Objective To survye the relationshi p between blood pressure and body mass index ( BMI) ,waist-to-height ratio( WHtR) and body surface area( BSA) amogn 7 to 13 years old children in Jin-pan id strict,Haikou city.Methods A total of 1 018 school-age children aged from 7 to 13 years old were se-lected from two elementary schools in Jinpan distir ct,Haikou cti y.Blo odp ressure,height, weight and wa ist circumferencew ere measuredi n all children.BMI,WHtR,BSA were calculated and statistci al analyis s was performed by SPSS 22.0 software.Results The Pearson Correlation Coefficient of BMI and bloodp er ssure showed that BMI was posti vely correlatde with ob th systolic and id astoil c blood pressure(r=0.489,0.454, P<0.01,respective ly).The Pearos n Correlation Cofe ficient of WHtR and blood pressure showed that WHtR was positively correlated with both systolic and diastolic blood pressure(r=0.294,0.310,P<0.01,respec-tively) .The Pearson Correlation Coefficient of BSA and blood pressure showed that BSA was positively cor-related with both systolic and diastolic blood per ssure(r=0.603,0.520,P<0.01,respectively).The WHtR adn BSA of hypetr ension group were higher than those of the non-hypertension group( P<0.01) in both male and female children.Conclusion The blood pressure in 7 to 13 years old school-age children of Jinpan dis-trict,Haikou city is related to the BMI,WHtR and BSA respectively.

Objective To identify the effect of health risk behaviors on accidental injury of adoles-cents.Then analyze the strength and approach of the health risk behaviors. Methods Cluster sampling on various stages and strata methods was adopted. The adolescents from grade one to three in junior school students and grade one to three in senior high school students completed the questionaire. A total of 4408 students were surveyed and 4309 samples were valid. Path analysis was used to understand how factors could influence injury incidence. Results The incidence of adolescent injury was 15.53%. Statistical differences were found between genders (male 17.77%,female 13.36%,χ2=15.91, P<0.01),education levels (junior high school 17.36%,senior high school 13.99%,χ2=11.45, P<0.01) and cities ( Beijing 12.97%,Zhongs-han 17.95%,χ2=20.33, P<0.01) . Those who got injured were found with more health risk behaviors. Health risk behavior was the direct influencing factor to injury,as well as a possible risk factor to multiple injuries. Conclusion Health risk behaviors can strongly affect adolescent injury,and can be an indicator. Reducing health risk behaviors is important in adolescent injury prevention.

Objective: To investigate factors influencing adolescent idiopathic scoliosis (AIS), and to provide a scientific basis for effective prevention and treatment programs. Methods: A questionnaire survey was conducted among 6 757 students who participated in the scoliosis screening program for primary and middle school students in Zhongshan City, China from April 2019 to March 2020. Visual examination and Adams flexion test were used to measure the rotation angle of trunk. For each student, individual and family demographics, family history of scoliosis, daily postural habits, school bag carrying habits, vision, health, school environment, and physical activity were collected by questionnaire. Factors influencing AIS were analyzed using Chi square test and multivariate Logistic regression. Results: The positive screening rate for AIS was 2.0%(135 cases). Multivariate Logistic regression analysis revealed that female gender, no family history of AIS, standing with lumbar spine tilted forward, habit of leaning to the left when seated, and a monthly family income of >10 000 yuan were related to the occurrence of AIS in adolescents ( OR =3.01, 0.38, 2.29, 1.74, 0.44, P <0.05). Conclusion Female students aged 10-16 years with a family history of scoliosis in Zhongshan are identified as a high risk group for scoliosis screening. Developing proper standing and sitting habits helps to reduce the risk of AIS in adolescents.

