The American Thyroid Association (ATA) announced that new clinical practice guidelines for the diagnosis and treatment of hypothyroidism were published in the latest issue of Thyroid. The guidelines were co-developed from a collaboration between the ATA and the American Association of Clinical Endocrinologists (AACE) and will be presented Sunday, October 23, at the 82nd Annual Meeting of the American Thyroid Association. Hypothyroidism is caused by an underactive thyroid gland that does not produce enough thyroid hormone. Symptoms of hypothyroidism tend to be mild and usually include dry skin, sensitivity to cold, fatigue, lethargy, muscle cramps, voice changes, and constipation. Iodine deficiency in the environment is the most common cause of hypothyroidism worldwide. However, in certain areas where iodine is self-sufficient, such as the United States, the most common cause is chronic autoimmune thyroiditis (Hashimoto’s thyroiditis). The current guidelines, which include 52 clinical evidence-based recommendations, are a collaboration of thyroid disease experts from the ATA and the AACE Joint Task Force and were led by Dr. Jeffrey R. Garber, who is also president of the American College of Endocrinologists (ACE) and chief of the Section of Endocrinology at Harvard Pioneer Medical Association. The guidelines were developed after a rigorous review of relevant medical literature and current standards of care, and with attention to the collective knowledge and experience of the working group’s experts in the diagnosis and care of patients with hypothyroidism. (The workgroup defined hypothyroidism as a thyrotropin level greater than 10 mU/l, and subclinical hypothyroidism as a thyrotropin level of less than 10 mU/l with a low free thyroxine (T4) level.) “The basis for the development of clinical practice guidelines for hypothyroidism stems from a comprehensive review and evaluation of published studies on hypothyroidism,” said Dr. Garber, “We believe that by providing evidence-based development of these guidelines, the treatment of patients with hypothyroidism and the quality of care will be improved by these universal, important, and stable treatments for the condition.” These key recommendations include: Endocrinologists should consider the impact of children and infants with heart disease or other endocrine disorders such as adrenal and pituitary disorders, pregnant patients and women. Serum thyroid-stimulating hormone is one of the best screening indicators for hypothyroidism. However, it is insufficient to assess hospitalized patients, patients in whom central hypothyroidism is present or suspected (central hypothyroidism is due to decreased secretion of pituitary gland hormones). Hypothyroidism should be treated with thyroxine (T 4). There are no clinical data to support the effectiveness of some products as “thyroid support” or “thyroid health promotion”. Combinations of tetraiodothyronine (T 4) and triiodothyronine (T 3), including e.g., dry thyroid tablets, should not be used during pregnancy or in women who are planning a pregnancy. Mildly elevated thyroid hormones in the elderly may be a sign of normal aging and do not necessarily indicate hypothyroidism.