Mycotoxin-caused myocardial injury has been demonstrated based on epidemiological and experimental studies. Citreoviridin (CIT) is a toxin from yellow-green Penicillium easily grown in wet and cold environment. The CIT-contaminated food intake could cause myocardial injury, which might be the etiology of endemic Keshan disease. The yellow mildewed rice could produce toxic CIT and induced beriberi-linked cardiac insufficiency. In view of the similarity between Keshan disease and cardiac beriberi (wet beriberi), it was considered that the two diseases might be the same illness with different names. Research data in recent years demonstrated that the CIT and other mycotoxins might be also associated with the vascular endothelial damage and the pathogenesis of atherosclerosis. The mycotoxin could trigger oxidative stress, free radical production, and abnormal energy metabolism in cardiomyocytes, which resulted in cell death through necrotic and apoptotic mechanisms. The mitochondrial pathway in myocardium played a critical role in mycotoxin-caused cytotoxicity. Importantly, the mycotoxins caused cell damage in vascular endothelium, which was a direct risk factor in the pathogenesis of atherosclerosis. Obviously, it is a new topic to elaborate the role of mycotoxins in the pathogenic mechanism of cardiovascular disease. There are a lot of questions needs to be answered in future study.

Objective:To recognize the spatial and temporal characteristics of iodine deficiency disorders (IDD), China national IDD surveillance data for the years of 1995-2018 were analyzed.Methods:Time series analysis was used to describe and predict the IDD related indicators, and spatial analysis was used to analyze the spatial distribution of salt iodine levels.Results:In China, the median urinary iodine concentration increased in 1995-1997, then decreased to adequate levels, and are expected to remain appropriate in 2019-2022. The goiter rate continually decreased and is expected to be maintained at a low level. Since 2002, the coverage rates of iodized salt and the consumption rates of qualified iodized salt (the percentage of qualified iodized salt in all tested salt) increased and began to decline in 2012; they are expected to continue to decrease. Spatial epidemiological analysis indicated a positive spatial correlation in 2016-2018 and revealed feature regarding the spatial distribution of salt related indicators in coastal areas and areas near iodine-excess areas.Conclusions:Iodine nutrition in China showed gradual improvements. However, a recent decline has been observed in some areas following changes in the iodized salt supply in China. In the future, more regulations regarding salt management should be issued to strengthen IDD control and prevention measures, and avoid the recurrence of IDD.

AbstractExcessive iodine can lead to goiters. However, the relationship between the water iodine concentration (WIC) and goiter rate (GR) is unclear. This study aims to explore the factors that influence children’s GR in areas with high WIC and analyse the threshold value of the GR increase associated with the WIC. According to the monitoring of the areas with high WIC in China in 2018–2020, a total of 54 050 children in eight high water iodine provinces were chosen. Drinking water, urine and edible salt samples of children were collected. The thyroid volume (Tvol) was measured. A generalised additive model (GAM) was used to analyse the relationship between the WIC and GR in children. Among the 54 050 children in areas with high WIC, the overall GR was 3·34 %, the median of water iodine concentration was 127·0 µg/l, the median of urinary iodine concentration was 318 µg/l and the non-iodised salt coverage rate (NISCR) was 63·51 %. According to the GAM analysis results, water iodine and urinary iodine are factors that influence the Tvol and GR, while the NISCR affects only the GR. When the WIC was more than 420 µg/l or the urinary iodine concentration was more than 800 µg/l, the GR increased rapidly. When the NISCR reached more than 85 %, the GR was the lowest. Thus, in areas with high WIC, WIC more than 420 µg/l may increase the risk of goiter, and the NISCR should be increased to over 85 % to avoid goiters in children.

