According to the Cleveland Clinic, approximately 20 million people in the United States have thyroid disease. Women are more likely to have thyroid problems than men. There are several causes of thyroid disease, depending upon which type of disorder a person has. Hyperthyroidism, hypothyroidism and thyroid cancer are all types of thyroid disease.
Hyperthyroidism, also called Graves Disease, occurs when the thyroid gland becomes overactive. An overactive thyroid produces excessive amounts of hormones called triiodothyronine (T3) and thyroxine (T4). T3 and T4 are responsible for regulating the body’s metabolism, or the conversion of calories into energy. Patients with hyperthyroidism burn energy so quickly that an increased caloric intake is not enough to help keep up with the body's metabolism.
Excessive iodine is often a cause of hyperthyroidism. A goiter, which is an enlarged thyroid, can produce too many T3 and T4 hormones. The nodules on the thyroid themselves may also cause hyperthyroidism, and are referred to as toxic nodules. Thyroiditis, an inflammation of the thyroid, can also spark the release of excess hormones. Another common cause of hyperthyroidism is the treatment of hypothyroidism through hormone replacement drugs. If the dosage of hormone replacement medications is too high, then the thyroid gland ends up with an excessive amount of hormones.
Hypothyroidism occurs when the thyroid becomes underactive and does not produce enough T3 and T4 hormones. When this happens, the body’s metabolism slows down. Weight gain is inevitable, as the body cannot burn calories into energy efficiently. Hypothyroidism is the most common form of thyroid disease.
Thyroiditis, or the inflammation of the thyroid gland, slows down the production of T3 and T4 hormones. Iodine deficiency, although not common in the United States due to iodized salt usage, is a cause of hypothyroidism. In order for the thyroid gland to make hormones, it needs iodine. Hypothyroidism may also be hereditary, a condition known as Hashimoto’s Disease. Up to 9 percent of women can get hypothyroidism after giving birth. This condition is called postpartum thyroiditis, and is often a temporary one. Also, according to the Cleveland Clinic, one in 4,000 newborns get hypothyroidism.
Thyroid cancer occurs when a nodule or tumor on the thyroid gland turns malignant (cancerous). Thyroid cancer is hereditary, but is also caused by radiation exposure to the neck and a diet that is extremely low in iodine. However, the majority tumors and nodules found on the thyroid are benign, or non-cancerous.