Objective To understand the current situation on coal-burning-borne endemic fluorosis control and prevention in Yunnan Province,timely discover problems in prevention and control of the disease,and achieve the "13th Five-Year Plan" objectives as scheduled.Methods Simple random sampling method was adopted to conduct investigations in Weixin County,Daguan County of Zhaotong City,and Fuyuan County of Qujing City in the key diseased areas of Yunnan Province in 2017.Three townships from each endemic fluorosis area were randomly selected,and 2 villages of each township were randomly selected.The use of improved stoves (types of stoves,integrity rate and correct use),knowledge and behavior changes of endemic fluorosis prevention among local grade five pupils and housewives or household heads and the condition of endemic fluorosis (dental fluorosis and urinary fluoride situation in children) were investigated in above mentioned villages.Results A total of 532 households were investigated.The consumption rate of self-produced corn and pepper were 53.4％ (284/532) and 44.7％ (238/532),respectively.Totally 81.0％ (431/532) of households burned coal,the average annual coal burning time per household was 6.3 months.Totally 44.5％ (237/532) of the households used the improved iron stove,89.5％ (476/532) used the electric cooker to cook rice,84.2％ (448/532) used the induction cooker to cook,and 36.7％ (195/532)used the portable open stove.The integrity rate of improved stoves and the correct usage rate were 86.9％ (206/237) and 84.0％ (199/237),respectively,among the 237 households using improved stoves.The awareness rate of the prevention and control of coal-burning-borne fluorosis in grade five pupils and housewives or household heads were 85.8％ (921/1 074) and 17.7％ (283/1 596),respectively.The correct drying rates of edible corn and peppers were 66.5％ (189/284) and 52.9％ (126/238),respectively.A total of 3 333 children aged 8-12 years old were examined and the dental fluorosis positive rate was 11.28％ (376/3 333).Totally 377 samples of immediate urine samples were detected,the geometric mean of urinary fluoride content of children was 0.37 (0.06-2.14) mg/L.Conclusions The situation of coal-burning-borne endemic fluorosis in Yunnan Province is effectively controlled,but the correct use rate of improved stoves,the correct drying rate of edible com and peppers are low,and do not meet the requirements of the "13th Five-Year Plan".

Objective:To accurately grasp the current status of water iodine distribution in environmental of Yunnan Province, and provide a basis for scientific iodine supplementation.Methods:In 2017, according to the "National Drinking Water Iodine Content Survey Program", a survey of water iodine content was conducted in townships. In 2018, a search survey was carried out for administrative villages with water samples of iodine content > 40 μg/L in drinking water found in previous surveys. In centralized water supply villages, 2 samples of end water were collected. In decentralized or partially decentralized water supply villages, each village was divided into 5 parts: east, south, west, north and center. In villages with more than 50 water sources, 10% of the water sources were selected from each part; villages with less than 50 water sources, one water source was selected from each part; villages with less than 5 water sources, all the water sources were selected to determine the water iodine content. At the same time, the mode of water supply and demographic data were investigated.Results:At the township level water iodine survey, a total of 24 589 water samples were collected from 1 389 townships in 129 counties of 16 prefectures (cities). The median water iodine content of township was 1.3 μg/L, ranging 0.0 - 9.3 μg/L. The population covered by the survey accounted for 53.94% (25 013 804/46 371 207) of the total population of the province. According to the survey results of high iodine villages, 93 administrative villages in 68 townships of 37 counties in 12 prefectures (cities) were surveyed, covering 40 940 households and 208 880 people. A total of 761 samples of drinking water were tested, and the median water iodine content of administrative villages was 1.3 μg/L (ranging 0.0 - 196.8 μg/L). There were 2 administrative villages with iodine higher than 100 μg/L, which were Xiaobona Administrative Village (145.8 μg/L) in Liuchang Township, Xiangyun County, and Dasongshu Administrative Village (196.8 μg/L) in Yangchang Township, Xuanwei City.Conclusions:The iodine content of water in Yunnan Province is generally low, which belongs to the area of environmental iodine deficiency. For the high iodine villages, further investigation should be carried out to clarify the prevention and control measures.

Objective To investigate the status of coal-burning type endemic fluorosis in Ludian County of Yunnan Province,to evaluate the prevention and control effect.Methods Multi-stage sampling was adopted in 2016.Five townships from Ludian endemic fluorosis areas and 2 villages of each township were randomly selected.The condition (children's dental fluorosis,urinary fluoride,adult skeletal fluorosis),epidemic factors (use of stoves,fluoride content of main household foods,indoor air fluoride content),health education awareness of endemic fluorosis were investigated in the above mentioned villages.Results The dental fluorosis positive rate of children aged 8-12 was 10.14％ (51/503) while a total of 503 children were investigated,the index of dental fluorosis was 0.16,and adult skeletal fluorosis detection rate was 1.92％ (2/104) while a total of 104 adults were investigated.The geometric mean of urinary fluoride content of children was 0.39 mg/L,ranging from 0.02 to 2.54 mg/L.Totally 98,161,and 151 samples of pepper,rice,and corn were detected.The medians of fluoride content were 0.96,0.42,and 0.43 mg/kg,respectively,ranging from 0.26 to 13.46,0.13 to 2.20,and 0.21 to 2.54 mg/kg,respectively,in which the fluorine contents of pepper 48.98％ (48/98) was higher than 1.0 mg/kg.The correct drying rates of both corn and pepper were 100.00％ (201/201),and the correct preservation rates of corn and pepper was 99.50％ (200/201) and 100.00％ (201/201),respectively.The use rate of improved stove,rate of intact stove,correct use rate of intact stove were 100.00％ (201/201),96.02％ (193/201) and 100.00％ (193/193),respectively.The fluoride contents in the indoor air of the families (the fire period was 0.32 μg/m3 and the fire extinguishing period was 1.22 μg/m3) from the areas of fluorosis which had properly used the improved stoves were lower than that of the national hygienic limit content (the one-hour average concentration limit is 20 μg/m3).The knowledge of prevention and control of coal-burning type fluorosis among fifth-grade primary school students and household heads was investigated in 104 and 201 people,respectively,with the awareness rates of 80.77％ (252/312) and 86.23％ (520/603),respectively.Conclusion By implementing the comprehensive prevention and control measures,which mainly focus on the improvement of the stove and the health education,the coal-burning fluorosis in Ludian County has been effectively controlled,and the prevention and control work has achieved remarkable results.