Objective: To gain a better understanding of the emotional and behavioral problems associated determinants of primary and middle school students from Guangdong Province during the COVID-19 pandemic, so as to provide a basis for developing targeted intervention strategies. Methods: Using the method of convenience sampling, an online questionnaire survey was carried out among primary and middle school students from Guangzhou, Zhanjiang and Zhongshan from March to April 2020. The emotional and behavioral problems of primary and middle school students were assessed using the Conners Parental Symptoms Questionnaire(PSQ), and a self compiled questionnaire was used to collect basic information related to the primary and middle school students and the influencing factors of emotional and behavioral problems. A total of 7 755 valid questionnaires were retrieved and statistically analyzed using the chi square test and multivariate Logistic regression. Results: The detection rate of emotional and behavioral problems among children and adolescents aged 6 to 17-years-old in Guangdong Province was 14.8%; that was 21.0%, 14.4%, 7.3 %, and 10.1% in lower primary school students, upper primary school students, junior high school students, and high school students, respectively. The detection rate of the psychosomatic and hyperactivity index in boys was higher than that observed in girls, and the detection rate of anxiety in boys was lower than that observed in girls( P <0.05). There were statistically significant differences in emotional and behavioral problems in children in different grades( P <0.05). The results of the regression analysis showed that male students were at risk of psychosomatic ( OR= 1.37 , 95%CI =1.04-1.82) and hyperactivity disorders( OR=1.58, 95%CI =1.21-2.06), whereas the male gender was a protective factor for anxiety( OR=0.50, 95%CI =0.39-0.64). Grades were identified as the influencing factors of all of the factors related to emotional and behavioral problems. Students who reported excessive screen time and insufficient sleep were more likely to experience emotional and behavioral problems. Conclusion The detection rate of emotional and behavioral problems among primary and middle school students in Guangdong Province during the COVID-19 epidemic was high, which was associated with sex, grade, screen time and sleep. It is necessary to develop and implement targeted intervention measures.

: To investigate the current status of online classes, screen time and its influencing factors among primary school students in Guangdong during the 2019 novel coronavirus pandemic. Methods: Using the convenience sampling method, a total of 5 266 pupils aged 6-12-years-old from Guangzhou, Zhanjiang, and Zhongshan participated in the online questionnaire. ANOVA or chi square tests were performed to compare differences in online classes and screen time between grades, and multinomial Logistic regression was performed to analyze the correlates of recreational screen time. Results: The prevalence of prolonged recreational screen time was 42.2% and 55.2% on weekdays and weekends, respectively. Recreational screen time increased by 40.31 min/d on weekdays and 33.07 min/d on weekends, compared to usual school semesters. The average duration of an online class was (26.07±9.62) min, which totaled (110.41±51.98)min per day. Sex, grade, being the only child, and parents education levels were identified as the influencing factors of prolonged recreational screen time. Children who practiced moderate levels (weekdays: OR =1.27; weekends: OR =1.40; P <0.05) or lower levels of physical activity (weekdays: OR =1.86; weekend: OR =1.84; P < 0.05 ) were at a higher risk of prolonged recreational screen time than those who practiced more vigorous physical activity. Children whose parents limited their screen time to a moderate (weekdays: OR=1.61, P <0.05) or lower level (weekdays: OR=1.32, P < 0.05 ) had a higher risk of prolonged recreational screen time than those with a higher frequency. Children with parents recreational screen time ≥ 2 h/d had a higher risk of prolonged recreational screen time than the reference group; children who exhibited moderate to vigorous levels of physical activity <1 h/d (weekdays: OR=1.31, P <0.05), and those used electronic devices for learning 1-2 h/d (weekdays: OR =2.65; weekend: OR =2.65; P <0.05) or for ≥2 h/d (weekdays: OR =4.05, weekend: OR=5.24, P < 0.05 ) were at a higher risk of prolonged recreational screen time than the reference group. Conclusion During the COVID-19 pandemic, the level of screen time among children in Guangdong was high. Behavioral monitoring and targeted interventions are needed to promote children s health.

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 investigate the incidence of malnutrition in children and adolescents aged between 8 and 16 years in Zhongshan, Guangdong Province and to explore the impact of lower body mass index in early childhood on malnutrition in children and adolescents. Methods: A retrospective cohort of 2 188 students with complete data on weight and height from grade one in primary school to grade one in high school in Zhongshan were included in this analysis. Normal weight individuals with BMI lower than the 50th percentiles (P50) were defined as lower BMI, according to "Report on the Physical Fitness and Health Surveillance of Chinese School Students" in 2005. Screening Standard for Malnutrition of School-age Children and Adolescents in 2014 (WS/T 456—2014) was used to define malnutrition. Prevalence and incidence of malnutrition was calculated, and chi-square test was used to compare the difference of the incidence of malnutrition between children with BMI Results: The prevalence of malnutrition was 15.08% for children in grade one of primary school, which reached highest of 16.32% in grade two of primary school and decreased to 7.27% in grade one in high school. The annual incidence of malnutrition among students with normal weight decreased from 8.37% in grade two in primary school to 1.22% in grade one in high school. Boys with lower BMI in grade one in primary school had the incidence of malnutrition with 12.47% in grade two in primary school, while those with BMI ≥P50 had the incidence of 0.63%. Girls with lower BMI had higher incidence of malnutrition than those with BMI ≥P50. Conclusion Incident malnutrition between grade one in primary school and grade one in high school is more likely to occur in early childhood. Lower BMI in early childhood significantly increases the risk of malnutrition in children and adolescents. Malnutrition prevention should be implemented from early childhood, especially for those with lower BMI.