目的 观察学龄儿童甲状腺结节的发生、性质变化和大小演变等情况,为评价我国儿童碘状态提供新指标并为碘过量监测服务.方法 采用典型抽样方法,选取309名巢湖市和308名肥东县两组人群队列,2016年开展基线调查,2018年和2019年各随访一次.调查儿童甲状腺时使用迈瑞便携式超声诊断仪进行检查.结果 第一组(巢湖市)儿童在基线调查和2次随访中甲状腺结节检出率分别是7.1％ (22/309)、6.1％ (19/309)和5.6％ (11/197),第二组(肥东县)在基线调查和2次随访中甲状腺结节检出率分别是8.4％(26/308)、6.2％(19/308)和3.8％(1/26).结节性质以囊性为主,三次调查中两组队列每次合计检出的甲状腺结节中囊性结节占比分别为97.9％(47/48)、92.1％(35/38)和91.7％(11/12).两组调查对象第一次随访新发甲状腺结节占比均为47.4％,第二次随访巢湖市新发甲状腺结节6例,其中2例为第一次随访时消失但第二次随访时又重新出现的甲状腺结节患者.结论 碘超足量地区儿童甲状腺结节检出率较高,有些结节在随访期间一直未消失并有新发结节产生,可以考虑将儿童甲状腺结节作为新的监测指标.

目的 通过动物试验模拟人群碘摄入,观察不同碘状态的饮用水暴露下大鼠甲状腺形态的变化,探索人群甲状腺结节形成机制.方法 选择断乳后1个月,体质量为120～140 g的Wistar大鼠,分四组,低碘组、适碘组、高碘Ⅰ组和高碘Ⅱ组.饲养6个月后,收集尿液,取出甲状腺,苏木精-伊红染色法(HE)光镜下观察大鼠甲状腺形态变化.结果 各组大鼠尿碘值间两两比较,组间差异均有统计学意义(P＜0.05),高碘Ⅱ组最高,为29 291.88 μg/L.HE染色光镜下观察,低碘组、适碘组大鼠甲状腺滤泡正常、无扩大、无融合,高碘Ⅰ组和高碘Ⅱ组大鼠甲状腺滤泡出现不同程度改变.结论 高碘饮用水能够使动物甲状腺滤泡发生改变,出现融合现象.

目的 建立我国充分补碘地区不同妊娠时期孕妇特异性血清游离甲状腺素(FT4)的参考上限值.方法 根据2012～2015年碘盐监测结果,在四川省内选择妊娠早、中、晚期孕妇共486例,其中孕早期妇女141例、孕中期妇女167例、孕晚期妇女178例.采集血清样本,应用全自动化学发光免疫分析法检测血清FT4,并建立参考上限值.结果 妊娠中期和晚期血清FT4水平较妊娠早期降低.妊娠早、中、晚期血清FT4参考上限值分别为19.58 pmol/L、19.61 pmol/L、19.82 pmol/L,中位数倍数(MoM)参考值范围分别为0.79～1.27、0.78～1.31、0.80～1.32.结论 制定不同妊娠时期孕妇血清FT4参考上限值对于个体碘状况评价乃至自身免疫性甲状腺疾病的监测具有基础意义.

Iodine deficiency disorders (IDD) are a series of diseases caused by iodine deficiency in the natural environment that include endemic goiter, cretinism, subclinical cretinism, fetal abortion, premature delivery, stillbirth, congenital malformation, etc (1). Since 1993 when the State Council held the “Mobilization meeting of eliminating IDD in China by the year 2000”, the Ministry of Health planned to set up an annual publicity day for the prevention and control of IDD. Through the coordination between the Ministry of Health and other relevant departments, IDD Day was set on May 5 in 1994, and on May 15 since 2002. Since 1994, IDD Day has played an active role in mobilizing all levels leaders of governments and relevant departments as well as the public to support salt iodization in China. After nearly 30 years, the measures have been enriched to include slogans, posters, activities, national workshops, international conferences, and WeChat publicization, webpages, interviews, music videos, etc. IDD knowledge has been successfully spread among Chinese people and therefore ensured the health of masses (2). The national IDD survey shows that China has been in sustainable elimination status of IDD since 2005 (3). The 27th IDD day in China is arriving on May 15, 2020, and the slogans, posters, and music videos have all been prepared well. doi: 10.46234/ccdcw2020.089

