Analysis of surveillance results on iodine nutrition among children aged 8-10 years in Tongchuan City Shaanxi Province from 2013 to 2015 / 中华地方病学杂志

ABSTRACT

Objective To analyze the iodine nutritional status and the trend of children aged 8-10 years in Tongchuan City after the implementation of the new iodized salt standard,and to provide scientific basis for prevention and treatment of iodine deficiency disorders (IDD) in the region.Methods In 2013-2015,one town was selected respectively from 5 areas (east,west,south,north,center) in 4 counties of the city.A central primary school was selected in each sampled town,42 children aged 8-10 years in every school were selected for detection of the thyroid volume by palpation,and for collection of 15 urine samples for determination of urinary iodine (42 urine samples were collected in 2015).Four villages were selected from each town,15 residents were selected to determine salt iodide content by quantitative detection.Urinary iodine was tested using arsenic cerium catalytic spectrophotometry (WS/T 107-2006).Salt iodine was tested using direct titration method (the arbitration method was adopted for quantitative determination in the case of Sichuan salt or other special salts,GB/T 13025.7-2012).Results The thyroid palpate welling rate was 3.40％ (29/854),4.52％ (38/840) and 2.98％ (25/840) in children aged 8-10,respectively,and there was no statistical significant difference between different years (x2 =3.078,P ＞0.05).Totally,1 320 urine samples were collected from 8-10 years old children,the median of urinary iodine (MUI) was 185.14 μg/L;in the 3 years,the MUI in each year was 229.43,183.34 and 173.80 μg/L,respectively.The proportion of urinary iodine under 50 μg/L was less than 20％,under 100 μg/L was also far below 50％;urinary iodine proportion in 100 ～ ＜ 200 μg/L rose year by year.There were significant differences in the MUI among the 8 and 9 years age groups (H =12.736,10.128,P ＜ 0.05),there was no significant difference in the 10 years age group (H =3.849,P ＞ 0.05).In gender groups,there was significant difference in the MUI among male children (H =9.261,P＜ 0.05),there was no significant difference in the MUI among female children (H =4.759,P ＞ 0.05).The median of salt iodine was 24.10,24.75 and 24.10 mg/kg,respectively.The coverage rates of iodized salt were all higher than 95％,the qualified rates of iodized salt were all higher than 90％.Conclusions After implementation of the new standard iodized salt,the iodine level of children aged 8-10 years is at the appropriate level.The IDD surveillance indicators all meet the national standards for elimination of the disease.