Objective: To investigate the relationship between body fat percentage (BF%) and high blood pressure among adolescents in Shanghai, and to provide basis for early prevention and intervention of cardcovascular diseases. Methods: By using stratified cluster sampling method, a total of 5 148 adolescent students in 16 schools from 16 districts of Shanghai were selected. Questionnaire survey and physical examination were performed. The bioelectrical impedance analysis (BIA) was used to measure body fat percentage. National Blood Pressure Reference for Chinese Han Children was used to define high blood pressure. And T test, chi-square test and Logistici regression were used to assess the relation between BF% with high blood pressure. Results: The prevalence of high blood pressure in 5 148 junior middle school students in Shanghai was 10.98%, with girls (13.13%) higher than boys (8.99%)(χ 2=22.48, P<0.01). The average total body fat percentage of male students was (20.90±10.73)%, which decreased with age (linear trend variance is 10.04, P<0.01). The average total body fat percentage of girls was (25.14±8.03)%, which increased with age (linear trend variance is 69.23, P<0.01). After adjusted for age, diet, exercise and other influencing factors, the prevalence of hypertension showed an increasing trend with the increase of body fat percentage for both boys and girls. The risk of high blood pressure in boys with BF%≥P 90 was 12.43 times higher than that in boys with BF%

Conclusion There was a positive correlation between body fat percentage and high blood pressure in adolescents. The prevalence of high blood pressure increased with the increase of body fat percentage, which was more obvious in boys.

Objective: To assess the changes of students’ hand washing behaviors after implementing comprehensive interventions, and to provide the reference for hand-washing promotion among students. Methods: The implementation of comprehensive intervention projects had been carried out in three aspects: hardware transformation, system establishment, health management and health education. A randomized controlled trial method was used to select each one primary and secondary school in 2016 from 17 districts in Shanghai, and 17 intervention schools and 17 control schools were taken as object. Non-participant observation was used for students’ hand washing behaviors for 4 times during May, 2016 to May, 2017. Descriptive analysis and chi square test were used to analyze the data. Results: Compared with the control group, the hand washing rate of the intervention group was lower than that of the control group at baseline. The intervention group has got a higher rate than that of the control group in the evaluation of 1, the assessment 2 and the assessment 3 after intervention. The difference was statistically significant(χ2=7.70, 24.23, 38.88, 21.71, P<0.05). Compared with the control group, the hand washing rate of the intervention group after class was lower than that of the control group. After the intervention, the rate of the intervention group was higher than that of the control group in the evaluation 1, the assessment 2 and the assessment 3 after the intervention. The difference was statistically significant (χ2=8.52, 33.79, 54.64, 13.99, P<0.05). Compared with the control group, there was no difference between the baseline intervention group and the control group before meals. The intervention group after intervention was higher than the control group in the evaluation of 1, evaluation 2 and evaluation 3. The difference was statistically significant (χ2=45.01, 42.19, 27.82, P<0.05). Conclusion After comprehensive intervention, the effect was significant under different temperature conditions, and the effect of intervention lasted for one year.

Objective: To understand the influencing factors and family burden of bicycle injury among middle school students in Shanghai for bicycle injury prevention. Methods: Based on 1∶2 matched case-control design, students who were injured when cycling were selected from Shanghai student injury case reporting system during Sept. 2017 to Dec. 2018 as the case group. The same-sex control was selected from the same grade in the same school with the case. A total of 61 cases and 122 control were selected. Self-reported questionnaires were conducted by parents of children. Univariate and multivariate logistic regression were used to analyze the influencing factors of bicycle injury. Results: Poor eyesight (OR=2.27, 95%CI=1.02-5.07), lots of intersections near the residence (OR=2.00, 95%CI=1.00-3.98), and lots of cyclists near the residence (OR=2.15, 95%CI=1.06-4.36) were positively correlated with bicycle injuries among middle school students. About 34.43% and 8.20% of parents reckon bicycle injuries had a moderate impact on family economic, daily activities and recreational activities. Among the students with bicycle injury, 70.49% of the students were absent from school because of illness, and 36.07% of their parents missed work because of illness. The average absence time for school and working were 10.79 days and 3.03 days respectively. The total economic loss caused by the lack of work was 84 950 yuan, with an average of 1 393 yuan. Conclusion Bicycle injury of middle school students in Shanghai causes certain family burden. Poor eyesight, lots of intersections near the residence, lots of cyclists near the residence are positively correlated with bicycle injuries among middle school students.

Objective: To evaluate the effects of physical activity interventions based on social ecology model, and to explore promising approach for increasing physical activity of students in large cities. Methods: A quasi-experimental design with parallel control was implemented. Students from grade 4 in 20 primary schools in 3 districts of Shanghai were recruited. Based on social ecology model, physical activity interventions were carried out in three levels: personal, social-and physical environment. The interventions lasted for 6 months. Questionnaires, physical examinations and physical fitness tests were carried out. Rank sum test, chi-square test and logistic stepwise regression was used to analyze the intervention effects. Results: In the intervention group, the proportion of students who favored physical activity increased from 47.9% to 50.7%. Time spent in moderate to vigorous intensity physical activity (MVPA) increased from 64 min/d to 70 min/d, mainly during the weekend. The interventions showed significant effects, especially for girls. In the intervention group, the proportion of students spent 1 h/d in MVPA increased from 53.7% to 57.7%(χ2=4.95, P<0.05). Multivariate analysis showed that after intervention, the proportion of students spent more than 1 h/d in MVPA in the intervention group was higher than that in the control group (OR=1.22, 95%CI=1.02-1.48, P=0.03). Conclusion Physical activity interventions based on social ecology model can increase uptake of physical activity among school students.

