Objective Toinvestigate iodine nutrition,thyroid volume and function of children and women in high water iodine areas,and to discuss the cut-off point of water iodine level where should be defined as iodine excessive areas.Methods In iodine excessive townships in Xiaodian and Qingxu Counties of Taiyuan City,all villages were divided to 4 groups according to the concentration of iodine in drinking water:50 ～ ＜ 100 μg/L (Group A),100 ～ ＜ 150 μg/L(Group B),150 ～ ＜ 300 μg/L(Group C) and ≥300 μg/L(Group D),and 2-3 villages were randomly selected from each group as investigation sites.Two hundred children aged 8-10 and 60 women (20 pregnant women,20 breasffeeding women and 20 women of childbearing age,respectively) were sampled.Drinking water,edible salt and once random urine samples for each studying object were collected,and the iodine content was measured.The goiter volume of children aged 8-10 and triiodothyronine (FT3),free thyroxine (FT4),thyroid stimulating hormone (TSH) of women were determined.Results Totally 708 children and 236 women were selected as respondents who ate non-iodized salt.Iodine content in drinking water of children in groups A,B,C and D was 73.8,144.7,258.5 and 501.0 μg/L,respectively,and that of women was 73.8,144.7,242.7 and 485.9 μg/L,respectively.Median urinary iodine of children in groups A,B,C and D was 274.3,312.8,455.6 and 793.5 μg/L,respectively,and that of women was 238.3,235.2,371.6 and 641.6 μg/L,respectively.The median urinary iodine of children and women increased with increasing water content of iodine.The goiter rate of children was 5.6％ (11/196),13.2％ (25/189),12.6％ (20/158) and 10.9％ (18/165) for each group,respectively,which also increased with increasing water content of iodine.In groups A,C and D,the FT3 and FT4 levels[pmol/L:(3.70 ± 0.59),(14.01 ± 2.44); (3.43 ± 0.57),(12.87 ± 2.12); (3.42 ± 0.47),(12.66 ±1.78)] in pregnant woman were lower than those in breasffeeding women[pmol/L:(4.26 ± ±0.57),(14.73 ± 2.36;(4.28 ± 0.40),(14.77 ± 1.19); (4.36 ± 0.65),(15.66 ± 2.84)] and women of childbearing age[pmol/L:(4.80 ±0.50),(17.47 ± 2.11); (4.21 ± 0.48),(15.83 ± 1.64); (4.26 ± 0.52),(15.53 ± 1.81)].With increasing water content of iodine,FT4 level was decreasing and TSH level was increasing gradually in women.Conclusions When water iodine exceeds 100 μg/L,goiter rate of children has increased significantly.Iodine excessive women and children have appeared one after another with increasing water content of iodine.Women incidence of subclinical hypothyroidism risk has increased with increasing water content of iodine,and the detection rate of subclinical hypothyroidism is significantly higher when water iodine is higher than 300 μg/L.The cut-off point of iodine excessive areas should be descend from 150 μg/L to 100 μg/L.

Objective To investigate the nutritional status of iodine among residents and the goiter disease of children in high water iodine areas in Shanxi Province,and to provide a scientific basis for establishment of longlasting control strategies and measures.Methods In 2012,according to the historical monitoring data,in the 10 high water iodine counties (citys,districts),one town was selected based on its location (east,west,south,north and middle) in each county (citie,district).In county (city,district) with 5 townships or less,all townships were selected.Four villages were selected in each township and fifteen residents in each village were selected to test salt iodine level.In five high water iodine counties (city,district),one or two high water iodine villages were selected,water samples were collected and the iodine content was measured; one hundred students aged 8-10 years old were chosen to examine their thyroid size.Thirty children were chosen from above students to collect their urine samples and to determine the iodine content.Results In 10 high water iodine counties (citys,districts),1 680 salt samples were tested.The rate of non-iodized salt was 85.2％ (1 432/1 680); in six villages of five high water iodine counties (citys,districts),the median of urinary iodine of 256 children aged 8 to 10 was 487.2 μg/L; in three villages which had improved the quality of water,the median of urinary iodine was 271.0 μg/L; other three villages which had not improved the quality of water,the median of urinary iodine was 692.6 μg/L.In those villages which had not improved the quality of water,urinary iodine of children ≥300 μg/L accounted for 85.8％ (139/162); in those villages which had improved the quality of water,high urinary iodine of children accounted for 41.5％ (39/94),and the difference was statistically significant (x2 =53.06,P ＜ 0.05).The thyroid was investigated among 591 children aged 8-10 years old,and the goiter rate was 6.6％(39/591).In those villages which had improved the quality of water,the goiter rate of children was 3.8％ (11/291),but in villages which had not improved the quality of water,the goiter rate of children was 9.3％ (28/300),and the difference was statistically significant (x2 =6.52,P ＜ 0.05).Conclusion The iodine nutrition level of residents in high water iodine areas in Shanxi is excessive,children's goiter disease has not been effectively controlled; water improvement to reduce iodine is the basic way to control the disease of high iodine.

