Objective: To evaluate the classroom environmental management and CO 2 volume concentration in primary and secondary schools from Liaoning, Tianjin, and Shanghai, thereby providing a scientific basis for developing targeted strategies to improve classroom air quality. Methods: From December 16 to 26, 2024, by using stratified random cluster sampling method, the questionnaire survey was conducted in 72 primary and secondary schools (24 each of primary, junior high, and regular high schools) across Liaoning, Tianjin and Shanghai. Information on heating, ventilation and other classroom environmental management was collected. Additionally, 108 classrooms were selected for on site microclimate measurements, including temperature, humidity, wind speed and CO 2 volume concentration. Univariate analysis and multiple linear regression models were employed to explore related factors of classroom CO 2 volume concentration. Results: Among the three provinces/municipalities, 20.8% of schools regularly monitored the microclimate. The overall compliance rate for classroom CO 2 volume concentration was 17.6%. Multiple linear regression analysis showed that CO 2 volume concentration in regular and junior high school classrooms were higher than in primary school classrooms ( β=0.067, 0.046, 95%CI =0.036-0.099, 0.013-0.080); classrooms ventilated regularly in the morning and afternoon had higher CO 2 volume concentration than those ventilated during every break between classes ( β=0.043, 95%CI = 0.007- 0.080); both temperature ( β=0.010, 95%CI =0.004-0.016) and humidity ( β=0.003, 95%CI =0.002-0.004) were positively correlated with CO 2 volume concentration (all P <0.05). Conclusions Excessive CO 2 volume concentration in primary and secondary school classrooms is a prominent issue, and ventilation frequency is a key intervenable factor for controlling CO 2 levels. It is recommended to promote ventilation during every break between classes as a core management measure and to emphasize air quality supervision in regular high school classrooms.

Objective: To understand the home reading-writing levels among children and adolescents in Shanghai after school, and to explore its association with screening myopia, so as to provide a scientific basis for the prevention and control of myopia. Methods: From April to December 2024, 641 primary and middle school students were recruited from 2 urban schools and 1 rural school in Shanghai to participate in the survey. An illuminance meter was used to measure the illuminance of home reading-writing activities after school. Screening myopia was determined through visual acuity examination and refractive detection under non ciliary muscle paralysis conditions among children and adolescents. A binary Logistic regression model was used to analyze the association between home reading-writing illuminance and screening myopia. Results: The detection rate of screening myopia among children and adolescents in Shanghai was 59.9%. The median home reading-writing illuminance after school was 340.9(112.2, 753.5) lx, and 45.4% was found of less than 300 lx. The family illuminance in the primary school stage [432.0 (136.9, 837.0) lx] was higher than that in the junior high school stage [113.1(53.7, 375.1) lx], and main urban area group [503.9 (212.6, 969.5) lx] was higher than that in the rural group [141.6 (53.7, 416.9) lx], the differences were statistically significant (Z=-7.56, -9.95,both P<0.05). The results of Logistic regression analysis showed that compared with the family illuminance of 150-500 lx, children and adolescents with family illuminance<150 and >500 lx had increased risks of screening myopia detection[OR(95%CI)=1.56(1.01-2.42), 1.74(1.15-2.62),both P<0.05]. Conclusions The home reading-writing illuminance after school is suboptimal. Both excessively low and high home reading-writing illuminance levels are associated with screen-detected myopia. It is necessary for children and adolescents to improve lighting conditions during evening reading-writing activities, and strengthen health education according to different regions and school stages.