Objective:To understand the contents of edible salt iodine and urinary iodine of children and pregnant women in Yunnan Province, and to evaluate the iodine nutrition status, so as to provide a basis for scientific prevention and treatment of iodine deficiency disorders (IDD).Methods:From November to December 2020, one county (city) was selected from each prefecture (city), two townships (towns and streets) were selected from each county (city) and two villages (neighborhood committees) were selected from each township (town and street) from each of the 16 prefectures (cities) in Yunnan Province as the investigation sites. A total of 20 non-boarding children (male and female balanced) aged 8 - 10 years old were selected from each primary school in each village (neighborhood committee) to collect salt and urine samples. A total of 80 children were investigated in each county (city). A total of 20 pregnant women were selected from each township (town and street) to collect salt and urine samples. A total of 40 pregnant women were investigated in each county (city). All salt samples and urine samples were tested for iodine contents.Results:A total of 2 009 salt samples and 2 041 urine samples (1 375 for children, 666 for pregnant women) were collected from children aged 8 - 10 years old and pregnant women in 16 counties (cities) of Yunnan Province. Among them, the median salt iodine was 26.0 mg/kg, the coverage rate of iodized salt was 100.0% (2 009/2 009), the qualified rate of iodized salt was 98.7% (1 982/2 009), and the consumption rate of qualified iodized salt was 98.7% (1 982/2 009). The difference of salt iodine content in key populations in different counties (cities) was statistically significant ( H = 258.98, P < 0.01). The median urinary iodine of children aged 8 - 10 years old was 188.5 μg/L. There was statistically significant difference in urinary iodine content among children of different ages ( H = 29.45, P < 0.01), but there was no statistically significant difference in urinary iodine content among children of different genders ( H = 1.43, P > 0.05). In addition, the median urinary iodine of pregnant women was 141.9 μg/L, 52.1% (347/666) was < 150 μg/L. There was statistically significant difference in urinary iodine content of pregnant women in different counties (cities, H = 88.32, P < 0.01). Conclusions:The qualified rate of iodized salt, the coverage rate of iodized salt and the consumption rate of qualified iodized salt in key populations of Yunnan Province are more than 90%, and the iodized salt supply is good. Iodine nutrition of children aged 8 - 10 years old is at an appropriate level (100 - 199 μg/L); iodine nutrition of pregnant women is in an state of iodine deficiency ( < 150 μg/L). It is suggested to strengthen IDD monitoring and health education among key populations, improve residents' awareness of disease prevention, and make scientific iodine supplementation.

Objective:To analyze the influencing factors of thyroid volume in children aged 8 - 10 in Yunnan Province, and provide scientific basis for improving iodine deficiency disorders monitoring.Methods:From March to July 2020, in 129 counties (cities, districts) under the jurisdiction of Yunnan Province, each county (city, district) was divided into 5 sampling areas based on east, west, south, north, and middle. One township was selected from each area, and 40 non-boarding children aged 8 - 10 from one primary school were selected from each township (age balanced, half male and half female) as survey subjects. One random urine sample and household edible salt samples were collected for urine iodine and salt iodine testing, and physical examination and thyroid volume measurement were conducted for children. The influencing factors of thyroid volume were analyzed using Pearson correlation.Results:A total of 24 934 urine samples were collected from children, with a median urine iodine of 233.2 μg/L. A total of 24 933 household edible salt samples were collected from children, the median salt iodine was 24.17 mg/kg, and the qualified rate of iodized salt was 96.63% (24 003/24 839); A total of 24 937 children were examined of their thyroid gland, with a median thyroid volume of 2.62 ml and a goiter rate of 1.12% (280/24 937). Among them, there were 12 410 boys and 12 527 girls, with thyroid volumes of 2.61 and 2.64 ml, respectively. The thyroid volume of boys was positively correlated with age, height, weight, body mass index, body surface area, and salt iodine ( r = 0.15, 0.21, 0.26, 0.18, 0.25, 0.03, P < 0.001). The thyroid volume of girls was positively correlated with age, height, weight, body mass index, and body surface area ( r = 0.17, 0.26, 0.28, 0.17, 0.27, P < 0.001). Conclusion:Children aged 8 - 10 in Yunnan Province are at an iodine excess level; the age, weight, height, body mass index, and body surface area are influencing factors of thyroid volume.