Objective To analyze the effect of adjustments of control strategy on epidemic trend of iodine deficiency disorders (IDD) in Shanxi Province after universal salt iodization (USI),and to provide basis for timely adopting targeted control countermeasure and scientifically adjusting intervention strategy.Methods A method of retrospective analysis was performed to collect data from IDD surveillance at national or province levels after 1995,and from iodized salt surveillance of the province after 2004.According to the statistics and analysis of children's goiter rate,median urinary,median and mean of salt iodine,coverage rate of iodized salt,qualified rate of iodized salt,consumption rate of qualified iodized salt and their relationship.Results Since 1995,the children's goiter rate by palpation and B-ultrasound showed a steady descending trend.The median salt iodine,mean salt iodine and children's median urinary iodine showed a trend of rise→decline→stable→decline.Namely:The three indicators began to rise year by year from 1995 (29.1 mg/kg,31.7 ± 15.0 mg/kg,199.3 μg/L),in 1999 (48.7 mg/kg,53.4 ± 29.4 mg/kg,407.5 μg/L) reached its climax; and then decreased,in 2001 (34.7 mg/kg,36.2 ± 11.9 mg/kg,282.1 μg/L)stoped; which were basically stable from 2001 to 2011; since 2013 (26.0 mg/kg,26.5 ± 6.3 mg/kg,192.0 μg/L),a significant decline began.The rate and edible rate of qualified iodized salt showed a trend of decline→rise→stable.Two indexes began to decline circuitously from 1995 (72.61％,68.25％),and dipped to a low point in 1999 (44.80％,43.67％); then began to rise,until 2002 (94.73％,91.80％) reached basic stability; and remained steady from 2002 to 2013.Conclusions Following the process of prevention and treatment of IDD for more than 30 years in Shanxi Province,with the depth understanding of the range of adequate iodine nutrition,according to the monitoringfeedback mechanism,the strategy of salt iodization has been adjusted several times,the target of continuous elimination of IDD has achieved since 2000 and the levels of iodine nutrition in population are more reasonable.Salt iodization strategy should continue to adhere to.

Objective To investigate resident iodine nutrition level in waterborne high iodine areas and prevalence of high iodine goiter in Shanxi Province.Methods In 2014,in Shanxi Province,in all the 10 high iodine counties (cities,districts),the jurisdiction area of each county (city,district) was divided into two blocks,high iodine and not high iodine districts,and in high iodine area of each county (city,area) according to their sub-area positions of east,south,west,north and center,a township was randomly selected (if the number of high iodine area in iodine excessive township ≤5,all townships were selected);four administrative villages in each monitoring township were randomly selected;in each administrative village,the edible salt samples of 15 randomly selected households were collected for detection of iodine content.Five counties (cities,districts) were selected from the province's 10 high iodine counties (cities,districts),water iodine content of 3 counties (cities,districts) was 150-300 μg/L,and 2 were ＞ 300 μg/L,one administrative village was selected from each county (city,area),household drinking water samples were collected to detect iodine content;and 100 elementary school children aged 8-10 were selected from the village where the monitoring stations located in for thyroid volume ultrasound measurement,and 30 of them were randomly selected for urinary iodine content detection.Results ① In the 10 high iodine counties (cities,districts),1 680 households salt samples were detected,and the rate of no iodine salt samples was 89.2％(1 499/1 680).② Fourteen water samples were collected in 5 counties (cities,districts),and the water iodine content was 155.7-467.3 μg/L.③ In the five high iodine counties (cities,districts),197 urine samples were collected from children aged 8 to 10.The median of urinary iodine was 466.5 μg/L;the median urinary iodine was 650.1 μg/L in water iodine≥300 μg/L children group which was significantly higher than that of the group with 150-300 μg/L water iodine content 332.5 μg/L (Z =-6.164,P ＜ 0.05);urinary iodine level of children and the water iodine of the corresponding village was positively correlated (r =0.543,P ＜ 0.05).④ In the five high iodine counties (cities,districts),543 children aged 8-10 were measured with their thyroid volume,the thyroid goiter rate was 6.8％(37/543);the goiter rate of water iodine ≥300 μg/L children group was [9.0％(28/311)] which was significantly higher than that in the iodine content of drinking water 150-300 μg/L group [3.9％(9/232),x2 =5.494,P ＜ 0.05].Conclusion The measurement of stopping iodized salt supply in high iodine areas in Shanxi Province is well implemented,iodine nutrition level and thyroid goiter rate in those areas are still too high,high iodine intervention measures can be focused on changing of the drinking water.

