Effectiveness of Multifaceted Strategies to Increase Influenza Vaccination Uptake: A Cluster Randomized Trial.

Importance: Influenza vaccination rates remain low among primary school students and vary by school in Beijing, China. Theory-informed, multifaceted strategies are needed to improve influenza vaccination uptake. Objective: To evaluate the effectiveness of multifaceted strategies in improving influenza vaccination uptake among primary school students. Design, Setting, and Participants: This cluster randomized trial was conducted from September 2022 to May 2023 across primary schools in Beijing, China. Schools were allocated randomly in a 1:1 ratio to multifaceted strategies or usual practice. Schools were deemed eligible if the vaccination rates in the 2019 to 2020 season fell at or below the district-wide average for primary schools. Eligible participants included students in grades 2 and 3 with no medical contraindications for influenza vaccination. Intervention: The multifaceted strategies intervention involved system-level planning and coordination (eg, developing an implementation blueprint, building social norms, and enhancing supervision), school-level training and educating school implementers (eg, conducting a 1-hour training and developing educational materials), and individual-level educating and reminding students and parents (eg, conducting educational activities and sending 4 reminders about vaccination). Main Outcomes and Measures: The primary outcomes were influenza vaccination uptake at school reported by school clinicians as well as overall vaccine uptake either at school or outside of school as reported by parents at 3 months. Generalized linear mixed models were used for analysis. Results: A total of 20 schools were randomized. One intervention school and 2 control schools did not administer vaccination on school grounds due to COVID-19, resulting in a total of 17 schools (9 intervention and 8 control). There was a total of 1691 students aged 7 to 8 years (890 male [52.6%]; 801 female [47.4%]) including 915 in the intervention group and 776 in the control group. Of all participants, 848 (50.1%) were in grade 2, and 1209 (71.5%) were vaccinated in the 2021 to 2022 season. Participants in the intervention and control groups shared similar characteristics. At follow-up, of the 915 students in the intervention group, 679 (74.5%) received a vaccination at school, and of the 776 students in the control group, 556 (71.7%) received a vaccination at school. The overall vaccination rates were 76.0% (695 of 915 students) for the intervention group and 71.3% (553 of 776 students) for the control group. Compared with the control group, there was significant improvement of vaccination uptake at school (odds ratio, 1.40; 95% CI, 1.06-1.85; P = .02) and overall uptake (odds ratio, 1.49; 95% CI, 1.12-1.99; P = .01) for the intervention group. Conclusions and Relevance: In this study, multifaceted strategies showed modest effectiveness in improving influenza vaccination uptake among primary school students, which provides a basis for the implementation of school-located vaccination programs of other vaccines in China, and in other countries with comparable programs. Trial registration: Chinese Clinical Trial Registry: ChiCTR2200062449.

Association of Peer Network with Childhood Obesity in DECIDE-Children Program.

Some studies have found associations between the peer network and childhood obesity. The present study aimed to analyze the association of the peer network with obesity-related cognition, behaviors and adiposity indicators, and explore whether peer network influences the effect of a childhood-obesity intervention. Based on DECIDE-Children, 1392 children's friendship nominations within the class were collected and peer network indicators including the network size, network density, and in- and out-degree centrality were calculated. The linear mixed model was used to analyze the association between peer network indicators and children's cognition, behaviors and adiposity indicators (body mass index (BMI), BMI z score, the prevalence of overweight and obesity). Children with a higher in-degree centrality had 34.4% (95%CI: 17.4% to 48.1%) lower risk of overweight or obesity. The baseline degree centrality was inversely associated with the BMI and BMI z score at the end of the trial. For each unit increase in in-degree centrality at baseline, the BMI at the end of the trial decreased by 0.047 (95%CI: 0.015 to 0.080), and the BMI z score decreased by 0.015 (95%CI: 0.003 to 0.028). Children's popularity reflected by centrality in their peer network was associated with cognition, behaviors, and adiposity indicators. Future childhood-obesity intervention research could pay more attention to socially inactive children.

