Iodine Deficiency Treatment & Management
- Author: Stephanie L Lee, MD, PhD; Chief Editor: George T Griffing, MD more...
Treatment of iodine deficiency
Correction of an individual's iodine deficiency should be instituted at a level recommended by the US Institute of Medicine (IOM) and the World Health Organization (WHO). In a nonpregnant adult, 150 mcg/day is sufficient for normal thyroid function.
Consultation with an endocrinologist should be considered when the etiology of thyroid abnormalities is unclear. Thyroidectomy may be indicated for patients with compressive symptoms of a large goiter.
At a population level, iodine deficiency disorder (IDD) can be prevented by the iodization of food products or the water supply. In practice, this is usually achieved by iodization of salt. An alternative in some developing countries has been the periodic injection of iodized oil supplements.[13, 16]
Iodine treatment-related hyperthyroidism
The primary complication of iodine therapy for IDD is the development of hyperthyroidism. This may occur, especially in patients older than 45 years, because of the hyperfunctioning areas of autonomy that tend to develop in patients with long-standing iodine-deficient goiters.
A Danish study investigating the incidence of hyperthyroidism associated with Denmark's iodine fortification program found that, based on the incident use of antithyroid medication in various parts of the country, the incidence of hyperthyroidism was greater among persons who had suffered from moderate iodine deficiency than it was among those who had had only a mild deficiency. In the moderately deficient population, the incident use of antithyroid medication increased the most in persons younger than 40 years or older than 75 years. Four years after iodine fortification began, the incidence of hyperthyroidism apparently began to decline, returning to prefortification rates in most population groups by the end of 6 years.
Sources of Iodine Replacement
Iodine replacement should be based on the recommendations of IOM and WHO. In an adult, 150 mcg/day is sufficient for normal thyroid function. Replacement of iodine is most easily achieved by requesting that the patient use iodized salt in his or her cooking and at the table or an iodine-containing daily multiple vitamin. Other dietary sources of iodine include milk, egg yolks, and saltwater fish. Not all daily or prenatal multiple vitamins contain iodine, but those that do, typically contain 150 mcg of iodine per tablet.
While a person who follows a vegan diet still might consume iodized salt, only 70% of salt sold from US supermarket shelves currently is iodized. Other major sources of US dietary iodine are saltwater fish, milk and milk products, and eggs. These food items are not included in a true vegan diet.
The Institute of Medicine (IOM) recommended dietary allowance (RDA) is 220 mcg/d of iodine for pregnant women. Not all daily or prenatal multiple vitamins contain iodine, but those that do typically contain 150 mcg of iodine per tablet. The IOM recommends 290 mcg/d for lactating women and 90-120 mcg/d for children aged 1-11 years. The adequate intake for infants is 110-130 mcg/d.
In developing countries, eradication of iodine deficiency has been accomplished by adding iodine drops to well water or by injecting people with iodized oil.
Using highly concentrated pharmaceutical agents such as a saturated solution of potassium iodide (SSKI), which has a concentration of 35,000-50,000 mcg/drop, is impractical and potentially dangerous.
Treatment of Nontoxic Goiters Caused by Iodine Deficiency
Long-term dietary iodine replacement at levels recommended by IOM and WHO may decrease the size of iodine-deficient goiters in very young children and pregnant women and is indicated for all patients with iodine deficiency. Generally, long-standing goiters associated with iodine deficiency disorder respond with only small amounts of shrinkage after iodine supplementation, and patients are at risk for developing hyperthyroidism. Patients do not routinely require specific therapy unless the goiter is large enough to cause compressive symptoms (eg, tracheal obstruction, thoracic inlet occlusion, hoarseness).
Exogenous levothyroxine (L-T4) can also be used to decrease goiter size but generally is not effective in adults and older children. Supplemental L-T4, when added to the T3 and T4 secretion by the autonomous nodules in the endemic goiter, may cause thyrotoxicosis. Long-term L-T4 therapy that results in the suppression of the TSH level to below-normal levels may have deleterious effects on cardiac and bone health; therefore, L-T4 therapy is no longer routinely administered to patients with goiter.
Radioactive iodine (iodine-131 [131 I]) has been used, primarily in Europe, to decrease thyroid volume in patients with euthyroid goiters (40-60% volume reduction). In the United States,131 I is the most common treatment for toxic multinodular goiters associated with hyperthyroidism. Risks associated with131 I therapy include permanent hypothyroidism.
The standard of care for large goiter associated with obstructive symptoms such as dough, stridor, and dysphagia is thyroidectomy. If the goiter extends into the anterior mediastinum, surgery is the recommend treatment even without obstructive symptoms. After the surgery, the patient need levothyroxine replacement therapy.
Zimmermann MB, Jooste PL, Pandav CS. Iodine-deficiency disorders. Lancet. 2008 Oct 4. 372 (9645):1251-62. [Medline].
Pearce EN, Andersson M, Zimmermann MB. Global iodine nutrition: Where do we stand in 2013?. Thyroid. 2013 May. 23(5):523-8. [Medline].
Liu L, Wang D, Liu P, Meng F, Wen D, Jia Q, et al. The relationship between iodine nutrition and thyroid disease in lactating women with different iodine intakes. Br J Nutr. 2015 Sep 14. 1-9. [Medline].