Objective: To understand the indoor light at night (LAN) exposure intensity during sleep among children and adolescents in Shanghai, so as to provide a basis for exploring potential health risks and formulating effective interventions. Methods: From April to December in 2024, a total of 628 students in grades 4-7 were recruited from three schools in Shanghai. A portable illuminance meter was used to measure LAN for one week, and participants recorded their sleep time. The Kruskal-Wallis H- test was used for comparison between groups, and the error bar chart was used to show the trend and variation range of average LAN exposure intensity in different sleep periods. Results: The indoor LAN exposure intensity of children and adolescents in Shanghai was [2.4(0.8, 5.9)lx] during sleep, and 28.8% of children and adolescents were exposed to indoor LAN≥5 lx. There was no significant differences in indoor LAN exposure intensity between boys [2.4(1.0, 5.9)lx] and girls [2.3(0.7, 5.9)lx] ( Z=-0.86, P > 0.05 ). The indoor LAN exposure intensity of primary school students [2.9(1.1, 6.6)lx] was higher than that of junior high school students [1.0(0.3, 3.1)lx] ( Z =-5.87), and indoor LAN exposure intensity of students in the main urban area [3.2(1.1, 7.8)lx] was higher than that of rural students [1.6(0.5, 4.3)lx] ( Z =-5.23)(both P <0.05). The indoor LAN exposure intensity showed an overall decreasing trend during sleep of children and adolescents ( tau=-0.81, P =0.02), with a slight increase before waking up. Conclusions Indoor LAN exposure intensity among children and adolescents in Shanghai is generally high, especially among primary school students and students living in the main urban area. Health policy and education should be strengthened to reduce the impact of LAN on children and adolescent health.

Objective:To explore the association between healthy lifestyle and co-morbidity of overweight/obesity and myopia in adolescents.Methods:Based on the Shanghai Municipal Dynamic Cohort of Student Common Diseases, we used the group-based trajectory model (GBTM) to establish a model for the development of adolescents' healthy lifestyle trajectories aged 11-14 years and the Cox proportional hazard regression model to assess the effects of different healthy lifestyles on the co-morbidity of overweight/obesity and myopia in adolescents.Results:A total of 2 331 adolescents were included in the analysis. The average follow-up time was 1.87 years, with age of (11.44±0.45) years at the initial follow-up, among 1 106 boys and 1 225 girls. During the 2-year follow-up period, the incidence rates of overweight/obesity, myopia, and co-occurrence of overweight/obesity and myopia were 25.9%, 77.0%, and 13.7%, respectively. GBTM identified 3 healthy lifestyles: the unhealthy group (7.3%), the relatively healthy group (50.2%), and the healthy group (42.5%). The risk of overweight/obesity was lower in the relatively healthy group than in the unhealthy group ( HR=0.694, 95% CI: 0.508-0.947). There was no statistically significant association between the GBTM lifestyle subgroups and myopia ( P>0.05). The risk of co-occurrence of overweight/obesity and myopia was lower in both relatively healthy group and healthy group than in the unhealthy group (relatively healthy group: HR=0.515, 95% CI: 0.348-0.763; healthy group: HR=0.571, 95% CI: 0.384-0.849). Sensitivity analyses showed this result to be stable for myopia, overweight/obesity and myopia co-morbidities. Conclusion:Persistent unhealthy lifestyle increases the risk of overweight/obesity and myopia co-occurrence in adolescents.

Objective: To understand the subjective and objective comfort evaluations of students from different age groups on desks and chairs, so as to provide reference for standardized allocation and use of desks and chairs. Methods: From January to April 2024, a total of 2 446 students were selected from 26 schools in 13 districts (counties/cities) in Shanghai, Tianjin, and Wuxi from Jiangsu Province by using cluster random method, including students in kindergartens, primary schools, junior high schools,senior high schools, colleges and universities. Standardized procedures were used to measure the height and weight of participants, and the matching desks and chairs models were selected according to the height. The subjective comfort of students on matching desks and chairs was investigated, and their objective comfort was evaluated by using a self designed questionnaire. The χ 2 test was used to analyze the differences of subjective perception and objective evaluation in comfort between different types of desks and chairs. Results: About 84.1% of the students subjectively thought that large desks and small chairs were very comfortable or relatively comfortable, followed by large desks and chairs (75.7%), and the proportion of small desks and chairs was the lowest among the three types (46.2%), and the difference was statistically significant ( χ 2=722.46, P <0.01). The reporting rates of primary school, junior high school and senior high school students who subjectively considered large desks and chairs to be very comfortable/relatively comfortable were higher than that of other types of desks and chairs, and the differences were statistically significant ( χ 2=297.49, 252.82, 343.67, P <0.01). However, there was no significant difference in the subjective comfort evaluation of different types of desks and chairs among kindergarten children ( χ 2=3.21, P >0.05), and 66.3% of the students in colleges and universities felt very comfortable/relatively comfortable when they used the matching standard desks and chairs. The objective evaluation results of the comfort for the three types of desks and chairs were consistent with the subjective evaluation, but the proportions of the objective evaluation as very comfortable/relatively comfortable were higher than that of the subjective evaluation ( χ 2=20.76- 813.47, P <0.01). Conclusions Large desks and chairs, as well as large desks with small chairs are perceived comfortable, while small desks and chairs are perceived less comfortable. It is recommended to match the large desks and chairs or large desks and small chairs that are suitable for them according to the "standard", to promote physical and mental health of students.

