Why is hypothyroid so common

Your thyroid uses iodine to make thyroid hormones. Eating foods that have large amounts of iodine—such as kelp, dulse, or other kinds of seaweed—may cause or worsen hypothyroidism. Taking iodine supplements can have the same effect. If you are pregnant, you need more iodine because the baby gets iodine from your diet. Talk with your doctor about how much iodine you need. The NIDDK conducts and supports clinical trials in many diseases and conditions, including endocrine diseases.

The trials look to find new ways to prevent, detect, or treat disease and improve quality of life. Clinical trials—and other types of clinical studies —are part of medical research and involve people like you. When you volunteer to take part in a clinical study, you help doctors and researchers learn more about disease and improve health care for people in the future.

Find out if clinical studies are right for you. Griffin P. Rodgers explaining the importance of participating in clinical trials. You can view a filtered list of clinical studies on hypothyroidism that are open and recruiting at www. You can expand or narrow the list to include clinical studies from industry, universities, and individuals; however, the National Institutes of Health does not review these studies and cannot ensure they are safe.

Always talk with your health care provider before you participate in a clinical study. The NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Hoang, D. Burch, M. How common is hypothyroidism? Who is more likely to develop hypothyroidism? Is hypothyroidism during pregnancy a problem? What are the complications of hypothyroidism? What are the symptoms of hypothyroidism?

Your symptoms should disappear and the serious effects of low thyroid hormone should improve. If you keep your hypothyroidism well-controlled, it will not shorten your life span.

Here are the major causes, from the most to the least common. But in almost every patient, hypothyroidism can be completely controlled. It is treated by replacing the amount of hormone that your own thyroid can no longer make, to bring your T4 and TSH levels back to normal levels.

Synthetic thyroxine pills contain hormone exactly like the T4 that the thyroid gland itself makes. All hypothyroid patients except those with severe myxedema life-threatening hypothyroidism can be treated as outpatients, not having to be admitted to the hospital.

The only dangers of thyroxine are caused by taking too little or too much. If you take too little, your hypothyroidism will continue. The most common symptoms of too much thyroid hormone are fatigue but inability to sleep, greater appetite, nervousness, shakiness, feeling hot when other people are cold, and trouble exercising because of weak muscles, shortness of breath , and a racing, skipping heart.

Patients who have hyperthyroid symptoms at any time during thyroxine replacement therapy should have their TSH tested. If it is low, indicating too much thyroid hormone, their dose needs to be lowered.

The goal of treatment is to get and keep your TSH in the normal range. Babies with hypothyroidism must get all their daily treatments and have their TSH levels checked as they grow, to prevent mental retardation and stunted growth.

Hypothyroidism Brochure PDF. El folleto de Hipotiroidismo. For information on thyroid patient support organizations, please visit the Patient Support Links section on the ATA website at www.

Hypothyroidism Underactive. Hypothyroidism FAQS. Autoimmune disease. This is more common in women than men. Autoimmune thyroiditis can begin suddenly or it can develop slowly over years. Surgical removal of part or all of the thyroid gland. If the whole thyroid is removed, people will definitely become hypothyroid. If part of the gland is left, it may be able to make enough thyroid hormone to keep blood levels normal.

Radiation treatment. All these patients can lose part or all of their thyroid function. Enhanced Digital Features. To view enhanced digital features for this article go to National Center for Biotechnology Information , U. Advances in Therapy. Adv Ther. Published online Sep 4. Author information Article notes Copyright and License information Disclaimer. Luca Chiovato, Email: ti. Corresponding author. Received Aug This article has been cited by other articles in PMC.

Funding : Merck. Plain Language Summary Hypothyroidism is one of the most common diseases worldwide, and levothyroxine is the usual medication prescribed to manage it. Introduction Hypothyroidism is a chronic disease associated with deficiency in the thyroid hormones, thyroxine T4 and triiodothyronine T3 [ 1 , 2 ].

Methods A search of the literature was conducted using PubMed and general search terms such as primary hypothyroidism, levothyroxine, aetiology, economic impact, quality of life and treatment guidelines. Hypothyroidism in Context Causes of Hypothyroidism As described earlier, hypothyroidism is characterised by deficiency in the T4 and T3 hormones [ 1 , 2 ].

Prevalence and Incidence The reported prevalence of hypothyroidism varies geographically, in part due to differences in disease definitions, poorly defined and diverse populations studied, variability in the sensitivity of measures of thyroid function used in the past, and iodine intake [ 27 ].

Impact of Iodine Worldwide, environmental iodine deficiency is the most common cause of thyroid disorders, including hypothyroidism [ 6 ]. Diagnosis of Hypothyroidism Hypothyroidism has a varied clinical presentation and non-specific symptoms, including weight gain, fatigue, poor concentration, depression, diffuse muscle pain, menstrual irregularities, and constipation [ 4 ], with no particular symptom definitively predicting the presence of hypothyroidism [ 52 ].

