A comparative analysis of monitoring results of iodine deficiency disorders between Xianyang City of Shaanxi Province and Yinchuan City of Ningxia after adjustment of salt iodine content / 中华地方病学杂志

ABSTRACT

Objective To compare the indexes related to monitoring of iodine deficiency disorders between Xianyang City of Shaanxi Province and Yinchuan City of Ningxia Autonomous Region in 2016 for providing a basis in evaluating control measures to iodine deficiency disorders. Methods In 2016, 13 counties (districts) in Xianyang City and 6 counties (districts) in Yinchuan City were conducted sample surveys in accordance with the requirements of the"National Iodine Salt Monitoring Program", and the surveillance results were analyzed. The main indicators included salt iodine content, urinary iodine content in children aged 8 - 10 and pregnant women and children's goiter rate. Salt iodine content was measured by direct titration according to the "Determination of Iodine in General Test Method for Salt Industry" (GB/T 13025.7-2012). Urinary iodine content was determined using arsenic cerium catalytic spectrophotometry (WS/T 107-2006). Children's goiter was determined by B-ultrasound examination based on the "National Diagnostic Criteria for Endemic Goiter" (WS 276-2007). Results In 2016, Xianyang City and Yinchuan City had monitored 3900 and 1800 salt samples, respectively, the medians of salt iodine were 30.2 and 27.8 mg/kg, respectively. The median of salt iodine in Xianyang City was higher than that in Yinchuan City (Z = 14.58, P < 0.05); non-iodized salt rate (0.18％, 7/3900), unqualified iodized salt rate (0.72％, 28/3900) in Xianyang City were lower than those in Yinchuan City (0.56％, 10/1800;1.50％, 27/1800; χ2=5.86, 7.88, P<0.05), and qualified salt iodide consumption rate in Xianyang City (99.10％, 3865/3900) was higher than that in Yinchuan City (97.94％, 1763/1800, χ2 = 13.24, P < 0.05). The median of urinary iodine in children in Xianyang City (247.75 μg/L) was higher than that in Yinchuan City (223.70 μg/L, Z = 21.04, P < 0.05), and the ratio of urinary iodine < 100 μg/L in Xianyang City (11.92％, 310/2600) was lower than that in Yinchuan City (15.08％, 181/1200, χ2= 7.29, P < 0.05). The median of urinary iodine in pregnant women in Xianyang City (176.86 μg/L) was lower than that in Yinchuan City (187.70 μg/L, Z = 7.33, P < 0.05), and the ratio of urinary iodine < 150 μg/L in Yinchuan City (38.50％, 231/600) was higher than that in Xianyang City (32.00％, 416/1300,χ2=7.72,P<0.05). The thyroid palpate swelling rates of children in Xianyang City and Yinchuan City were 1.94％(53/2730) and 2.22％ (28/1260), respectively, the rates between the two cities was not statistically significant (χ2=0.34, P > 0.05). Conclusions The monitoring indexes of iodine deficiency disorders in Xianyang City and Yinchuan City have reached the national standard for eliminating iodine deficiency disorders. In comparison, Yinchuan City should further strengthen the monitoring of iodine nutrition level in children and pregnant women, iodized salt market supervision and health education.