Objective: To investigate the differences in the comfort of desks and chairs furniture among students with different body types according to the standard, so as to provide a reference for guiding students with overweight and obesity to choose the correct study furniture and revising the standards. Methods: From January to April 2024, 2 443 students from 26 schools in 13 districts (counties/cities) in Shanghai, Tianjin, and Jiangsu Province were selected by the cluster random sampling method to conduct physical examination. The subjective and objective evaluations of the comfort of height matched desks and chairs were investigated. The students were divided into non overweight, overweight, and obesity groups according to relevant criteria, and stratified analysis was performed. The χ 2 test was used to analyze differences in the comfort evaluations of desks and chairs among students with different body types. Results: Among the 2 443 students surveyed, 16.7% and 12.6% were respectively classified as overweight and obese. All students assigned the highest comfort ratings to large desks and small chairs (84.1%), and consistency was observed between students subjective and objective evaluations. The reporting rate of samll desks and chairs of obesity students subjective evaluation was lower (36.8%) than that of overweight and non overweight/obesity students (52.1%, 48.0%) ( χ 2=14.63, P <0.01). The overweight and obese group of primary school students had a worse evaluation of the comfort of large desks and chairs and small desks and chairs than those of the non overweight and obese groups( χ 2=15.78, 7.63, P <0.05). Among high school students, the overweight and obese group had worse evaluation of the comfort of large desks and chairs, as well as large desks and small chairs, than those of the non-overweight and obese groups( χ 2=9.62, 11.77, P <0.05). The objective evaluations revealed low compliance ratings on the posture of the thighs and calves for naturally forming an angle greater than 90° (55.6%), and headroom height under the table (50.3%) with small desks and chairs ( χ 2=94.05, 166.47, P <0.05). Conclusions Compared with non overweight/obese students, students with overweight and obese students report poor comfort evaluations of height matched desks and chairs. Revision of the standard should consider the body types of students, and evaluations of the comfort of desks and chairs furniture by students with overweight and obesity should be improved.

Objective:To explore the association between healthy lifestyle and co-morbidity of overweight/obesity and myopia in adolescents.Methods:Based on the Shanghai Municipal Dynamic Cohort of Student Common Diseases, we used the group-based trajectory model (GBTM) to establish a model for the development of adolescents' healthy lifestyle trajectories aged 11-14 years and the Cox proportional hazard regression model to assess the effects of different healthy lifestyles on the co-morbidity of overweight/obesity and myopia in adolescents.Results:A total of 2 331 adolescents were included in the analysis. The average follow-up time was 1.87 years, with age of (11.44±0.45) years at the initial follow-up, among 1 106 boys and 1 225 girls. During the 2-year follow-up period, the incidence rates of overweight/obesity, myopia, and co-occurrence of overweight/obesity and myopia were 25.9%, 77.0%, and 13.7%, respectively. GBTM identified 3 healthy lifestyles: the unhealthy group (7.3%), the relatively healthy group (50.2%), and the healthy group (42.5%). The risk of overweight/obesity was lower in the relatively healthy group than in the unhealthy group ( HR=0.694, 95% CI: 0.508-0.947). There was no statistically significant association between the GBTM lifestyle subgroups and myopia ( P>0.05). The risk of co-occurrence of overweight/obesity and myopia was lower in both relatively healthy group and healthy group than in the unhealthy group (relatively healthy group: HR=0.515, 95% CI: 0.348-0.763; healthy group: HR=0.571, 95% CI: 0.384-0.849). Sensitivity analyses showed this result to be stable for myopia, overweight/obesity and myopia co-morbidities. Conclusion:Persistent unhealthy lifestyle increases the risk of overweight/obesity and myopia co-occurrence in adolescents.

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 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.

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.