Iodine nutritional status of 8-10 years old children after adjustment of salt iodine content in Hangzhou City Of Zhejiang Province

Objective To explore the impact of iodine nutrition on pregnant women before and after adjusting the iodine content in iodine salt. Methods Twelve counties (areas, cities) in Hangzhou were divided into urban, suburban and rural areas before and after adjusting the iodine content of salt. One survey spot was selected in each district and one hundred pregnant women were selected; family salt and urinary samples of each pregnant woman were collected. The levels of salt and urinary iodine were measured by the methods of picric sodium thiosulfate titrimetric (GB 13025.7-2012) and spectrophotometer (WS/T 107-2006), respectively. Results One thousand two hundred and thirty-nine and one thousand two hundred and thirty-three household salt samples were collected before and after adjusting the iodine content in iodine salt. The median of salt iodine of pregnant women (23.30 mg/kg) before adjusting the iodine content in iodine salt was lower than that after adjusting the iodine content in iodine salt (30.09 mg/kg, χ2=-4.71, P < 0.01). The iodine salt coverage rate and the consumption rate of qualified iodized salt after adjusting the iodine content in iodine salt [93.92% (1 158/1 233), 93.84% (1 157/1 233)]were higher than those before adjusting the iodine content in iodine salt [91.85% (1 138/1 239), 91.37% (1 132/1 239), χ2= 4.01, 5.51, all P < 0.05]. The iodine salt coverage rate and the consumption rate of qualified iodized salt in urban and suburb areas after adjusting the iodine content in iodine salt [99.42% (510/513), 100.00% (203/203), 97.86% (502/513), 100.00% (203/203)] were higher than those before adjusting the iodine content in iodine salt [86.71% (450/519), 98.00% (196/200), 77.26% (401/519), 85.00% (170/200)], but the iodine salt coverage rate and the consumption rate of qualified iodized salt in rural area before adjusting the iodine content in iodine salt [94.62% (492/520), 86.92% (452/520)] were higher than those after adjusting the iodine content in iodine salt [85.69% (443/517), 76.98% (398/517), χ2= 64.22, 2.32, 100.02, 32.90, 23.31, 17.33, all P < 0.05]. One thousand two hundred and thirty-four and one thousand two hundred and thirty-one household urine samples were collected before and after adjusting the iodine content in iodine salt. The median of urinary iodine (MUI, 114.80 μg/L) of pregnant women after adjusting the iodine content in iodine salt was lower than that before adjusting the iodine content in iodine salt (168.60 μg/L, χ2= 36.92, P < 0.01). The MUIs of pregnant women in urban, suburban, and rural areas (171.30, 170.20 and 162.40 μg/L) before adjusting the iodine content in iodine salt were higher than those after adjusting the iodine content in iodine salt (101.00, 149.48 and 119.90 μg/L, χ2=-7.78, -2.63, -6.28, all P < 0.01). The differences of urinary iodine between groups were statistically significant in urban, suburban and rural areas after adjusting the iodine content in iodine salt (χ2= 32.86, P < 0.01), the MUI of pregnant women in urban areas was lower than those in the suburban and rural areas (χ2= 6.70, 8.13, all P < 0.05). Conclusions After adjusting the iodine content of salt in Hangzhou, the iodine-nutrition level of pregnant women is decreased. But the consumption rates of qualified iodized salt and the MUIs in urban, suburb, rural areas are different, so the coverage of iodized salt at household level needs to be enhanced and the health education should be highlighted. Key words: Iodine; Nutrition assessment; Pregnancy; Salt iodization

