What is the most common autoimmune disease causing hypothyroidism in the US?

Hashimoto's thyroiditis is the most common autoimmune disease causing hypothyroidism in the United States. This condition results from an autoimmune attack on the thyroid gland, where the body’s immune system mistakenly targets and destroys thyroid cells. The inflammation and destruction lead to a decrease in thyroid hormone production, resulting in hypothyroidism.

The prevalence of Hashimoto’s thyroiditis is significant, as it often goes unrecognized for many years. It can manifest with various symptoms due to the gradual decline in hormone levels, such as fatigue, weight gain, cold intolerance, and depression. The autoimmune nature of Hashimoto's means that it is related to other autoimmune conditions, and there is an increased incidence in individuals with a family history of autoimmune diseases.

Other conditions mentioned, like Graves' disease, are associated with hyperthyroidism, and subacute and silent thyroiditis often lead to transient thyroid dysfunction instead of chronic hypothyroidism. Thus, while they each have distinct characteristics and effects on thyroid function, it is Hashimoto’s thyroiditis that is primarily responsible for the majority of hypothyroid cases linked to autoimmune processes.