Excessive iodine intake in schoolchildren.

PURPOSE: Inadequate iodine intake may result in iodine deficiency disorders (IDD). Thus, for more than 50 years, policies for the regulation of salt fortification with iodine have existed in Brazil. In 2003, a study on 6-14-year-old schoolchildren from regions of the state of São Paulo showed a median urinary iodine concentration of 360 µg/L. The objective of the present study was to assess the iodine nutrition status among schoolchildren. METHODS: The study was conducted on 828 schoolchildren aged 4-13 years from eight schools in the interior of the state of São Paulo. A casual urine sample was collected from each volunteer for iodine determination by the adapted method of Sandell-Kalthoff. RESULTS: Only 1.9% (n = 16) of the children evaluated had low values of urinary iodine (<100 µg/L), while 24.6% had urinary iodine excretion values between 200 and 300 µg/L, and 67.1% had values above >300 µg/L. CONCLUSIONS: The results show that the iodine nutritional status of the schoolchildren studied is characterized by a high urinary iodine excretion, which might reveal an increase in iodine consumption by this population.

Iodação do sal e ingestão excessiva de iodo em crianças / Salt iodination and excessive iodine intake among schoolchildren

O presente trabalho tem como objetivo avaliar a excreção urinária de iodo e relacionar com a sua quantidade presente no sal de consumo humano. Participaram do estudo 145 crianças de duas escolas: uma de zona rural e outra de urbana. Foram realizadas avaliação antropométrica e coleta de amostra de urina e do sal de cozinha cada uma das crianças voluntárias. Na escola rural, 3,8% das crianças apresentaram deficiência de iodo. Entretanto, a maioria dos valores de iodúria ficou acima de 300μg/L (62,03%) com 59,49% das amostras do sal de cozinha entre 20 e 60mg de iodo por quilo de sal. Para a escola urbana, 3,03% das crianças apresentaram iodúria inferior à 100μg/L, sendo que, 90,91% das crianças apresentaram valores de iodúria superior a 300μg/L. Desse total, 84,85% das amostras do sal de cozinha encontrava-se entre 20 e 60mg de iodo por quilo de sal. A deficiência de iodo na população estudada está controlada, destacando-se agora uma nova realidade de alta prevalência de excesso de iodo urinário.

The objective of the present study was to evaluate the urinary excretion of iodine and relate it to the amount present in salt for human consumption. The study involved 145 children from two schools: a rural one and an urban one. We performed anthropometric measurements and collected a urine sample and a kitchen salt sample from each child. In the rural school, 3.38% of children had iodine deficiency. However, most of the values of urinary iodine were above 300 μg/L (62.03%) and 59.49% of the kitchen salt samples contained 20 to 60 mg iodine per kilo of salt. In the urban school, 3.03% of the children had urinary iodine excretion of less than 100 μg/L and 90.91% of the children had urinary iodine values exceeding 300 μg/L. Of this total, 84.85% of the kitchen salt samples contained 20 to 60 mg iodine per kilo of salt. Iodine deficiency is controlled in this population, with the current reality showing a high prevalence of excess urinary iodine.