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.

Objective:To evaluate the testing capability of urinary iodine laboratories in Gansu Province and analyze the existing problems.Methods:Z-score method and uncertainty analysis were used to analyze the external quality control assessment results of urinary iodine laboratories in Gansu Province from 2017 to 2021 (data were collected from Gansu Center for Disease Prevention and Control).Results:From 2017 to 2021, the participation rate in the assessment of urinary iodine laboratories in the province was 100.0% (473/473), the feedback rate was 99.8% (472/473), and the pass rate was 91.9% (434/472). The pass rates for assessment from 2017 to 2021 were 82.7% (62/75), 93.9% (93/99), 94.9% (93/98), 92.0% (92/100), and 94.0% (94/100), respectively. The pass rates for provincial, municipal, and county assessments were 5/5, 98.6% (69/70), and 90.7% (360/397), respectively. The proportions of │Z│≤2, 2 <│Z│ < 3, and│Z│≥3 between laboratories in the province were 84.5% (399/472), 9.3% (44/472), and 6.2% (29/472), respectively. The proportions of│Z│≤2, 2 <│Z│ < 3, and│Z│≥3 within the laboratories were 88.6% (418/472), 9.1% (43/472), and 2.3% (11/472), respectively. There was a significant difference in the composition of │Z│ scores between laboratories annually (χ 2 = 24.60, P = 0.002), the proportion of│Z│≤2 increased from 66.7%(50/75) in 2017 to 90.0% (90/100) in 2021. The│Z│ scores between and within provincial laboratories were both ≤2. The proportion of │Z│≤2 between municipal and county-level laboratories was 91.4% (64/70) and 83.1% (330/397), respectively, the proportion of│Z│≤2 within laboratories was 92.9% (65/70) and 87.7% (348/397), respectively. There was no difference in the composition of│Z│ scores between and within provincial, municipal, and county-level laboratories( P < 0.05). The proportion of two concentration quality control blind sample results in the province that were both within the uncertainty range was 89.2% (421/472). From 2017 to 2021, they were 81.3% (61/75), 91.9% (91/99), 84.7% (83/98), 92.0% (92/100), and 94.0% (94/100), respectively, with statistically significant differences (χ 2 = 9.69, P = 0.021); provinces, cities, and counties were 5/5, 95.7% (67/70), and 87.9% (349/397), respectively, with statistically significant differences (χ 2 = 23.60, P = 0.023). Conclusions:Through continuous external quality control assessments of all established urinary iodine laboratories in Gansu Province, the overall testing capacity of urinary iodine laboratories at all levels has been continuously improved. However, in the future, it is still necessary to strengthen laboratory testing capabilities and improve the level of urine iodine detection.

Iodine nutrition is very important to human health, especially for brain development, urinary iodinary is one of the basic indicators reflecting the nutritional status of iodine, and is an important basis for scientific evaluation of iodine nutrition. In order to provide support and assistance for improving the network syetem of iodine nutrition monitoring laboratories, we summarized and explored the construction process, quality control, and management methods of 85 county-level urinary iodine laboratories in Gansu Province from 2016 to 2018.

Objective:To investigate the iodine nutritional status of population in Gansu Province, and to provide a scientific basis for policy adjustment of relevant departments.Methods:In 2019, a cross-sectional survey was conducted in 87 monitoring units in 86 counties (districts and cities) of 14 cities (prefectures) in Gansu Province for iodine deficiency disorders (IDD). Instant urine samples and salt samples of children aged 8 to 10 years and pregnant women were collected for detection of urinary iodine and salt iodine. B-ultrasound was used to check the thyroid volume of children in 40 monitoring units.Results:A total of 17 772 children aged 8 to 10 years were investigated. The median urinary iodine (MUI) of children was 197.4 μg/L, the MUI of 14 cities (prefectures) ranged from 160.6 to 233.4 μg/L. There were statistically significant differences in MUI among children of different genders and ages ( P < 0.001). Totally 8 269 children were examined by B-ultrasound, the children's goiter rate was 1.4% (118/8 269). There were statistically significant differences in the thyroid volume among children of different genders and ages ( P < 0.05). A total of 8 605 pregnant women were investigated. The MUI of pregnant women was 178.6 μg/L, and the MUI of 14 cities (prefectures) ranged from 156.5 to 275.0 μg/L. There was no statistical significant difference in MUI among pregnant women in different pregnancies ( P > 0.05). A total of 26 377 samples of salt consumed by children and pregnant women were detected. The median salt iodine was 24.71 mg/kg. The coverage rate of iodized salt and the consumption rate of qualified iodized salt were 99.44% and 93.59%, respectively. Twenty-three counties (districts and cities) failed to meet the elimination standard of IDD in the single indicator. Conclusions:IDD is in a state of continuous elimination in Gansu Province; iodized salt supervision needs to be further strengthened; there is an imbalance of control measures between regions.