Background: The appropriate range of median urinary iodine concentration (MUI) in children has always been controversial. To prevent the occurrence of a goiter epidemic in Shanghai, we explored the appropriate range of MUI by integrating multiple monitoring results. Methods: This study summarized and analyzed the monitoring data from 1997, 1999, 2011, 2014, and 2017 of children living in Shanghai. In each monitoring year, the probability-proportional-to-size sampling technique was used to select 30 sampling units. In each sampling unit, one primary school was randomly selected. From each selected school, 40 children 8- to 10-year-old were randomly recruited to measure thyroid volume (Tvol) and their household salt iodine intake. Results: In 1997, 1999, 2011, 2014, and 2017, MUI of 8- to 10-year-old children was 228, 214, 182, 171, and 183 mu g/L, and median Tvol (MTvol) was 2.9, 1.2, 1.0, 1.8, and 2.8 mL, respectively. There was a linear correlation between goiter rate and MTvol (r = 0.95, p = 0.014; 100 x goiter rate = 1.314 x MTvol -1.287). Generalized additive model (GAM) was used to predict MTvol as follows, MTvol = 0.60689 + 0.00302 MUI +0.999928 s (MUI) -0.05172 mean salt iodized concentrations (MSIs) +0.03481 x 100 x iodized salt coverage rate +0.00000969 per capita disposable income +0.271422 s (per capita disposable income) -0.38772 x monitoring year gap. The results revealed that the average relative error between predicted and actual value was 15.2%. GAM results showed that at 27-277 mu g/L MUI, the goiter rate was Conclusions: Iodine status is appropriate in Shanghai. Under the existing economy and MSI, the optimal range of MUI should be 70-277 mu g/L in 8- to 10-year-old children living in Shanghai.

Iodine deficiency can impair human health severely and cause iodine deficiency disorders (IDD), including endemic goiter, endemic cretinism, endemic subclinical cretinism, and so on. From 2838 to 2698 BC, China had made effort to control endemic goiter. However, the large-scale prevention work had not started in a real sense until the founding of the New China. At that time, all regions of China except Shanghai were affected by endemic goiter at different levels. Supply of iodized salt, iodized oil, and iodine-rich foods, iodization of drinking water, and iodinated food were the mainly recommended measures for controlling IDD. The surveillance and assessment systems for IDD elimination in China were well organized and carefully designed. Today, China has eliminated IDD on a national basis in many provinces. It is considered one of the most successful IDD elimination programs in the world and has set an excellent example for the rest of the world. According to the most recent national IDD surveillance survey carried out in 2014, China is in the status of sustainable IDD elimination nationwide, which is attributed to the leading roles of government, high-quality and sufficient iodized salt supply, comprehensive legislation, regulations, standards and technical proposals, intensive surveillance and assessment, health-related promotional and educational activities, and international collaboration.

The objectives of this study were to explore reference intervals of ratios of concentrations of urinary iodine to creatinine (UIC/UCr) in pregnant women, to determine specific reference intervals for thyroid hormone concentrations (FT3, FT4, TSH) in the first trimester of pregnancy, and provide a comprehensive evaluation of iodine nutritional status and thyroid function. Cross-sectional data analysis, including questionnaires and thyroid ultrasonograms, were used to exclude subjects who had a history of thyroid disease, a family history of thyroid disease, or thyroid morphological abnormalities. Tests of thyroid hormone were evaluated together with urinary iodine concentration (UIC), urinary creatinine concentration (UCr), and salt iodine concentration in pregnant women. For the sample of pregnant women eligible for inclusion, the 95% reference intervals of the bilateral limits of UIC/UCr and thyroid hormone concentrations in pregnant women were determined by the percentile method. Pregnant women were recruited in Harbin, Heilongjiang Province, a particular geographical area of China, where iodine nutrition is adequate. The median UIC was 141.47 μg/L, while the median UIC/UCr was 141.12 μg/g. The reference intervals of thyroid hormone concentrations in the first trimester were FT3 3.63–6.12 pmol/L, FT4 11.89–22.91 pmol/L, and TSH 0.013–3.814 mIU/L. The reference intervals of UIC/UCr were 52.47 to 532.09 μg/g (first trimester 47.25–353.91 μg/g, second trimester 57.95–639.08 μg/g, third trimester 46.98–494.73 μg/g).The established UIC/UCr medical reference intervals and thyroid hormone concentration reference intervals may be used for iodine nutritional assessment and thyroid disease screening in pregnant women.