Zimmermann MB. Iodine deficiency in pregnancy and the effects of maternal iodine supplementation on the offspring: a review. Am J Clin Nutr. 2009 Feb. 89(2):668S-72S. [Medline].
WHO Secretariat, Andersson M, de Benoist B, Delange F, Zupan J. Prevention and control of iodine deficiency in pregnant and lactating women and in children less than 2-years-old: conclusions and recommendations of the Technical Consultation. Public Health Nutr. 2007 Dec. 10(12A):1606-11. [Medline].
Delange F. Optimal iodine nutrition during pregnancy, lactation and neonatal period. Int J Endocrinol Metab. 2004. 89:3851.
Azizi F, Smyth P. Breastfeeding and maternal and infant iodine nutrition. Clin Endocrinol (Oxf). 2009 May. 70(5):803-9. [Medline].
Pearce EN, Pino S, He X, Bazrafshan HR, Lee SL, Braverman LE. Sources of dietary iodine: bread, cows' milk, and infant formula in the Boston area. J Clin Endocrinol Metab. 2004 Jul. 89(7):3421-4. [Medline].
Hollowell JG, Staehling NW, Hannon WH, et al. Iodine nutrition in the United States. Trends and public health implications: iodine excretion data from National Health and Nutrition Examination Surveys I and III (1971-1974 and 1988-1994). J Clin Endocrinol Metab. 1998 Oct. 83(10):3401-8. [Medline]. [Full Text].
Caldwell KL, Jones R, Hollowell JG. Urinary iodine concentration: United States National Health And Nutrition Examination Survey 2001-2002. Thyroid. 2005 Jul. 15(7):692-9. [Medline].
Caldwell KL, Miller GA, Wang RY, Jain RB, Jones RL. Iodine status of the U.S. population, National Health and Nutrition Examination Survey 2003-2004. Thyroid. 2008 Nov. 18(11):1207-14. [Medline].
Caldwell KL, Pan Y, Mortensen ME, Makhmudov A, Merrill L, Moye J. Iodine status in pregnant women in the National Children's Study and in U.S. women (15-44 years), National Health and Nutrition Examination Survey 2005-2010. Thyroid. 2013 Aug. 23(8):927-37. [Medline].
Zimmermann MB, Aeberli I, Torresani T, et al. Increasing the iodine concentration in the Swiss iodized salt program markedly improved iodine status in pregnant women and children: a 5-y prospective national study. Am J Clin Nutr. 2005 Aug. 82(2):388-92. [Medline]. [Full Text].
Bath SC, Steer CD, Golding J, Emmett P, Rayman MP. Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). Lancet. 2013 Jul 27. 382(9889):331-7. [Medline].
Williams GR. Neurodevelopmental and neurophysiological actions of thyroid hormone. J Neuroendocrinol. 2008 Jun. 20(6):784-94. [Medline].
Zimmermann MB, Wegmuller R, Zeder C, et al. Rapid relapse of thyroid dysfunction and goiter in school-age children after discontinuation of salt iodization. Am J Clin Nutr. 2004 Apr. 79(4):642-5. [Medline]. [Full Text].
Santiago-Fernandez P, Torres-Barahona R, Muela-Martínez JA, et al. Intelligence quotient and iodine intake: a cross-sectional study in children. J Clin Endocrinol Metab. 2004 Aug. 89(8):3851-7. [Medline]. [Full Text].
Zimmermann MB, Moretti D, Chaouki N, et al. Development of a dried whole-blood spot thyroglobulin assay and its evaluation as an indicator of thyroid status in goitrous children receiving iodized salt. Am J Clin Nutr. 2003 Jun. 77(6):1453-8. [Medline]. [Full Text].
Zimmermann MB, Aeberli I, Andersson M, Assey V, Yorg JA, Jooste P. Thyroglobulin is a sensitive measure of both deficient and excess iodine intakes in children and indicates no adverse effects on thyroid function in the UIC range of 100-299 µg/L: a UNICEF/ICCIDD study group report. J Clin Endocrinol Metab. 2013 Mar. 98(3):1271-80. [Medline].
Krejbjerg A, Pedersen IB, Laurberg P. Can Elastography Predict Growth of Incidental Thyroid Nodules? A Pilot Two-Year Follow-Up Study. Ultrason Imaging. 2015 Sep 7. [Medline].
Zimmermann MB. Iodine requirements and the risks and benefits of correcting iodine deficiency in populations. J Trace Elem Med Biol. 2008. 22(2):81-92. [Medline].
Cerqueira C, Knudsen N, Ovesen L, et al. Association of iodine fortification with incident use of anti-thyroid medication - A Danish nationwide study. J Clin Endocrinol Metab. 2009 Apr 14. [Medline].
Zimmermann MB, Boelaert K. Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol. 2015 Apr. 3 (4):286-95. [Medline].
|Median urine iodine, mcg/L||>100||50-99||20-49||< 20|
|Goiter prevalence||< 5%||5-20%||20-30%||>30%|
|Neonatal thyroid-stimulating hormone (TSH),
>5 IU/mL whole blood
|Adapted from the World Health Organization (WHO)/United Nations Children's Fund (UNICEF)/International Council for Control of Iodine Deficiency Disorders (ICCIDD).|