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The thyroid is a gland that controls key functions of your body. It is a butterfly-shaped organ located in the front of the neck. The thyroid gland makes thyroid hormones. These hormones help to maintain your body’s metabolism or production of energy. Disease of the thyroid gland can affect nearly every organ in your body and harm your health.
1. The most common thyroid disorder is:
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The most common thyroid disorder is hypothyroidism, or an underactive thyroid. In hypothyroidism, the thyroid gland doesn’t make enough thyroid hormone. The most common cause of this disorder worldwide is a diet that doesn't have enough iodine in it. In the U.S. in the early to mid-1900s, about half of all adults in the "goiter belt"—the Great Lakes and inland mountain areas—had a goiter. This is an enlargement of the thyroid gland that happens when a person doesn't get enough iodine. Today iodine is added to table salt, so U.S. diets don't lack this trace element. Today, the most common cause of hypothyroidism in the U.S. is an autoimmune disease called Hashimoto's thyroiditis. The normal function of the body’s immune system is to protect against bacteria, viruses, and other foreign substances. For a person with Hashimoto’s thyroiditis, the body’s immune system attacks the thyroid cells as foreign bodies and destroys them. The thyroid gland is then unable to make enough thyroid hormone to meet the body’s need. Other causes of hypothyroidism include surgical removal of the thyroid, radiation treatment, congenital hypothyroidism, medications, and conditions of the pituitary gland.
