Objective: To explore the association between watching TV and watching computer and visual acuity among children and adolescents, and to provide reference for Chinese students to choose electronic products in life and study. Methods: Subjects were from 2014 Chinese National Surveys on Students’ Constitution and Health(CNSSCH). In this survey, 213 857 Han students participated. The visual acuity results of 5 m visual acuity chart examination were recorded, and the time of completion of homework and the time of different video behaviors were investigated. Results: The incidence of reduced vision acuity among Chinese students increases with the time spent on homework and computer(χ2=3 748.99, 949.39, P<0.01).And it decreased as time spent at the computer increased(χ2=2 725.08, P<0.01). It was found that the incidence of poor vision of students who watched TV for a long time was lower(61.81%), followed by those who watched TV and watched computer for the same time(70.62%), and those who watched computer for a long time(79.03%). The results were statistically significant(χ2=4 862.43, P<0.01). The results of multivariate Logistic regression analysis showed that compared with the students who watched TV for a long time, the students who watched TV for the same time and watched computer for a long time were more likely to have poor vision(OR=1.17, 1.21, P<0.01). Conclusion When using electronic products, the preference of watching large electronic screens is conducive to reducing the impact of video behavior on students' eyesight.

Objective: To explore the epidemiological characteristics of injury among middle school students in Zhongshan city, Guangdong Province, and to provide evidence for appropriate student injury prevention strategies and injury monitoring programs. Methods: The cluster random sampling method was used to collect injury information among 2 212 middle school students in urban and suburban areas of Zhongshan city. SPSS 22.0 was used for statistical analysis. Results: Among all the 2 212 middle school students, the incidence of injury was 17.95%. The incidence of injuries (20.9%)and mutiple injuries(6.67%)among boys was higher than that of girls(15.42%,4.61%),and the differences were of statistical significance(χ2=11.21,4.45,P<0.05). The incidence of multiple injuries among junior high school students(6.70%) was higher than that among high school students(4.48%)(χ2=5.20，P<0.05). The injury occurred in the school (63.76%) was higher than that occurred outside of the school (36.24%). Most injures were more likely to occur in sports area in school(33.16%),and most injuries were found occured while doing physical activities(38.01%). Conclusion The prevention of injury among middle school students should focus on junior high school students and male students. School-based injury prevention and health education should focus on campus sports-related injury.

Objective: To evaluate the physical fitness and its regional distribution of students aged 13-18 years in China, using the National Standards for Students’ Physical Fitness (revised in 2014). Methods: We recruited 105 834 students aged 13 to 18 years from the Chinese National Survey on Students Constitution and Health project in 2014. Related total scores, rates for qualified and for excellence (the proportions of individuals whose total score greater than or equal to 60.0 or 90.0) of these students were gathered. T test was applied to compare means of total score in different groups. χ² test was used to compare the differences of qualified or excellence rates between different groups while Pearson correlation method was applied to test the relation of each index with per capita GDP. Results: The average score was (70.1±10.7) among students aged 13 to 18 years in China. 88 805 (83.9%) students whose score exceeded 60.0 while 1 734 (1.6%) exceeded 90.0. Average score, rates of both qualified or excellence of students aged 13 to 15 appeared higher than those aged 16 to 18 but lower in males than in females. However, the rate of excellence was much higher in male students. Students living in urban areas showed both lower average score and qualified rate but higher rate of excellence than those living in rural areas. Both qualified and Excellent rates decreased with the increase of age in both sexes. We also noticed that both higher physical fitness and health status appeared in students from the east coast. Pearson correlation coefficient of each index (average score, qualified or Excellent rate) on per capital GDP appeared as 0.56, 0.43 and 0.65, respectively. Conclusion In 2014, the physical fitness of Chinese students aged 13 to 18 was not satisfactory, with older students and those living in underdeveloped areas, in particular.

