2002—2011年天津市居民碘营养水平调查及适宜食用盐碘含量分析

A survey of iodine nutrition status of Tianjin residents between 2002 to 2011 and analysis of suitable iodinecontent in salt

目的掌握天津市居民食用碘盐情况和碘营养水平，为科学补碘提供依据。方法抽样方法：①盐碘：2002—2011年，按照全国碘缺乏病监测方案，在天津市18个区（县）采集居民户家食用盐盐样，进行盐碘含量测定。②儿童碘营养：2002、2005、2009、2011年分4次进行儿童碘营养状况调查。其中，2002年和2005年在天津市每个区（县）抽取2所小学，每所小学按照年龄、性别均等原则抽取8—10岁儿童40名，进行甲状腺检查，同时抽取20名儿童，采集随机1次尿样，进行尿碘含量测定。2009年，在每个区（县）按东、西、南、北、中5个方位各抽取1个乡（镇、街道），不足5个乡时全部抽取，每个乡（镇、街道）抽取1所村小学，每所小学抽检8-10岁儿童20名．进行尿碘含量测定。2011年采取按人口比例概率抽样方法，在全市抽取30所小学，每所小学抽查40名8-10岁儿童，进行甲状腺检查。同时抽取12名儿童，进行尿碘含量检测。③育龄妇女碘营养：2007、2008和2010年，在汉沽区分别选取150、50、60名育龄妇女，采集尿样，进行尿碘测定。④孕妇和哺乳期妇女碘营养：2011年在天津市抽取的小学附近选择3个乡，每个乡抽取孕妇和哺乳期妇女各5人，采集尿样，进行尿碘检测。检验方法：①盐碘采用《制盐工业通用试验方法碘离子的测定》（GB／T13025．7—1999）直接滴定法，川盐及其他强化食用盐采用仲裁法进行测定；②甲状腺检查采用B超法，按地方性甲状腺肿的诊断标准（WS276—2007）进行判定；③尿碘测定采用砷铈催化分光光度方法（WS／T107—2006）测定。结果2002—2011年合格碘盐食用率、碘盐合格率、碘盐覆盖率和非碘盐检出率分别为92．7％（43489／46926）、97．4％（43489／44694）、95．1％（44694／46926）和4．8％（2273／46926），盐碘中位数在29．2—36．7mg／kg。4次监测儿童尿碘中位数分别为228．0、221．5、191．8和194．7μg／L，3次监测儿童甲状腺肿大率分别为2．1％（27／1258）、1．6％（19／1186）和2．1％（26／1219）。孕妇和哺乳妇女的尿碘中位数分别为145．2和136．0μg／L。3次监测的育龄妇女尿碘中位数分别为130．7、196．1和229．5μg／L，且随着碘盐覆盖率的增加而有所提高。结论天津市居民的碘营养处于适宜水平，育龄妇女和哺乳期妇女尿碘处于适宜水平，而孕妇则低于适宜水平。天津市盐碘水平定为30mg／kg。或者普通居民盐碘定为25mg／kg、孕妇盐碘定为30mg／kg较为适宜。

Objective To investigate the consumption status of iodized salt and iodine nutrition status of Tianjin residents, and to provide a scientific basis for iodine supplementation. Methods Sampling methods： ① Salt iodine： According to ＂The National Project of Surveillance on IDD＂, the iodine in salt samples from 18 Tianjin districts （counties） was tested between 2002 to 2011. ②Iodine nutritional status of children： Investigation of iodine nutritional status of children was conducted four times in 2002, 2005, 2009 and 2011. In 2002 and 2005, two primary schools were selected in each district. By age, gender parity principle, 40 subjects aged from 8 to 10 in each school were randomly ＇selected to perform thyroid examination and 20 of them were selected to collect urine samples for determination of urinary iodine. In 2009, according to their sub-area positions in the north, the south, the east, the west and the center of each district, 5 primary schools were selected in each town （if there were less than five towns in the district, all towns had been selected）. Twenty subjects aged from 8 to 10 in each school wereselected to collect urine samples for determination of urinary iodine. In 2011, probability sampling method （PPS） was used to select 30 primary schools, and then 40 children aged from 8 to 10 were randomly selected in each school to examine thyroids. At the same time, urine samples from 12 children of the 40 selected children were tested. ③Iodine nutritional status of women of childbearing age： In 2007, 2008 and 2010, 150, 50 and 60 women of childbearing age were selected in Hangu District, urine samples of them were collected for determination of urinary iodine. ④Iodine nutritional status of pregnant and lactating women： In 2011, 3 towns around each primary school were selected. Five pregnant and five lactating women were selected in each town, urine samples of them were collected for determination of urinary iodine. Test methods ： ①Salt iodine was tested by direct titration, while Sichuan salt and other reinforced edible salt by arbitration determination based on the ＂General Test Method in Salt Industry-Determination of Iodide Ion＂ （GB/T 13025.7-1999）. ②Thyroid was tested by B-type-ultrasound and judged according to ＂Diagnostic Criterion of Endemic Goiter＂ （WS 276-2007）. ③Urinary iodine was tested by the ＂Method for Determination of Iodine in Urine by As3-Ce4＋ Catalytic Spectrophotometry＂ （WS/T 107-2006）. Results From 2002 to 2011, the consumption rate of qualified iodized salt, the rate of qualified iodized salt, the coverage rate of iodized salt, the rate of non-iodinated salt was 92.7%（43 489/46 926）, 97.4%（43 489/44 694）, 95.1% （44 694/46 926） and 4.8%（2273/46 926）, respectively. The median salt iodine was in the range of 29.2 - 36.7 mg/kg. Children＇s urinary iodine was monitored 4 times, the median urinary iodine was 228.0,221.5,191.8, and 194.7 μg/L, respectively. Children goiter rates were 2.1% （27/1258）, 1.6% （19/1186） and 2.1% （26/1219） of the 3 times monitored. The median urinary iodine in pregnant and lactating women was 145.2 and 136.0 μg/L. The median urinary iodine in women of childbearing age was 130.7,196.1 and 229.5 μg/L, which increased with the increase of coverage of iodized salt. Conclusions The iodine nutrition of Tianjin residents, women of childbearing age and lactating women are at appropriate level. The iodine nutrition of pregnant women is lower than appropriate level. Recommended salt iodine level in our city is 30 mg/kg, or 25 mg/kg for ordinary residents, and 30 mg/kg for pregnant women.