Objective To investigate the iodine nutritional status of the crowd that did not participate in the iodine deficiency disorders （IDD） survey in iodine deficiency areas in Jiangsu Province so as to provide a basis for prevention and control of IDD.Methods Eight to ten years old children were chosen from the counties（cities,districts） of Jiangsu Province that did not participate in the IDD survey and urine samples of students and salt samples of their families were researched.In each county （city,district） one township （street） was selected according to 5 directions of east,south,west,north,center; in each township one primary school was selected and in each primary school 20 children aged 8-10 were chosen half of the male and female,to collect their urine samples and salt samples at their families.Urinary iodine was measured using arsenic cerium catalytic spectrophotometric method （WS/T 107-2006）,and salt iodine was measured using direct titration of universal test method in salt industry （GB/T 13025.7-1999）.Iodine nutrition criterion of international health organization recommended staindard：children urinary iodine 〈 100 μg/L as iodine deficiency,100-199 μg/L as iodine appropriate,200-299 μg/L as iodine more than appropriate,≥ 300 μg/L as iodine excess.Results A total of 7 523 urinary samples of 8-10 years old children were collected from 76 iodine deficiency counties （cities,districts）,and the median of urinary iodine was 235.0 μg/L.In all investigated counties （cities,districts）,the medians of urinary iodine of 22 counties（cities,districts） were 100-199 μg/L,42 counties（cities,districts） were 200-299 μg/L,and 12 counties （cities,districts） were ≥300 μg/L.A total of 7 523 salt samples were collected,and the median of salt iodine was 29.68 mg/kg; Taizhou City had the highest salt iodine median,which was 31.43 mg/kg; and Lianyungang City,the lowest,25.11 mg/kg.The coverage rate of iodized salt was 98.6%（7 417/7 523）; iodized salt qualification rate was 98.6% （7 312/7 417）; and consuming rate of qualified iodized salt was 97.2%（7 312/7 523） in 76 iodine deficiency counties （cities,districts）.Conclusions The progress in prevention and control of IDD in iodine-deficient areas that did not participate in IDD survey in the past is good in Jiangsu Province; the overall level of iodine nutrition of whole population is adequate.But the median of urinary iodine in some counties （cities,districts） is at a higher level. Key words: Children; Iodine deficiency disorders; Urinary iodine; Salt iodine

Objective To investigate the coverage rate of iodized salt and the nutritional status of school-aged children before and after adjustment of salt iodine concentration in Haishu District, Ningbo City. Methods The observation period (2010- 2016) was divided into three sub-periods: before the adjustment (2010, 2011), adjustment period (2012- 2014) and after the adjustment (2015, 2016). Household salt samples and urine samples of school-aged children aged 8- 10 were collected during the 3 periods in Haishu District, Ningbo City, and the iodized salt coverage rate, qualified iodized salt consumption rate, urinary iodine concentration were determined. Results Totally 600, 900 and 615 household salt samples were collected in the 3 periods, respectively. The medians of salt iodine in the 3 periods were 27.30, 23.50 and 23.10 mg/kg; while the iodized salt coverage rates were 97.83% (587/600), 94.67% (852/900) and 84.72% (521/615), and the qualified iodized salt consumption rates were 96.50% (579/600), 92.11% (829/900) and 74.63% (459/615), respectively. There were significant differences in the iodized salt coverage rates and qualified iodized salt consumption rates among the 3 periods (χ2= 86.13, 162.57, P < 0.01); and significant decreases of the iodized salt coverage rates and qualified iodized salt consumption rates were observed in the 3 periods (χ2trend= 77.34, 141.11, P < 0.01). The median urinary iodine concentration of the school-aged children in the 3 periods were 171.18, 161.95 and 186.07 μg/L; the differences of urinary iodine were statistically significant among the 3 periods (H= 11.81, P < 0.01). Conclusions In Haishu District, significant decreases of the iodized salt coverage rates and qualified iodized salt consumption rates are observed after the adjustment of salt iodine concentration. However, the iodine nutrition is adequate in school-aged children. Key words: Iodine; Salts; Child; Urine