Objective To assess iodine nutrition and thyroid function in children and pregnant women before and after iodized salt concentration decline,and investigate the appropriate concentration of iodized salt.Methods Cluster sampling was carried out,study areas in Shandong and Gansu provinces were selected according to the coverage rate of iodized salt which was more than 95％ and the levels of iodine and fluoride in drinking water which were less than or equal to 10 μg/L and 1 mg/L,respectively in 2012 and 2014.Before (2012) and after (2014) iodized salt concentration decline:children and pregnant women were selected;salt,drinking water and urinary samples were collected;the iodine content of salt,the iodine and fluoride content of drinking water,and urinary iodine were tested.B ultrasound was used to examine the thyroid volume and the total goiter rate (TGR) was calculated in children.The blood sample was collected to test thyrotropin (TSH) and thyroglobulin (Tg) in the 2 groups of subjects.Results Before iodized salt concentration decline,the children median urinary iodine (MUI) concentrations of Shandong and Gansu provinces were 291.4 and 321.9 μg/L,which at the over appropriate and overdose levels,respectively.MUI of Shandong and Gansu provinces were 220.5 and 274.7 μg/L in pregnant women,which were at adequate and over appropriate levels.After iodized salt concentration decline,MUI of Shandong and Gansu provinces were 199.8 and 178.2 μg/L in children,and were 178.6 and 159.2 μg/L in pregnant women,which were all at adequate levels.Children's TGR declined from 7.95％ (7/88) to 5.88％ (7/119) in Shandong Province,children's TGR rose to 5.77％ (6/104) from 2.06％ (2/97) in Gansu Province,there was no statistical differences (x2 =0.34,1.81,P ＞ 0.05).Before and after iodized salt concentration decline,there were no differences statistically in TSH levels of children and pregnant women in Shandong and Gansu provinces (Z =-1.08,-0.83,-1.30,-0.80,P ＞ 0.05).Mter iodized salt concentration decline,the Tg levels were significantly lower than that before intervention in children and pregnant women in Shandong Province (Z =-10.78,-7.04,P ＜0.01);the Tg level was increased than that before intervention in pregnant women group in Gansu Province (Z =-2.78,P ＜ 0.01).Conclusion After iodized salt concentration declined,iodine nutrition and thyroid function status of Shandong Province are reasonable,but the indicators of Gansu Province have a trend of iodine deficiency,monitoring needs to be strengthened,and iodized salt content needs to be adjusted in time.

Objective Using the iodine level found in epidemiological investigation spot to study the effects of potassium iodate and potassium iodide on morphology and function of thyroid.Methods The mice were divided into four groups randomly according to the mice's weight:normal fodder group(NG),normal potassium iodate group(NO),high potassium iodate group(HO) and high potassium iodide group(HI).After 90 days,the weight of thyroid,the thyroid serum hormone and urinary iodine were tested.Moreover,morphology of thyroid was investigated under light microscope and electronic microscope.Results When iodine dose is 100 μg/L,it could induce colloid goiter and the increase of absolute and relative weight of thyroid.Compared with NG,the serum T4 and urinary iodine increased significantly in HO and HI,the serum T3 had no significant difference between HO and HI.The urinary iodine in HO was higher than that in HI.Compared with NG,there was no significant difference in NO except the urinary iodine.Conclusions When iodine dose is 100μg/L,both potassium iodate and potassium iodide can induce colloid goiter and the change of thyroid's function in mice,and there is no significant difference between them.The utilization of potassium iodate is lower than that of potassium iodide.