Objective: To understand epidemiological characteristics of echinococcosis among children and adolescents in Lhasa, and to provide basic data and theoretical support for echinococcosis prevention and control. Methods: The data of echinococcosis screening in Lhasa in 2017 were collected from 3-18 years old, and portable ultrasound and serum echinococcosis antibody tests were used for screening, and the diagnosis was made based on the epidemiological history and clinical manifestations. Results: The overall echinococcosis detection rate of children and adolescents aged 3-18 years in Lhasa was 0.12% (114/95 835).Among different age groups, the echinococcosis rate of children and adolescents aged 16 to 18 was the highest (0.17%). Among the population with different education levels, the echinococcosis rate of children and adolescents with primary education level was the highest (0.45%).The echinococcosis detection rate of herdsmen was the highest among different occupational groups (0.59%). Among the population with different living patterns, echinococcosis rate was the highest (0.70%) in "settled in winter and nomadic in summer" group. The rate of echinococcosis of children and adolescents were the highest in "nomadism" group and "half farming and half nomadism" group (both 0.20%) among different family production mode. Among different endemic counties, the echinococcosis detection rate of children and adolescents in Dangxiong county and Mozhugongka county were the highest, both of which are 0.18%.All the above differences are statistically significant(χ2=16.77,23.76,69.76,16.49,14.74,25.25,P<0.01).There was no significant difference in echinococcosis detection rate between boys and girls(P>0.05). Conclusion Echinococcosis is more likely to be detected in children and adolescents who are older and have a lower education level, whose production and lifestyle are involved in animal husbandry, and who live at a higher altitude. Therefore, the prevention and control of echinococcosis among children and adolescents, especially the health education, should be the focus of the government’s work.

Objective: To understand the nutritional status among Chinese students of five ethnic minorities aged 7-18 years. Methods: Chinese National Survey on Students Constitution and Health in 2014 applied multi-stage stratified cluster random sampling, including 214 354 students from 31 province of China mainland. 73 students whose height or weight information were missing, were excluded. 25 968 minority students aged 7-18 years from Inner Mongolia Autonomous Region, Ningxia Hui Autonomous Region, Xinjiang Uygur Autonomous Region, Guangxi Zhuang Autonomous Region and Jilin Provinces were included for data analysis, including Mongolian (n=5 107), Hui (n=5 308), Uygur (n=5 740), Zhuang (n=5 267) and Korean (n=4 546) students. According to the BMI standard of Working Group on Obesity in China (WGOC) and the new students' health standard of Screening Standard for Malnutrition of School-age Children and Adolescents (WS/T 456-2014) , students were defined as wasting, normal weight, overweight and obesity groups and the nutritional status in different minorities and other characteristics was described and analyszed. Results: The prevalences of wasting in Zhuang, Hui, Uygur, Korean and Mongolian students were 6.1% (318/5 267), 5.1% (266/5 308), 3.2% (187/5 740), 2.6% (116/4 546) and 1.3% (65/5 107) in descending order (χ²=212.60, P<0.001), respectively. The prevalences of overweight in Korean, Mongolian, Hui, Uygur and Zhuang students were 15.2% (686/4 546), 13.1% (669/5 107), 10.3% (549/5 308), 7.8% (446/5 740) and 7.8% (413/5 267) in descending order (χ²=220.80, P<0.001), respectively. The prevalences of obesity in Korean, Mongolian, Hui, Zhuang and Uygur students were 15.3% (695/4 546), 9.5% (488/5 107), 5.7% (304/5 308), 4.6% (242/5 267) and 3.6% (206/5 740) in descending order (χ²=647.02, P<0.001), respectively. The prevalences of wasting in Mongolian, Uygur and Korean rural students were 1.7% (44/2 623), 3.9% (113/2 868) and 3.4% (74/2 154), higher than urban students (all P values <0.05) which were 0.8% (21/2 484), 2.6% (74/2 872) and 1.8% (42/2 392) in Mongolian, Uygur and Korean students. The prevalence of obesity in Mongolian, Hui, Uygur, Zhuang and Korean urban students were 10.8% (269/2 484), 7.6% (193/2 554), 4.1% (117/2 872), 5.9% (153/2 601) and 16.6% (396/2 392), higher than rural students (all P values <0.05) which were 8.3% (219/2 623), 4.0% (111/2 754), 3.1% (89/2 868), 3.3% (89/2 666) and 13.9% (299/2 154) in Mongolian, Hui, Uygur, Zhuang and Korean students. The prevalence of obesity in Hui, Zhuang and Korean boys were 7.2% (188/2 570), 6.0% (157/2 628) and 17.2% (394/2 282), respectively, higher than that of girls which were 4.2% (116/2 738), 3.3% (85/2 639) and 13.3% (301/2 264) (all P values <0.05). Conclusion The prevalence of wasting, overweight and obesity varied by ethnic minorities in mainland China. The prevalence of overweight and obesity appears higher among mongolian and Korean students, while the prevalence of wasting was higher in Zhuang students.

