Epidemiology of iodine deficiency diseases in the Republic of Tuva according to the results of screening for congenital hypothyroidism

Abstract

Besides detection and treatment of congenital hypothyrosis, neonatal screening for hypothyrosis can be used for analysis of iodine deficiencies at the population level and for evaluating the severity of iodine deficiency.

We evaluated the significance of iodine deficiency diseases in various regions of the Tyva Republic by the results of screening for congenital hypothyrosis. Use of criteria for diagnosis of iodine deficiency (neonatal TTH) required no extra expenses, because the congenital hypothyrosis screening program has been functioning in the Republic since 1995. TTH was measured in whole neonatal blood by the dry spot method using Delphia immunodiagnostic system at Department of Biomedical Problems, Ministry of Health of Republic of Tyva, in the town of Kyzyl. We analyzed TTH in 8427 newborns born from June 1, 1995 to September 1, 1998.

Analysis of the incidence of neonatal TTH demonstrated the severity of iodine deficiencies in various regions of the Republic and the areas of severe iodine deficiency at the West. For the entire Tyva, blood TTH levels under 5 microunits/liter was 43.2%, which corresponds to severe iodine deficiency. The incidence of transitory hypothyrosis (TTH 25 microunits/liter and higher) in the Republic is 5.36%, which is 30 times higher than in Europe. Therefore, urgent measures are to be taken to liquidate severe iodine deficiency in Tyva.