Objective To observe the implementation of national food safety standard for “Iodine Concentration in Edible Salt”（GB 26878-2011） and its effectiveness on iodine nutritional status of key populations. Methods Information of iodine concentration in edible iodized salt of various provinces （autonomous regions and municipalities, including Xinjiang Production and Construction Corps） was collected using Baidu Searching Engine through the establishment of key words. Sal t samples were collected in Tianjin City and Aksu Region of Xinjiang , and the salt iodine concentration in both places was 30 mg/kg. In Tianjin, Hongqiao, Tanggu and Hangu, Beichen were selected as representatives of the downtown areas, the coastal areas and the suburbs, respectively and counties of Baodi and Ji were iodine deficiency areas in history. Sampling work was carried out from August 2012 to March 2013 in Tianjin. In Aksu, Yatuoer Township and Charqi Town in Baicheng County, Aotebeixi and Aketuohai Townships in Wushen County were chosen as iodine deficiency areas, and the survey was carried out from January＆amp;nbsp;to September 2013 . Random urine samples of school-age children （ 8 - 10 years old ） , pregnant women and lactating women were collected; urinary iodine was measured following the Method for Determination of Iodine in Urine by As3＋-Ce4＋ Catalytic Spectrophotometry（WS/T 107-2006） and iodine in edible iodized salt was measured following the General Test Method in Salt Industry Determination of Iodideion （ GB/T 13025 . 7-1999 ） . Results Fourteen of the provinces（autonomous regions and municipalities, including the Corps of Xinjiang） chose 25 mg/kg as their iodine concentration in edible iodized salt and 13 provinces chose 30 mg/kg. Besides, there were another 5 provinces providing 30 mg/kg particularly for pregnant women and lactating women while 25 mg/kg for other populations. In Tianjin, the medians of iodine concentration in edible iodized salt were ranged from 24.4 - 32.1 mg/kg in retail stores and 26.4 mg/kg at households. The household coverage rate of iodized salt and the proportion of households using adequately iodized salt were 78.5%（168/214） and 62.6%（134/214）, respectively. The median ranges of urinary iodine were 178.2 - 183.9 μg/L in school children, 124.3 - 130.9 μg/L in pregnant women and 72.7 - 109.5 μg/L in lactating women. In Aksu, the medians of iodine concentration in edible iodized salt were 27.1 and 26.5 mg/kg in retail stores and households, respectively. The household coverage rate of iodized salt and the proportion of households using adequately iodized salt were 100.0% （363/363） and 98.9%（359/363）, respectively. The median ranges of urinary iodine were 174.8 - 293.0, 154.9 - 230.0 and 135.8 - 239.3 μg/L among school children, pregnant women and lactating women, respectively. The median of iodine concentration in a special edible iodized salt sample reached 49.1 mg/kg, and qualified rate was 0（0/11） in Aksu. Conclusions All provinces , municipalities and autonomous regions （ including the Corps of Xingjiang ） in China have adjusted the iodine content in edible iodized salt in accordance with GB 26878-2011. However, in Tianjin the household iodine concentration in edible salt is lower than the local standards; the household coverage rate of iodized salt and the proportion of households using adequately iodized salt are lower than the national standards; pregnant women and lactating women are at risk of mild iodine deficiency. Key words: Iodized salt; Urinary iodine; Children; Pregnant women; Lactating women

Objective To understand the level of urinary iodine of schoolchildren and salt iodine content of their families in a primary school and to analysis influence between salt iodine content and urinary iodine level in Haimen City,Jiangsu Province.Methods A cross-sectional study was conducted in a primary school of Haimen City in 2012.With the method of stratified cluster sampling,all students aged 9 ～ 12 were extracted in grades 3-5,urine samples and salt samples of their family were collected.Urinary iodine and salt iodine were determined according to ＂Method for Determination of Iodine in Urine by As3＋-Ce4＋ Catalytic Spectrophotometry＂ （WS/T 107-2006） and ＂Direct Titration of Universal Test method in Salt Industry＂ （GB/T 13025.7-1999）.Results Totally,452 students from grades 3-5,including 233 boys and 219 girls were selected by cluster-stratified sampling.The median of children＆#39;s urinary iodine was 231.90 μg/L,while the median of boys and girls was 235.40 and 222.60 μg/L,respectively.The median of urinary iodine of 9,10,11 and 12 year old students was 253.65,195.70,236.40 and 241.70 μg/L,respectively.The proportion of less than 100 μg/L and ≥300 μg/L was 7.7% （35/452） and 27.7% （125/452）,respectively.There were no significant differences between different gender and age students.Among the 452 salt samples collected the median of salt iodine was 27.50 mg/kg.The coverage rate of iodized salt,the qualified rate of iodized salt and the intake rate of qualified iodized salt were 98.9% （447/452）,95.1% （425/447） and 94.0% （425/452）,respectively.After consumptionn of non-iodized salt （〈 5 mg/kg）,unqualified iodized salt（5 ～ 〈 20 mg/kg or 〉 50 mg/kg） or qualified iodized salt [（35 ± 15）mg/kg],the median of urinary iodine of children was 177.30,211.95 and 232.90 μg/L,respectively.Correlation analysis showed that there was no relationship between iodine content of salt and urinary iodine level of schoolchildren （r =0.085,P 〉 0.05）.Conclusions Current nutritional level of schoolchildren in Haimen City is higher than the appropriate amount.Household salt iodine content of edible salt does not affect urinary iodine level of the children significantly. Key words: Cross-sectional study; Children; Urinary iodine; Salt iodine

