Neonatal Thyroid-Stimulating Hormone Screening as an Indirect Method for the Assessment of Iodine Deficiency in Estonia

Abstract

According to neonatal thyroid screening the incidence of congenital hypothyroidism in Estonia is 1:2,860. Transient hyperthyrotropinemia with a raised thyroid-stimulating hormone level of 5 μU/ml occurred in 17.7% of infants and was not associated with low birth weight, small birth length, low gestational age or congenital anomalies. Based on WHO criteria (WHO/UNICEF, 1994) it corresponds to mild iodine deficiency in Estonia (3% or less is in iodine-sufficient areas). This is in agreement with the previously reported median urinary iodine content of 65 μg/l in children. The frequency of infants with TSH >5 μU/ml was 16.4, 21 and 17.2% in three regions (north, central and south) of Estonia, respectively, indicating mild to moderate iodine deficiency. These findings show the possibility of using the results of newborn screening for congenital hypothyroidism to assess the severity of iodine deficiency in Estonia. The introduction of universal iodine prophylaxis is recommended.

Neonatal thyroid screening in a mild iodine deficiency endemic area in Iran

“…[8,9] In some European countries, the recall rate was between 0.16% and 2.7%. [10,11] Also, a recall rate of 1.6% with a cut off point of 20 µU/mL has been reported in Turkey. [12] Several studies have confi rmed the validity of this policy as an acceptable index for evaluating iodine intake in populations.…”

Neonatal Thyroid-Stimulating Hormone Concentrations in Belgium: A Useful Indicator for Detecting Mild Iodine Deficiency?

“…However, although several studies attempted to apply neonatal TSH values in determining population iodine status and some have proven to be successful [5]; [6]; [8]; [25], some have provided conflicting or uncertain data [10]; [11].…”

Neonatal Thyroid-Stimulating Hormone Screening as a Monitoring Tool for Iodine Deficiency in Turkey

“…This tool has been used to assess the severity of ID and also to monitor the outcome of iodine prophylaxis programs in countries or sub-national regions (7,15,16,17,18,19,20,21,22). Although some of them have provided conflicting results especially in cut off values (15,16), there are many successful country examples (17,18,19,20,21,22). In Thailand, with the application of a geographic information system to their neonatal TSH screening program, it has been possible to identify ID down to the sub-district level.…”