Objective To assess the health risks of fluoride in drinking water in rural schools in drinking-water fluorosis areas in Shaanxi Province, and to provide a scientific basis for formulating measures to prevent fluoride and improve water quality. Methods The drinking water of rural schools in Guanzhong and northern Shaanxi Province was monitored from 2017 to 2020. The fluoride concentration was evaluated in accordance with the ^“Sanitary Standards for Drinking Water^” (GB5749-2006). The health risk assessment method recommended by USEPA was used to assess the health risk of rural students exposed to fluoride through drinking water in the two regions. Results A total of 2 826 water samples were monitored from 2017 to 2020. The overall compliance rate of fluoride in water quality was 92.29%, with an average concentration of 0.500 mg/L. The non-carcinogenic health risk of fluoride in drinking water in rural schools in drinking-water fluorosis areas was <1. There was no statistically significant difference in non-carcinogenic health risk of fluoride in water quality between different regions of the same age group (P > 0.05). In the same age group, the non-carcinogenic health risk of fluoride in groundwater was higher than that in surface water (P < 0.05). The order of non-carcinogenic health risk of fluoride in drinking water with different water treatment methods from high to low was disinfection only > sedimentation filtration > conventional treatment > untreated (P < 0.05). Conclusion The non-carcinogenic risk of oral intake of fluoride in drinking water from rural schools in drinking-water fluorosis areas in Shaanxi Province is still at an acceptable level. In the future, it is necessary to continue to promote comprehensive prevention and treatment measures focusing on water improvement and fluoride reduction.

Objective:To evaluate the health risk of fluoride in rural drinking water in drinking-water-borne endemic fluorosis(referred to as drinking-water-borne fluorosis) areas of Shaanxi Province, and to provide scientific basis for the formulation of water improvement and fluoride reduction measures.Methods:The fluoride monitoring results of rural drinking water in Guanzhong Plain and Loess Plateau of Northern Shaanxi in drinking-water-borne fluorosis areas of Shaanxi Province in 2020 were collected from the "National Drinking Water Quality and Sanitation Monitoring Information System". Using the health risk assessment method recommended by the United States Environmental Protection Agency (USEPA), the level of fluoride exposure of adults in fluorosis areas through drinking water was evaluated, and the health risk value was calculated.Results:A total of 4 342 rural drinking water samples from drinking-water-borne fluorosis areas were monitored. The overall compliance rate of fluoride in water quality was 95.39% (4 142/4 342), and the fluoride content median was 0.470 mg/L; the health risk value was 0.368, and the non-carcinogenic risk was low. A total of 200 water samples with fluoride exceeding the standard were detected, and the fluoride content median was 1.450 mg/L; the health risk value of the fluoride excess water samples was 1.135, indicating a high non-carcinogenic risk. There were significant differences in fluoride content in rural drinking water between different regions, water sources and treatment methods ( H = - 7.73, - 7.60, 34.40, P < 0.05). Conclusions:The non-carcinogenic risk of fluoride exposure of adults in drinking-water-borne fluorosis areas through drinking water in Shaanxi Province is relatively low, and the non-carcinogenic risk caused by water samples with excessive fluoride is relatively high. In the future, it is necessary to continue to promote the comprehensive prevention and control measures focusing on improving water and reducing fluoride.