Effect of a Multifaceted Intervention on Children's Body Image and the Mediating Role of Body Image in Changes in Adiposity Indicators.

Besides genetic factors and energy-related behaviors, psycho-cultural factors are also important in obesity etiology. Previous studies have suggested that improving body image might be an effective method for managing body weight. Thus, this study aimed to evaluate the effects of a multifaceted intervention on the body image of children and explore whether body image played a mediating role in changes in adiposity indicators. This study was embedded in a cluster randomized controlled trial, involving 1287 children from 24 primary schools in three cities in China (Beijing, Changzhi and Urumqi). The 9-month multifaceted intervention on childhood obesity included five components (three targeted children and two targeted environments), and randomization was performed by an independent person who was blinded to the schools. Two indicators (body size perception and body size expectation) were chosen to characterize body image and were measured by Ma figural stimuli at baseline and the end of the trial. Changes in body image indicators were classified as conducive to weight loss or not. Other anthropometric measures and self-reported behaviors were also collected at both time points. Generalized linear mixed models were used in the analyses. Compared to the controls (n = 648), the proportion of body size perception conducive to weight loss increased in the intervention group (n = 639), with an odds ratio of 2.42 (95%CI: 1.70~3.45, p < 0.001). The proportion of body size expectation conducive to weight loss also increased more in the intervention group than in the controls (OR = 1.74, 95%CI: 1.14~2.66, p = 0.010). In children whose baseline nutritional status was "normal weight with higher BMI" or "overweight/obese", the improvements in body size perception and body size expectation partly mediated the association between the intervention and changes in BMI, BMI Z score, waist circumference and body fat percentage (p < 0.05). This multifaceted study effectively improved the body image of children, which, in turn, led to beneficial changes in adiposity indicators. For the first time, body size perception and body size expectation have been confirmed to be important factors associated with the beneficial effect of a childhood obesity intervention, suggesting that body image components should be generalized in the future.

A cluster randomized trial of a comprehensive intervention nesting family and clinic into school centered implementation to reduce myopia and obesity among children and adolescents in Beijing, China: study protocol.

BACKGROUND: Myopia and obesity in children and adolescents have become serious public health problems that endanger public health, especially in China. Unhealthy lifestyle behaviors are environmental drivers of both myopia and obesity. This protocol describes a study to evaluate the effectiveness of "22510SS", that is 2 h of daytime outdoor activities ('2'); Limit screen time to no more than 2 h per day ('2'); Consume at least 5 servings of fruits and vegetables daily ('5'); Attain 1 h of physical activity daily ('1'); Consume 0 sugar-sweetened beverages ('0'); Reasonable sleep duration ('S'); Regular supervision ('S'). A school-based, multifaceted intervention strategy for myopia and obesity prevention, and to assess and explore the implementation of "22510SS" with regards to acceptability, feasibility, adoption, usage and maintenance. METHODS AND ANALYSIS: This study aims to develop a comprehensive intervention strategy "22510SS" based on the socio-ecological model, and A two-arm cluster randomized trial with a parallel-group of a 1:1 allocation ratio in 36 primary and secondary schools to test its evidence-based intervention programs on the effects and implementation of myopia and obesity epidemics in children and adolescents in grades 4 and 7. The primary outcomes will include differences in visual acuity, body mass index, outdoor activity indicators, screen time, fruit and vegetable intake, high-quality protein intake, sugar-sweetened beverage intake, sleep duration, and level of monitoring among children and adolescents. Secondary outcomes will assess the acceptability, feasibility, uptake, use, and maintenance of the intervention. Effects on the primary and secondary outcomes will be analyzed using linear and logistic regression analyses, as well as difference-in-difference analysis, taking into account cluster effects and possible confounding factors. Process assessments will also be conducted through quantitative and qualitative analyses, including acceptability, feasibility, gender, adoption, implementation, and sustainability. DISCUSSION: This study will evaluate the effectiveness of "22510SS" and examine its implementation in the school-based network nesting family and clinic. Following this intervention study, the integrated intervention program focused on myopia and obesity among children and adolescents have great potential to be implemented in China to promote and support healthy lifestyle behavior change and reduce the risk of myopia and obesity in children and adolescents. TRIAL REGISTRATION: NCT05275959. Registered 23 Mach 2022.

