Objective: To investigate the sleeping status of the first grade primary students aged 6-8 in Beijing, to investigate the association between maternal parenting stress and children s sleep, and to inform intervention of addressing sleep problems among children in Beijing. Methods: Online survey was conducted based on the child cohort study designed to study puberty, obesity, and cardiovascular risk (PROC). The Children s Sleep Habits Questionnaire (CSHQ) and Parenting Stress Index Short Form (PSI-SF) were completed by parents, and 1 136 school aged children and their mothers were included as study participants. Logistic regression models were used to determine the association between maternal parenting stress and children s sleep. Results: The prevalence of sleep problems among first grade primary students was 78.52%. Among the children who received PSI-SF, the score of children with sleeping problems(86.66±17.31) was higher than that of the children with no sleeping problems(78.59±17.75)( t =6.42, P <0.01). After adjusting sociodemographic characteristics, multivariable logistic regression results showed children of mothers with parenting stress were more likely to have sleep problems ( OR =2.52, 95% CI =1.55-4.11, P <0.01). Taking 3 dimensions in PSI-SF as independent variables, the analysis indicated that compared with the children having mothers free from parental stress and difficult children, the children with mothers with parental stress were more likely to suffer from the sleeping problems( OR = 1.66 ,1.76, P <0.05). Conclusion Sleep problems are prevalent among first grade primary students, and it underscores providing psychological support to alleviate maternal parenting stress to address children s sleep problems.

Objective: To explore the association of body fat mass and distribution indices including fat mass percentage (FMP), visceral fat area (VFA) and percentage of trunk fat mass (%TFM) with blood pressure in children to inform early management of blood pressure in children. Methods: Based on the Beijing Child Growth and Health Cohort in Shunyi District, lifestyle questionnaire survey, baseline and follow up physical examination were conducted among children from October to November 2018 and September 2020. Bioelectrical impedance analysis (BIA) was used to measure the body composition, and 1 098 participants with completed data were finally included. Results: Both body fat indices and blood pressure increased with age in boys and girls. For FMP, VFA, and %TFM, no significant differences presented between sex at baseline, while FMP, VFA, and %TFM were significantly higher in boys than girls at follow up ( t=2.73, 3.76, 3.41, P <0.01). Before and after adjusting for age, height and lifestyles or not, linear mixed effect models showed longitudinal associations existing between body fat indices and blood pressure in both boys and girls ( β=0.64-3.48, P <0.05). The association coefficients of body fat indices with systolic blood pressure were ranked as %TFM>FMP>VFA in both boys and girls. The association coefficients of body fat indices with diastolic blood pressure were ranked sequentially as FMP>%TFM>VFA in boys, and VFA>FMP>%TFM in girls. Conclusion Longitudinal associations are observed between body fat indices and blood pressure in children. Primordial prevention of high pressure should pay attention on body fat distribution.

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.

Objective: The study aimed to explore sex differences in the growth and physical development of Beijing school-aged children and adolescents. Methods: Data obtained from regular health examinations of 94 122 school-aged children and adolescents aged 6-18 years old were collected from primary and high schools in Shunyi District from 2009 to 2018, and a longitudinal dataset was compiled with complete anthropometric parameters including height, weight, and BMI levels after linkage of individuallevel information. The age-specific growth rate was calculated and a linear mixed-effects model was used to identify sex differences according to chronological or relative age to peak height velocity (PHA). Results: Height, weight, and BMI levels increased with age in both boys and girls. Girls were taller than boys in the 10-11 year-old age group, catch-up growth in height was observed in boys at age 12, whose height surpassed that of girls thereafter. Boys had a higher weight and BMI than girls in all age groups (P<0.01). Sex differences were found in the growth rates of height, weight, and BMI levels(t=-67.56，-47.46，3.22，P<0.01), which was demonstrated by the interaction effect of sex and age in the linear mixed-effects model. The PHA in boys was 12 years old, which was two years later than the PHA in girls. Boys reached peak weight velocity at 12 years old, lagging one year behind girls who reached their peak at 11 years old. The curves of the BMI growth rate with age showed double peaks in boys and the first peak appeared at 10 years, which was one year earlier than girls. The change in weight was highly synchronized in time with the increase in height, after adjusting for the growth rate of weight by PHA. Weight velocity increased with age before the onset of puberty until PHA, and then it declined; boys presented with obvious fat accumulation before the onset of puberty. Conclusion Sex differences in the growth and physical development of school-aged children and adolescents were persistent and apparent, and the change in weight was highly synchronized in time with the increase in height.