Abstract Background In 1996, Shanghai implemented universal salt iodization and has became the last provincial unit in China to carry out this intervention. In this study, we summarized achievements in past 20 years, to provide suggestions and evidence for the next stage of iodine supplementation. Methods This study summarized and analyzed monitoring data of children from 1997, 1999, 2005, 2011, 2014, and 2017 in Shanghai. In each monitoring year, 30 streets or towns were selected using the probability-proportional-to-size sampling technique. One primary school was selected from each street or town by a simple random sampling technique. From each school, 40 children aged 8 to 10 years were randomly selected. The number of children was divided equally by sex and age. Results In 1997, 1999, 2005, 2011, 2014, and 2017, median urinary iodine (MUI) was 227.5 μg/L, 214.3 μg/L, 198.1 μg/L, 181.6 μg/L, 171.4 μg/L, and 183.0 μg/L, goiter rate was 3.07, 0.40, 0.08, 0.08, 0.86, and 1.90%, and median thyroid volume (MTvol) was 2.9 mL, 1.2 mL, 2.4 mL, 1.0 mL, 1.8 mL, and 2.8 mL, respectively. There was a linear correlation between goiter rate and median thyroid volume (MTvol) (r = 0.95, P = 0.014). Household salt iodine concentration (SIC) was dropping every monitoring (P < 0.05). There was a significant difference among different household SIC groups in MUI in 1999 and 2017, and in MTvol in 1999 (P < 0.05). No significant differences were detected in the other years. Conclusions In Shanghai, the iodine status of 8 to 10 years old children is adequate. Household SIC have little effect on iodine status of children. Future studies should analyze the dietary sources of iodine, especially from pre-packaged and prepared-away-from-home foods or meals. The regular monitoring of iodine status is important to human health.

Universal salt iodisation (USI) has been successfully implemented in China for more than 15 years. Recent evidence suggests that the definition of 'adequate iodine' (100-199 µg/l) be revised to 'sufficient iodine' (100-299 µg/l) based on the median urinary iodine concentration (MUI) in school-age children. The objective of this study was to determine the prevalence of thyroid dysfunction in populations after long-term salt iodisation and examine whether the definition of adequate iodine can be broadened to sufficient iodine based on the thyroid function in four population groups. A cross-sectional survey was conducted in six provinces in the northern, central and southern regions of China. Four population groups consisting of 657 children, 755 adults, 347 pregnant women and 348 lactating women were recruited. Three spot urinary samples were collected over a 10-d period and blood samples were collected on the 1st day. In the study, among the adults, pregnant women and lactating women, the prevalence rates of elevated thyroglobulin antibody and thyroid microsomal antibody levels were 12·4, 8·5 and 7·8 %, and 12·1, 9·1 and 9·1 %, respectively. Abnormally high thyroid dysfunction prevalence was not observed after more than 15 years of USI in China because the thyroid dysfunction rates were all <5 %. The recommended range should be cautiously broadened from adequate iodine to sufficient iodine according to the MUI of school-age children considering the high levels of hormones and antibodies in the other populations. Adults, particularly pregnant women positive for thyroid antibodies, should be closely monitored.

OBJECTIVE The aim of this study was to evaluate the impact of the revised Chinese National Standard GB26878-2011 'Iodine Content in Edible Salt' on the iodine status among the Chinese population. METHODS In 2011 and 2014, the probability proportionate to size sampling (PPS) was used in each Chinese province to obtain the representative data. In each sampling unit, school children aged 8-10 years and pregnant women were selected. Key indicators included urinary iodine concentration (UIC), thyroid volume (TV), and the iodine content in edible household salt. RESULTS The median urinary iodine concentration (MUIC) decreased between 2011 and 2014 from 238.6 to 197.9 µg/L in school-age children. The number of provinces with iodine excess decreased to zero. The proportion of children whose UIC was > 300 µg/L was 18.8% and decreased to 11% compared with 29.8% in 2011. There was no significant difference in UIC < 50 µg/L between 2014 (4.3%) and 2011 (3.7%) (P > 0.05). The MUIC among pregnant women in 2014 was more concentrated between 110 and 230 µg/L. The goiter rate among children aged 8-10 years was unchanged, both the goiter rate of 2011 and 2014 remaining below 5%, in view of the sustainable elimination of iodine deficiency disorders. CONCLUSION The National Standard GB26878-2011 'Iodine Content in Edible Salt' that was introduced in March 2012 resulted in an overall improvement in iodine status, reducing the risk of excessive iodine intake in the Chinese population.