The Effect of a Multifaceted Intervention on Dietary Quality in Schoolchildren and the Mediating Effect of Dietary Quality between Intervention and Changes in Adiposity Indicators: A Cluster Randomized Controlled Trial.

Some studies have found associations between dietary quality and obesity and their concurrent changes were observed in a few interventions. The present study aimed to assess the effect of a multifaceted intervention for childhood obesity on dietary quality and examine the mediating effect of dietary quality between the intervention and changes in adiposity indicators. Based on the social ecological model, the cluster randomized controlled trial included five components (three targeted children and two targeted their environment). In total, 1176 children from three cities in China participated in a baseline (2018) and end-of-trial (2019) examination, including 605 children in the intervention group and 571 in the control group. Self-reported behavior and anthropometric measures were collected at both time points. The Diet Balance Index Revision (DBI-07) was calculated to assess dietary quality. Generalized linear mixed models were used to estimate the intervention effect on dietary quality and its mediating effects were examined. Compared to the controls, the proportion of sugar-sweetened beverage (SSB) intake (OR = 0.27, p < 0.001, corrected p < 0.001) decreased in the intervention group. Higher bound scores (HBS) of the DBI-07 indicating over-intake decreased in the intervention group compared to the controls (mean difference = −1.52, p = 0.005, corrected p = 0.015). Changes in the HBS partially mediated the associations between the intervention and changes in body mass index, waist circumference, and body fat percentage. Future intervention should promote knowledge, attitudes, and behaviors related to dietary quality.

Effectiveness of a Multifaceted Intervention for Prevention of Obesity in Primary School Children in China: A Cluster Randomized Clinical Trial.

Importance: A rapid nutritional transition has caused greater childhood obesity prevalence in many countries, but the repertoire of effective preventive interventions remains limited. Objective: To determine the effectiveness of a novel multifaceted intervention for obesity prevention in primary school children. Design, Setting, and Participants: A cluster randomized clinical trial was conducted during a single school year (from September 11, 2018, to June 30, 2019) across 3 socioeconomically distinct regions in China according to a prespecified trial protocol. Twenty-four schools were randomly allocated (1:1) to the intervention or the control group, with 1392 eligible children aged 8 to 10 years participating. Data from the intent-to-treat population were analyzed from October 1 to December 31, 2019. Interventions: A multifaceted intervention targeted both children (promoting healthy diet and physical activity) and their environment (engaging schools and families to support children's behavioral changes). The intervention was novel in its strengthening of family involvement with the assistance of a smartphone app. The control schools engaged in their usual practices. Main Outcomes and Measures: The primary outcome was the change in body mass index (BMI; calculated as weight in kilograms divided by height in square meters) from baseline to the end of the trial. Secondary outcomes included changes in adiposity outcomes (eg, BMI z score, prevalence of obesity), blood pressure, physical activity and dietary behaviors, obesity-related knowledge, and physical fitness. Generalized linear mixed models were used in the analyses. Results: Among the 1392 participants (mean [SD] age, 9.6 [0.4] years; 717 boys [51.5%]; mean [SD] BMI, 18.6 [3.7]), 1362 (97.8%) with follow-up data were included in the analyses. From baseline to the end of the trial, the mean BMI decreased in the intervention group, whereas it increased in the control group; the mean between-group difference in BMI change was -0.46 (95% CI, -0.67 to -0.25; P < .001), which showed no evidence of difference across different regions, sexes, maternal education levels, and primary caregivers (parents vs nonparents). The prevalence of obesity decreased by 27.0% of the baseline figure (a relative decrease) in the intervention group, compared with 5.6% in the control group. The intervention also improved other adiposity outcomes, dietary, sedentary, and physical activity behaviors, and obesity-related knowledge, but it did not change moderate- to vigorous-intensity physical activity, physical fitness, or blood pressure. No adverse events were observed during the intervention. Conclusions and Relevance: The multifaceted intervention effectively reduced the mean BMI and obesity prevalence in primary school children across socioeconomically distinct regions in China, suggesting its potential for national scaling. Trial Registration: ClinicalTrials.gov Identifier: NCT03665857.