Objective To explore the relationship between drinking water, iodized salt and children＇s excessive iodine intake in children living in waterborne high iodine areas. Methods Three townships were selected by simple random sampling among the townships with median water iodine being 150 - 300 μg/L in Hengshui City of Hebei Province to investigate the urinary iodine level （ammonium sulfate digestion arsenic cerium catalytic spectrophotometry） of children aged 8 to 10 years, while the iodine content of drinking water （standard testing method for drinking water） and iodized salt（direct titration method） were also investigated in the villages where these children lived. Results A total of 24 water samples were collected in 12 villages of 3 townships, with median water iodine being 247.2μg/L. A total of 240 edible salt samples from households in these villages were collected, with iodized salt coverage being 80.8% （194/240）. A total of 326 spot urine samples of children aged 8 - 10 years were collected. The median iodine of these samples was 518.1 μg/L, and the proportion of urinary samples with iodine content over 300 μg/L was 82.5% （269/326）. Children＇ median urinary iodine in each of the 12 villages investigated correlated positively with the median water iodine of the corresponding village （Spearsman, r = 0.79, P 〈 0.05）, but not with median salt iodine （Spearsman, r = - 0.17, P 〉 0.05）. The multiple linear regression analysis indicated that 68.7% of the variability in median urinary iodine was associated with variability in water iodine in the 12 villages. Conclusions Drinking water is the key contributor to children＇s excessive iodine intake. Withdrawing iodized salt could not completely correct excessive iodine intake. Intervention should be focused on finding water source with proper iodine content. Key words: Iodine ; Drinking; Salts ; Data collection

Objective To understand the status of iodine nutrition of children aged 8-10 years and pregnant women in Shizuishan City. Methods In 2017, five sampling districts were divided into east, west, south, north and middle districts in three counties (Dawukou District, Huinong District and Pingluo County) of Shizuishan City, one township (town, street) was selected in each district, one primary school was selected in each township (town, street), 40 children aged 8-10 years were selected in each primary school, and 20 pregnant women were selected in each township (town, street). In Dawukou District and Huinong District of Shizuishan City, 50 g of edible salt and 10 ml of urine samples were collected from the homes of children and pregnant women; in Pingluo County 50 g of edible salt samples were collected from the homes of children and pregnant women. Iodine in edible iodized salt was measured by redox titration and urinary iodine content was measured by arsenic-cerium catalytic spectrophotometer. Results A total of 900 edible salt samples were collected, the median iodine content in salt was 24.50 mg/kg, the coverage rate of iodized salt was 97.67% (879/900), the qualified rate of iodized salt was 86.92% (764/879), and the edible rate of qualified iodized salt was 84.89% (764/900). A total of 400 urine samples of children were tested, the median urinary iodine was 213 μg/L. There was statistically significant difference in urinary iodine among children between Dawukou District and Huinong District (the median urinary iodine was 246 and 194 μg/L, respectively, Z=-4.827, P 0.05). A total of 200 urine samples of pregnant women were tested, and the median urinary iodine was 173 μg/L. There were no significant differences in urinary iodine content between pregnant women in different counties(districts), and between pregnant women at different pregnancy stages (P > 0.05). Conclusion The iodine nutrition status of the children aged 8-10 years and pregnant women in Shizuishan City is generally at the appropriate level. Key words: Iodine; Deficiency diseases; Nutritional status; Salts; Urine

