[Iodine deficiency disorder persistance after introduction of iodized salt in a previously endemic goiter area]

Correction of iodine deficiency diminishes the incidence of toxic nodular goitre. The aim of this study was to assess the etiology of thyrotoxicosis in two areas with different goitre prevalence in Galicia, fifteen years after the institutional campaign of salt iodination. Results of the present survey are compared with those from a study performed ten years ago.

Two hundred and two thyrotoxic patients attended in La Coruña (coastal zone) and Lugo (inland zone) from January 2000 to May 2002 were included. Clinical and exploratory data were recorded. Thyroid hormones, thyroid-directed antibodies and thyroid stimulating immunoglobulin (TSI) were measured. A thyroid 99m technetium or 123 iodine scintigram was performed.

In the whole group 58.6% of the cases were diagnosed of nodular goitre, 30.3% of Graveś disease, 7.1% of iodine induced thyrotoxicosis and 3.5% of subacute thyroiditis. In coastal zone these percentages were 52.2, 37.0, 5.4 and 4.3%, respectively. In the inland area, 64.2% nodular goitre, 24.5% Graveś disease, 8.5% iodine induced thyrotoxicosis and 2.8% subacute thyroiditis. The most frequent diagnosis in both the whole group and in each area was toxic multinodular goitre.

In some areas of Spain, toxic nodular goitre continues to be the most frequent cause of thyrotoxicosis. It is necessary to insist on implementation and monitoring of iodine supplementation programs.