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Objective:To compare the coverage rate of non-iodized salts, children's iodine nutrition and the change trend of goiter rate between the original water source high iodine areas in Henan Province in 2017 and the newly designated water source high iodine areas in 2019.Methods:Using a cross-sectional survey method, household edible salt monitoring was conducted in all 20 counties (cities, districts) with high iodine content in Henan Province in 2017. Ten counties (cities, districts) were selected to monitor water iodine, urinary iodine and thyroid volume of children aged 8 to 10 years. A total of 4 430 salt samples and 1 012 urine samples were collected, and thyroid volume of 1 012 children were measured. In 2019, monitoring of household edible salt, water iodine, urinary iodine, and thyroid volume was carried out in all 55 newly designated counties (cities, districts) with high iodine village. A total of 9 835 salt samples and 9 830 urine samples were collected, and the thyroid volume of 8 896 children was measured. The monitoring results of two years were compared, and the relationship between children's urinary iodine and goiter rate was analyzed by univariate logistic regression.Results:In 2019, the water iodine content in newly designated high iodine areas decreased compared to the original high iodine areas in 2017 (119.8 to 191.0 μg/L), and the difference was statistically significant ( Z = - 2.48, P = 0.013). The rate of non-iodized salts in 2019 was only 35.5% (3 494/9 835), significantly lower than that in 2017 (96.2%, 4 263/4 430, χ 2 = 4 536.74, P < 0.001). The median urinary iodine of children in 2017 and 2019 were 338.2 and 317.8 μg/L, respectively, the difference between the two years was statistically significant ( Z = - 2.46, P = 0.014). In 2017 and 2019, the goiter rate of children aged 8 to 10 years was 1.5% (15/1 012) and 2.1% (187/8 896), respectively, and there was no significant difference between the two years (χ 2 = 1.76, P = 0.185). The results of univariate logistic regression analysis showed that, compared with the control group with urinary iodine < 100 μg/L, the risk of goiter rate (but the enlargement rate did not exceed 5%) increased with the increase of urinary iodine level (100 - 199, 200 - 299 and ≥300 μg/L groups), and the differences were statistically significant [odds ratio ( OR) = 8.64, 7.68, 10.69, P < 0.05]. Conclusion:After the implementation of the new demarcation standard for areas with excessive iodine in water sources, the supply of non-iodized salts in Henan Province is relatively lagging behind, and the iodine nutrition level of children is still high, but the goiter rate is relatively stable.
ABSTRACT
Objective:To investigate the iodine nutritional level of residents in iodine adequate areas in Henan Province, and provide basis for making policy of targeted guidance and rational iodine supplementation.Methods:In the 156 counties of Henan Province in 2020, one township was selected from each location (east, west, south, north and middle) in each county; one school was selected from each township; 40 children aged 8-10 years in the school and 20 pregnant women in the township were selected to collect their urine and salt samples to test urine and salt iodine levels. One third of the counties were selected to examine the thyroid gland of children. Individuals lived in villages with water iodine between 40 and 100 μg/L were included in the study.Results:In iodine adequate areas, a total of 2 097 salt samples were collected from children and tested, the consumption rate of qualified iodized salt was 93.6% (1 962/2 097). A total of 2 096 urine samples were collected from children and tested, and the median urinary iodine was 288.0 μg/L. The goiter rate of children was 0.7% (5/723). A total of 1 068 salt samples from pregnant women were tested, and the consumption rate of qualified iodized salt was 93.0% (993/1 068). A total of 1 068 urine samples from pregnant women were tested, with a median urinary iodine 232.7 μg/L. Stratified by water iodine (40-59, 60-79, 80-100 μg/L), the median urinary iodine of children was 273.8, 288.6, and 305.9 μg/L, respectively, statistically significantly different between groups ( H = 15.79, P < 0.001); the goiter rate of children was ≤2%, and the difference between groups was statistically significant (χ 2 = 7.31, P = 0.026); but the median urinary iodine of pregnant women was not significantly different ( H = 1.82, P = 0.402). Under different water iodine conditions, there was no significant difference in urinary iodine levels in children and pregnant women between the high salt iodine concentration group (≥21 mg/kg) and the low salt iodine concentration group (< 21 mg/kg, P > 0.05). Conclusions:The iodine nutrition level of children in iodine adequate areas in Henan Province is relatively high, and the iodine nutrition of pregnant women is appropriate. The goiter rate of children is at a relatively low level. Continuous surveillance should be conducted to comprehensively evaluate the iodine nutrition level. Various measures will be taken by regions and populations.