Objective: To explore the relationship between myopia and nutritional status among upper elementary students in Shanghai. Methods: A stratified cluster sampling method was used to select 5 576 fourth and fifth grade students from 16 districts in Shanghai, vision test, physical examination and questionnaire survey were administered. Two level multivariate Logistic regression and mixed linear models were used to analyze the relationship between myopia, spherical equivalent (SE) and nutritional status. Results: The detection rates of overweight and obesity were 17.0%(949) and 18.7%(1 042), respectively. There was a statistical difference in the proportion of the nutritional status in boys and girls( χ 2=210.94, P <0.01), with overweight and obesity in boys higher than those of girls. The overweight boys were more likely to have myopia (univariate analysis: OR=1.23, P =0.04; multivariate analysis: OR=1.21, P =0.06) than the normal weight boy. Overweight students tended to had more negative refractive than those with normal weight in both boys and girls(multivariate analysis, boys: β =-0.19, girls: β=-0.24, P <0.05). Myopia risk and refractive power in obese students showed no statistical difference with normal weight students( P >0.05). Conclusion Overweight students have lower SE than the normal weight among upper elementary students of Shanghai, more researches are needed to confirm this finding and to provide theoretical bases for myopia prevention and control.

Objective: To understand the current status and associated factors of comorbidity of common illnesses among primary and middle school students in Shanghai, so as to provide a reference for improving the pathogenic environment and preventing the occurrence of comorbidity of common illnesses. Methods: From September to November 2021, a stratified cluster sampling method was used to select 30 331 middle school students from 112 schools in 16 districts of Shanghai, each with 2 primary schools, 2 junior high schools, 2 high schools and 1 vocational high school. Elementary school students, their health status and influencing factor questionnaires were analyzed. Results: The detection rate of two or more common diseases such as myopia, overweight and obesity, high blood pressure, and abnormal spinal curvature among primary and secondary school students in Shanghai was 38.91%, of which 29.64% of primary and secondary school students had two diseases at the same time, and 9.19% had three diseases, 0.09% had 4 diseases. The detection rate of comorbidity was higher in boys (44.12%) than in girls (33.40%), and higher in junior high school students (40.40%) than in high school students (38.58%) and primary school students (38.01%). The differences were statistically significant (χ2=366.44, 50.33, P<0.01). Multifactor Logistic regression analysis showed that girls sometimes supervise themselves and often remind themselves that their sitting and standing postures were negatively correlated with the common comorbidities of primary and secondary school students (OR=0.64, 0.93, 0.90); junior middle school students and watching TV/d ≥1 h, using computers for ≥1 h/d, and using mobile electronic devices for >1 h/d were positively correlated with the comorbidity of common diseases among primary and secondary school students (OR=1.07, 1.10, 1.06, 1.10) (P<0.05). Conclusions The prevalence of comorbidity of common illnesses among primary and middle school students in Shanghai is not optimistic, which might be associated with combined effects of various external environmental factors. Targeted intervention should be implemented to effectively prevent the occurrence of comorbidities among students.

Objective To evaluate the effect of child obesity intervention comprehensive program on the improvement of overweight,obese control and knowledge-attitude-practice.Methods The study design was under cluster-randomized controlled trial,with 965 children in the intervention and 895 children in the control groups.Repeated measurement data on child obesity was analyzed through Generalized Estimating Equation models.Results The risk of becoming overweight or obesity in the intervention group was 0.824 times more than children in the control group,showing a reduction of 17.6％ the risk of being overweight or obese (P=0.031).In addition,the possibility of increasing one unit of correct rate on obesity related knowledge,children in the intervention group children was 1.044 times (P=0.001) than in the control group.On the mean obesity related correct attitude rate,it was 1.023 times (P=0.001) in the intervention group of the control group.Regarding the possibility of increasing one unit om the mean obesity related behavior score,children in the intervention group was 1.522 times (P=0.001) than those in the control group (P=0.046).Conclusion The comprehensive child obesity intervention program could effectively reduce the risk of developing overweight or obeseity and improving the obesity related knowledge,attitude and behavior in children.

Objective To evaluate the effect of applying sitting posture corrector on improving reading and writing posture of elementary school students， and provide scientific evidence for prevention and control of myopia in children and adolescents. Methods One elementary school each in urban and suburban areas of Shanghai was selected using a convenience sampling strategy. Furthermore， two classes each in Grade 3 and 4 were selected as the intervention group （282 students were included in the study）， and the other two classes each in Grades 3 and 4 were selected as the control group （294 students were included in the study）. Students in the intervention group used the sitting posture corrector in the classrooms for 4 months （from September 2020 to January 2021）， while those in the control group did not use the sitting posture corrector. Relevant data were collected before and after the intervention through a self-administered questionnaire and visual examination. Statistical analysis was performed using chi-square test and generalized estimating equation. Results Before the intervention， 13.5% （38/282） of students in the intervention group and 12.2% （36/294） in the control group had good reading and writing posture （ χ ² = 0.195， P >0.659）. After the intervention， 18.4% （52/282） of students in the intervention group had good reading and writing posture， which was higher than that （11.2%， 33/294） in the control group （ χ ²=5.957， P =0.015）. Before and after the intervention， there was no significant differences in the prevalence of myopia between students in the intervention and control groups （all P >0.05）. Generalized estimating equation analysis showed that students in the intervention group were 1.502 times more likely to have good reading and writing posture than those in the control group after the intervention （ P =0.043）. Conclusion Applying sitting posture corrector in schools could improve students' reading and writing posture.