Effectiveness of a comprehensive intervention for childhood obesity on self-efficacy, weight perception, and behavior change / 中国学校卫生

Objective@#To evaluate the effectiveness of a comprehensive intervention for childhood obesity on self-efficacy, weight perception, and stage of behavior change, and to provide a scientific evidence for childhood obesity interventions.@*Methods@#The study was a cluster randomized controlled trial. Twelve primary schools and 1 889 children (aged 7-11 years) from Dongcheng District in Beijing were recruited in September, 2013, and were administered a comprehensive intervention for childhood obesity. Six schools (930) were randomly allocated to the intervention group, and six schools (959) were randomly allocated to the control group. A face-to-face questionnaire survey was carried out, R 4.0.3 software was used to analyze the data, and multiple linear regression model was used to analyze the intervention effect.@*Results@#After the intervention, mean (standard deviation) scores of self-efficacy among children in the intervention and control groups were (4.4±0.9) and (4.2±1.1), respectively. After the intervention, the proportion of children in the intervention group who underestimated or overestimated their body weight was 28.4% and 11.3 %, respectively, while the figures in the control were 37.1% and 6.9%; compared with the control, the risk of underestimating body weight decreased among children in the intervention group( OR=0.64, 95%CI=0.52-0.80, P <0.01), while the risk of weight overestimation increased( OR=1.79, 95%CI=1.26-2.54, P <0.01). After the intervention, the proportion of children in the contemplation or action stage of behaviour change was 65.3% and 83.6%, while the figures in the control group were 59.8% and 69.8 %, respectively; in comparison with the control group, more children in the intervention group were in comtemplation ( OR= 1.28 , 95%CI=1.03-1.59, P =0.02) or action stage of behaviour change( OR=2.59, 95%CI=2.04-3.27, P <0.01).@*Conclusion@#The comprehensive intervention for childhood obesity improved self-efficacy, weight perception, and facilitated behavior change, but may increase the risk of weight overestimation.

Influence of school climate on influenza vaccination among middle school students in four cities in China / 中国学校卫生

Objective@#This study aims to explore the influencing factors of influenza vaccination in middle school students, and to provide a theoretical basis for improving the influenza vaccination rate and inform interventions.@*Methods@#By using mixed research method, a combination of qualitative research and quantitative research, a survey was conducted among 9 145 middle school students selected from Beijing, Anhui, Shaanxi, Guangdong via the online survey using Wenjuanxing software. Multivariate Logistic regression models were used to analyze the influencing factors of influenza vaccination. After a purposeful sampling, 35 middle school students were invited for semi structured interviews and NVivo plus software were used for data analysis.@*Results@#The self reported influenza vaccination rate of the middle school students was 38.2%. No experience of discussing an influenza vaccine with others ( OR=1.37, 95%CI =1.17-1.60) and devaluing the discussion about vaccination ( OR=1.30, 95%CI =1.08-1.57) was negatively associated with vaccination( P <0.05); The head teacher suggestion(OR=0.39, 95%CI =0.32-0.48), peers vaccination( OR= 0.29, 95%CI =0.25-0.33), and awareness of what the vaccine was and being able to explain it clearly( OR=0.68, 95%CI =0.61-0.75), discussing with others( OR=0.76, 95%CI =0.67-0.86), feeling the discussion is valuable( OR=0.66, 95%CI = 0.59- 0.73), being able to positively influence others( OR=0.61, 95%CI =0.55-0.68), being positively influenced by others ( OR= 0.62, 95%CI =0.54-0.71) were more likely to take vaccination via separated models( P <0.05). The interview results showed that the teacher s cognition and attitude towards the influenza vaccine could directly or indirectly affect the students vaccination decision, and the positive school opinion atmosphere may improve students vaccination rate.@*Conclusion@#It is suggested that the schools should increase students vaccination rate through head teachers guidance and organizing students to participate in discussion on influenza topics.