Objective: This study aimed to explore the association between malnutrition and the level of blood pressure (BP) as well as elevated BP (EBP) in Han students aged 7 to 18 years in China. Methods: 170 037 subjects with normal nutritional status and malnutrition were enrolled in this study from 2014 Chinese National Surveys on Students' Constitution and Health with a multi-stage stratified cluster random sampling framework covering 31 provinces, autonomous regions and municipalities after the exclusion of 44 317 overweight and obese students. According to the standard of "Screening Standard for Malnutrition of School-age Children and Adolescents" (WS/T456-2014), the nutritional status of children were classified into two categories, normal nutritional status and malnutrition containing stunting, mild wasting and moderate severe wasting. The level of BP and prevalence of EBP were compared between students with normal nutritional status and malnutrition. The multivariate logistic regression model was used to analyze the association between malnutrition and EBP. Results: The levels of systolic BP (SBP) and diastolic BP (DBP) in Chinese Han students aged 7-18 years who were non-overweight and non-obesity status were (103.4±12.3) and (64.7±9.5) mmHg (1 mmHg=0.133 kPa), respectively. The prevalence of EBP, systolic EBP and diastolic EBP in Chinese Han malnourished students (N=21 012) were 3.1% (n=649), 1.5% (n=324) and 2.1% (n=445), respectively, which was significantly lower than those (N=148 320) with normal nutritional status (4.5% (n=6 707), 2.6% (n=3 872) and 2.7% (n=3 959)), and the corresponding differences were statistically significant (P<0.05). The OR (95%CI) between malnutrition and EBP was 0.68 (0.62-0.73), which were 0.65 (0.58-0.72) and 0.68 (0.60-0.77) for boys and girls. The OR (95%CI) between EBP and stunting as well as mild wasting and moderate severe wasting were 0.69 (0.62-0.77), 0.63 (0.55-0.72) and 0.79 (0.60-1.05), respectively. Conclusion The level of BP and prevalence of EBP in Chinese Han students with malnutrition were lower than those with normal nutritional status. The negative correlation existed between malnutrition and EBP in Chinese Han students aged 7 to 18 years.

Objective: To investigate the prevalence and related factors of dyslipidemia among children and adolescents aged 6-17 years in 7 provinces in China. Methods: Using the method of stratified cluster random sampling, 93 primary and secondary schools were selected from Guangdong, Hunan, Liaoning provinces, Shanghai, Chongqing, Tianjin municipalities and Ningxia Hui Autonomous Region in China, 2012. A total of 16 434 students aged 6-17 years old with completed physical and lipid profiles parameters were selected into this study from above 93 primary and secondary schools. Dyslipidemia was determined by the definition of Expert Advice on Prevention and Treatment of Dyslipidemia in Children and Adolescents in 2009. Logistic regression model was used to explore the factors related to dyslipidemia. Results: The prevalence of elevated total cholesterol, elevated triglyceride, elevated low-density lipoprotein cholesterol, low high-density lipoprotein cholesterol, and dyslipidemia was 5.4% (887 cases), 15.7% (2 578 cases), 3.0% (492 cases), 13.5% (2 221 cases) and 28.5% (4 679 cases) among children and adolescents aged 6-17 years, respectively. Sugary drinks intake ≥once per week (OR=1.14; 95%CI: 1.05-1.24), sedentary time >10 hours per day (OR=1.14, 95%CI: 1.01-1.28), overweight (OR=1.50, 95%CI: 1.33-1.70), and obesity (OR=2.62, 95%CI: 2.31-2.96) were significantly associated with the prevalence of dyslipidemia. Conclusion The prevalence of dyslipidemia was high among children and adolescents aged 6-17 in 7 provinces in China, 2012. Sugary drinks intake ≥once per week, sedentary time >10 hours per day, overweight and obesity might be the risk factors of dyslipidemia among children and adolescents.

Objective: To analyze the prevalence of physical fitness among Chinese Han students aged 13-18 years in 2014, and explore related influencing factors. Methods: This study recruited 106 881 Han students aged 13-18 years who had taken physical fitness test from Chinese National Survey on Students' Constitution and Health in 2014. After the exclusion of 1 047 students without complete records of physical fitness test, 105 834 students were included in the final analysis. According to the National Student Physical Health Standard modified in 2014, seven indicators including body mass index, vital capacity, 50-m run, sit-and-reach, standing broad jump, pull-ups/curl-ups and endurance run were tested to calculate the total score of students' physical fitness. Students with score ≥60 were regarded as qualified students. Multivariate non-conditional logistic regression model was used to analyze influencing factors of physical fitness. Results: Among Chinese Han students aged 13-18 years, the total score was 70.1±10.7 and the qualified rate was 83.9% (n=88 813). Boys (83.5% (44 197/52 910)) had a lower qualified rate of physical fitness than girls (84.3% (44 616/52 924)) (P<0.001), and 13-15 age group (86.5% (46 255/53 465)) was higher than the 16–18 age group (81.3% (42 558/52 369)) (P<0.001). Except for 16–18-year-old boys from central region, normal body mass index, eastern region, good socioeconomic status, enough PE class, exercise time ≥1 h/d, homework time ≥2 h/d, TV time <1 h/d were all related to high qualified rates of physical fitness (P<0.05). Conclusion Chinese Han students aged 13-18 years were in good physical condition. The qualified rates of physical fitness were significantly different by gender and age groups. Nutritional status, region, socioeconomic status, PE class, exercise time per day, homework time per day, and TV time per day were related factors of physical fitness.

