【作者】 石平；

【导师】 周玲； 赵金扣；

【作者基本信息】 南京医科大学 ， 流行病与卫生统计学， 2004， 硕士

【摘要】 碘是人体必需的微量元素，它是合成甲状腺激素的原料之一。碘是通过甲状腺激素发挥代谢和发育(体格发育和脑发育)的调节作用。长期碘摄入不足会造成以脑发育障碍为主要特征的碘缺乏病(Iodine Deficiency Disorders,IDD)，而长期碘摄入过量也会导致碘过多病(Iodine Excess Disorders,IED)。在实施全民食盐加碘(Universal Salt Iodization,USI)防治IDD的今天，人们非常关心人体每天碘摄入的适宜量、安全范围，现行的全民食盐加碘是否会造成人群的高碘摄入及其诱发的可能危害。 事实证明，USI是我国消除碘缺乏病的最根本策略，已取得了巨大的胜利。但也存在一些问题：USI实施后碘性甲亢(Iodine-induced hyperthyroidism,IIH)等疾病发病率在近期有所增加，局部地区高碘环境导致高碘甲状腺肿流行，目前加碘盐浓度是否适宜且能满足各种人群碘营养需要等，本文从探讨解决上述问题的角度出发，通过我国现有监测资料的分析、轻度缺碘地区供应不同浓度碘盐对主要指标的影响以及江苏省外环境碘的分析，为我国调整碘缺乏病防治对策积累了进一步的证据。 第一部分 全民食盐加碘后2～4年甲状腺容积变化及其与人群尿碘水平关系分析 收集1997年和1999年全国第2次和第3次碘缺乏病监测资料，分析全民食盐加碘后2～4年全国8～10岁学龄儿童甲状腺容积的变化趋势、尿碘变化趋势及二者间的关系。主要结果如下： 1．1997、1999年两次监测甲状腺容积频数分布和甲状腺肿大率比较分析 1997年全国监测点8～10岁儿童甲状腺容积B超实测值有效例数为31343例，均数3.37ml、中位数3.27ml、众数2.85ml、97％分位数 南京医科大学硕士学位论文6.30ml。1 999年全国监测点8一10岁儿童甲状腺容积B超实测值有效例数为34545例，均数3.58 ml、中位数3.45，二1、众数3.16 ml、97%分位数6.4om一。两者频数分布差异有显著性(x胜382.0268，P<0.001)o分年龄计算的甲状腺容积1997年和}999年差异亦有显著性，1999年各性别年龄组甲状腺容积大于!997年。但是，按B超法计算的甲状腺肿大率1999(8.49%)和1997年(8.27%)之1’司无统计学差异(xZ=1.幻8，P>0 .05)。2.1997、1999年两次监测儿童尿碘浓度频数分布比较分析 1997年和1999年尿碘浓度频数分布差异显著(xZ=3 36.7以)3，P<0.05)。虽然1997年尿碘均数(343.80拼g/L)稍高于1999年(318.35林g/L)，但是其尿碘中位数(265.50抖g/L)却比一999年(27 1 .40拼g/L)的稍小，且1 997年尿碘值大于800“g几所占比例(5.87%)大于1999年(2.03%)，说明1997年特高尿碘值所占比例较1999年大。另外，各省除西藏外尿碘浓度均达到了国家消除标准(尿碘中位数)1 00拼叭)，但是部分省份尿碘中位数与尿碘频数分布说明的问题不一致(，J、于50雌几所占比例大于20%)。以上分析表明，1997年和1999年期间有相当数量的人群还受着碘缺乏的危害，而同时又有相当数量的人群处于高尿碘水平(尿碘中位数>800林留L)。3 .1 997、】999年各省甲状腺容积和尿碘变化趋势分析 两次监测甲状腺容积下降最明显的省(市)有上海、天津和江苏，而升高最明显有青海、新疆和贵州省;两次监测儿童尿碘值中位数升高最明显的有贵州、江苏、云南省，下降最大的有山东、河南、吉林省。各省尿碘值的变化趋势与甲状腺容积的变化趋势并不一致(r=一0.084，P=0 .533)。说明消除碘缺乏病的过程中尿碘与甲状腺容积之间不存在必然的相关关系。第二部分苏中轻度缺碘地区实施不同浓度食盐加碘后碘营 养状况调查和分析 为了解我国食用盐加碘新标准(35士15mg/kg)实施2年多以来轻度缺碘地区5种重点人群的碘营养状况，以评价现行的碘盐浓度能否 南京医科大学硕士学位论文满足不同重点人群的碘营养需求;同时比较轻度缺碘地区不同加碘盐浓度1年后人群碘营养变化情况，为进一步调整碘盐浓度和实施因地制宜供应不同浓度碘盐提供科学依据，选择扬州市高邮张轩镇和宝应子英镇作为实验组，高邮武安作为对照组，分别给予不同浓度碘盐(lomg/kg、15mg/kg和35mg/kg)，进行社区干预试验。主要结果如下:1.干预前后盐碘浓度比较 高邮张轩(lomg/kg)和宝应子英(15mg/kg)两实验地区干预前后盐碘中位数比较差异有显著性(Z值分别为一14.798、一14.949;P值均小于0.001)，而高邮武安对照组干预前后盐碘中位数比较差异无显著性(Z=0.128，P>0.05)，但是高邮武安干预前后盐碘浓度频数分布有显著性差异(x“=25.276，P<0.01)。2.干预前后五种人群尿碘浓度比较 高邮张轩实验组干预后5种人群中除哺乳妇女外尿碘中位数均见下降，育龄妇女、O一2岁婴幼儿下降有显著性(P<0 .001)，8一10岁学龄儿童下降不显著(P>.05)，但是其尿碘频数分布干预前后差异有显著性(xZ一14.165，P<0 .05)。哺乳妇女反而上升且有显著性差异(P<0 .05)。宝应子英实验组干预后尿碘中位数除育龄妇女和。一2岁婴幼儿有显著下降外(P<0.001)，8一10岁学龄儿童、孕妇和哺乳妇女都无明显变化(P>.05)，其中8一10岁学更多还原

