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 investigate the intelligence status of children aged 10 - 12 in rural areas of Linxia Hui Autonomous Prefecture (referred to as Linxia) in Gansu Province.Methods:From September to November 2019, a cross-sectional study was carried out to investigate the intelligence status of children aged 10 to 12 in 8 counties (cities) of Linxia. Chinese Raven's Progressive Matrices (rural version) was used for intelligence test and children's intelligence quotient (IQ) was calculated by regular mold to evaluate children's intelligence level.Results:A total of 1 721 children in Linxia were tested for intelligence, with an average IQ of 103.2. Among them, low intelligence (≤69) accounted for 1.0% (18/1 721), borderline (70 - 79) accounted for 3.0% (52/1 721), middle and lower (80 - 89) accounted for 8.4% (144/1 721), moderate (90 - 109) accounted for 56.6% (974/1 721), middle and upper (110 - 119) accounted for 21.9% (377/1 721), excellent (120 - 129) accounted for 7.8% (135/1 721), extremely excellent (≥130) accounted for 1.2% (21/1 721). There were 635, 598 and 488 children aged 10, 11 and 12, respectively, with an average IQ of 106.1, 103.3 and 99.2. There were 919 males and 802 females, with an average IQ of 102.9 and 103.4, respectively.Conclusion:In 2019, the intelligence of children aged 10 to 12 in rural areas of Linxia has reached the moderate level.

Objective:To analyze the monitoring data of Kashin-Beck disease (KBD) in Gansu Province and learn about the long-term trend of KBD incidence.Methods:The X-ray detection rate of children with KBD in Gansu Province from 1990 to 2021 was collected through Gansu Provincial Center for Disease Control and Prevention. Joinpoint regression model was used to analyze the trend of X-ray detection rate of KBD in children. The annual percent change (APC) and average annual percent change (AAPC) were used to analyze the trend of the observed indicators. In addition, a polynomial regression model was constructed to fit the change of X-ray detection rate of children with KBD over time.Results:From 1990 to 2021, a total of 126 726 children were examined for KBD by X-ray in Gansu Province, with 3 011 positive cases, X-ray detection rate of KBD in children was 0 in 2019 - 2021. Joinpoint regression model analysis showed that the X-ray detection rate of children with KBD in Gansu Province from 1990 to 2018 showed a decreasing trend (AAPC = - 14.40%, P = 0.001). The APC of 1990 - 1998, 2002 - 2008 and 2008 - 2012 was - 17.75%, - 21.89% and - 49.89%, respectively, showing a decreasing trend ( P < 0.05). The APC of 2012 - 2018 was 6.15%, but the trend change was not statistically significant ( P = 0.475). The curve fitting of X-ray detection rate of KBD in children in Gansu Province over time was carried out, and the quadric polynomial equation was y = 0.000 314 5 x4 - 0.021 37 x3 + 0.487 1 x2 - 4.635 x + 22.08. Conclusions:The condition of KBD in children of Gansu Province has been effectively controlled. The X-ray detection rate has remained at a relatively low level since 2012, and it has reached a state of elimination since 2019.

