Abstract
The occurrence of iodine-induced hyperthyroidism (IIH) has been reported after iodine supplementation from clinics and hospitals, but not following an epidemiologic survey. We studied the prevalence of thyroid derangement in a population following iodine supplementation. One yr after more than 75% of the population had been consuming 40 ppm iodized salt; information regarding history of endemic goiter and iodized salt production, distribution, consumption and monitoring were collected in four cities of the Islamic Republic of Iran. A total of 6048 subjects were randomly selected. All subjects were assessed for size of goiter, and urinary iodine and serum T4, T3, TSH, anti-thyroglobulin and antithyroperoxide were measured. Before iodine supplementation, all four cities were areas of endemic goiter. The rate of household consumption of iodized salt was 50, 75 and 90% in 1994, 1995 and 1996, respectively. Ninety-one percent of the salt samples contained 15–55 ppm iodide. Total goiter rate was 57, 62 and 68%; median urinary iodine was 188, 197 and 190 μg/l in the age groups of 6–18, 19–40 and >40 yr, respectively. Prevalence of clinical and subclinical hyperthyroidism was 0.34 and 0.41 and those of clinical and subclinical hypothyroidism were 0.51 and 1.07%, respectively. Nine point eight and 18% in the 19–40 yr age group and 17.6 and 25.6% in >40 yr old subjects had positive anti-thyroperoxidase and antithyroglobulin, respectively. This systemic epidemiologic study in an iodine deficient population showed that, following a well-executed iodine supplementation program, the occurrence of IIH is rare.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Coindet JF. Decouvete’d un remede contrele goiter. Ann Chim Et Phys 1820, 15: 49.
Hetzel BS. Iodine-induced thyrotoxicosis (jodbasedow). In: Stanbury JB, Hetzel BS eds. Endemic Goiter and Endemic Cretinism. New York: Wiley. 1980, 562.
Fradkin JE, Wolff J. Iodide-induced thyrotoxicosis. Medicine 1983, 62: 1–20.
Pennington JA. A review of iodine toxicity reports. J Am Diet Assoc 1990, 90: 1571–81.
Bourdoux PP, Ermans AM, Mukalay A, et al. Iodine-induced thyrotoxicosis in Kivu, Zaire [Letter]. Lancet 1996, 347: 552–3.
Todd CH, Allain T, Gomo AZ, et al. Increase in thyrotoxicosis associated with iodine supplements in Zimbabwe [letter]. Lancet 1995, 346: 1563–4.
Stanbury JB, Ermans AE, Bourdoux P, et al. Iodine-induced hyperthyroidism: occurrence and epidemiology. Thyroid 1998, 8: 83–100.
WHO. Recommended iodine levels in salt and guidelines for monitoring their adequacy and effectiveness. WHO, Division of Nutrition, Geneva, 1997.
Kohn LA. The Midwestern American “epidemic” of iodineinduced hyperthyroidism in the 1920s. Bull N Y Acad Med 1976, 52: 770–81.
McClure RD. Thyroid surgery as affected by the generalized use of iodized salt in an endemic goiter region preventive surgery. Ann Surg 1934, 100: 924–7.
Hartsock CL. Abuse of iodine, especially of iodized salt, in the prevention of goiter. Ann Intern Med 1927, 1: 24–8.
Connolly RJ, Vidor GI, Stewart JC. Increase in thyrotoxicosis in endemic goiter area after iodation of bread. Lancet 1970, 1: 500–2.
Vidor G, Stewart JC, Wall JR, et al. Pathogenesis of iodineinduced thyrotoxicosis: Studies in northern Tasmania. J Clin Endocrinol Metab 1973, 31: 901–9.
Connolly RJ. An increase in thyrotoxicosis in southern Tasmania after an increase in dietary iodine. Med J Austral 1971, 1: 1268–71.
Emami A, Shahbazi H, Sabzevari M, et al. Goiter in Iran. Am J Clin Nutr 1969, 22: 1584–8.
Azizi F, Kimiagar M, Bastani J, Navai L, Ghazanfari F. Evaluation of goiter in Shahriar. J Beheshti Med Sch 1985, 9: 75–80.
Azizi F, Kimiagar M, Navai L, Navarabadi M, Mostafavi H. Goiter in Tehran and suburbs. Recent progress in thyroidology. Proceedings of the Third Asia and Oceania Thyroid Association Meeting (Vichayanart, A. et al. eds.). Dec. 4–6, 1986, p.50.
Kimiagar M, Azizi F, Mavai L, Yassai M, Nafarabadi M. Survey of iodine deficiency in a rural area near Tehran: Association of food intake and endemic goiter. Eur J Clin Nutr 1990, 44: 12–22.
Azizi F, Kimiagar M, Nafarabadi M, Yassai M. Current status of iodine deficiency disorders in the Islamic Republic of Iran. EMR. Health Serv J 1990, 8: 23–7.
Azizi F, Sheikholeslam R, Hedayati M, et al. Sustainable control of iodine deficiency in Iran: beneficial results of the implementation of the mandatory law on salt iodization. J Endocrinol Invest 2002, 25: 409–13.
Azizi F. Assessment, monitoring and evaluation of iodine deficiency disorders in the Middle East and Eastern Mediterranean Region. Sara. Publ Tehran 2002.
Roti E, Degli Uberti E. Iodine excess and hyperthyroidism. Thyroid 2001, 11: 493–500.
WHO/UNICEF/ICCIDD. Assessment of the iodine deficiency disorders and monitoring their elemination. Report of consultation, May. 4–6 WHO/NHD/01.1, Geneva, 2001.