Objective:To study the iodine nutritional status and thyroid function of adult males in iodine nutrition appropriate rural areas of Gansu Province.Methods:In 2017, Liangzhou District and Linze County of Gansu Province with suitable children iodine nutrition were selected as the study areas and 52 males aged 20 - 49 years old were investigated in each study area. One random urine sample was collected to determine urinary iodine. Fasting blood samples were collected to determine serum thyroid-stimulating hormone (TSH), free triiodothyronine (FT 3), free thyroxin (FT 4), thyroglobulin antibody (TgAb) and thyroid microsomal antibody (TMAb). At the same time, thyroid examination was performed by B-ultrasound. Results:The median urinary iodine of adult males in Liangzhou District and Linze County was 180.2 and 161.0 μg/L, respectively, and the difference was statistically significant ( P < 0.05). There was no goiter in adult males in Liangzhou District and Linze County. The serum TSH (median), FT 3 and FT 4 (mean value) of adult males in Liangzhou District and Linze County were 1.85, 1.61 mU/L, 5.19, 5.16 pmol/L and 16.58, 16.30 pmol/L, respectively. There were no significant differences between the two areas ( P > 0.05). The overall abnormal rate of thyroid function in the two areas was 6.7% (7/104), mainly subclinical hypothyroidism (6/7). The incidences of thyroid dysfunction in Liangzhou District and Linze County were 5.8% (3/52) and 7.7% (4/52), respectively, with no statistical difference between the two areas ( P > 0.05). The total positive rate of antibody was 12.5% (13/104). The positive rates of antibody in Liangzhou District and Linze County were 13.5% (7/52) and 11.5% (6/52), respectively, with no statistical difference between the two areas ( P > 0.05). Both TgAb and TMAb were positive in 9/13 of antibody positive persons, of which the proportion of antibody positive persons in Liangzhou District and Linze County were 7/7 and 2/6, respectively. The 11/13 of the total antibody positive persons were simple antibody positive without thyroid hormone and TSH abnormalities. Conclusion:The iodine nutrition of adult males in iodine nutrition appropriate rural areas of Gansu Province is suitable, but there is a potential risk of thyroid disease in this population, which should be paid attention to and checked regularly.

Objective:To investigate and analyze the living conditions of patients with Kaschin-Beck disease in Gansu Province, and to provide scientific basis for accurate treatment of the patients.Methods:From 2018 to 2019, case investigation, clinical examination and X-ray examination of patients with Kaschin-Beck disease were carried out in the Kaschin-Beck disease area of Gansu Province. The contents of the survey included basic information of the patients, clinical diagnosis classification, disease information, surgery and drug treatment, etc.Results:A total of 23 909 patients with Kaschin-Beck disease were diagnosed in 37 counties (districts) of 7 cities (states). The patients with grade Ⅰ, grade Ⅱ and grade Ⅲ accounted for 64.04% (15 312 cases), 26.12% (6 244 cases) and 9.84% (2 353 cases), respectively; 90.74% (21 694 cases) of the patients were over 50 years old, Han nationality was 97.15% (23 228 cases), and peasants were 99.25% (23 729 cases). The patients mainly had multiple joint thickening and deformation (89.30%, 21 350 cases) and pain (87.04%, 20 810 cases). Joint thickening and deformation and pain were more common in finger joint, knee joint and ankle joint. The thickening and deformation of the three joints accounted for 89.97% (21 512 cases), 78.18% (18 692 cases) and 63.81% (15 257 cases), respectively; pain accounted for 80.66% (19 285 cases), 78.75% (18 828 cases) and 64.50% (15 422 cases), respectively; 83.83% (20 044 cases) had joint rest pain, 82.63% (19 757 cases) had joint movement pain and 76.03% (18 177 cases) had joint morning stiffness. Surgical treatment was completed in 1.97% (470 cases). Long-term drug treatment (more than 6 months in the whole year) accounted for 47.78% (11 424 cases); the annual cost of drug treatment was mainly less than 500 yuan, accounting for 57.72% (13 800 cases).Conclusions:The quality of life of patients with Kaschin-Beck disease in Gansu Province is low. We should pay more attention to adult patients with Kaschin-beck disease and strengthen management and treatment.

