Objective: To understand the dynamic change rule and trend of the vital capacity of students in Tongzhou district, and to provide data support for the development of targeted physical exercise intervention mode. Methods: According to the routine physical examination data of students in Tongzhou District in the academic year 2011-2019, the physical examination data of 3 197 students with complete physical examination information were selected according to the proportion of students in urban areas and towns and gender differences. SPSS 17.0 was used for statistical analysis of the screening data. Results: The mean vital capacity of 3 197 students increased with the increase of grades. Except for grade 2 to grade 5 of primary school and grade 2 to grade 3 of junior high school, the mean vital capacity of urban students was higher than that of rural students ( P <0.05). The mean vital capacity of male students was higher than that of female students in all grades ( P <0.05). The vital capacity of male students and female students increased rapidly twice in grade 5 of primary school and grade 3 of junior high school( P <0.05), the growth rate of male students in two stages was larger than that of female students, the increase rates were 277.21 and 400.20 mL. The mean vital capacity was shown in this way:obese>overweight>normal weight>malnutrition ( P <0.05). The excellent rate of vital capacity evaluation in girls was higher than that in boys from grade 3 of primary school to grade 2 of junior middle school ( P <0.05). Except for grade 1 and 2 of primary school, the excellent rate of vital capacity evaluation in other grades was found as follows:obese>overweight>normal weight>malnutrition. The failure rate of boys was higher than that of girls ( P <0.05), except grade 3 of primary school. The failure rate from grade 5 to grade 3 showed the trend:malnutrition>normal weight>overweight>obesity ( P <0.05). In different groups, the failure rate of grade 1 of primary school and grade 1 of junior high school were the two peaks, which basically showed a decreasing trend followed by decreasing one. Conclusion The level of vital capacity of students in Tongzhou District is relatively low, so the school, family and society should focus on students vital capacity level. It should be one of the key tasks to enhance the physical quality of the students to increase the vital capacity of the boys and the students with abnormal weight.

Objective:To assess the predictive values of bioelectrical impedance analysis(BIA)-measured body fat indices to abnormal lipid profiles, and to preliminary propose optimal cut-off values of body fat in children and adolescents.Methods:Children and adolescents, aged 6-16 years, were selected from 30 schools (8 primary schools, 21 middle schools and one 12-year education school) in Dongcheng, Tongzhou, Fangshan and Miyun districts of Beijing by adopting a stratified cluster sampling method from November 2017 to January 2018.Questionnaire survey, body mass index(BMI), body fat mass index (FMI), fat mass percentage (FMP) and four lipid profiles were conducted.Results:A total of 14 309 participants, aged (11.0±3.3) years, were enrolled in the analysis, with 49.9% boys.In boys and girls, the percentile values ( P60- P95) fitted by FMI and FMP with K-median-coefficient of variation(LMS) method were taken as the cutting points, and P75 values were selected as the cut-off points of excessive body fat for their better sensitivity, specificity, predictive value and area under curve (AUC) for identification of abnormal lipid profiles.Boys with FMI above P75 accounted for 28% of the total population, and controlling boys with FMI below P75 could prevent dyslipidemia of 8%-57%.FMI in girl population occupied about 26% of the above, and controlling FMI in girl population below this cut-off point may prevent dyslipidemia from 8%-42%.FMP observed similar results to FMI.Assessed by FMI or FMP with P75 cut-off values, adiposity performed better than BMI for recognizing abnormal lipid profiles in boys (AUC: 52.4%-69.6% vs.50.2%-67.1%, P<0.05) rather than in girls ( P>0.05). In addition, when FMI or FMP beyond P90, the specificity of each abnormal lipid profiles was around 90%. Conclusions:The recommend cut-off points for body fat may be to assess children′s adiposity, and can be applied in preventive activities.

