ABSTRACT
Se evaluó la prevalencia de bocio por palpación de la glándula tiroidea en 1296 escolares de educación básica de una zona con alta ingesta de yodo (Calama) y se comparó con la de otra zona de ingesta normal de yodo (Punta Arenas). En una sub muestra del 10 por ciento de los escolares se midió la excreción de yodo urinaria y los niveles de hormonas tiroídeas en sangre. En ambas localidades se seleccionaron aleatoriamente del comercio 148 muestras de sal para consumo humano en las que se determinó la concentración de yodo. Se encontró una prevalencia de bocio de 11,1 por ciento (10,0 por ciento en varones y 12,5 por ciento en mujeres) mayoritariamente bocio grado Ia (7,2por ciento), sin diferencias por zona (11,6 por ciento en Calama y 10,6 por ciento en Punta Arenas). La concentración de yodo en la sal de consumo humano en ambas localidades fue adecuada a la exigencia actual del Reglamento Sanitario de los Alimentos (RSA) (33,3 µgI/g sal en Calama, 34,0 en Punta Arenas). La excreción de yodo en la orina fue significativamente más alta en Calama (460 ± 190 µgI/L)que en Punta Arenas (273 ± 155). No se detectaron diferencias en los niveles de T4 y TSH (Calama 7.1 ± 1.5 y 3.3 ± 1.8 y Punta Arenas 7.2 ± 1.1 y 2.9 ± 1.2 respectivamente) en tanto que las valores de T3 en ambas localidades mostraron diferencias significativas (103.9 ± 33.1 y 145.0 ± 26.0 respectivamente, p<0.001) . Se observó sólo una tendencia al aumento de la prevalencia de bocio, con persistencia de valores elevados de yoduria en Calama, lo que sugiere una fuente de yodo extra en esta localidad, cuya procedencia desconocemos y es necesario investigar.
Goiter prevalence determined by palpation of thyroid gland was evaluated in 1296 primary school age children from an area of high iodine intake (Calama) and compared with an area of normal iodine intake (Punta Arenas). Urinary iodine excretion and plasmatic thyroid hormones were measured in 10 percent of school children. In both areas 148 samples of salt for human consumption were randomly selected to measure iodine concentration. A goiter prevalence of 11,1 percent (10,0 percent in males and 12,5 percent in females) mainly goiter grade Ia (7,2 percent), without differences per area (11,6 percent in Calama and 10,6 percent in Punta Arenas) was found. Iodine concentration in salt for human consumption at both areas was adequated according the present Food Sanitary Regulation (FSR) in Chile (33,3 (gI/g salt in Calama, and 34,0 in Punta Arenas). Urinary iodine excretion was significantly higher in Calama (460 ( 190 (g I/L) than in Punta Arenas (273 ( 155 (g I/L). No differences were detected in T4 and TSH plasma levels (Calama 7.1 ( 1.5 and 3.3 (1.8; and Punta Arenas 7.2 ( 1.1 and 2.9 ( 1.2 respectively), while T3 plasma levels were significantly higher in Punta Arenas (103.9 ( 33.1 y 145.0 ( 26.0 respectivamente, p<0.001) . Only a tendency to a higher goiter prevalence with persistent and significantly higher urinary iodine excretion in children at Calama was observed, suggesting an extra source of iodine in this area, with an unkown origen that must be investigated.
Subject(s)
Humans , Child , Goiter/epidemiology , Iodine , Iodine Deficiency , Students , Thyroid Gland , Chile , Sodium Chloride/standards , Micronutrients , Prevalence , Thyroid Hormones , Iodine/urine , Iodine/bloodABSTRACT
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).
Subject(s)
Humans , Male , Female , Child , Diet , Goiter, Endemic/epidemiology , Iodine , Sodium Chloride, Dietary , Chile/epidemiology , Iodine/urine , Prevalence , Sodium Chloride, Dietary/analysisABSTRACT
Background: although endemic goiter is an easily controlled chronic disease, it continues to be a serious global public health problem. Aim: To study iodine nutrition in school age children from different areas of Chile. Subjects and methods: Thyroid gland was palpated in 4181 school age children from Calama, Santiago, Temuco and Punta Arenas. Urinariy iodine excretion was measured to 9 percent of these children and iodine concentration in salt for human consumption obtained in each of these areas was determined. Results: A 9 percent goiter prevalence in boys and 11 percent prevalence in girls was detected. The prevalence of goiter Ia was 6.5 percent and the figure in different geographic areas was similar. Iodine concentration in salt for human consumption was adequate according to Chilean legislation (82.6, 95.7, 96.8 and 93.2 ug ugI/g salt in Calama, Santiago, Temuco and Punta Arenas respectively). Urinary iodine excretion in boys and girls was 1695 and 1802 ug l/g creatinine in Calama, 680 and 732 in Santiago, 574 and 690 in Temuco, 570 and 528 in Punta Arenas. These values are well above recommendations. Conclusions: Endemic goiter is no longer a problem in Chile, the importance of a continuous surveillance of iodine nutrition in Chile and the reduction of salt iodine concentration required by Chilean legislation is underscored