In Shanghai, a new iodized salt standard was implemented in 2012. To provide evidence to the government, we compared iodine status before (35 mg/kg) and after (30 mg/kg) adjustment in vulnerable populations living in Shanghai. The probability-proportional-to-size sampling technique was used to select at least 360 pregnant women for urine iodine test and at least 1200 students for thyroid measurement and the household salt test. Of these students, at least 360 performed urine iodine test. The median thyroid volume and the median household salt iodine concentration of children aged 8–10 years were 1.80 ml and 24.8 mg/kg in 2015, and 0.97 ml and 28.3 mg/kg in 2011. The median urine iodine concentration (UIC) of pregnant women was 126.52 and 139.77 μg/L in 2015 and 2011. All differences were statistically significant (P < 0.05). The median UIC of students was 171.40 and 181.63 μg/L in 2015 and 2011, the difference was not statistically significant. Multivariate linear regression analysis showed that thyroid volume in children was associated with sex, age, region, and household salt iodized concentration. The current iodized salt concentration meets the basic needs of the population’s iodine requirements except for pregnant women. Periodic monitoring is necessary particularly in vulnerable groups.

Both Shanghai and Switzerland are developed regions with long-standing salt iodization programs and periodic monitoring. However, the two regions have their own approach to the implementation of the iodized salt policy. In Shanghai, monitoring was carried out every few years, using probability-proportional-to-size sampling technique to select 30 sampling units. Each unit consisted of more than 12 pregnant women and one randomly selected primary school. Urine samples were then taken from the chosen pregnant women and randomly recruited students of that school for iodine test. Data of Switzerland used in this comparative study was extracted from published researches. In Shanghai, the median urinary iodine concentration (UIC) in 2014 was 20% lower than in 1999 (P < 0.05). The median UIC of pregnant women in 2014 was 9.5% lower than that in 2011 (P < 0.05). In terms of iodized salt concentration, opposite to the increasing in Switzerland, it has exhibited a downward trend in Shanghai (P < 0.05). For the years monitored, the iodized salt concentration in Shanghai was significantly (P < 0.05) higher than in Switzerland. Though the UIC of children exhibited a downward trend in Shanghai (P < 0.05), it was still significantly (P < 0.05) higher than in Switzerland over the same monitoring period. However, the UIC in pregnant women was a totally different story, which was significantly (P < 0.05) lower in Shanghai than in Switzerland. Iodized salt is very important for maintaining sufficient iodine level in the population. Appropriate concentration of iodine in fortified salt needs to be decided according to local conditions. Special attention should be paid to the iodine level of pregnant women in Shanghai, and more education about iodine is necessary for the public health.

