This chapter discusses the effect of iodization on normal thyroid physiology and hyperthyroidism over the period of time during which salt iodization was introduced in India. Since the introduction of salt iodization, the prevalence of iodine deficiency disorders has decreased significantly. The increase in urine iodine levels by about three-five-fold has been accompanied by a decrease in the rate of goiter by as much as fivefold. Simultaneously, plasma inorganic iodine levels have increased up to ten-fold in the latest study of iodine kinetics in the normal individuals. This has been accompanied by a decrease in thyroid iodine clearance from plasma, and hence a decrease in radioiodine thyroid uptake, altering the normal values of this clinical test from the mean of 51% to 19% at 24 h. Although no data are available on the prevalence of hyperthyroidism in India, the response of Graves' disease to treatment may have been altered with increasing iodine consumption. Higher urinary iodine concentrations are associated with a poorer response of Graves' disease to antithyroid medication. The response of Graves' disease to treatment with antithyroid medication is delayed after iodization. The response may be poorer in patients with higher urine iodine levels. No systematic data are available on the change in occurrence of Graves' disease, iodine-induced thyrotoxicosis and thyroid cancer with the introduction of iodization in India.
|Original language||English (US)|
|Title of host publication||Comprehensive Handbook of Iodine|
|Number of pages||5|
|State||Published - Dec 1 2009|
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)