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Objective To understand the impact of system reform of salt industry on iodine nutrition of people in Gansu Province, and to provide a scientific basis for policy adjustment of relevant departments. Methods The investigation period (2014-2021) was divided into two sub-periods: before system reform of salt industry (2014-2016) and after system reform of salt industry (2017-2021). Thirty counties were selected according to the method of “population proportional probability sampling (PPS)” in 2014. According to the iodine deficiency disease monitoring program of Gansu Province, from 2016 to 2021, children aged 8-10 years and pregnant women were taken as research objects to collect urine samples for urine iodine detection. Children in 2014 and 2018 were selected to measure thyroid volume. Results A total of 90 989 children urine iodine samples were investigated, and the median urinary iodine (MUI) of children was 194.70µg/L; 7 663 and 83,326 children's urinary iodine samples were investigated in the two periods, the MUI was 180.73 µg/L and 196.00 µg/L, respectively, and the difference was statistically significant (P<0.05). A total of 44 741 pregnant women's urinary iodine samples were investigated, and the MUI of pregnant women was 176.50 µg/L; 4 480 and 40 261 pregnant women's urinary iodine samples were investigated in the two periods, the MUI was 160.61 µg/L and 178.10 µg/L, respectively, and the difference was statistically significant (P<0.05). The thyroid volume of 1 555 children and 8 509 children was investigated in the two periods, the median thyroid volume was 2.70 mL and 2.55 mL , respectively, and the difference was statistically significant (P<0.05). The rates of goiter in children were 3.15% and 1.26%, respectively, and the difference was statistically significant (P<0.05). Conclusion The iodine nutrition of people in Gansu Province has not fluctuated significantly after the reform of salt industry system and has maintained an appropriate level. It is necessary to pay attention to the potential risk of insufficient iodine nutrition level and thyroid health of key populations such as children and pregnant women and strengthen health education of scientific iodine supplementation.
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Objective:To learn about the iodine nutritional status of children aged 8 - 10 and pregnant women in Zhaoyuan City of Shandong Province, and to provide a basis for prevention and control of iodine deficiency disorders in the future.Methods:In 2008 and 2021, a census method was used to collect drinking water samples from all 724 villages (neighbourhood committee) in Zhaoyuan City. In 2018 and 2022, a multi-stage cluster random sampling method was used to investigate the daily per capita salt intake of residents. From 2017 to 2022, multi-stage random sampling method was used to collect household salt and urine samples from children aged 8 - 10 and pregnant women. Among them, thyroid volume tests were conducted on the sampled children in 2017, 2019, 2020 and 2022, and iodine supplementation surveys were conducted on the sampled pregnant women in 2019 - 2022. The iodine content in water was determined by As 3+-Ce 4+ catalytic spectrophotometry using ammonium persulfate digestion. The iodine content in potassium iodate salt was determined by direct titration method in "General Test Method in Salt Industry-Determination of Iodine" (GB/T 13025.7-2012). And other fortified iodized salt, unqualified iodized salt and non-iodized salt were retested using the redox titration method. Urinary iodine was determined by "Determination of iodine in urine - Part 1: As 3+-Ce 4+ catalytic spectrophotometry" (WS/T 107.1-2016). The children's thyroid gland was examined by using DP-2200Plus fully digital portable ultrasound instrument and 75L38EB ultrasound probe, and the goiter rate was calculated. Results:The median water iodine levels in Zhaoyuan City in 2008 and 2021 were 5.71 and 1.30 μg/L, respectively. The daily per capita salt intake of residents in 2018 and 2022 was 9.36 and 7.83 g, respectively. It is estimated that the per capita iodine intake in 2018 was (180.64 ± 71.00) μg/d and in 2022 was (124.25 ± 72.23) μg/d. From 2017 to 2022, the consumption rate of qualified iodized salt in both children and pregnant women was less than 90%; and from 2018 to 2022, the coverage rate of iodized salt was < 95%. The median urinary iodine of children was 184.00 μg/L, at an appropriate level, there was a statistically significant difference in urinary iodine content among children in different years ( H = 77.39, P < 0.001). From 2017 to 2022, the median urinary iodine of pregnant women was between 100 and 150 μg/L, there was no statistically significant difference in urinary iodine content among pregnant women in different years ( H = 5.33, P = 0.208). The goiter rate of children in 2017, 2019, 2020 and 2022 was 3.00% (24/800), there was no statistically significant difference in goiter rate among children in different years ( P = 1.000). A total of 400 pregnant women were investigated for iodine supplementation, the rate of iodine supplementation was 90.50% (362/400). Conclusions:Zhaoyuan City has reached the elimination standard for iodine deficiency disorders, but some pregnant women are at risk of iodine deficiency. Continuous monitoring and attention should be paid to the iodine nutritional status of pregnant women.