Compliance and associated factors of smartphone application usage in child dietary and exercise intervention / 中国学校卫生

Objective@#To study the compliance and associated factors of smartphone application (APP) usage in childhood dietary and exercise intervention.@*Methods@#Based on one childhood intervention of diet and exercise in Beijing, Changzhi of Shanxi Province and Urumqi of Xinjiang Province, 694 children (and their primary caregivers) in the intervention group were investigated regarding usage of APP during the intervention. Compliance of APP usage was evaluated by the click times of APP, and Logistic regression models were used to analyze influencing factors of the compliance.@*Results@#The median (inter quartile range) click times of APP in the four modules (information dissemination, behavior monitoring, homework uploading and feedback) were 10 (5，21), 20 (14，26), 7(4，10), 26 (15，53), respectively. Multivariable logistic regression analysis found that compliance of APP usage was higher among subjects in Changzhi region ( OR =1.67，95% CI =1.12-2.48), whose primary caregiver was mother ( OR =1.55，95% CI =1.09-2.22), or whose mother did not work ( OR =0.47， 95% CI =0.31-0.74).@*Conclusion@#Compliance of APP usage was generally high in the childhood intervention of diet and exercise. Some factors are associated with compliance of APP usage. Findings of the study provide a scientific basis for better implementation of APP based childhood interventions of diet and exercise in the future.

[Value of body fat mass measured by bioelectrical impedance analysis in predicting abnormal blood pressure and abnormal glucose metabolism in children].

OBJECTIVE: To study the value of body fat mass measured by bioelectrical impedance analysis (BIA) in predicting abnormal blood pressure and abnormal glucose metabolism in children. METHODS: Stratified cluster sampling was used to select the students aged 6-16 years, and a questionnaire survey and physical examination were performed. The BIA apparatus was used to measure body fat mass. Body mass index (BMI), body fat mass index (FMI), and fat mass percentage (FMP) were calculated. Fasting blood glucose level were measured. RESULTS: A total of 14 293 children were enrolled, among whom boys accounted for 49.89%. In boys and girls, the percentile values (P60, P65, P70, P75, P80, P85, P90, P95) of FMI and FMP fitted by the LMS method were taken as the cut-off values. Based on the receiver operating characteristic curve analysis, the P70 values with a better value in predicting abnormal blood pressure and blood glucose metabolism were selected as the cut-off values for excessive body fat. When FMI or FMP was controlled below P70, the incidence of abnormal blood pressure or abnormal glucose metabolism may be decreased in 8.25%-43.24% of the children. CONCLUSIONS: The evaluation of obesity based on FMI and FMP has a certain value in screening for hypertension and hyperglycemia in children, which can be further verified in the future prevention and treatment of obesity and related chronic diseases in children.

Current status and demand of health services in primary and middle school clinic in 16 provinces of China / 中国学校卫生

Objective@#To analyze the current situation and needs of primary and secondary school health clinic services, and to provide a reference for strengthening school health service in China.@*Methods@#Investigation provinces were selected according to China s three major economic zones, 1 or 2 survey centers were selected from each province, 16 provinces and 26 survey centers were selected. In each survey centers, six schools from primary and secondary schools, junior high schools and high schools in urban and rural areas were randomly selected as research sites. Each research site randomly selected 10 students in each grade(grade three, four, five from primary schools) to fill in the questionnaire anonymously. A total of 4 661 valid questionnaires were collected.@*Results@#Among the services provided by the school clinics to students, "trauma treatment" "consulting health problems" "physical examination" accounted for 49.4%, 40.5% and 39.0% respectively. Within the past one year, 45.1% students went to the school clinic for consultation or consultation 1-3 times, 6.4% for 4-5 times, and 3.7% for 6 times or more. When students were sick in school, 65.8%(primary school), 64.0%(junior high school), and 54.4%(high school) of them selected to go to the school clinic. When suddenly suffered trauma in school, 78.2%(primary school), 73.2%(junior high school) and 69.6%(high school) of the students went to the school clinic.@*Conclusion@#Primary and middle school students have a great demand for school health services, and it is necessary to continue to strengthen the construction of primary and secondary school health clinics.

