Association of Salt Iodization and Urine Iodine Concentration in Schoolchildren from Public Schools in Northeast of Brazil.

Abstract

Iodine deficiency (ID) is recognized as a leading risk factor for child development. Universal salt iodization (USI) is an effective and well-established intervention strategy for the prevention of iodine deficiency disorders (IDD). To evaluate the levels of iodine in household salt samples and the urinary iodine concentration (UIC) in schoolchildren aged 6 to 14years in public schools in Bahia, Brazil. A cross-sectional study was conducted with 1231 students (6 to 14years old) from 17 public schools in Bahia. The iodine concentration was evaluated in salt and UIC samples. The adapted Sandell-Kolthoff reaction was used to determine urinary iodine levels. A spectrophotometer (UV-Vis) was used to examine the reduction of ceric ammonium sulfate. A standard iodine solution using a potassium iodate was used to extrapolate the iodine concentrations. The total of 665 salt samples had a median iodine concentration of 24mg/kg (25th-75th percentile 17.0 to 28.5mg/kg). The largest proportion (79.6%) of salt samples had iodine concentration in the recommended range, 17.6% of the samples presented iodine at a salt concentration below the established level (<15mg/kg) and a small proportion was above it (2.8%). The general mean urinary iodine concentration (MUIC) was 217.53 ± 28.30μg/L and median was 205.50μg/L. The students evaluated and the salt samples analyzed showed satisfactory results, as recommended by Brazilian legislation and nutritional recommendations of the World Health Organization (WHO).