Objective:To explore the distribution characteristics of common clinical manifestations of elbow joint in patients with endemic fluorosis and their correlation with the influencing factors.Methods:A cross-sectional survey was conducted on all permanent adult residents in 13 endemic fluorosis villages in Gaotai and Gaolan counties of Gansu province. The survey included: ① Demographic information, family history, and current medical history. ② Physical examination specifically focued on the orthopedic clinical presentations. ③Taking DR films of the forearm (including elbow joint) and calf (including knee joint), and classify the elbow joint to grade K-L based on X-ray manifestations. ④ Measuring height and weight, and calculating BMI index. ⑤Applying the Mayo elbow joint rating scale to evaluate elbow joint function. Based on the survey results, the distribution characteristics of clinical symptoms and signs of elbow joint in patients with skeletal fluorosis, as well as the distribution characteristics and correlation of factors affecting elbow joint function such as age, gender, disease course, BMI, K-L grade, etc were described. The comparison of counting data and rates were analyzed with χ2 test or Fisher exact probability test. Pearson′s test was used for correlation analysis of continuous data that conforms to normal distribution, and Spearman test was used for non-normal distribution measurement and counting data. The correlation analysis of ordered hierarchical data was conducted using Kendall′s Tau- b test. Results:①Among 501 patients with skeletal fluorosis, a total of 465 cases (92.8%) were diagnosed with elbow joint pain. A total of 185 cases (36.9%) were with elbow joint tenderness, 300 cases (59.9%) were with elbow joint enlargement, 415 cases (82.8%) were with morning stiffness of the elbow joint, 102 cases (20.4%) were with cubital tunnel syndrome, 153 cases (30.5%) were with positive forearm extensor tendon traction test, and 97 cases (19.4%) were with positive forearm flexor tendon traction test. The detection rate of elbow joint rotation limitation was the highest among those with ROM ranging from 30 ° to 70 ° (261/501, 52.1%), and the detection rate of elbow joint extension and flexion limitation was the highest among those with ROM ranging from 50 ° to 90 °(274/501, 54.7%). ②Among 501 patients with skeletal fluorosis, a total of 465 cases were found to have symptoms and positive signs in the elbow joint, with the detection rate in males being lower than that in females, with a significant difference ( χ2=41.19, P<0.001). The majority of patients were between the ages of 50 and 65 (274/501, 58.9%), with a body mass index of <18 (217, 46.67%), K-L arthritis with a radiologic grade of Ⅲ (256/501, 55.0%), and a disease course of >30 years (217/501, 46.67%). ③The correlation between clinical characteristics, the Mayo score, and various influencing factors of skeletal fluorosis found a high correlation between pain and age ( r=0.79, P<0.001) and pain and disease course ( r=0.71, P<0.001). The ROM of extension and flexion was negatively correlated with age ( r=-0.43, P<0.001), K-L grade ( r=-0.67, P<0.001), and disease course ( r=-0.48, P<0.001); Elbow tunnel syndrome was positively correlated with age ( r=0.72, P<0.001). The Mayo functional score was negatively correlated with age ( r=-0.35, P<0.001). Conclusion:Early morning stiffness of the elbow joint (<30 min), limited rotation of the elbow joint, limited extension and flexion of the elbow joint, and cubital tunnel syndrome (degree Ⅰ) have a high detection rate in the population with skeletal fluorosis. Age, course of disease, and degree of joint degeneration have a significant impact on elbow joint function in patients with fluorosis.

Objective:To compare the application effect among Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scale, Medical Outcomes Study 36-item Short Form (SF-36) scale and "Assessment for Therapeutic Efficacy on Kashin-Beck Disease" (WS/T 79-2011) standard in the evaluation of therapeutic effect of patients with Kashin-Beck disease, which could provide basis for the treatment evaluation of patients with Kashin-Beck disease.Methods:A total of 213 patients with Kashin-Beck disease in Gansu Province were investigated. WOMAC scale, SF-36 scale and standard of WS/T 79-2011 were used to analyze the quality of life of patients before and after treatment. The reliability, construct validity, content validity, discriminant validity of WOMAC and SF-36 scales were compared. Correlation between WOMAC, SF-36 scales and standard of WS/T 79-2011 were evaluated.Results:Both WOMAC and SF-36 scales had good construct validity and content validity (construct validity showed WOMAC and SF-36 scales contained 1 and 2 common factors, respectively; content validity showed WOMAC and SF-36 scales contained 3 and 8 common factors, respectively). The reliability and discriminant validity of WOMAC scale were better than those of SF-36 seale (reliability showed WOMAC reliability coefficient ≥0.934, the reliability coefficient of SF-36 scale was ranged from 0.386 to 0.999. Discriminant validity showed there were differences in 3 dimensions of the WOMAC scale before and after treatment, while there were differences in 6 out of 8 dimensions of the SF-36 scale). The correlation coefficients between WOMAC scale and standard of WS/T 79-2011 ranged from 0.175 to 0.437, the correlation coefficients between SF-36 scale and standard of WS/T 79-2011 ranged from - 0.434 to - 0.099 ( P < 0.05). Conclusion:The reliability, discriminant validity and correlation with the standard of WS/T 79-2011 of WOMAC scale are better than those of SF-36 scale in efficacy evaluation of patients with Kashin-Beck disease.

