Screening for congenital hypothyroidism as an additional method for studying the epidemiology of iodine deficiency diseases

Abstract

Epidemiological screening has been carried out in West Siberia in order to assess the prevalence of iodine deficiencies. The incidence of goiter was assessed, iodine excretion with the urine measured in children, and levels of neonatal thyrotropic hormone (TTH) measured in the course of screening for congenital hypothyrdsis. The findings confirmed the significance of measuring TTH in the newborns for detecting the degree of iodine deficit. The incidence of increased TTH level (more than 25 IU/liter) in the newborns of West Siberia (1.69%) is notably higher than in previously screened provinces of Canada and Australia without iodine deficit and Southern Poland cities with a moderate iodine deficit. Analysis of the frequency distribution of neonatal TTH levels in various geographical regions of the Tyumen district indicates a higher incidence of iodine deficiencies near and beyond the Polar Circle and in the Urals. These findings coincide with previous data on increased incidence of goiter and decreased iodine excretion with the urine in these regions. Monitoring of TTH levels within the framework of program of screening for congenital hypothyrosis can be used to assess the prevalence of iodine deficiencies in the population.