Joint effect of school and family on domestic second-hand smoke exposure in middle school students / 中国学校卫生

Objective@#To observe the joint effect of school and family tobacco control on middle school students, and to explore its effectiveness in reducing second-hand smoke exposure in middle school students’ families, as so asto provide a new way of thinking for controlling smoking among middle school sudents.@*Methods@#A questionnaire survey was conducted on the study of 2 125 primary and high school students in four middle schools in the Dongcheng District of Beijing by means of a stratified group sampling method. Personal information of students, tobacco control environment around the family, school and surrounding ares, as well as the knowledge, attitude and behavior of students related to tobacco control was collected.@*Results@#The exposure rate of second-hand smoke in the families of middle and high school students in Dongcheng District of Beijing was 33.41%. Smoking by at least one parent was positively correlated with second-hand smoke exposure in the student’s home (OR=22.88, P<0.05). Among the students who saw the "clear no-smoking label" on campus, the exposure rate (4.92%) when the smoking restriction was set on the home was lower than that of those who did not have a regulation in the home (58.94%) (χ2=452.57, P<0.01). The results of Logistic regression showed that there was a combination of family smoking restrictions and second-hand smoke exposure in middle and high school students who had seen the smoking ban on campus (OR=0.08) and had the school’s tobacco control education (OR=0.08).@*Conclusion@#The joint tobacco control measures between school and family can effectively reduce the exposure rate of second-hand smoke in middle school students’ families, which is better than the effect of tobacco control alone.

Relationship between nutrition status and physical fitness in 8-10 year-old children in 3 cities / 中国学校卫生

Objective@#To study the relationship between nutrition status and physical fitness in 8-10 year-old children in 3 cities, and to provide a scientific reference for improving physical condition of chidren of pre-school age.@*Methods@#To investigate the weight, height and physical fitness (standing long jump, endurance running, rope skipping in one minute and sit-ups in one minute) of 1 384 children in grade four from 24 primary schools in Beijing, Changzhi, Urumchi in 2018. Evaluated overweight and obesity by using the standard of “Screening for Overweight and Obesity among School-age Children”. Then used mixed linear model to compare the physical fitness of students with different nutritional status and to analyze the relationship between BMI and physical fitness.@*Results@#The prevalence of overweight and obesity were 17.41% and 23.48%, respectively. And the prevalence in boys was both more than that in girls(χ2=9.84，47.68，P<0.01). The increase in BMI of children from the same age and the same gender was related with the decrease in physical fitness by correlation analysis(P<0.05). In comparison method, the performance of the students of normal weight was better than obese students, but the male and female students had got the same results in their physical fitness test(P<0.05).@*Conclusion@#There is a negative correlation between nutrition status and physical fitness and the physical fitness in normal weight and obese children are better than the overweight children or obese children.

A school-based, multi-faceted health promotion programme to prevent obesity among children: protocol of a cluster-randomised controlled trial (the DECIDE-Children study).

INTRODUCTION: Obesity is a public health concern that is becoming increasingly more serious worldwide. Effective and sustainable childhood obesity prevention strategies may help to reduce the prevalence of obesity and may have an impact on lifelong health. However, few such strategies have been rigorously evaluated for Chinese children in different regions of China. METHODS AND ANALYSIS: The Diet, ExerCIse and CarDiovascular hEalth-Children is a cluster-randomised controlled trial that aims to assess the effectiveness and sustainability of a school-based, multi-faceted intervention to prevent obesity among Grade 4 primary school students (8-10 years old) in China. Twenty-four schools (approximately 1200 students) from above average, average and below average developed regions in China will be randomised to an intervention (12 schools) or usual practice (12 schools) group. The intervention will last for one school year (9 months) and consists of activities towards students, parents and school environment. A smartphone application will be used to assist in providing information on, monitoring and providing feedback on the behaviours and body weight of the students. Data will be collected at baseline, 4 months, 9 months and 21 months. The primary outcome will be the difference between groups in the change in students' body mass index at 9 months after the baseline investigation. The secondary outcomes will include the differences between groups in the changes in anthropometric measures, diet, physical activity levels and other measures at the follow-up visits. A variety of process evaluation methods will be used to evaluate the implementation process of the complex intervention. ETHICS AND DISSEMINATION: This study was approved by the Peking University Institution Review Board (IRB00001052-18021). The results will be disseminated through publication in peer-reviewed journals, presentations at conferences and in lay summaries provided to school staff and participants. TRIAL REGISTRATION NUMBER: NCT03665857.