Objective To study the nutritional status of pregnant women in Shanxi Province before and after the implementation of the new standards of iodized salt content, provide the basis for scientific supplementation of iodine for pregnant women. Methods According to the method of population proportion sampling, 30 county-level monitoring sites were selected, a primary school was selected from each county (city, district) by the method of simple random sampling and 40 students in 2011 or 50 students in 2014 aged 8-10 years were selected in each school, direct titration was used to detect salt iodine; at the same time, 20 pregnant women were selected from each town where the primary school was located and urinary iodine was determined using arsenic cerium catalytic spectrophotometry (WS/T 107-2006). Results A total of 1 182 and 1 437 salt samples was detected in Shanxi Province in 2011 and 2014, the median of salt iodine was 30.5 and 24.1 mg/kg, respectively, and the difference was statistically significant (H= 567.45, P < 0.01); it was 95.41%, 80.31%, 76.62% of the coverage rate of iodized salt, qualified rate of iodized salt, qualified iodized salt consumption rate in 2014, respectively; which were compared with those in 2011 (97.63%, 97.49%, 95.18%), the differences were statistically significant (χ2= 9.27, 232.40, 166.25, P < 0.01). A total of 440 and 630 urinary samples of pregnant women were tested in 2011 and 2014, the median of urinary iodine was 279.6 and 177.1 μg/L, respectively, iodine nutrition of pregnant women was more than adequate in 2011, and iodine nutrition was suitable in 2014. The difference was statistically significant (H= 153.89, P < 0.01). The proportion of pregnant women's median of urinary iodine less than 150 μg/L in 2014 [41.11% (259/630)] was significantly higher than that in 2011 [8.18% (36/440) , χ2= 140.68, P < 0.01]. The constituent ratio of 250 to 500 μg/L was significantly decreased [23.65% (149/630) vs 54.77% (241/440), χ2= 108.33, P < 0.01). Conclusion It is at a reasonable level of iodine nutrition level of pregnant women in Shanxi after the adjustment of iodized salt content, but the ratio of < 150 μg/L is increasing, which needs to be paid attention to. Key words: Salts; Iodine; Pregnant women; Nutrition

Objective To evaluate urinary iodine change of the target population with different iodine contents in drinking water after non-iodized salt intervention so as to provide evidence for making strategies of scientific supply of iodized salt. Methods Three counties were chosen as investigation site by adopting purposive sampling method. The school children aged 8 - 13 years old and women aged of 18 - 49 years old in each selected family were used as investigation subjects. The families with different iodine contents in drinking water were chosen to substitute non-iodized salt for their current iodized salt for the 2 months through field trail study. Iodine content in the drinking water of each selected family was determined, and urine samples of the target population were collected for determination of iodine change respectively before and 1, 2 months after the intervention. Linear regression was used to analyze the factors that affected the urinary iodine concentration. Results The median of iodine in drinking water of families in the investigation site was 99.4 μg/L, and the scope was 5.0-867.6 μg/L. Before intervention, the medians of urinary iodine of school children and women were > 300 μg/L except the groups of iodine content in the drinking water less than 30 μg/L and 30 μg/L groups. Two months after the intervention, the scope of the median urinary iodine of school children was 188.5-308.3 μg/L, which was reduced obviously than that before intervention(287.9-514.2 μg/L) ; in women, it was also reduced obviously(181.1-301.7 μg/L) than that before intervention(299.9-632.2 μg/L), in the 140 μg/L groups of iodine content in the drinking water. Two months after the intervention in the group of iodine content in the drinking water above 150 μg/L, the medians of urinary iodine of school children and women were > 400 μg/L. The difference of average urine iodine level before and after was no statistical significance(X~2 = 2.684, 1.742, all P > 0.05). The urine iodine level of target population increased gradually with the elevation of water iodine level 2 months after the intervention (P < 0.05). Linear regression equation was obtained(r=0.950,0.938, all P < 0.01). When the median urinary iodine was 200 μg/L, the median iodine in drinking water was 103.4 μg/L. Conclusions The iodine nutrition level of school children and women are not deficient after stopping iodized salt supplement. Measures should be taken to stop the supply of iodized salt areas where the iodine content is more than 103.4 μg/L and less than or equal 150 μg/L in drinking water. It is necessary to take measures to improve water quality and to decrease iodine content in addition to stopping supply of iodized salt in areas where iodine content is more than 150 μg/L in dringking water. Key words: Iodine; Salts; Intervention studies