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Objective:To investigate the iodine content in drinking water of residents in Henan Province, and clarify the distribution characteristics of water iodine in Henan Province.Methods:In 2017, in all counties (cities and districts, hereinafter referred to as counties) of Henan Province, taking township (town, subdistrict office, hereinafter referred to as township) as the unit to carry out an investigation of iodine content in drinking water; and in the township with water iodine content of 10 μg/L or more, taking administrative village (neighborhood committee, hereinafter referred to as the administrative village) as the unit to carry out the drinking water iodine content investigation. Supplementary investigation was conducted from 2018 to 2020 in administrative villages where water iodine levels had never been tested or had not been tested after replacing water sources. At least 25 ml water samples were collected at each sampling site, and the water iodine content was determined by cerous sulfate catalytic spectrophotometry.Results:From 2017 to 2020, the median water iodine in Henan Province was 8.20 μg/L. A total of 50 124 administrative villages in 2 465 townships, 160 counties and 18 provincial-level cities were investigated for iodine content in drinking water, of which 65.5% (32 807/50 124) of the administrative villages had a median water iodine < 40 μg/L, belonging to iodine deficiency area; 16.9% (8 473/50 124) of the administrative villages had a median water iodine of 40-100 μg/L, suitable for iodine; and 17.6% (8 844/50 124) of the administrative villages had a median water iodine > 100 μg/L, belonging to water source high iodine area.Conclusions:Henan Province as a whole is at the state of iodine deficiency in the external environment. Most administrative villages are iodine deficiency areas. There are certain proportion of water source areas with high iodine and areas with suitable iodine.
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Objective:To investigate the iodine nutritional status of children aged 8-10 years old and pregnant women in Henan Province.Methods:From March to September 2020, a cross-sectional survey was conducted in 18 provincial-level cities and 9 directly administered counties (collectively referred to as provincial-level cities) and 155 counties (cities, districts) in Henan Province. One township was selected from each county (city, district) in five directions: east, west, south, north, and central. One primary school was selected from each township, and 40 non boarding children aged 8-10 years old (half male and half female) were selected from each primary school; 20 pregnant women were selected from each township. Home edible salt samples and once urine samples from children and pregnant women were collected, to detect salt iodine and urinary iodine levels. Thyroid volume of children in 1/3 of the monitored counties (cities, districts) under the jurisdiction of each provincial-level city was examined.Results:A total of 31 645 home edible salt samples were collected from children aged 8-10 years old, with a median salt iodine of 25.8 mg/kg, the iodine salt coverage rate was 97.8% (30 941/31 645) and qualified iodine salt consumption rate was 93.4% (29 545/31 645). A total of 15 234 home edible salt samples were collected from pregnant women, with a median salt iodine of 25.7 mg/kg, the iodized salt coverage rate was 98.1% (14 937/15 234), and the qualified iodized salt consumption rate was 92.2% (14 040/15 234). A total of 31 642 urine samples from children aged 8-10 years old were tested, with a median urine iodine of 235.0 μg/L; 15 234 urine samples from pregnant women were tested, with a median urinary iodine of 196.5 μg/L. The thyroid volume of 13 792 children was examined, and the rate of goiter was 1.2% (165/13 792).Conclusions:Iodine nutrition of 8-10 years old children in Henan Province is at an over appropriate iodine level, and the prevalence of goiter is less than 5%. Pregnant women's iodine nutrition is at an appropriate iodine level.