Objective:The study retrospectively identified the correlative factors of low back pain after single-level oblique lateral interbody fusion (OLIF).Methods:Records of 93 patients (55 males and 38 females) who underwent OLIF (oblique lateral interbody fusion) surgery for lumbar degenerative diseases from May 2016 to September 2019 were analyzed retrospectively and patients' age was 55.73±9.48 years (range 32-78 years). There were 18 patients underwent L 3, 4 segment (19.35%), 73 patients underwent L 4, 5 segment (78.50%), and 2 patients underwent L 5S 1 segment (2.15%). There were 43 patients underwent OLIF stand alone and 50 patients underwent OLIF combined with lateral or posterior internal fixation. The follow-up time was 22.86±5.90 months (range 12-32 months). According to whether the visual analog scale (VAS)≥3 at the last follow-up visit, the patients were divided into low back pain group and no low back pain group. The demographic characteristics (age, gender, body mass index and comorbidities), basic surgical data (surgical segments, surgical methods, surgical time, intraoperative bleeding, endplate injury or not during operation), imaging data (lumbar lordosis, segmental lordosis, intervertebral height and cage subside) and lumbar function were recorded. The potential related factors were analyzed by univariate analysis, and the factors with P<0.05 were selected in the multivariate logistic regression model. Then the risk factors of low back pain after OLIF were determined by multivariate logistic regression analysis. Results:Nineteen patients with VAS score equal or greater than 3 were included in low back pain group, and the remaining 74 patients were included in no low back pain group. There was no significant difference in baseline data such as age, gender, BMI, follow-up time and comorbidities between two groups. There was no significant difference in VAS score between the two groups before operation ( t=0.818, P=0.414), but there was significant difference in VAS score at last follow-up visit ( t=6.958, P<0.001). The incidence rate of osteoporosis in low back pain group (63.16%) was significantly higher than that in no low back pain group (25.68%) ( t=9.558, P=0.002). There was no significant difference in vertebral height between the two groups ( t=1.008, P=0.316), however, the vertebral height was higher in no low back pain group ( t=2.537, P=0.316) at the last follow-up. The incidence of cage subsidencewas 8.11% in no low back pain group and 36.84% in low back pain group and there was significant difference between the two groups ( t=10.381, P=0.001). Multivariate logistic regression analysis showed that osteoporosis ( P=0.009), intraoperative bone endplate injury ( P=0.031), decreased intervertebral space height ( P=0.029) and cage subsidence ( P=0.016) were associated with low back pain after single-level OLIF. Conclusion:Low back pain is one of the common complications after OLIF. Osteoporosis, intraoperative bony endplate injury, decreased intervertebral space height and cage subsidence were closely related to postoperative low back pain. In order to reduce the incidence of postoperative low back pain and improve the clinical outcomes, attention should be paid to the protection of the bony endplate, rational use of internal fixation and active anti-osteoporosis treatment after operation.

Objective:To investigate the effect of Clostridium perfringens combined with live bacteria therapy on intestinal flora, inflammation and immune indicators in children with pneumonia and antibiotic associated diarrhea.Methods:From December 2016 to October 2019, 44 neonates with pneumonia and antibiotic associated diarrhea diagnosed and treated in the Sixth People's Hospital of Datong were selected in the study, and they were divided into control group and observation group according to the random number table method, with 22 cases in each group.On the basis of routine symptomatic treatment, the control group was treated by oral administration of Saccharomyces boulardii, and the observation group was treated with Clostridium perfringens combined with live bacteria powder.The treatment course was two weeks.The intestinal flora, inflammatory factors and immune function of the two groups were compared.Results:There were no statistically significant differences in the levels of IL-2, IL-6 and TNF-α between the two groups before treatment(all P>0.05), and the levels of IL-2, IL-6 and TNF-α in the two groups after treatment were significantly improved(all P<0.05). The levels of IL-2[(34.20±8.55)ng/L vs.(40.13±10.32)ng/L], IL-6[(21.02±5.66)ng/L vs.(31.25±7.82)ng/L] and TNF-α[(30.10±6.20)ng/L vs.(43.55±9.52)ng/L] in the observation group were significantly lower than those in the control group( t=7.501, 6.885, 8.264, all P<0.05). There were no statistically significant differences in the number of Lactobacillus, Bifidobacterium and Eubacterium in the two groups before treatmentt(all P>0.05), and the number of Lactobacillus, Bifidobacterium and Eubacterium in the two groups after treatment increased significantly(all P<0.05). The number of Lactobacillus[(9.50±0.53)×10 8 CFU/mL vs.(8.95±0.44)×10 8 CFU/mL], Bifidobacterium[(10.60±0.53)×10 8 CFU/mL vs.(9.90±0.46)×10 8 CFU/mL] and Eubacterium[(8.93±0.68)×10 8 CFU/mL vs.(8.08±0.40)×10 8 CFU/mL] in the observation group were significantly higher than those in the control group( t=5.065, 6.547, 5.116, all P<0.05). There were no statistically significant differences in the levels of CD 3+ , CD 4+ , CD 8+ and CD 4+ /CD 8+ between the two groups before treatment(all P>0.05), and the levels of CD 3+ , CD 4+ , CD 8+ and CD 4+ /CD 8+ in the two groups after treatment were significantly improved(all P<0.05). The levels of CD 3+ [(62.55±5.06)% vs.(57.12±4.39)%], CD 4+ [(40.52±3.52)% vs.(36.43±2.55)%], CD 4+ /CD 8+ [(1.78±0.22) vs.(1.43±0.13)] in the observation group were significantly higher than those in the control group( t=7.504, 6.958, 5.452, all P<0.05). The level of CD 8+ [(21.22±2.05)% vs.(25.44±2.49)%] in the observation group was significantly lower than that in the control group( t=5.112, P<0.05). Conclusion:Clostridium perfringens combined with live bacteria in the treatment of neonatal pneumonia with antibiotic associated diarrhea can improve intestinal flora, reduce inflammatory response and improve immune function, and the effect is better.