Objective To master the status of iodine content in drinking water and iodine nutritional status of population before and after the salt iodine concentration reduction in 2012 in Meizhou City, and to provide a scientific basis for safety assessment of salt iodine content after adjustment of the policy. Methods Using stratified random sampling method, drinking water samples were collected, and iodide content was measured by cerous sulfate catalytic spectrophotometry. Urine samples of children aged 8 - 10 were collected, in which the iodide content was quantitatively tested by arsenic cerium catalytic spectrophotometry. Samples of household edible salt were collected to determine iodine content by direct titration in 2012 before (September 2011), and after the salt iodine concentration reduction (September 2012 and September 2013). Results A total of 422 water samples were measured, the median iodine content of water was 2.4 μg/L. The water iodine median was 2.1 μg/L in centralized water supply (n = 163), and 2.9 μg/L in decentralized water supply (n = 259), the difference was statistically significant (U = - 2.526,P < 0.05). Totally 800 and 803 urine samples of children aged 8 - 10 were collected in 2011 and 2012, median urinary iodine was 216.5 and 207.5 μg/L, respectively, which were higher than that in 2013 (n = 807, 190.0 μg/L, χ2 = 17.040, 24.868, all P < 0.05). Urinary iodine ≥300 μg/L ratio was significantly decreased (2013 than 2011 and 2012, 19.3% (156/807) vs. 26.5% (212/800) and 24.5% (197/803), χ2 = 6.363, 11.695, all P < 0.05), and urinary iodine < 100 μg/L rose in the proportion (2013 than 2011, 18.0% vs. 13.5%, χ2 = 6.045,P < 0.05). A total of 2 410 household salt samples were tested, and the coverage rate of iodized salt, iodized salt qualified rate, the consumption rate of qualified iodized salt were all higher than 98.8%. Totally 800, 803 and 807 salt samples were collected in 2011, 2012 and 2013, the salt iodine medians were 31.0, 27.7 and 25.4 mg/kg, respectively, the difference between the salt iodine medians was statistically significant (H = 91.422,P < 0.05). Conclusions Iodine excess risk is significantly decreased, and the level of iodine nutritional status of the city's population is appropriate after the salt iodine concentration reduction in 2012. The salt iodine concentration adjusted is suitable and safe. Key words: Drinking; Urine; Salts; Iodine

Objective To explore the impact of iodine nutrition on pregnant women after adjusting the iodine content in iodized salt in Hangzhou and provide a scientific basis for supplementation of iodine to pregnant women. Methods After adjusting the iodine content of salt from 2012 to 2014, proportional probability sampling method was used to select 300 families and 100 pregnant women from every county (area, city) of Hangzhou City, and the household salt and urine samples were collected to detect iodine. Results Totally 3 904, 3 900 and 3 900 samples of household salts were collected with the medians of salt iodine concentration of 23.77, 22.75 and 23.30 mg/kg of each year from 2012 to 2014, respectively. The qualified rate of iodized-salt was 95.87% (3 550/3 703), 97.04% (3 510/3 617) and 96.53% (3 564/3 692) and the consuming rate of qualified iodized salt was 90.92% (3 550/3 904), 90.01% (3 510/3 900) and 91.38% (3 564/3 900), respectively, from the year 2012 to 2014. Totally 1 300, 1 217 and 1 315 urine samples of pregnant women were collected and the median of urinary iodine (MUI) of each year from 2012 to 2014 was 119.90, 136.40 and 124.00 μg/L, respectively. Conclusion After adjusting the iodine content of salt in Hangzhou, the salt iodine consumption levels of pregnant women's family are stable, but the level of urinary iodine is low, which should be pay attention to. Key words: Pregnant women; Iodine; Salt; Urine