Objective To investigate the prevalence of thyroid nodules in the adults in high water iodine area and to reveal the risk factors of thyroid nodules.Methods Questionnaire investigation,determination of urinary iodine and thyroid ultrasound were carried out for residents aged 18 to 65 years old in Gaoche Village of Wenshui County in Shanxi Province,with the exception of pregnant and lactating women.Possible risk factors for thyroid nodules were analyzed.Results Of the 286 residents,89 cases of thyroid nodule were detected and the prevalence rate was 31.1％.The prevalence rate was 25.7％ (35/136) in male and 36.0％ (54/150) in female,there was no significant difference between sex (x2 =2.49,P ＞ 0.05).The average age of the cases with thyroid nodules was (49.6 ± 11.3) years old and was (43.5 ± 11.6) years old in cases without thyroid nodules,there was significant difference between age groups (t =4.11,P ＜ 0.05).The median of urinary iodine of the cases with thyroid nodules was 453.0 μg/L and was 408.4 μg/L in cases without thyroid nodules,there was no significant difference in the median of urinary iodine (Z =-0.616,P ＞ 0.05).The prevalence rate of solitary nodule was 57.3％ (51/89) and multiple nodules 42.7％ (38/89).As to the property nodule,the cyst nodule,the cyst-solid nodule and the solid nodule was 49.4％ (44/89),29.2％ (26/89) and 21.3％ (19/89),respectively.The results of Logistic regression showed that the prevalence of thyroid nodule increased with age (OR =1.048,95％CI:1.024-1.073,P ＜ 0.05) and the multiple nodule increased with age (OR =1.086,95％CI:1.044-1.129,P ＜ 0.05).The cyst nodule was a more common form in women (OR =2.559,95％CI:1.245-5.262,P ＜ 0.05).The prevalence of cyst-solid nodule increased with age (OR =1.125,95％CI:1.065-1.189,P ＜ 0.05).Conclusions The prevalence of the thyroid nodule in adults is high and the thyroid nodules are mainly the cyst nodules.The prevalence of the thyroid nodule is increased with age,especially the multiple nodules and the cyst-solid nodule in high water iodine area.The cyst nodule is a more common form in women.

Objective To investigate the prevalence of hypertension in adults in different water iodine areas and to explore the epidemiological association between high iodine intake in drinking water and hypertension.Methods In 2016,Xiwenzhuang Village of Taiyuan City as an appropriate-indine area,Gaoche Village and Maxi Village of Wenshui County were selected in Shanxi Province as a high-iodine area and a low-iodine area,respectively,and conducted questionnaire surveys,clinical hypertension examinations,and determination of urinary iodine levels of residents aged 18 to 65 years.Results A total of 853 people were investigated,including 283 in high-iodine area,258 in appropriate-indine area and 312 in low-iodine area.The medians urinary iodine in high,appropriate and low iodine areas were 423.0,218.5 and 126.6 μg/L,respectively,and the difference was statistically significant (H =289.7,P ＜ 0.05).The detection rates of hypertension in adults with high,appropriate and low iodine levels were 38.9％ (110/283),41.9％ (108/258) and 34.0％ (106/312),respectively,the difference was not significant statistically between the three groups (x2 =3.87,P ＞ 0.05).There was no significant difference in the detection rate of hypertension among males [45.9％(62/135),50.0％ (53/106),40.8％ (53/130)] in different areas (x2 =2.04,P ＞0.05),and no significant difference in the detection rate of hypertension among females [32.4％ (48/148),36.2％ (55/152),29.1％ (53/182),x2 =1.89,P ＞ 0.05];The difference between the three groups was not significant statistically in the detection rate of hypertension both among the 18-＜ 45 years group and 45-65 years group (x2 =1.22,5.66,P ＞ 0.05).Conclusion Drinking water with excess iodine might not increase the risk of hypertension in adults in Shanxi Province.