Objective:To analyze the epidemic range of tea-drinking-borne endemic fluorosis in Gansu Province and accurately grasp the information of tea-drinking-borne endemic fluorosis patients, so as to provide basis for popularizing low fluorine brick tea and carrying out patient rescue and treatment.Methods:From 2019 to 2020, 12 counties (cities) in Gansu Province with a history of drinking brick tea were selected as the survey points according to the "Investigation Plan of Endemic Fluorosis of Tea Drinking Type in China in 2019" and the relevant information in Gansu Province. A cross-sectional survey was conducted in all villages with the habit of drinking brick tea (including the investigation of the fluoride content in drinking water, tea, the fluoride intake of the population, the dental fluorosis and urinary fluoride content of children aged 8 to 12, and the skeletal fluorosis and urinary fluoride content of adults), and the survey results were analyzed.Results:The survey covered 125 townships in 12 counties (cities), with 8 625 households in 860 villages. One thousand six hundred and seventy-two drinking water samples were collected, and the fluoride content in water ranged from 0.01 to 1.81 mg/L. Six villages with fluoride content > 1.0 mg/L were screened. A total of 3 664 tea samples were collected, the average fluorine content of brick tea was 481.33 mg/kg, and the fluorine content ranged from 31.88 to 1 643.40 mg/kg. There were 1 076 tea samples with fluorine content less than 300 mg/kg, and the qualified rate of fluorine content in brick tea was 29.37% (1 076/3 664). Among the 12 counties (cities), 92 townships and 496 villages were still drinking brick tea. The drinking rate of brick tea in villages was 57.67% (496/860), and the annual per capita consumption of brick tea was 1.21 kg. The average daily intake of tea fluoride in adults was 1.57 mg/d. In Maqu County, Aksai County, Tianzhu County and Sunan County, the daily intake of tea fluoride of adults in 31 villages of 13 townships was more than 3.5 mg, involving 5 272 households and 15 272 people. Sixty-five patients with dental fluorosis were found in the above 31 villages. The detection rate of dental fluorosis was 3.50% (65/1 856), mainly in very mild and mild cases. Urine samples were collected from 326 children. The median of urinary fluoride was 1.44 mg/L. The clinical investigation of skeletal fluorosis was carried out in 2 189 adults. X-ray examination of bones and joints was performed in 123 patients with definite clinical symptoms and/or signs of skeletal fluorosis. Seven cases of skeletal fluorosis were positive, the detection rate was 0.32% (7/2 189). Urine samples were collected from 83 adults. The median of urinary fluoride was 1.83 mg/L. Two villages with moderate disease were identified as Yehuwan Village in Anyuan Town of Tianzhu County and Nannigou Village in Zhuaxixiulong Town. Four villages in the mild diseased areas were identified as Daiqian Village in Zhuaxixiulong Town, Xiding Village in Dahonggou Town, Tuta Village in Danma Township of Tianzhu County and Annanba Village in Akeqi Township of Akesai County.Conclusion:Most of the endemic areas of tea-drinking-borne endemic fluorosis in Gansu Province have been under control, but the risk of tea fluoride exposure still exists in some areas, so it is urgent to take targeted prevention and control measures.

Objective:To analyze the characteristics of thyroid diameter and volume of children aged 8 - 10 years in Gansu Province, and to provide a basis for standardizing B-ultrasound examination of children's thyroid volume and establishing a normal reference value of children's thyroid volume.Methods:The data of thyroid volume by B-ultrasound and urinary iodine determination of children aged 8 - 10 years in Gansu Province were from Institute of Endemic Disease, Gansu Center for Disease Control and Prevention. Based on the measured data of thyroid B-ultrasound of 8 - 10 years children in Gansu Province, the characteristics and relationship between thyroid diameter and volume were analyzed by nonparametric test.Results:The medians of urinary iodine of 8, 9, 10 years children ( n = 500, 503, 496) were 166.62, 167.16 and 178.78 μg/L, respectively. The length, width, thickness and volume of the left and right lobes of the thyroid in children were skewed distribution. There was a positive correlation between the left and right diameters (length, width and thickness) and between left and right thyroid volumes ( r = 0.76, 0.85, 0.72, 0.88, P < 0.001). There was no significant difference in the six diameter lines and volume values of thyroid between genders ( P > 0.05), but there was significant difference between ages ( P < 0.001). The means thyroid volume of 8, 9 and 10 years children were 2.6, 2.9 and 3.2 ml, respectively, the medians were 2.5, 2.7 and 3.0 ml, respectively, and the 97th percentile ( P97) were 4.4, 4.9 and 6.5 ml, respectively. The thyroid volume of 10 years group was higher than the current national standard (6.0 ml). The median ranges of thyroid volume of children aged 8, 9 and 10 years at the county level were from 1.8 ml to 4.1 ml, from 1.8 ml to 4.3 ml and from 1.9 ml to 4.4 ml, respectively. There was significant difference in thyroid volume of children at the county level in all age groups ( P < 0.05). Conclusions:Compared with the national standard, the P97 value of thyroid volume of children aged 8 - 10 years in Gansu Province is slightly different. The reference value of thyroid volume should be formulated according to age, and a unified reference value can be used for different genders at the same age.