Objective: To explore sex differences between weight and systolic blood pressure (SBP) changes among school-age children and adolescents in Beijing, and to provide a basis for priority intervention to control the rapid growth of body weight and blood pressure. Methods: Anthropometric measurement data of 70 288 children and adolescents from primary and high schools in Shunyi District were collected from 2009 to 2018, and a longitudinal dataset with complete data related to weight and BP after individual data linkage was compiled. The age-specific weight and SBP growth rates were calculated, and a linear mixed-effects model was used to identify sex differences in chronological growth rates. Results: Weight and SBP increased with age in both boys and girls, and the mean weight and SBP were higher in boys than in girls across all age groups. The result of the linear mixed-effects model indicated apparent sex differences in weight and SBP growth rates, with an age and sex interaction term(β=-0.35, -0.40, P<0.01). The age at peak weight velocity (PWA) was 12 years old and the age at peak SBP velocity was 13 years old in boys, which occurred one and three years later than for girls, respectively. In addition, the peak weight and SBP velocity were higher in boys than in girls. The curves of the SBP growth rate adjusted for the PWA, showed that the peak SBP velocity occurred two years before PWA and the second peak SBP velocity occurred at the PWA, which indicated "double peaks" in both boys and girls. The SBP growth rate was always higher in boys than in girls, and the rates declined after PWA. Conclusion Sex differences in weight and SBP growth rates were persistent and obvious in school-age children and adolescents in Beijing and the change in SBP was highly time synchronized with the increase in weight.

Objective: This study aims to investigate the willingness and influencing factors of COVID-19 vaccination among Chinese middle school students, and to provide a reference for promoting the implementation of COVID-19 vaccination among middle school students. Methods: An online survey was conducted among middle school students in Beijing, Anqing of Anhui Province, Xi an of Shaanxi Province and Shenzhen of Guangdong Province, and 9 153 participants were enrolled in the present study. Single factor analysis and multinomial Logistic regression was used to determine the related factors of COVID-19 vaccination willingness. Results: The prevalence of vaccine acceptance, vaccine hesitancy and vaccine refusal among middle school students were 60.05%, 31.59% and 8.36%, respectively. The results of Chi square analysis showed there were significant difference of COVID-19 vaccination willingness among sex, school residence, grade, region, vaccination willingness of surrounding classmates, vaccination willingness of others, fear of SARS-CoV-2 and risk of SARS-CoV-2 infection( χ 2=8.43-1 059.43, P <0.05). Multinomial Logistic regression analysis presented that, compared to "vaccine acceptance" group, those girls, non resident in school, living in Beijing or Anqing, disagree or uncertain with influenced by peers, disagree or uncertain with influenced by others, uncertain with fear of SARS-CoV-2, disagree or uncertain with having risk of SARS-CoV-2 infection were more likely to show vaccine hesitancy( OR =1.22,1.21,1.49,1.69,1.75,2.54,1.41,2.32,3.32,1.99,2.38, P <0.05). And those non boarding in school, living in Beijing or Xi an, disagree or uncertainty influenced by peers, disagree or uncertainty influenced by others, disagree with fear of SARS- CoV- 2, disagree or uncertainty in having risk of SARS-CoV-2 infection were more likely to show vaccine refusal ( OR =1.27, 2.29 ,1.46,3.88,2.37,2.31,1.47,2.14,4.24,1.47, P <0.05). Conclusion The willingness of COVID-19 vaccination among middle school students in four cities is low, and targeted interventions should be advocated to form herd immunity.

The continuously spreading of SARS-CoV-2 poses a threat not only to public health but also to all aspects of socio-economics. Current public health measures are costly and have potential health risks, thus, it is imminent that developing efficient and economical early warning surreillance tools from a public health perspective. In this review, we summarized the current COVID-19 epidemiological surveillance measures and the efficiency, economic, and cutting edge of wastewater-based epidemiology (WBE). The WBE-based surveillance is organized and reviewed from three aspects: early warning system for the timing of epidemic, routine epidemic surveillance, and parameters determination of predicting epidemiological models of COVID-19. It reveals the application value of WBE as an early warning and surveillance system of public health, and then, discussing its current weakness and strength, adding literature for a WBE-based surveillance system for COVID-19 epidemic in China.