Objective To master the iodine nutritional status of residents and to evaluate the effect of iodine nutrition improvement on residents health after the adjustment of salt iodine concentration. Methods According to the method of population proportion sampling, 30 county-level monitoring sites were selected in 2014, a primary school was selected from each county (city, district) by the method of simple random sampling and 50 students aged 8 - 10 (half males and half females) were selected in each school, B ultrasound was used to detect thyroid volume, arsenic cerium catalytic spectrophotometry (WS/T 107-2006) was used to detect urinary iodine, direct titration was used to detect salt iodine; At the same time, 20 pregnant women were selected from each town and urinary iodine was determined. All results were compared with the results of 2011 to evaluate the effect of iodine nutrition improvement on resident's health after the adjustment of salt iodine concentration. Results A total of 1 437 edible salt samples were tested, the median of salt iodine concentration was 24.1 mg/kg. Based on the new standard (18 - 33 mg/kg), the coverage rate of iodized salt was 95.4%(1 371/1 437), the qualified rate of iodized salt was 80.3%(1 101/1 371), the consumption rate of qualified iodized salt was 76.6% (1 101/1 437). A total of 1 496 urine samples of children and 630 urine samples of pregnant women were tested, the median of urinary iodine of children and pregnant women was 224.6 and 177.1 μg/L, respectively, which were significantly lower than those of 2011 (274.6, 279.6μg/L), the differences were statistically significant (H=70.10, 153.50, all P<0.05). The proportion of counties which iodine nutrition of children and pregnant women in suitable range was 36.7% (11/30) and 56.7% (17/30), which were higher than those of 2011 [6.5%(2/31), 25.8%(8/31)], the differences were statistically significant (χ2 = 7.88, 5.00, all P < 0.05). Totally 1 552 children were examined thyroid in Shanxi Province, the rate of goiter was 4.4% (69/1 552). Conclusion The new standard of iodine concentration makes it possible to maintain a sustainable elimination of iodine deficiency disorders, and it can improve the iodine nutrition of children aged 8-10 years and pregnant women to more reasonable level.

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 (x2 =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),x2 =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),x2 =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.

Objective To understand the iodine nutritional status and thyroid function of different populations after 20 years of universal salt iodization in iodine deficiency area of Shanxi Province, and to provide data support for scientific iodine supplementation according to local conditions. Methods In 2014, six townships (Chengguan, Dadeng, Dengzhuang, Gucheng, Xiangling and Fencheng townships) in Xiangfen County, Linfen City, Shanxi Province, were selected as the place of investigation. Four hundred school-age children aged 6 - 12 years (school-age children), 400 child-bearing women aged 18 - 44 (child-bearing women), 400 pregnant women, 400 lactating women and their 0 - 6 months breast-feeding infants (breast-feeding infants), and 400 children aged 7 -24 months were selected by two-stage sampling method. Water samples of school-age children's domestic drinking water and salt samples for domestic consumption were collected, and the water iodine and salt iodine were detected by arsenic and cerium catalytic spectrophotometry ( recommended by the National Iodine Deficiency Disorders Reference Laboratory) and "General Test Method in Salt Industry-Determination of Iodine" (GB/T 13025.7-2012). Random urine samples of all subjects were collected, urine iodine was detected by "Method for Determination of Iodine in Urine by As3+-Ce4+ Catalytic Spectrophotometry" ( WS/T 107-2006 ) . Samples of filter paper dried blood spots (DBS) of school-age children, child-bearing women, pregnant women, lactating women and breast-feeding infants were collected, and serum total thyroxine (TT4) and thyroid stimulating hormone (TSH) levels were detected by time-resolved fluorescence immunoassay. Results A total of 290 water samples were collected, and the median of water iodine was 9.37μg/L. A total of 406 salt samples were collected, the median of salt iodine was 25.0 mg/kg, the coverage rate of iodized salt was 98.52％ (400/406), and the consumption rate of qualified iodized salt was 92.61％ (376/406). Urine samples of 389 school-age children, 379 child-bearing women, 363 pregnant women, 365 lactating women, 366 breast-feeding infants, and 366 children aged 7 - 24 months were collected, and the medians of urine iodine were 200.7, 175.0, 186.0, 113.2, 285.8 and 204.8 μg/L, respectively. Among them, school-age children, breast-feeding infants, and children aged 7-24 months were over the appropriate level, while the rest populations were at the iodine appropriate levels. Blood samples of 402 school-age children, 397 child-bearing women, 398 pregnant women, 390 lactating women, and 386 breast-feeding infants were collected, and the medians of TT4 were 127.2, 110.2, 141.7, 95.8 and 139.0 nmol/L, respectively; the medians of TSH were 1.2, 0.9, 0.8, 0.9 and 0.9 mU/L, respectively, and they were all within the reference ranges. The abnormal rates of TT4 (8.46％, 33/390) and TSH (7.95％, 31/390) in lactating women were higher than those in school-age children, child-bearing women, pregnant women and breast-feeding infants [TT4 abnormal rates were 0.25％(1/402), 1.26％ (5/397), 0.50％ (2/398), 1.04％ (4/386), respectively; TSH abnormal rates were 1.24％ (5/402), 1.51％ (6/397), 1.51％ (6/398) and 0.78％ (3/386), respectively, P < 0.05]. The rate of thyroid dysfunction in lactating women (7.95％, 31/390) was higher than those in the rest populations [1.24％ (5/402), 1.51％ (6/397), 1.51％ (6/398), 0.78％ (3/386), P < 0.05]. Conclusions The iodine intake of different populations in the survey area is generally sufficient, and the current salt iodine content standard can meet the iodine nutrition needs of different populations. Lactating women have a high rate of thyroid dysfunction. It is suggested to stick to the strategy of universal salt iodization to prevent iodine deficiency hazards in iodine deficiency areas, and further strengthen the monitoring of iodine nutrition and thyroid function of pregnant women and lactating women.

