Iodine nutrition of special groups in Tianjin after implementation of new salt iodine standard

Objective To investigate the iodine nutritional level of three special groups(pregnant women,lactating women and children aged 8-10 years) in Tianjin after the implementation of new salt iodine standard and to provide a scientific basis for salt iodine concentration adjustment. Methods In 2012 and 2013, two primary schools were selected in each of the six counties in the city, 25 ml urine of 36 children aged 8-10 years in each school were randomly collected, and 100 g edible salt were collected in every child family.A total of 30 early, middle, late pregnant women and 30 lactating women in each county were selected respectively, the random sample of 25 ml urine were collected. The salt iodine was determined by direct titration, Sichuan salt and other fortified salt by arbitration determination. The urinary iodine was determined by arsenic cerium catalytic spectrophotometry. Results As for 8-10 years old children, pregnant women, lactation women, the medians of urine iodine were 180.0, 127.2 and 85.8 μg/L respectively. The level of urinary iodine of children of different parts was appropriate, and that for the pregnant women was lower than appropriate. The iodine nutrition level of lactation women in coastal counties was appropriate, other parts insufficient. The median of iodized salt iodine was 23.30 mg/kg. Conclusion Urine iodine of three special groups in Tianjin exists obvious differences in people and regions. Iodine nutrition of pregnant and lactation women is insufficient. The median salt iodine concentration is below the standard(30 mg/kg) required in Tianjin. The amount of salt iodine added should be increased to comply with the standard.