Objective:To comprehensively investigate the epidemic scope, geographic features and threatened population of tea drinking type endemic fluorosis in Gansu Province.Methods:From June 2019 to December 2020, according to the "2019 Investigation Plan on the Epidemic Situation of Tea Drinking Type Endemic Fluorosis" and the relevant information about the living habits of residents in cities (prefectures) in Gansu Province, 12 counties (cities) in 4 cities (prefectures) of Gannan, Wuwei, Jiuquan and Zhangye, which had the habit of drinking border-sale tea, were selected as the survey sites. The survey contents included temperature, altitude, the number of townships (towns), the number of administrative villages (residents' committees, referred to as villages), the total population under its jurisdiction, ethnic composition, production methods, drinking condition of border-sale tea, fluoride content of tea, etc. The fluoride content of tea was tested according to "The Fluoride Content of Brick Tea" (GB 19965-2005), and the evaluation of whether the fluoride content exceeded the standard (> 300 mg/kg) was carried out.Results:The annual average temperature of the survey sites ranged from 0.2 to 12.7 ℃, except for Zhouqu County, the annual average temperature of the other 11 counties (cities) was < 10 °C; the average altitude ranged from 1 200 to 4 874 m, and there were 6 counties (Maqu, Tianzhu, Subei, Sunan, Aksay and Luqu) with an altitude > 3 000 m. The total population of the 12 counties (cities) was 1 051 843, of which 492 597 (46.83%) were ethnic minorities who had the habit of drinking border-sale tea; among them, there were 474 620 Tibetans, 10 152 Yugurs, 4 660 Mongolians and 3 165 Kazaks. In 860 villages of 125 townships (towns), a survey was conducted on drinking condition of border-sale tea, and the survey rate was 79.48% (860/1 082); the drinking border-sale tea rates of villages and families were 57.67% (496/860) and 42.41% (3 658/8 625), respectively. From the perspective of production methods, the drinking border-sale tea rates of villages and families in the pastoral counties such as Aksay, Subei, Maqu, Luqu and Sunan, as well as in the semi-agricultural and semi-pastoral county of Tianzhu, were all > 95%. A total of 3 664 tea samples were tested, with an average fluoride content of 481.33 mg/kg. There were 2 588 tea samples with a fluoride content > 300 mg/kg, accounting for 70.63% (2 588/3 664).Conclusions:There are still a large number of populations who drink border-sale tea in Gansu Province, mainly distributes in the low-temperature and high-altitude pastoral counties such as Aksay, Subei, Maqu, Luqu and Sunan. The ethnic group most threatened by tea drinking type endemic fluorosis is Tibetans.

Objective:To evaluate the iodine level of drinking water in different ecological regions in Gansu Province, and to provide a basis for preventing iodine deficiency disorders in accordance with local conditions.Methods:In May to July 2017, according to different topography, landforms and climatic conditions, Gansu Province was divided into six ecological regions: desert area, Hexi Corridor gobi area, Loess Plateau hilly area, Qinling Zhongshan gorge area, Gannan Plateau grassland and meadow area, and Loess Plateau gully area. One county was selected from each of the five districts in the east, west, south, north, and central areas in each ecological regions. Drinking water samples were collected in each county based on the township, and the water iodine content was determined by arsenic-cerium catalytic spectrophotometry.Results:A total of 4 037 water samples were collected in 527 townships of six ecological regions, the water iodine range was 0.10 - 97.60 μg/L, with a median of 2.10 μg/L. Among them, the medians water iodine of the six ecological regions were less than 40 μg/L, the difference between different ecological regions was statistically significant ( H = 1 007.440, P < 0.01); the unified centralized, partially centralized and dispersed water supply water samples were 157, 2 263 and 1 617, and the medians water iodine were 1.61, 2.42, and 1.83 μg/L, respectively, and there was statistically significant difference among different water supply methods ( H = 37.164, P < 0.01). Stratified by water supply method, the differences in water iodine between different ecological regions of the same water supply method were statistically significant ( H = 32.628, 580.630, 391.070, P < 0.01); stratified by ecological region type, the differences of different water supply methods in desert area, Hexi Corridor gobi area, Qinling Zhongshan gorge area, Gannan Plateau grassland and meadow area were statistically significant ( Z = - 2.770, H = 6.369, 9.936, 12.666, P < 0.05). Conclusions:The six ecological regions in Gansu Province are all iodine-deficient areas. The water iodine content varies among different ecological region types and different water supply methods. Surveys on water iodine content and the operating status of water supply facilities should be carried out regularly, and measures should be adjusted in time to prevent and control iodine deficiency disorders in accordance with local conditions.