Objective To explore the prevalence of physical activity time ＜1 hour and related factors in students aged 9-22 years in China.Methods A total of 220 159 students (110 039 boys and 110 120 girls) aged 9-22 years who completed the questionnaire of physical activity and lifestyle behaviors were selected from "2014 National Physical Fitness and Health Surveillance" for the current study.All the participants were divided into 2 groups,i.e.physical activity time ＜ 1 hour and physical activity time ≥ 1 hour according the suggestion of Central Government,stratified by age and gender.x2 tests were used to compare the difference in the prevalence of physical activity time ＜ 1 hour between boys and girls in every age groups.Univariate and multivariate log-binomial regression models were used to explore the factors that influenced the prevalence of physical activity time ＜ 1 hour.Results The boy's prevalence of physical activity time ＜1 hour was 73.3％,with the lowest (57.0％) in 9-years-old group,and highest (82.5％) in 18 years old group.The girl's prevalence of physical activity time ＜ 1 hour was 79.1％,with the lowest (60.1％) in 9-years-old group,and highest (89.8％) in 21 years old group.Overall,The prevalence of physical activity time ＜ 1 hour was significantly higher in girls than in boys (P＜0.001),and the prevalence were significantly higher in girls than in boys in all the age groups (P＜0.001),and it was observed that the prevalence of physical activity ＜ 1 hour increased with age in both boys and girls (P＜0.001).Multivariate log-binomial regression model found that being girl (PR=1.05,95％CI:1.05-1.06),parents' disliking children to participate physical activity (PR=1.08,95％CI:1.07-1.09),heavy homework (PR=1.13,95％CI:1.12-1.14),long homework time (PR=1.08,95％CI:1.07-1.08),long time spending on electronic screen watching (PR=1.01,95％CI:1.00-1.01) and disliking physical class (PR=1.11,95％CI:1.10-1.12) could be the risk factors for physical activity time ＜ 1 hour,however,living in rural area (PR=0.99,95％CI:0.98-0.99) and no supporting from parents for children to participate physical activity (PR=0.99,95％CI:1.98-1.00) could be the protective factors,but no consistent association with the time of TV watching was observed (P=0.226).Conclusions The prevalence of physical activity time ＜ 1 hour was high in students aged 9-22 years in China.Female,parents;disliking children to participate physical activity,heavy homework,long homework time,long electronic screen watching time and disliking physical class might be the risk factors.

Objective To understand and evaluate the prevalence of myopia and its trend in children and adolescents aged 7-18 years in Han ethnic group in China from 2005 to 2014,and provide evidence for the prevention of myopia.Methods The data of 2005,2010 and 2014 Chinese National Students Constitution and Health Surveys were collected.The children and adolescents with complete detection data of binoculus were selected as study subjects.The sample size of three studies were 233 108,215 319 and 212 743,respectively.The method of curve fitting was used to simulate the myopia detection increase model and analyze the gender and area specific myopia detection increase trends and characteristics from 2005 to 2014.Results The overall myopia detection rate increased gradually in the children and adolescents aged 7 to 18,which was 47.5％ in 2005,55.5％ in 2010 and 57.1％ in 2014,respectively.The increase slowed in 2014.A "parabola" shape of myopia detection increase rate was observed.Myopia detection rate increased with age before puberty and decreased with age after puberty gradually.A "cross phenomenon" of myopia detection increase was observed in boys and girls between urban and rural areas.The increase of myopia detection was mainly in urban students before puberty and in rural students after puberty.The age of myopia prevalence peak has become earlier constantly in children and adolescents aged 7-18 years from 2005 to 2014,which was 13 years old in 2005,12 years old in 2010 and 11 years old in 2014.The increase rate was about 7％.During 2005-2014,the increase rate of myopia detection gradually increased in younger students and tended to zero in older students.Conclusion The detection rate of myopia was still high in children and adolescents in China.The age of myopia prevalence peak has become earlier gradually.