Objective To understand the status and dynamic changes in the treatment of rural garbage and sewage in Shaanxi Province and provide the basis for relevant departments to formulate policies and measures. Methods Every year from 2016 to 2018, 600 administrative villages in 30 agricultural counties were randomly selected as monitoring points, and 3 000 households were selected as monitoring households. Monitoring data was obtained through data reading, interviews, and on-site observations. Results The three-year rural population coverage rate of the garbage treatment plant was 28.31%, 36.10%, 39.36%, respectively, and the sewage treatment plant coverage rate was 12.27%, 20.39%, 15.02%, respectively. The annual differences were statistically significant（χ²=23.24、22.42，P=0.00）. The proportion of monitoring points for the three-year unified collection of domestic garbage was 30.50%, 43.67%, 51.00%, respectively, and the percentage of monitoring points for incineration garbage was 16.67%, 15.00%, 8.33%, respectively, and the annual differences were statistically significant（χ²=53.25、20.19，P=0.00）. The proportion of domestic sewage discharge monitoring points through pipelines was 12.67%, 11.17%, 31.17%, respectively, and the proportion of monitoring points discharged into treatment plants was 4.33%, 6.00%, 15.17%, respectively, and the annual differences were both statistically significant（χ²=99.45、52.50，P=0.00）. Conclusion In recent years, the rural garbage and sewage treatment situation in Shaanxi Province had improved, but there was still much room for improvement. It is recommended to increase environmental protection publicity and government investment, strengthen daily supervision, pay equal attention to construction and management, control the random stacking and discharging of garbage and sewage, and enhance the disposal rate of garbage and sewage.

Objective: To understand the status and trend of heavy metal indicators of drinking water in rural schools in different regions of Shaanxi Province, so as to provide scientific basis for safety of drinking water in rural schools. Methods: In 2017-2019, 697 rural school water supply projects in Shaanxi Province were tested for heavy metal indicators in the peripheral water. According to the sanitary standard for drinking water (GB 5749—2006), five heavy metal indicators, including arsenic, cadmium, hexavalent chromium, lead and mercury, were analyzed and evaluated in different years and regions. Results: A total of 2 298 valid water samples were collected and analyzed in 3 years. Except that lead and mercury are all up to standard, the standard rates of other heavy metals such as arsenic, cadmium and hexavalent chromium were 98.83%, 99.91% and 96.95% respectively. Compared with the Northern Shaanxi plateau and Qinba mountain area, the standard rate of water arsenic in Guanzhong Plain was lower (χ2=5.67, 13.59,P<0.01). The standard rate of hexavalent chromium was the highest in Qinba mountain area, followed by Guanzhong Plain, and the lowest in Northern Shaanxi plateau (χ2=20.48, 17.05, 48.32, P<0.01). Two samples of cadmium exceeding standard were from the Northern Shaanxi plateau. Conclusion The heavy metal index of drinking water in rural schools in Shaanxi Province exceeds the standard, which has obvious regional characteristics. We should focus on the harm of arsenic, hexavalent chromium and other heavy metals to the health of students in the Northern Shaanxi plateau and Guanzhong Plain. Cadmium and mercury in drinking water in local areas should be paid continued attention. Safety of drinking water in schools should be ensured from the aspects of water source selection and water treatment technology.

Objective To analyze the change in trends and existing problems of the water quality testing capabilities of the Centers for Disease Control and Prevention (CDC) in different cities and counties (districts) in Shaanxi Province from 2017 to 2019, and to provide references for laboratory capacity building. Methods A unified questionnaire was developed to investigate the water quality testing ability of all CDCs in different regions of Shaanxi Province, and the data were reported through the ^“National Drinking Water Quality Inspection Information System^”. Results From 2017 to 2019, in the testing of conventional indicators, the average number detected by the municipal CDCs was 37, 37, and 38, respectively, and all of them passed the measurement certification/laboratory accreditation. The average number detected by the county (district) CDCs was 30, 29, and 30, respectively, and only 65.14% of the county (district) CDCs passed the measurement certification/laboratory accreditation. In the testing of unconventional indicators, the average detectable number by city-level CDCs was 3, 5, and 4, respectively, while the average detectable number by county (district)-level CDCs was at most 1 item. There was no statistically significant difference in the average detection ability of CDCs at the city and county (district) levels in different regions in the same year (P>0.05); there was no significant difference in the average detection ability of CDCs at the city and county (district) levels in the same region in different years (P>0.05). Conclusion There is no difference in the CDC water quality testing level in different regions of Shaanxi Province, and the testing capacity needs to be further improved. It is recommended that the government should increase funding for disease control institutions, optimize the allocation of equipment and strengthen the construction of professional teams.

