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: 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 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: To investigate consistency of whole-body muscle mass (WBMM) assessed using multi-frequency bioelectrical impedance analysis (MF-BIA) and dual energy X-ray Absorptiometry (DXA) measurement, and to delvelop the correction regression formulas for the method of MF-BIA. Methods: 1 488 participants who resided in Beijing longer than one year, under 22 to 55 years of age, with self-report BMI ≥24 kg/m² were voluntarily recruited based on convenience sampling in Beijing, from April 1^st 2014 to May 2^nd 2014. After excluded 171 participants who BMI ≤24 kg/m² or with organic diseases when physical examination, Finally 1 317 overweight/obese participants were enrolled into the current study. All the subjects received the measurement of WBMM using both MF-BIA and DXA methods. The paired-samples T test was used to compare the difference of measurement values between MF-BIA and DXA methods. We evaluated the agreement of WBMM measured by MF-BIA and DXA using the interclass correlation coefficients (ICC) and the Bland-Altman plots, and using linear regression method established correction regression formulas. Results: The differences of overweight male, obese male, overweight female, and obese female were (3.29 ± 1.94), (2.05 ± 2.65), (0.17 ± 1.85), and (-2.22 ± 2.89) kg between methods of MF-BIA and DXA, respectively; Except the overweight female, the others groups had the statistically significant difference (P<0.05). The ICC for overweight male, obese male, overweight female, and obese female were 0.958, 0.956, 0.911, and 0.851, respectively (P<0.001). Bland-Altman plots showed that the limit of agreement for four groups were -0.51-7.09, -3.14-7.24, -3.46-3.80, and -7.88-3.44 kg, respectively. Correction regression formulas: overweight male population: y_DXA=-0.648+ 0.952 x_MF-BIA; obese male population: y_DXA=-3.646 + 1.026x_MF-BIA; overweight female groups: y_DXA=-4.800 + 1.117 x_MF-BIA; obese female group: y_DXA=-9.884+ 1.287x_MF-BIA. Conclusion The correlation and agreement of WBMM measured by the methods of BIA and DXA were relative weak in Chinese excess weight male and obese female adults. Therefore, measuring WBMM by MF-BIA method in these adults should be corrected to reduce bias compared with the DXA method.

Objective: To investigate the characteristics of geographic distribution and change trend of myopia prevalence for children and adolescents aged 7-18 years old from 2005 to 2014, which provides the basis for the prevention of myopia. Methods: Research material was selected from the data of 2005, 2010, and 2014 Chinese National Survey on Students Constitution and Health, including 31 provinces (with the exception of Hong Kong, Macao, and Taiwan). The complete detection data of binoculus in children and adolescents aged 7-18 years old were selected as our research objects. The research objects of three studies were 233 505, 216 474, and 215 160, respectively. We analyzed the characteristics of geographic distribution and change trend of myopia prevalence for children and adolescents aged 7-18 years old in 31 provinces from 2005 to 2014. Results: The overall myopia detection rates in Chinese children and adolescents aged 7 to 18 years old in 31 provinces were 47.4% (111 707/235 505), 55.6% (120 456/216 474), and 57.2% (122 965/215 160) in 2005, 2010 and 2014, respectively. The growth range in this two phases were 8.0 percentage points, and 1.6 percentage points, respectively, and the difference was statistically significant (P<0.05). The detection rate of Myopia was growing quickly from 2005 to 2010 and only three provinces were in the situation of decline state including Tianjin, Hainan, and Ningxia. 90.3 percent (28/31) of provinces were in the situation of growth state and the growth range was 1.3%-22.3%. The growth of myopia was in the situation of slowdown from 2010 to 2014, and 38.7 percent (12/31) of the provinces were in negative growth districts including Hebei, Shanxi, Inner Mongolia, Zhejiang, Fujian, Shandong, Hubei, Guangxi, Guizhou, Tibet, Qianghai, and Xinjiang. The growth range in other provinces was 0.4%-24.7%. Conclusion The myopia detection rate was at a higher level and growing constantly in China. There was large difference for myopia of children and adolescents among the 31 provinces. However, the overall growth rate of myopia in children and adolescents was in the situation of a relatively low level form 2010 to 2014.