Dunn JT, Crutchfield ME, Gutekunst R, Dunn AN. Methods for measuring iodine in urine. Geneva, ICC/IDD/UNICEF/WHO publication. 1993.
Baltisberger BL, Minder CE, Burgi H. Decrease in incidence of toxic nodular goiter in a region of Switzerland after full correction of mild iodine deficiency. Eur J Endocrinol 1995, 132: 546–9.
Delange F, de Benoist B, Alnwick D. Risks of iodine-induced hyperthyroidism after correction of iodine deficiency by iodized salt. Thyroid 1999, 9: 545–56.
Zanzi I, Bradford I, Cordova J. Aspectos epidemiologicos del hypertiroidismo en Chile. Rev Med Chile 1973, 100: 1055–63.
Martins C, Lima N, Knobel M, Medeiros-Neto H. Natural course of iodine-induced thyrotoxicosis (jodbasedow) in endemic goiter area: A 5 year follow-up. J Endocrinol Invest 1989, 12: 239–44.
Wanatable T, Moran D, El Tamera E, et al. Iodized oil in the prophylaxis of endemic goiter in Argentina. In: Dunn JT, Mederios G eds. Endemic goiter and cretinism: continuing threats to world health. PAHO Scientific Publication No. 292, PAHO Washington, DC, 1974, p. 231.
Croxon MS, Gluckman PD, Ibbertson HK. The acute thyroidal response to iodized oil in severe endemic goiter. J Clin Endocrinol Metab 1976, 42: 926–30.
Kevany J, Fierro-Benitez R, Pretell EA, Stanbury JB. Prophylaxis and treatmet of endemic goiter with iodized oil in rural Ecuador and Peru. Am J Clin Nutr 1969, 22: 1597–607.
Maberly GF, Corcoran JM, Eastman CJ. The effect of iodized oil on goiter size, thyroid function and the development of the jod basedow phenomenon. Clin Endocrinol 1982, 17: 253–9.
Azizi F, Kimiagar M, Ghazi AA, Nafarabadi M. The effects of iodized oil injection in eu- and hypothyroid iodine deficient girls. J Endocrinol Invest 1997; 20: 18–23.
Azizi F, Daftarian N. Side-effects of iodized oil administration in patients with simple goiter. J Endocrinol Invest 2000, 23: 301–5.
Elnager B, Eltom M, Karlsson FA, et al. The effects of different doses of oral iodized oil on goiter size, urinary iodine, and thyroid-related hormones. J Clin Endocrinol Metab 1995, 80: 891–7.
Van Leeuwen E. Een vorm van genuine hyperthyreose (M. Basedow zonder exophthalmus) na gebruik van gejodeerd brood. Ned Tijdschr Geneeskd 1954, 98: 81–9.
Mostbeck A, Galvan G, Bauer P, et al. The incidence of hyperthyroidism in Austria from 1987 to 1995 before and after an increase in salt iodization in 1990. Eur J Nucl Med 1998, 25: 367–74.
Galofre JC, Fernandez-Calvet L, Rios M, Garcia-Mayor RV. Increased incidence of thyrotoxicosis after iodine supplementation in an iodine sufficient area. J Endocrinol Invest 1994, 17: 23–7.
Surks MI, Sievert R. Drugs and thyroid function. N Engl J Med 1995, 333: 1688–94.
Lazarus JH, Parkes AB, N’Diaye JR, et al. Endemic goiter in Senegal-Thyroid function, etiological factors and treatment with oral iodized oil. Acta Endocrinol 1992, 126: 149–54.
Pharoah PO, Connolly KJ. A controlled trial of iodinated oil for the prevention of endemic cretinism: a long-term follow-up. Int J Epidemiol 1987, 16: 68–73.
Phillips DI, Osmond C. Iodine supplementation with oral or intramuscular iodized oil. A two-year follow-up of a comparative trial. Int J Epidemiol 1989, 18: 907–10.
Ranganathan S, Reddy V. Human requirements of iodine & safe use of iodized salt. Indian J Med Res 1995, 102: 227–32.
Weetman AP, McGregor AM. Autoimmune thyroid disease: further development in our understanding. Endocr Rev 1994, 15: 788.
Dayan CM, Daniels GH. Chronic autoimmune thyroiditis. N Engl J Med 1996, 335: 99–107.
Boukis MA, Koutras DA, Souvatzoylou A. Thyroid hormone and immunologic studies in endemic goiter. J Clin Endocr Metab 1983, 57: 859–62.
Kahaly G, Dienes HP, Beyer J, Hommel H. Randomized double-blind, placebo-controlled trial of low dose iodine in endemic goiter. J Clin Endocrinol Metab 1997, 82: 4049–53.
Prentice LM, Phillips DI, Sarsero D, et al. Geographical distribution of subclinical autoimmune thyroid disease in Britain: a study using highly sensitive direct assays for autoantibodies to thyroglobulin and thyroid peroxidase. Acta Endocrinol 1990, 123: 493–8.
Roti E, Gardini E, Minelli R, et al. Prevalence of anti-thyroid peroxidase antibodies in serum in the elderly: comparison with other rests for anti-thyroidies. Clin Chem 1992, 38: 88–92.
Hollowell JG, Staehling NW, Flanders WD, et al. Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab 2002, 87: 489–99.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Azizi, F., Hedayati, M., Rahmani, M. et al. Reappraisal of the risk of iodine-induced hyperthyroidism: An epidemiological population survey. J Endocrinol Invest 28, 23–29 (2005). https://doi.org/10.1007/BF03345525
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF03345525