Objective: To explore the related factors and working way of adolescent injury,and to provide a basis for the effective prevention and intervention of adolescent injury. Methods: The framework of the questionnaire in this study was developed based on the Social Ecology Model. A cross-sectional survey was conducted on a valid sample of 4 309 students from 8 junior high schools and 8 senior high schools in Beijing and Zhongshan city respectively, using stratified random cluster sampling method. Students from grade 7 to grade 12 were invited to participate and investigated with injury prevalence. Results: The incidence of adolescent injury by person and by person-time was 15.53% and 22.49% respectively, and there were differences by sex, age and regions(χ2=15.92，11.45，20.33，P<0.05). The occurrence of adolescent injury was affected by adolescent psychological behavior and social environment through different underlying pathways. The intrapersonal factors and perception of environmental safety showed direct effects on the adolescents’ injuries (effect size was 0.29 and 0.05 respectively, P<0.05). Conclusion Adolescent injury is associated with diverse factors and pathways in a synergistic and complex manner, suggesting that a three-dimensional and diverse strategy should be taken to intervene the injures.

Objective: To explore the association between middle school students health literacy and bully victimization and associated sex difference, and to provide guidance for bully prevention in adolescents. Methods: During November 2017 to January 2018, 18 900 junior and senior high school students were enrolled from Hefei of Anhui Province, Shenyang of Liaoning Province, Yangjiang of Guangdong Province and Chongqing by multistage cluster sampling. A self rated questionnaires were used to collect demographic information, health literacy, and bully victimization. Group differences by different characteristics and the association between health literacy and bully victimization were analyzed. Results: The detection rates of campus and cyber bullying victimization were 15.8% (2 992/18 900) and 9.1% (1 723/18 900). Boys, junior high school students, students with poor family financial status and few close friends had a detection rate of 28.0%, 18.8%, 23.3%, and 33.6% of school bullying, which are higher than those of the control group ( χ 2=225.64, 148.07, 141.13, 143.49, P <0.01); boys, students with poor household income and few close friends, the detection rates of cyber bullying were 10.9%, 14.4%, and 20.1%, respectively, are higher than the control group ( χ 2=62.96, 112.82, 88.49, P <0.01). Multivariate Logistic regression analysis indicated that students with low overall and dimensions scores of health literacy were more likely to suffer from campus and cyber bullying, except for the dimension of physical activity. In addition, at all levels of health literacy, males are more likely to be bullied than females ( P <0.05). Conclusion Health literacy of middle school students is related to bully victimization, which is sex specific. Intervention programs of bullying should focus on health literacy enhancement.

Objective: To explore the association between health literacy and drinking behaviors among middle school students in six provinces of China, and to provide scientific basis for the prevention and intervention of drinking behaviors. Methods: From November 2015 to January 2016, 22 628 students were enrolled from Ulanqab, Shenyang, Xinxiang, Bengbu, Chongqing and Yangjiang by multistage stratified cluster sampling method. And a questionnaire survey was conducted among them to collect demographic information, health literacy and drinking behaviors. Rates on drinking behaviors were compared in students with specific characteristics. Multiple Logistic regression analyses were conducted to examine the association between health literacy and drinking behaviors. Results: The proportion of ever drinking, current drinking, binge drinking, drunkenness was 60.0%(13 580), 16.8%(3 799), 5.9%(1 344) and 9.9%(2 250), respectively. After adjusting for gender, grade, family address, siblings, accommodation type, parental educational level, and self reported family income, compared to the high level health literacy, the low level health literacy was significantly associated with ever drinking (OR=1.76, 95%CI=1.62-1.91), current drinking(OR=1.37, 95%CI=1.23-1.52), binge drinking (OR=1.39, 95%CI=1.18-1.63), and drunkenness(OR=1.68, 95%CI=1.47-1.92), respectively(P<0.01). Conclusion Health literacy of middle school students was related to drinking behaviors. The occurrence of health risk behaviors such as drinking can be prevented and reduced by improving students health literacy level.