IODINE
DEFICIT IN THE CANARY ISLANDS THROUGH THE PROGRAM OF NEONATAL SCREENING OF
CONGENITAL HYPOTHIROIDYSM
Domenech E, Goya M, Borque
P, Carles E, Morales Y,Rodriguez Y, Barroso F
Department of Pediatrics,
University of La Laguna (Tenerife), Spain
Objective: Analyze the value of the level
of neonatal thyrotropin (TSH) as indicator of prevalence of iodine deficit
in the general population.
Background: WHO/UNICEF/ICCIDD has established that if
the frequency of neonatal TSH above 5 mU/ml blood is below 3% indicates a normal
iodine supply, that a frequency of 3-19.9% indicates mild iodine deficiency
and that frequencies of 20-39.9% and above 40% indicate moderate to severe
ID.
Methods: 11.806 NB have been studied that correspond to all the births from
September 2000 to March 2001 in the Canary Islands. The determination of TSH in blood dried up in
filter paper was carried out in the reference center of neonatal screening
by the immunofluorescence method (Delphia). The percentage of newborns
whose TSH values were between 5 and 10 mU / ml was calculated by each island. Taken
samples of cord blood were not used.
Results: 1477 NB had values of TSH
between 5-10 mU/ml (8.49 % of NB) at 5.4 days of life
(range 2.9-6.3). By islands the percentage of NB
with values of TSH between 5-10 mU/ ml were: Gran
Canaria 18.7 %, Lanzarote 7.2 %, Fuerteventura 5.6 %, Tenerife 7.3 %, La
Palma 9.9 %, La Gomera 6.7 % and El Hierro 12.5 %. In Gran Canaria the
samples of blood were taken in 79.3% of the cases with less than 48 h. of
life and in these infants the TSH was between 5 and 10 mU/ ml
in 20.9% of them, while in 20.7% of the NB the samples were obtained with
more than 3 d. of life and the percentage of values of TSH between 5-10 mU/ml
was of 10.2%.
Conclusion: There is a mild iodine deficit in the Canary Islands, according to
the values of TSH in the neonatal screening of Congenital Hypothyroidism.