Objective To understand the condition of iodine deficiency disorders,and the iodine nutritional status of population before adjustment of iodine level in edible salt in Liaoning Province.Methods Thirty countries （cites,districts） which were divided into coastal,inland,city,rural areas according to location and population characteristics were sampled by population probability sampling method in the whole province; one township （town,street office） was sampled from each country （city,district）; one village （neighborhood） and one school were chosen from each township（town,street office）.Forty children aged 8-10 were selected from each school to measure their thyroid volumes and household salt samples were collected to detect their iodine content; fourteen of those 40 children were selected to detect their urinary iodine content.In each village （neighborhood）,five drinking water samples were collected in the east,the west,the south,the north and the center positions.Two tap water samples were collected to detect their iodine content if the water supply was centralized.Around each school; three townships were selected,in each township,random urine samples were collected from 5 pregnant women and 5 lactating women to detect their iodine content.Thyroid volume was examined by ultrasound method; the salt iodine was tested by the method of direct titration; iodine content of urine and drinking water was tested by arsenic cerium catalytic spectrophotometry.Results Totally one thousand two hundred and nineteen children aged 8-10 were examined; twenty-nine children were diagnosed goiter,and the goiter rate was 2.4%（national standards：〈 5%）.One thousand two hundred and nineteen edible salt samples were tested,and the median salt iodine level was 30.1 mg/kg.The iodized salt coverage rate was 99.3%（1 211/1 219）,and the consumption rate of qualified iodized salt was 97.9%（1 194/1 219）.Four hundred and eighty urine samples were tested,and the median urinary iodine level was 189.0 μg/L（suitable content of salt iodine was 100-199 μg/L） ; urinary iodine 〈 20 μg/L accounted for 0.6%（3/480）.Ninety-nine drinking water samples were selected,and the average iodine content of the drinking water was （5.9 ± 5.7）μg/L.Four hundred and fifty-one urine samples of pregnant women and four hundred and fifty urine samples of lactating women were selected,and the median urinary iodine level of pregnant women and lactating women was 163.2,151.0 μg/L（suitable contents of urinary iodine in pregnant women and lactating women were 150-249 μg/L,〉 100 μg/L）.The median urinary iodine of pregnant women was 135.4 μg/L in coastal city,138.0 μg/L in coastal rural,168.0 μg/L in inland city,171.1 μg/L in inland rural.The difference of urinary iodine between coastal region and inland region was significant（H =14.287 6,P 〈 0.05）.Conclusions The iodine nutrition conditions of pregnant women,lactating women and children are adequate in Liaoning Province,but the iodine nutritional status is insufficient in pregnant women from the coastal areas. Key words: Thyroid; Urine; Salts; Iodine; Monitoring

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 (χ2= 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~ 0.05). In gender groups, there was significant difference in the MUI among male children (H= 9.261, 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. Key words: Child; Iodine; Deficiency diseases; Monitoring