Table 1 Available formulations of levothyroxine. Open in a separate window. The Use of Levothyroxine to Treat Hypothyroidism Upon diagnosis of hypothyroidism, lifelong treatment with levothyroxine is often initiated [ 4 , 53 , 67 , 68 , 71 — 73 ], except in cases where hypothyroidism is caused by transient forms of thyroiditis or by drugs which can be discontinued [ 50 ].

Acknowledgements This supplement has been sponsored by Merck. Authorship All named authors meet the International Committee of Medical Journal Editors ICMJE criteria for authorship for this article, take responsibility for the integrity of the work as a whole, and have given their approval for this version to be published.

Compliance with Ethics Guidelines This article is based on previously conducted studies and does not contain any studies with animals performed by any of the authors. Footnotes Enhanced Digital Features To view enhanced digital features for this article go to References 1.

Shift from levothyroxine tablets to liquid formulation at breakfast improves quality of life of hypothyroid patients. Malaty W. Primary hypothyroidism. Accessed 4 Jan Hypothyroidism: an update. Am Fam Physician.

Intraepidermal nerve fiber density reduction as a marker of preclinical asymptomatic small-fiber sensory neuropathy in hypothyroid patients. Eur J Endocrinol. Vanderpump MP. The epidemiology of thyroid disease. Br Med Bull. Epidemiology of subtypes of hypothyroidism in Denmark. The incidence and prevalence of thyroid dysfunction in Europe: a meta-analysis. J Clin Endocrinol Metab.

The spectrum of thyroid disease in a community: the Whickham survey. Clin Endocrinol Oxf ; 7 — Comparative study of thyroid function and types of thyroid dysfunction in two areas in Denmark with slightly different iodine status. Clinical, behavioural and pharmacogenomic factors influencing the response to levothyroxine therapy in patients with primary hypothyroidism-protocol for a systematic review. Syst Rev. Kraut E, Farahani P.

Clin Invest Med. Is delayed diagnosis of hypothyroidism still a problem in Faisalabad, Pakistan. J Pak Med Assoc. Hypothyroidism in pregnancy: consequences to neonatal health.

Raval AD, Sambamoorthi U. Incremental healthcare expenditures associated with thyroid disorders among individuals with diabetes. J Thyroid Res.

Diminished quality of life and increased brain functional connectivity in patients with hypothyroidism after total thyroidectomy. Inadequate levothyroxine replacement for primary hypothyroidism is associated with poor health-related quality of life-a Brazilian multicentre study.

Hypothyroidism is a predictor of disability pension and loss of labor market income: a Danish register-based study. J Clin Endocrinol Metabol. Excess mortality in patients diagnosed with hypothyroidism: a nationwide cohort study of singletons and twins. World Health Organization.

WHO model list of essential medicines. Defending plasma T3 is a biological priority. Clin Endocrinol. Relationships between circulating and intracellular thyroid hormones: physiological and clinical implications.

Endocr Rev. Principles of endocrinology. Williams textbook of endocrinology. Philadelphia: Saunders Elsevier; Persani L. Clinical review: Central hypothyroidism: pathogenic, diagnostic, and therapeutic challenges. The Colorado thyroid disease prevalence study.

Arch Intern Med. The prevalence of thyroid dysfunction in a population with borderline iodine deficiency. Low prevalence of hypothyroidism among Black and Mulatto people in a population-based study of Brazilian women.

Clin Endocrinol Oxf ; 66 — Iodine and mental development of children 5 years old and under: a systematic review and meta-analysis. Assessment of iodine deficiency disorders and monitoring their elimination. A guide for programme managers. Poverty and immigration as a barrier to iodine intake and maternal adherence to iodine supplementation.

J Endocrinol Invest. Tomer Y. Mechanisms of autoimmune thyroid diseases: from genetics to epigenetics. Annu Rev Pathol. Thyroid peroxidase and thyroglobulin auto-antibodies in patients with newly diagnosed overt hypothyroidism. Thyroid antibody status, subclinical hypothyroidism, and the risk of coronary heart disease: an individual participant data analysis. Thyroid peroxidase and thyroglobulin autoantibodies in a large survey of populations with mild and moderate iodine deficiency.

Hashimoto H. Thyroid volume in hypothyroidism due to autoimmune disease follows a unimodal distribution: evidence against primary thyroid atrophy and autoimmune thyroiditis being distinct diseases. Iodine intake as a determinant of thyroid disorders in populations. Effect of iodine intake on thyroid diseases in China. N Engl J Med. Kim D.