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Objective To understand the dynamic conditions after reaching the stage goal of elimination of iodine deficiency disorders (IDD) in Wenzhou, and to provide a scientific basis for prevention and treatment of IDD. Methods Three counties that the annual consumption rate of qualified iodized salt < 80% in 2014 and had the prevalence of endemic cretinism in history, Cangnan, Taishun and Yongjia, were selected as high risk monitoring areas. Three townships were selected in each area, and two primary schools were selected from each township, and 40 children urine samples were collected in each school (half male and half female) and the age of children were 8-10 years old. And near the location of these primary schools, we randomly selected 10 pregnant women in each village, and estimated the urinary iodine level and salt iodine concentration, respectively. The examination of thyroid by B ultrasound was performed in children by provincial professionals. Urinary iodine was determined using the arsenic cerium catalytic spectrophotometric method (GB/T 13025.7-2012). Salt iodine was determined by direct titration. Results Endemic cretinism case was not found in this survey, total goiter rate of 8-10 years old children was 2.04%(16/783). The median of urinary iodine was 116.1 and 108.2 μg/L, respectively, in 8 - 10 years old children and pregnant women. Iodized salt coverage rate was 90.48%(171/189), the intaking rate of qualified iodized salt was 84.66% (160/189). The concentration of pregnant women urinary iodine and salt iodine was positively correlated (r=0.54, P< 0.05). Conclusions Children's iodine nutrition is in the appropriate level, but pregnant women are in iodine definciency in Wenzhou City.
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Objective To assess the effectiveness of prevention program on iodine deficiency disorders and iodine nutritional status of residents in Guangdong Province.Methods Probability proportionate to size sampling(PPS) was employed in surveillance of iodine deficiency disorders.Thirty counties(cities,districts) were selected in Guangdong Province.In each county(city,district) one township(street) was selected; in each township (street) one primary school was selected and in each primary school 40 children aged 8-10 were chosen to examine their thyroid and to collect salt samples at their home for determination of salt iodine.Out of the 40 children,12 children were chosen to collect urine samples for determination of urinary iodine.From the primary schools chosen,40 grade 5 students were selected for intelligence quotient(IQ) test.In the nearby of the primary schools,3 townships(towns,street) were selected and in each township(town,street) 5 pregnant and 5 lactating women were selected to collect their urine samples for determination of urinary iodine.Type-B ultrasonic was used in measuring the thyroid volume.The iodine content of urine samples was measured by the method of arsenic and cerium catalysis spectrophotometry.The iodine content of salt was determined quantitatively with the titration method.IQ was tested by Chinese combined Raven's test.According to geographical location and the implementation of iodized salt,the effects of iodized salt on iodine deficiency disorders were analyzed in the plains and the Pearl River Delta Coastal region with mild iodine deficiency(iodized salt implementation region,referred to as the plains and the PRD),historical iodine deficiency areas (iodized implementation region) and the eastern and the western coastal areas of Guangdong(areas with non-iodized salt problem,referred to as the eastern and the western Guangdong).Results A total of 1200 children aged 8 to 10 were examined by type-B ultrasonic test,and goiter rate was 3.5％ (42/1200).The differences of goiter rate between the plains and the PRD,the historical iodine deficiency areas and the eastern and the western Guangdong were statistically significant (x2 =6.6,P ＜ 0.05).The goiter rate (6.1％) in the eastern and the western Guangdong was significantly higher than that of the plains and the PRD and the historical iodine deficiency areas (3.3％,2.0％,x2 =5.6,7.1,all P ＜ 0.05).A total of 1200 salt samples were examined.The median and coefficient of variation of iodine in the salt were 31.0 mg/kg and 23.2％,respectively.Coverage of iodized salt was 97.5％(1170/1200) while 96.1％(1153/1200) of consumed iodized salt was qualified.The median urinary iodine of 1200 children aged 8-10 was 186.5 μg/L,and the differences of median urinary iodine between the plains and the PRD,the historical iodine deficiency areas and the eastern and the western Guangdong were statistically significant(x2 =5.9,P ＜ 0.05).The median urinary iodine of the eastern and the western Guangdong(162.4 μg/L) was significantly lower than that of the plains and the PRD(207.5 μg/L,x2 =8.7,P ＜ 0.01).The difference of median urinary iodine between the plains and the PRD,the historical iodine deficiency areas and the eastern and the western Guangdong was statistically significant(x2 =58.9,P＜ 0.01).The median urinary iodine of the eastern and the western Guangdong(109.6 μg/L) was significantly lower than that of the historical iodine deficiency areas and the plains and the PRD(152.9,155.2 μg/L,x2 =18.3,20.6,all P ＜ 0.05).The mean IQ of the 1208 grade 5 students was 102.8 ± 14.3.The IQ of the plains and the PRD(104.3 ± 13.9) and the historical iodine deficiency areas(102.7 ± 14.3) was significantly higher than that of the eastern and the western Guangdong(100.3 ± 14.7,t =3.8,2.1,P＜ 0.01 orP＜ 0.05).Conclusions The goal of iodine deficiency disorders elimination is achieved as scheduled in Guangdong Province.The health level of general population has been improved significantly.Iodine nutrition is in the appropriate range (100-199 μg/L) in general population but low in pregnant women.The selling of non-iodized salt in the eastern and the western Guangdong Province should be followed closely.