Objective:To investigate the epidemiological situation of drinking water-type endemic fluorosis in Gansu Province, and scientifically evaluate the effectiveness of water improvement and fluoride reduction projects in preventing and controlling the disease.Methods:The drinking water-type endemic fluorosis areas in Gansu Province were divided into five regions according to different ecological types: the Longzhong Loess Plateau Hilly Area in central Gansu, the Longdong Loess Plateau Gully Area in eastern Gansu, the Longnan Qinling Zhongshan Canyon Area in southern Gansu, the Gobi area of the Hexi Desert, and the Alpine Grassland Meadow Area in southern Gansu. In 2021, a survey was conducted on the basic situation, running situation of the water improvement and fluoride reduction projects, fluoride content in drinking water(fluorine ion-selective electrode), and the prevalence of dental fluorosis (Dean) among children aged 8 to 12 in all drinking water-type endemic fluorosis villages in the five regions. The pertinent assessments were executed in accordance with national guidelines such as the "Standards for Drinking Water Quality" (GB 5749-2006) and "Diagnosis of Dental Fluorosis" (WS/T 208-2011).Results:A total of 2 000 villages in drinking water-type endemic fluorosis areas were monitored, among which 1 999 villages had implemented water improvement and fluoride reduction projects, with a coverage rate of 99.95% (1 999/2 000). All water improvement and fluoride reduction projects were operating normally, with no intermittent operation or scrapping. A total of 34 616 children aged 8 to 12 were investigated for dental fluorosis. The detection rate of dental fluorosis was 4.18% (1 448/34 616), and the dental fluorosis index was 0.09. There was a statistically significant difference in the detection rate of dental fluorosis among children of different ages (χ 2 = 69.77, P < 0.001). The difference in the detection rate of dental fluorosis among children of different ecological types of areas was statistically significant (χ 2 = 775.11, P < 0.001). The dental fluorosis index of children aged 8 - 12 was significantly correlated with the historical water fluoride level ( r = 0.29, P = 0.042). The water improvement time in the Gobi area of the Hexi Desert was significantly correlated with the detection rate of dental fluorosis in local children ( r = - 0.48, P = 0.023). Conclusions:In 2021, the prevention and control of drinking water-type endemic fluorosis in all villages in Gansu Province has reached the national control standards. However, due to the different ecological characteristics and changes in water source distribution in different ecological types of areas, it is still necessary to further strengthen the monitoring of the condition of drinking water-type endemic fluorosis in all the affected villages and consolidate the existing prevention and control achievements.

Objective:To master the epidemic trend of Kashin-Beck disease (KBD) in Gansu Province and provide a scientific basis for prevention and treatment of KBD.Methods:All children aged 7 - 12 or 16 years old were selected as the survey subjects in 37 KBD districts and counties in Gansu Province, clinical and X-ray monitoring results of KBD in children from 2004 to 2018 were collected to analyze the epidemic trend of the disease.Results:From 2004 to 2018, a total of 97 190 children were examined clinically and 94 180 X-ray films were taken in Gansu Province. Four hundred and twenty-eight clinical positive cases were detected, with a detection rate of 0.44%. There were 649 X-ray positive cases, and the detection rate was 0.69%. There were 435 metaphyseal positive cases, the detection rate was 0.46%. There were 214 positive cases of bone end, and the detection rate was 0.23%. The clinical positive rate was the highest (7.17%, 58/809) in 2004, followed by 2007 (4.60%, 51/1 109) and 2005 (4.48%, 187/4 173), and the positive rate in other years was less than 3%. The positive rate of X-ray was the highest (9.59%, 58/605) in 2004, followed by 2005 (5.10%, 213/4 173), 2008 (3.66%, 45/1 228) and 2006 (3.04%, 125/4 107), the positive rate of other years was less than 3%.Conclusions:The clinical positive rate and X-ray positive rate of KBD in children in Gansu Province are decreased rapidly and then maintain a low fluctuation. The effect of comprehensive prevention and control measures is remarkable.

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 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.