[Study on the relations among the screen-based sedentary behaviors, family factors and body mass index of children].

OBJECTIVE: To explore the relations among screen-based sedentary behaviors (SSB), family factors and body mass index (BMI) of children, and to study how family factors have effect on BMI through influencing SSB. METHODS: A total of 1,846 students aged 7-11 years from 12 primary schools in one district of Beijing were included. Their body weight and height were measured to calculate the BMI. The time of SSB and family factors were investigated by using questionnaires. The time of SSB was the total time of watching TV and videos, playing computer games and iPad each day during the past 7 days recalled by children. The family factors included the parents' education, occupation, the parents'time of SSB, whether the parents told their child the harm of SSB, the parents'time limit for the children's SSB. The parents'education and occupation were used for calculating the family socioeconomic score. RESULTS: The median time of SSB for children was 1 hour/day, and the interquartile range was 1 hour/day. The BMI of the children with the parents' time limit for the children's SSB less than 120 min/day were smaller than the children with the parents'time limit not less than 120 min/day, in both the boys (1.63 kg/m2, P<0.001) and the girls (0.85 kg/m2, P=0.004). The family socioeconomic score, the parents'SSB time, whether the parents told their children the harm of SSB were not related to the children's BMI . The mediation effects of SSB time for children on the association between the parents'time limit for the children's SSB and BMI were -0.222 kg/m2 (95%CI:-0.432, -0.095) for boys and -0.187 kg/m2 (95%CI: -0.507, -0.049) for girls, which accounted for 13.67% of the total effects for boys and 22.11% for girls. CONCLUSION: The parents' time limit for the children's SSB has effect on their BMI through influencing their SSB time. Parents' supervision on the behaviors of children produces larger benefit for BMI than health education conveyed by parents. Therefore, parents' participation in supervising the behaviors of children are indispensable for preventing and controlling childhood obesity.

Effect of a school-based peer education intervention on physical activity and sedentary behaviour in Chinese adolescents: a pilot study.

OBJECTIVE: To evaluate the effect on physical activity and sedentary behaviour of a pilot school-based peer education programme in urban Beijing, China. DESIGN: 4 junior high schools were matched by school size and randomised to intervention (n=346) and control group (n=336). INTERVENTION: Trained peer leaders from grade 7 by research staff delivered weekly 40-min lessons to their classmates over four consecutive weeks. Students in control schools received no intervention. OUTCOME MEASURES: A validated 7-day youth physical activity questionnaire was used to evaluate physical activity and sedentary behaviours at baseline (September 2010), 3 months (December 2010) and 7 months (May 2011). Generalised linear mixed models were applied to evaluate the effect. RESULTS: There was a significant decrease in time in sedentary behaviour on weekdays, 20 min/day at 7 months (p=0.020) reported by students in the intervention schools compared with control schools. This reduction was mainly due to a reduction of 14 min/day in computer usage on weekdays (p=0.0009). There were no significant differences in time on other sedentary behaviours, including television and DVD, video game, extracurricular reading, writing, drawing and listening to music, passive commuting and sitting to talk. There was also no significant difference in time in moderate-to-vigorous physical activity between intervention and control group. CONCLUSIONS: Peer education appears to be a promising intervention in reducing sedentary behaviours in adolescents in China. These results need confirmation in a larger study. CLINICAL TRIAL REGISTRATION NUMBER: ACTRN12612000417886 at http://ANZCTR.org.au.