More than 12% of the United States population develop a thyroid condition during their lifetime, according to the American Thyroid Association (ATA). The organization of thyroid specialists suggests that an estimated 20 million Americans are currently living with some form of thyroid disease; however, up to 60% of those people are unaware of their condition.
Much remains unknown about thyroid diseases, including causes and risk factors. While the ATA has raised the profile of thyroid diseases in the last 40 years and developed key guidelines and clinical best practices to better serve patients with thyroid disease, more work must be done. For Thyroid Awareness Month this January, we share information about the latest research and treatments available for this endocrine condition.
Thyroid Conditions Overview
A person can develop numerous thyroid conditions. Several of these conditions are described below.
Hypothyroidism and Hashimoto’s Thyroiditis: Hypothyroidism, or an underactive thyroid gland, has many potential causes, including thyroiditis, medication side effects, too much or too little iodine, and surgical removal of the thyroid. Autoimmune diseases may also cause hypothyroidism—the most common are Hashimoto’s thyroiditis and atrophic thyroiditis. Symptoms generally encompass the body’s processes slowing down: dry skin, forgetfulness, depression, easy to fatigue, and constipation.
Hyperthyroidism and Graves’ Disease: Hyperthyroidism, also known as Graves’ disease, is caused by antibodies in the blood that switch the thyroid “on,” causing it to produce an overabundance of thyroid hormone. Graves’ disease in particular tends to run in families and occurs more often in young women. Hyperthyroidism may also be characterized by the presence of nodules in the thyroid, known as toxic nodular or multinodular goiter. An overactive thyroid can lead to thyrotoxicosis. Symptoms include nervousness and anxiety, irritability, sweating, heart racing, muscle weakness, and weight loss.
Thyroid eye disease: Thyroid eye disease is also known as Grave’s ophthalmopathy and typically develops in people with hyperthyroidism caused by Graves’ disease. Eye symptoms associated with Graves’ ophthalmopathy usually begin within six months of the onset of Graves’ disease and include ocular irritation or grittiness, redness or inflammation of the conjunctiva, excessive tearing, dry eyes, and double vision.
Goiter: Goiter is the abnormal enlargement of the thyroid gland, but the presence of a goiter does not always indicate that the thyroid gland is malfunctioning. Iodine deficiency is one of the most common causes of goiter formation worldwide but is no longer common in the United States. Hashimoto’s thyroiditis and Grave’s disease are two of the most common causes of goiter development in the United States. Goiter treatment generally depends on the cause and can include iodine supplementation or radioactive iodine therapy.
Thyroid nodules: A thyroid nodule is an abnormal growth of thyroid cells that forms a lump in the thyroid gland. While most are benign, some do contain thyroid cancer. Many of these nodules do not cause symptoms and are identified as an incident finding during routine evaluations or due to abnormal thyroid function tests. A thyroid surgeon should remove nodules known to be cancerous.
Thyroid cancer: Thyroid cancer is relatively uncommon in the United States, compared with other types of cancer. Despite its rarity, fewer than 2,000 patients die from thyroid cancer each year. Types of thyroid cancer include:
- papillary and follicular thyroid cancer
- anaplastic thyroid cancer
- medullary thyroid cancer
These cancers are often asymptomatic, lacking the presence of nodules or blood-based markers. Other cancer-like thyroid conditions include microcarcinomas, multiple endocrine neoplasia type 2, and primary thyroid lymphoma.
Iodine deficiency: Although the body does not create iodine, it’s requires it to produce the thyroid hormone. An iodine deficiency can lead to thyroid goiter or hypothyroidism.
Postpartum thyroiditis: Postpartum thyroiditis is thyroid inflammation following giving birth. Thyroiditis can cause thyrotoxicosis and hypothyroidism. The hypothesized cause of postpartum thyroiditis is believed to be an autoimmune disease similar to Hashimoto’s thyroiditis. Women with positive antithyroid antibodies are at a much higher risk of developing this condition.
Addressing Prevention and Asymptomatic Concerns
Thyroid cancers are often asymptomatic. They present as a lump or nodule in the thyroid and cannot usually be identified via standard thyroid blood tests. Instead, these cancers are most commonly identified incidentally during a neck examination, CT scan, or ultrasound, and symptoms are rare. Nodules that do cause symptoms often cause pain in the neck, jaw, or ear, or compression of the windpipe or esophagus if the nodule is large enough. Thyroid cancer is diagnosed by fine needle aspiration biopsy of the thyroid nodule.
The most common thyroid cancer is papillary thyroid cancer, accounting for 70% to 80% of all cases, followed by follicular thyroid cancer (10% to 15%). Papillary thyroid cancer typically has an excellent prognosis, even in the face of lymph node spread. Medullary and anaplastic thyroid cancers each account for 2% of all thyroid cancers; anaplastic thyroid cancers are the most aggressive and the least likely to respond to treatment.
Thyroid diseases can be difficult to prevent because many are asymptomatic. Regular bloodwork to monitor thyroid hormones—including thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4)—and thyroid antibody tests to identify thyroid peroxidase and thyroglobulin antibodies can help physicians identify conditions. However, not all blood tests are useful in all situations.
Radioactive iodine uptake testing can help evaluate thyroid function. High radioactive iodine uptake is seen in patients with hyperthyroidism, while low radioactive iodine uptake is associated with hypothyroidism.