Objective To test the expectation that urine iodine will decrease 5.5 μg/L ～ 7.4 μg/L by 1 mg/kg salt iodine concentration cut,and test the feasibility of salt iodine concentration cut.Method In the year (2011) before and 2 years (2014) after salt iodine concentration cut,5 towns(subdistricts) in every district (county) are sampled according to the orientations of east,west,south,north,and medium,4 villages or resident committees are selected in each town (subdistricts) as sampling points,table salts from 15 families on every sampling point are collected to test salt iodine concentration.According to PPS sampling method,the counties (districts) are ascertained in which the 30 points fall within.Then,40 ～ 50 children of 8 to 10 years old in one primary school are extracted,half male and half female.Urine and family salt specimens are collected to test iodine,and thyroid of the children are examined.Results The iodine salt coverage of children families is 99.7％ in 2011 and 98.8％ in 2014,shows significant difference (x2 =6.09＞3.84,P＜0.05).While,that of residents is 99.6％ in 2011 and 99.6％ in 2014,shows no difference.In 2011,the average salt iodine concentrations of residents and children families are 31.07 mg/kg and 30.5 mg/kg,and the standard deviation is 6.5 mg/kg and 6.6 mg/kg respectively.In 2014,the average salt iodine concentrations of residents and children families are 26.7 mg/kg and 26.3 mg/kg,and the standard deviation is 5.0 mng/kg and 4.3 mg/kg respectively,decreased 5.2 mg/kg and 4.2 mg/kg significantly (t =70.11,19.50＞2.58,P＜0.01).The median urine iodine is 254.1 μg/L in 2011 and 222.7 μg/L in 2014,decreased 31.4 μg/L significantly (x2 =23.45＞6.63,P＜0.01).The urinary iodine frequencies of the groups of ＜50 μg/L,50 μg/L-,100 μg/L-,200 pg/L-and ≥300 μg/L are 2.4％,6.9％,23.3％,30.9,36.5％ in 2011,and 2.9％,8.3％,30.8％,30.7％,27.3％ in 2014.Group 100 μg/L-increased significantly(x2 =20.45＞6.63,P＜0.01),group ≥ 300μg/L decreased significantly (x2 =28.39＞6.63,P＜0.01).Other groups have no significant difference(x2＜3.84,P＞0.05).Children goiter rates are 5.5％ in 2011 and 3.2％ in 2014,decreased 41.8％ significantly(x2 =8.79＞6.63,P＜0.01).Conclusion After salt iodine cut,the salt iodine concentration has decreased 5 mg/kg in residents and 4.3 mg/kg in children families,median urine iodine has decreased 31.4 μg/L.Urine iodine decreased 6.3 μg/L and 7.3 μg/L along with 1 mg/kg salt iodine cut.The result meets the expectation that urine iodine will decrease 5.5 μg/L ～ 7.4 μg/L by 1 mg/kg salt iodine concentration cut.After salt iodine cut,children iodine nutrition still exceeds appropriate level.To reach the appropriate level,the salt iodine concentration should decrease to 20 mg/kg.

National iodine-deficiency disorder surveillance surveys were conducted in 1999, 2005, and 2011 in China. Probability-proportional-to-size sampling technique was used to select sampling units. The mean of thyroid volume (Tvol) in the 100 to 199 µg/L UIC (urinary iodine concentration) group was significantly lower than that in the 200 to 299 µg/L UIC group in 2011 ( P < .05). The status in the 100 to 199 µg/L versus ≥300 µg/L and 200 to 299 µg/L versus ≥300 µg/L groups in 1999, and 100 to 199 µg/L versus ≥300 µg/L group in 2011 were the same ( P < .05). The mean Tvol in the <100 µg/L UIC group was significantly higher than that in the 100 to 199 µg/L UIC group in 1999 ( P < .05). Both insufficient and excess iodine may be associated with an increase in Tvol, and adequate iodine intake should be defined as median UIC 100 to 299 µg/L.

OBJECTIVE:We aimed to evaluate goiter prevalence and iodine nutritional status in areas with high levels of water iodine; to monitor the prevalence of iodine deficiency disorders (IDD) in areas at high risk of IDD; and to compare the prevalence of goiter and urine iodine (UI) concentrations between children living in the two areas.METHODS:Based on surveillance from 2012-2014, we analyzed the concentration of UI and prevalence of goiter in 8-10-year-old children from 12 high-risk IDD provinces, and from 8 provinces and municipalities with excessive water iodine. We calculated goiter prevalence for each UI level according to World Health Organization (WHO) standards and constructed predictive prevalence curves.RESULTS:The goiter prevalence and median UI of children from areas with high water iodine were not optimal, being above the WHO standards (5% and 100-199 μg/L, respectively), whereas those in high-risk areas fell within the standard. UI and goiter prevalence exhibited a U-shaped relationship in high-risk endemic areas and a parabolic relationship in areas of iodine excess.CONCLUSION:Iodine surplus in high-iodine areas leads to high goiter prevalence and UI. However, in high-risk areas, UI was optimal and goiter prevalence met the national criteria for IDD elimination.