【Abstract】 Iodine is one of human body’s necessary micronutrients. It is one of raw materials for synthesis of thyroid hormone which plays an important role in metabolism and development (both mental and physical) of human body. Lack of iodine in our body can lead to iodine deficiency disorders (IDD), which is characterized by retarded mental and physical development. Meanwhile, long excessively absorbed iodine may result in iodine excess disorders (IED). Today, after implementing Universal Salt lodization (USI) for many years, people get puzzled about the questions what is the adequate intake of iodine (AI), recommended dietary allowance (RDA) and tolerable upper intake level (UL), and if the present iodine content in iodized salt is optimal, not low or high.It is known to all that USI is the most effective policy to eliminate IDD, and gained giant success in our country. However, there are also many problems including the incidence of iodine-induced hyperthyroidism (IIH) and other diseases induced by iodization; endemic iodine-induced goiter in many areas caused by excessive iodine in drinking water of natural origin in our country; and ensurance of optimal iodine nutritional status of various populations. The present thesis tries to answer the above-mentioed questions by analyzing the existing surveillance data in China, conducting survey to compare the effectiveness on population indicators of iodized salt with different iodine contents, and geographic information analysis of iodine concentrations in drinking water in Jiangsu province. The present thesis provides additional evidence for adjustment of USI policy in China.Section One: Relationship between thyroid volume and urinaryiodine after 2-4 years of universal salt iodizationData from the 2nd and 3rd China national IDD surveillance were collected to analyze the tendency of thyroid volume (TV) variation, urinary iodine (UI) variation and the relationship between TV and UI among children aged 8-10 years in China after 2-4 years of universal salt iodization. The main results are presented as follows:1. Comparison of distributions in thyroid volume of children aged 8-10 years in 1997 and 1999.In 1997, the statistics of TV (ml) of 31343 children aged 8,9,10 years in China were 3.37 of mean, 3.27 of median, 2.85 of mode, 6.30 of 97% percentile. In 1999, the statistics of TV (ml) of 34545 children aged 8,9,10 years in China were 3.58 of mean, 3.45 of median, 3.16 of mode, 6.40 of 97% percentile. There was a significant difference ( x 2=382.0268, P<0.001 ) in the distribution. Significant difference was also found for Thyroid Volume calculated by age. The two rates of goiter between 1999 (8.49%) and 1997 (8.27%) measured by B-ultrasonography were not significantly different ( x2=1.408, P>0.05 ) .2. Comparison of distributions of urinary iodine concentrations of children aged 8-10 years in 1997 and 1999.The frequency distributions of urinary iodine concentrations of children aged 8-10 years in 1997’s and 1999’s were significantly different ( x2=336.7603, P<0.05 ) . In 1999, the mean of urinary iodine concentration (318.35ug/L) is lower than that in 1997 (343.80ug/L), but the median in 1999 (271.40ug/L) is slightly higher than that in 1997 (265.50ug/L). The number of sampling hits which urinary iodine concentrations were higher than 800ug/L in 1997 (5.87%) are more than those in 1999 (2.03%). This suggests that iodine nutrition in individualsin some provinces in 1997 were excessive. The medians of urinary iodine concentration in whole country except Tibet Province were above 100ug/L. But the number of sampling hits which urinary iodine concentrations were lower than 50u.g/L in some provinces are more than 20%. This phenomena indicated that there were still some people under the threat of IDD, and at the same time, some high urinary iodine concentration in 1997 and 1999 indicates that some districts in China in both years had risk of being excessive iodine nutrition.3. Relationship between thyroid volume and urinary iodineThe thyroid volume is uneve更多还原