Current and Future Research and Treatments
Funding for thyroid research has not increased appreciably over the last 20 years. Still, it is necessary to answer key research questions that will impact the lives of the 5% of Americans living with thyroid disease.
Roughly 5,000 research papers on thyroid health were published in 2019. Most focused on thyroid cancer, but some studies were vital in shedding new insight into T3 therapy. Some other important research topics include the impact of various thyroid conditions on pregnancy and heart health, the transition from Hashimoto’s thyroiditis to Graves’ disease that some patients experience, the role of vitamin D in improving thyroid health, and the role of THS levels in identifying and diagnosing thyroid diseases. Researchers are also focusing on developing new treatments and updating treatments currently in practice.
One research study focused on Graves’ ophthalmopathy found that a “considerable benefit” to patients is associated with the addition of antiproliferative agents like mycophenolate or azathioprine to standard glucocorticoid treatment. In addition to target biologic therapies like teprotumumab, rituximab, and tocilizumab, these new agents can reduce the deterioration that might occur after patients stop steroid therapy.
In another study, researchers provided an update on novel therapies being considered to treat thyroid autoimmune diseases, including PPAR-alpha or -gamma ligands, antibodies, and other small molecules that target CXCL10 or CXCR; antigen-specific treatments for Graves’ disease that induce T-cell tolerance through TSH-R peptide immunization; and drugs like etanercept and tocilizumab that target cytokines in Graves’ ophthalmopathy. However, more studies are needed to evaluate the efficacy of these novel therapies further.
It has been well-documented that thyroid disease impacts heart function. Researchers are now also focusing on evaluating potential pharmacotherapeutic strategies to manage these conditions, including one study on thyroid disease-induced pericarditis. The review, published in the Annals of Pharmacotherapy, provides physicians with a single reference source for treating this condition—previously lacking in the medical literature—and potential drug-drug and drug-disease interactions that might worsen patient outcomes.
Finally, researchers have delved deeper into the role of nutritional factors in treating Hashimoto’s thyroiditis. Diet therapy—the proper nourishment of the body to regulate the immune system via an anti-inflammatory diet—is being evaluated as a vital treatment methodology because patients with Hashimoto’s thyroiditis often experience either over- or undernutrition and associated nutritional deficiencies.
ClinicalTrials.gov currently has 423 studies evaluating various thyroid diseases.
Increasing Thyroid Awareness
One fundamental way to increase awareness of thyroid diseases is by providing the necessary funding to organizations that are supporting thyroid research. For example, the ATA publishes informational brochures and provides layperson summaries of medical literature, physician referrals, and support communities to the public, and provides research and education grants, career training, and continuing education to thyroid professionals.
American Thyroid Association. General information/press room. https://www.thyroid.org/media-main/press-room/. Accessed December 22, 2020.
American Thyroid Association. Thyroid patient information. https://www.thyroid.org/thyroid-information/. Accessed December 22, 2020.
American Thyroid Association. Thyroid function tests. https://www.thyroid.org/thyroid-function-tests/. Accessed December 22, 2020.
American Thyroid Association. Thyroid cancer (papillary and follicular). https://www.thyroid.org/thyroid-cancer/. Accessed December 22, 2020.
American Thyroid Association. Current research. https://www.thyroid.org/patient-thyroid-information/clinical-trial-studies-thyroid/. Accessed December 22, 2020.
Boost Thyroid. Thyroid research in 2019. https://www.boostthyroid.com/blog/thyroid-research-in-2019. Published December 19, 2019. Accessed December 22, 2020.
Taylor PN, Zhang L, Lee RWJ, et al. New insights into the pathogenesis and nonsurgical management of Graves orbitopathy. Nat Rev Endocrinol. https://www.nature.com/articles/s41574-019-0305-4. Published December 30, 2019. Accessed December 22, 2020. doi: 10.1038/s41574-019-0305-4.
Ferrari SM, Fallahi P, Elia G, et al. Novel therapies for thyroid autoimmune diseases: An update. Best Pract Res Clin Endocrinol Metab. https://www.sciencedirect.com/science/article/abs/pii/S1521690X19301174?via%3Dihub. Published November 28, 2019. Accessed December 22, 2020. doi: 10.1016/j.beem.2019.101366
Schwier NC, O’Neal K. Pharmacotherapeutic management strategies for thyroid disease-induced pericarditis. Ann Pharmacother. https://journals.sagepub.com/doi/10.1177/1060028019889065. Published online November 19, 2019. Accessed December 22, 2020. doi: 10.1177/1060028019889065.
Ihnatowicz P, Dryweiń M, Wator P, Wojsiat J. The importance of nutritional factors and dietary management of Hashimoto’s thyroiditis. Ann Agric Environ Med. http://www.aaem.pl/The-importance-of-nutritional-factors-and-dietary-management-of-Hashimoto-s-thyroiditis,112331,0,2.html. Published June 19, 2020. Accessed December 22, 2020. doi: 10.26444/aaem/112331
ClinicalTrials.gov search: thyroid disease. https://clinicaltrials.gov/ct2/results?cond=Thyroid+Disease. Accessed December 22, 2020.
American Thyroid Association. January is thyroid awareness month. https://www.thyroid.org/january-thyroid-awareness/. Published January 16, 2016. Accessed December 22, 2020.
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