthyroidism.
- Surgery to remove much or all of the thyroid gland because of disease.
- Radiation treatment for neck or head cancer.
- Certain medications that can reduce thyroid gland functioning
The most common causes of hyperthyroidism in later life include:
- Graves' disease, an autoimmune disorder where your own antibodies attack the thyroid gland, which causes it to produce too much thyroid hormone. This is the most common cause of hyperthyroidism in older adults in the United States.
- Cancerous or non-cancerous thyroid gland tumors.
- Cancerous or non-cancerous pituitary gland tumors.
- Other disorders that cause enlargement of the thyroid gland.
Thyroid nodules may be caused by:
- Ongoing or chronic inflammation of your thyroid gland due to Hashimoto's disease.
- Insufficient iodine in your diet. However, this is rare in the U.S., where iodized salt is added to many prepared foods.
Thyroid Cancer Risks
You have a higher than average risk of developing thyroid cancer if you:
- Are older than 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
- Are male
Last Updated July 2020