Chapter 84 - Iodine Supplementation Fails to Target the Elderly: Perspectives from Austria

Abstract

This chapter discusses changes in the incidence of hyperthyroidism and histological types of thyroid cancer, in addition to the changes in urinary iodine excretion and goiter prevalence due to salt iodization. The introduction of salt iodization in an IDA leads to an improvement in iodine supply, measurable in an increase of urinary iodine excretion. Improvement in iodine supply leads to a marked reduction of goiter prevalence in young people, but has failed to target the elderly. The improvement of iodine intake in Austria led to a transient increase in hyperthyroidism caused by thyroid autonomy, but decreased thereafter. The improvement of iodine intake in Austria has also led to a permanent increase of autoimmune thyroid diseases: Hashimoto's disease and Graves' disease. Increase in iodine supply changes the histological type of thyroid cancer: sufficient iodine supply leads to an increase of papillary thyroid cancer, a thyroid cancer type with a better prognosis. Follicular thyroid cancer, dedifferentiated follicular thyroid cancer, and anaplastic cancer have become less frequent in Austria. The introduction of salt iodization led to an improvement in iodine supply with a marked reduction of goiter prevalence in young people, but failed to target the elderly. The improvement in iodine intake also led to an increase in hyperthyroidism and autoimmune thyroid diseases, as well as to changes in histological types of thyroid cancer.