Nutrición de yodo en escolares de cuatro zonas de Chile en el año 2001 / Iodine nutrition in school children of four areas of Chile during the year 2001

ABSTRACT

Background: In Chile, the recommendation for salt iodination was reduced from 100 to 40 ppm, after detecting high urinary iodine excretion in school age children. Aim: To assess iodine nutrition in school age children after the modification of salt iodination. Subjects and methods: Iodine nutrition was studied in 3712 school age Chilean children of primary level in 4 areas (Calama, Santiago, Temuco and Punta Arenas) through palpation of thyroid gland, urinary iodine excretion and iodine concentration in salt for human consumption of the surveyed areas. Results: A 6.4% goiter prevalence was found (5,9% in boys and 6,8% in girls). Grade Ia goiter was more common (5.0%), without detecting differences between areas (7.3% in Calama, 5.9% in Santiago, 5.9 in Temuco and 6.7 in Punta Arenas). Iodine concentration in salt for human consumption of the areas was adequate according to the recent modification of Chilean legislation (25.4 mgI/g salt in Calama, 36.2 in Santiago, 27.7 in Temuco and 33.4 in Punta Arenas). Urinary iodine excretion was very high according to recommendation in boys and girls (2838 and 2852 mgI/g salt in Calama, 700 and 837 in Santiago, 1318 and 1438 in Temuco, 407 and 312 in Punta Arenas). Conclusions: Endemic goiter is not longer a problem in Chile. Salt iodination is in agreement with present legislation. However, urinary iodine excretion increased in Calama and Temuco, did not change in Santiago and decreased only in Punta Arenas in spite of the changes in the legislation. It is necessary to investigate the causes of the high urinary iodine excretions detected in school age children, and it is very important to have a continuous surveillance of iodine nutrition in Chile (Rev Méd Chile 2003; 131 1390-8).