Objective: To investigate and analyze the drinking water quality among rural primary and secondary schools in Guanzhong area in 2018, and to provide a basis for the targeted improvement of water supply facilities. Methods: Develop a questionnaire on the basic situation of centralized water supply in rural schools, according to the Standard Test Method for Drinking Water (GB/T 5750—2006) and the Sanitary Standard for Drinking Water (GB 5749—2006) for the rural school network in Guanzhong area. The peripheral water collection and testing carried out single factor and multifactor statistical analysis on the relationship between water quality influencing factors and water quality pass rate. Results: The total qualified rate of drinking water quality in rural schools in Guanzhong area was 59.1%. Univariate analysis showed that water quality rate was affected by four factors including water source type, engineering type, sanitation permit and disinfection equipment use, and the difference was statistically significant(P<0.05). Unconditional two-class logistic regression analysis showed that disinfection (OR=3.14), engineering type (OR=2.05), and sanitation permit (OR=1.99)(P<0.05) affected the water quality pass rate. Conclusion It is recommended to further strengthen the investment in the renovation of water supply for rural schools in Guanzhong area, and specifically strengthen water supply treatment and standard disinfection.

Objective: To understand the disinfection status and microbial pollution of water supply project in rural schools in Shaanxi Province in 2018, and to provide basis for improving drinking water quality in rural schools. Methods: Data of water quality of water supply project in rural schools of Shaanxi Province in 2018 was collected, and the disinfectant surplus and microbial index compliance rate were analyzed according to "Sanitary Standard for Drinking Water" (GB 5749-2006). Results: The overall compliance rate of microbial indicators of water supply projects in rural schools in Shaanxi Province was 68.09%, and that of groundwater microbial indicators(71.97%) was higher than that of surface water(61.42%)(χ2=15.68, P<0.01); The overall compliance rate of microbial indicators in flood season(71.85%) was higher than that in dry season(64.34%)(χ2=7.44, P<0.01); The rate of reaching the standard of disinfectant residue was 77.27%. The rate of reaching the standard of microbial index of water samples with disinfection measures was higher than that of water samples without disinfection measures (χ2=31.88, P<0.01), The rate of reaching the standard of microbial index of water samples with disinfectant residue(88.89%) was higher than that of water samples with disinfectant residue(44.44%)(χ2=12.28, P<0. 01). Conclusion The main cause of microbial contamination of drinking water in rural schools in Shaanxi Province is inadequate equipment of disinfection equipment in water supply projects or not being used as required. It is suggested that schools, education and health departments should take measures to strengthen supervision and management of water plants to ensure the normal use of disinfection equipment.

Objective: To understand the environmental sanitation situation of rural schools in different geographical areas of Shaanxi, and to provide scientific basis for improving hygiene and sanitation in Chinese rural schools. Methods: Each year during 2016 to 2018, 150 townships in 30 counties of rural areas were randomly selected in various districts and cities throughout the province. In each township one junior high school and one elementary school were randomly selected, and the data was obtained through resource access, interviews, and on-site observations. The data was statistically analyzed and evaluated according to the northern, central and southern regions. Results: The differences of drinking ways among students in the schools were of statistical significance(χ2=25.89,P<0.01). The major drinking water method of students in the monitoring schools of the three regions all was providing boiled water, accounting for 56.16%, 65.88%, 50.39%, all of which have direct drinking unboiled water phenomenon; The water supply method of the self-provided centralized water supply school is mainly precipitation filtration in the central and southern regions, accounting for 38.46%, 53.21%, and untreated in the northern region(60.61%); The differences of the proportions of having sanitary toilets, detached toilets in schools, having toilets in teaching buildings, and having toilets in dormitory buildings in three regions were of statistical significance(χ2=32.04, 12.73, 20.78, 33.11, P<0.01) The proportion of schools with squat toilets in men’s toilets was greater than that of women’s(χ2=86.53, 44.77, 21.88, P<0.01). The differences of the proportion of schools with faucets available in toilets and within 5 meters around toilets, with sinks in or around the toilets, with sinks equipped with soap in or around the toilets were of statistical significance(χ2=90.02, 10.40, 41.96, P<0.01). Conclusion During 2016 to 2018, the environment sanitation of the three major rural primary and middle schools in Shaanxi Province needs to improve corresponding supporting facilities, and increase publicity to improve teachers and students’ awareness of health and safety.