The continuously spreading of SARS-CoV-2 poses a threat not only to public health but also to all aspects of socio-economics. Current public health measures are costly and have potential health risks, thus, it is imminent that developing efficient and economical early warning surreillance tools from a public health perspective. In this review, we summarized the current COVID-19 epidemiological surveillance measures and the efficiency, economic, and cutting edge of wastewater-based epidemiology (WBE). The WBE-based surveillance is organized and reviewed from three aspects: early warning system for the timing of epidemic, routine epidemic surveillance, and parameters determination of predicting epidemiological models of COVID-19. It reveals the application value of WBE as an early warning and surveillance system of public health, and then, discussing its current weakness and strength, adding literature for a WBE-based surveillance system for COVID-19 epidemic in China.

Objective:The study is to explore the association between trunk fat index (TFI) and carotid intima-media thickness (cIMT) among children aged 6-8 years old in Shunyi District, Beijing.Methods:The participants were enrolled from the child cohort on sensitization, puberty, obesity and cardiovascular risk (PROC) conducted in Shunyi District, Beijing from October 2018 to June 2019. The PROC used a community-based census-like design, and all eligible first-grade children from six public non-boarding primary schools in urban area were approached. Finally, a total of 1 503 children with written informed consent from parents and had complete data of TFI and cIMT were included for the present study. Sequential baseline surveys including anthropometric measurements, laboratory testing and ultrasonography measurement were conducted to collect the data on height, weight, body composition, blood pressure, serum lipids and cIMT. Linear regression was used to determine the predictors of cIMT, receiver operating characteristic (ROC) curve analysis was used to determine the cut-off value of TFI to identify children with high cIMT, and analysis of covariance was used to evaluate the post-consistency classification of cIMT by TFI.Results:The age of 1 503 participants was (6.7±0.3) years, and 752 boys accounted for 50.0%. The average cIMT was (0.358±0.024) and (0.355±0.023) mm, and the M( P25, P75) of TFI was 0.70 (0.22, 1.78) and 0.74 (0.23, 1.52) kg/m 2 for boys and girls, respectively. The detection rates for boys and girls of high cIMT were 2.1% and 3.3%, respectively. Linear regression analysis showed that height, systolic blood pressure (SBP), diastolic blood pressure (DBP), TFI were positively correlated with cIMT in boys ( P values<0.05). And height, SBP, triglyceride (TG), TFI were positively correlated with cIMT, and high-density lipoprotein cholesterol (HDL-C) was negatively correlated with cIMT in girls ( P values<0.05). ROC curve analysis indicated that the best cut-off values for TFI to identify children with high cIMT were 1.78 and 1.14 kg/m 2, at P75 and P66 for boys and girls, respectively. After grouped with the cut-off value of TFI and adjusted for age, height, SBP, DBP, TG, HDL-C, multivariable covariance analysis showed a consistent cut-off of inter-group cIMT mean by TFI groups ( P values<0.005). Conclusion:TFI is associated with cIMT, which underscore its application potential in identifying early vascular structural damage.

Objective:To explore the association between blood pressure (BP) and the left ventricular mass (LVM) in children aged 6-8 years.Methods:The participants were from the community-based census-like design child cohort on sensitization, puberty, obesity and cardiovascular risk (PROC) conducted in six public non-boarding primary schools in Shunyi District, Beijing. Repeated three measurements on anthropometrical, M-mode and 2-dimensional (2D) echocardiographic imaging (2D/M ECHO) and blood biochemical assay, and BP measurements were carried out at baseline and follow-up from October 2018 to June 2019. A total of 1 659 children who had repeated BP measurements and cardiac structure information were included in this study. The average value of last two measurements of BP was determined as BP value for analysis. Formula recommended by Devereux was used to calculate the mass of left ventricle. Robust linear regression models were used to explore the association between BP and LVM in different groups.Results:The average age of all patients was (7.10±0.29) years old, including 832 boys (50.15%). Of all, 83.54% (1 386/1 659) were grouped as normal BP with average LVM (58.54±13.33) g, and 16.46% (273/1 659) as elevated BP group with LVM (63.84±15.78) g ( P<0.001). The LVM of the normal BP group was lower than elevated BP group in overall participants, boys and girls ( P<0.005). Univariate analysis showed that systolic BP was associated with LVM in overall, boys and girls ( P<0.001) respectively. While diastolic BP was associated with LVM in overall and girls ( P<0.03). Multivariable analysis indicated that the associations between systolic BP and LVM were observed in overall, boys and girls ( P<0.05) with the β (95% CI)=0.14 (0.08, 0.21), 0.18 (0.08, 0.27) and 0.12 (0.03, 0.22), respectively. However, the associations of diastolic BP and LVM were not significant. Conclusion:Systolic BP is highly associated with LVM and elevated BP could increase the LVM in children. Boys with elevated BP present a larger LVM and might indicate higher risk of left ventricular hypertrophy in adulthood.