Objective:To learn about the status of iodine deficiency disorders (IDD) and iodine nutrition of residents in Shanxi Province since the implementation of the standard of "Iodine Content in Edible Salt" (GB 26878-2011), to evaluate the level of prevention and control of IDD, and to provide scientific basis for adjusting prevention and control strategies.Methods:The data of core indicators monitored by Shanxi Province in accordance with the requirements of the national iodized salt and IDD monitoring program for each year from 2012 to 2021 were comprehensively reviewed, and the change trends of the indicators such as coverage rate of iodized salt, consumption rate of qualified iodized salt, children's median urinary iodine and goiter rate, and pregnant women's median urinary iodine were analyzed; the evaluation of IDD elimination in counties (cities and districts, hereinafter referred to as counties) was analyzed.Results:From 2012 to 2021, the coverage rate of iodized salt in Shanxi Province was remained > 95%; from 2012 to 2014 (transition period between new and old standard iodized salt), the consumption rate of qualified iodized salt had an upward trend (χ 2trend = 2 703.32, P < 0.001), with a downward trend from 2015 to 2017 (before and after the reform of the salt industry system, χ 2trend = 122.18, P < 0.001), and with an upward trend from 2018 to 2021 (after the reform of the salt industry system, χ 2trend = 455.11, P < 0.001), from 2018, the consumption rate of qualified iodized salt remained > 90%; from 2015 to 2021, the average content of salt iodine was between 23 - 25 mg/kg, and the coefficient of variation of salt iodine was 15% - 18%. From 2014 to 2021, the median urinary iodine of children in Shanxi Province remained at 200 - 250 μg/L, the median urinary iodine of pregnant women remained at 150 - 200 μg/L, and the goiter rate of children remained below 5%. Every year, iodine nutrition of pregnant women in some counties was insufficient. In 2016, the proportion of counties with insufficient iodine nutrition of pregnant women was high, reached 30.0% (12/40); from 2018 to 2021, the proportion of counties with insufficient iodine nutrition of pregnant women had a downward trend (χ 2trend = 9.37, P = 0.002), which was 11.1% (13/117) in 2021. In 2020, 117 counties in the province reached the IDD elimination standard, with a compliance rate of 100.0%. Conclusions:Since the implementation of the current salt iodine content standard for 10 years, the consumption rate of qualified iodized salt has gradually stabilized and remained at a high level, which can ensure that IDD is in a sustainable state of elimination in Shanxi Province, and the iodine nutrition of school-age children and pregnant women is generally at a suitable level. However, there are a certain number of counties with insufficient iodine nutrition of pregnant women. It is recommended to guide pregnant women to supplement iodine or set the average standard of salt iodine for pregnant women separately.