Objective s To understand current situation in national prevention and control of iodine deficiency disorders (IDD), and to evaluate the progress in eliminating IDD in 31 provinces and Xinjiang Production and Construction Corps (Corps) in China. Methods In 2011, 30 units were sampled in each of 31 provinces and Corps in China based on the sampling method of Probability Proportional to Size. After excluding townships of water iodine level higher than 150 μg/L, 1 primary school was chosen in each unit, by the randomized sampling method, 40 students in each school were sampled for examining their thyroid volume, among them, 12 students were tested for their urinary iodine level and for their household salt iodine level and per capital daily salt intake. Near the location of these primary schools, 3 townships were chosen, 5 pregnant women and 5 lactating women in each township were sampled to test their urinary iodine level. Besides, 1 water sample was sampled according to the location in each village (east, west, south, north, and middle) in non-central water supplying villages, and 2 tap water samples in central water supplying villages. The ultrasound was used to detect goiter size according to the diagnostic criteria for endemic goiter; As3+-Ce4+ catalytic spectrophotometry using ammonium per sulfate digestion (WS/T 107-2006) was used to test the urinary iodine level; the testing method recommended by the National Iodine Deficiency Disorders Reference Lab was applied to test the water iodine level, the direct titration method among the generic methods of iodide testing for salt production industry (GB/T 13025.7-1999) was used to determine the salt iodine level; and the arbitration method was adopted for quantitative determination in case of well salt or special salts and the salt intake was estimated based on three-day weighed food record. Evaluation standards are as follows: urinary iodine level of children: deficient is the median of urinary iodine (MUI) less than 100 μg/L, adequate is MUI at 100-199 μg/L, more than adequate is MUI at 200-299 μg/L, and excessive is MUI equal to or greater than 300 μg/L; salt iodine: definition of qualified iodized salt is (35 ± 15) mg/kg; non-iodized salt (GB 5461-2000) is iodine less than 5 mg/kg; definition of unqualified iodized salt is iodine between 5-< 20 mg/kg or higher than 50 mg/kg. The total population of the sixth national census was used for statistical data correction. Results Among 31 provinces and Corps, children's goiter rate was 2.4%, which was obviously lower than the IDD elimination standard at the national level (< 5%); the national iodized salt coverage rate was 98.0% and the consumption rate of qualified iodized salt was 95.3%, both figures had achieved the national standard (the iodized salt coverage should be greater than 95% and the consumption rate of qualified iodized salt greater than 90%). The median of salt iodine was at 30.2 mg/kg; the MUI of children, pregnant women and lactating women was 238.6, 184.4 and 174.4 μg/L, respectively. Urinary iodine of children was higher than adequate level, of both pregnant women and lactating women were at adequate level. The surveillance results of water iodine in 25 provinces revealed that the median was at 5.6 μg/L; the salt intake surveillance results among students' households in 24 provinces and the Corps revealed that the daily intake was 10.1 g per person a day. Conclusions National IDD prevention and control strategy integrated with universal salt iodization as a key measure has achieved remarkable impacts. IDD has been eliminated at the national level. Key words: Iodine; Deficiency disorders; Children; Women; Urinary; Salts; Epidemic studies

Objective To analyze the status of iodine nutrition after implementing new standard of iodized salt in Hubei Province, and to evaluate the effectiveness of prevention and control measures. Methods In 2016, in 103 counties (cities, districts) of Hubei Province, the townships (streets) under the jurisdiction of each county (city, district) were divided into five regions: east, south, west, north, and middle. One township (street) was selected from each region, and one primary school was selected from each township(street). From each primary school 40 children aged 8 - 10 (half males half females) were selected to collect salt samples from their households. Twenty pregnant women from townships(streets) near the selected schools were chosen to collect edible salt samples from their households. According to the method of population proportionate sampling (PPS), 35 counties (cities, districts) were chosen from 103 counties (cities, districts). Thyroid volume of children aged 8 - 10 was examined, and urinary iodine of children and pregnant women were tested. Iodine nutrition criteria: the median urinary iodine of children < 100 μg/L is iodine deficiency, 100 - < 200 μg/L is iodine appropriate, 200 - < 300 μg/L is iodine overdose, ≥300 μg/L is iodine excess; pregnant women urinary iodine median < 150 μg/L is iodine deficiency, 150 -< 250 μg/L is iodine appropriate, 250 - < 500 μg/L is iodine overdose, and ≥500 μg/L is iodine excess. Results Totally 30 967 edible salt samples from children's and pregnant women's households were examined, and the median of salt iodine was 23.85 mg/kg. The coverage rate of iodized salt was 99.46% (30 799/30 967) , the consumption rate of qualified iodized salt was 94.00% (29 108/30 967). Totally 6 789 children aged 8 - 10 were examined thyroid volume and detected urinary iodine, the goiter rate was 0.85% (58/6 789) and the median urinary iodine was 263.54 μg/L. Totally 3 348 urine samples of pregnant women were examined, and the median urinary iodine was 166.71 μg/L. Conclusions The salt iodine content of residents and the goiter rate of children in Hubei Province meet the national standard for eliminating iodine deficiency disorders. The iodine nutrition level of children and pregnant women is iodine appropriate or iodine overdose. The iodine nutrition level monitoring of key populations should be continuously strengthened. Key words: Iodine; Deficiency disease; Salts; Urine; Goiter