Objective: To describe the baseline characteristics of School-based Cardiovascular and Bone Health Promotion Program(SCVBH) in Beijing. Methods: Children and adolescents were selected in 30 schools (8 primary schools, 21 middle schools and one 12-year education school) from Dongcheng, Tongzhou, Fangshan and Miyun districts of Beijing by using a stratified cluster sampling method. 15 391 students in grade 1 to 4 from primary schools, grade 1 from junior and senior high schools were enrolled in the investigation with an exclusion of students who were not able to participate due to trauma or other uncomfortable physical conditions. The baseline survey including a questionnaire survey, physical examination and blood biochemical test was conducted from September 2017 to January 2018. Obesity, blood pressure, fasting blood glucose, lipid, bone density and grip were evaluated. Results: The prevalence of obesity, hypertension, hyperglycemia (impaired fasting glucose and diabetes), dyslipidemia, lower bone density were 22.3%(3 394), 14.8%(2 248), 10.4%(1 490), 20.3%(2 919) and 2.1%(316) in total respectively, and 27.2%(2 081), 16.3%(1 244), 12.8%(922), 22.2%(1 595) and 1.2%(94) for boys, 17.3%(1 313), 13.3% (1 004), 7.9%(568), 18.4%(1 324) and 2.9%(229) for girls. Boys had higher prevalence of obesity, hypertension, hyperglycemia, and dyslipidemia and lower prevalence of low bone density than girls (all P values <0.05) The mean of body mass index, systolic blood pressure, fasting plasma glucose and grip of boys were significantly higher than that of girls (all P values <0.05).The mean of body mass index, systolic blood pressure, fasting plasma glucose and grip of boys were significantly higher than that of girls (all P values <0.05), the mean of fat mass percentage, total cholesterol, triglyceride, high density lipoprotein-cholesterol and low density lipoprotein-cholesterol of boys were significantly lower than those of girls (all P values <0.05). Conclusion The prevalence of risk factors of chronic cardiovascular disease was high and the low bone density was appearing in children and adolescents in this study. The promotion of cardiovascular and bone health should be implemented in children and adolescents.

Objective: To describe the status of cardiovascular health (CVH) of children and adolescents aged 6-16 years in Beijing during 2017-2018. Methods: The school-based Cardiovascular and Bone Health Promotion Program(SCVBH) was conducted from November 2017 to January 2018. 15 391 children and adolescents aged 6-16 years were selected from grade 1 to 4 in 8 primary schools, grade 1 in 21 middle schools and senior grade 1 in one twelve-year education school in Dongcheng, Fangshan, Miyun and Haidian Districts of Beijing by using a cluster sampling method. Seven cardiovascular health indicators, including smoking, body mass index, dietary intake, physical activity, blood pressure, blood glucose, and total cholesterol, were categorized as poor, intermediate, and ideal according to American Heart Association (AHA) criteria. The status of CVH was evaluated according to the criteria of the ideal CVH related behaviors and factors defined by AHA. Results: The proportion of children and adolescents with an ideal smoking, dietary intake and physical activity indicators reached 99.2%(4 982/15 108), 19.7%(2 921/14 805), 17.8% (2 499/14 056), respectively. The proportion of children and adolescents with 7 and 4-5 ideal cardiovascular health indicators was 1.7%(209/12 560) and 65.1%(8 176/12 560). The proportion of children and adolescents with 4-7 ideal cardiovascular health indicators, 2-4 ideal health behavior indicators and 2-3 ideal health factors was significantly higher in urban than that in rural all P values<0.001. The proportion of females with 4-7 ideal cardiovascular health indicators, 2-4 ideal health behavior indicators and 2-3 ideal health factors was significantly higher than that in males (all P values<0.001). Conclusion The prevalence of ideal cardiovascular health of children and adolescents aged 6-16 years in Beijing during 2017-2018 was very low, particularly for healthy dietary intake and physical activity. Effective public health interventions should be implemented to improve the status of cardiovascular health of them.

Objective: To investigate the sleep status in children and adolescents and explore the relationship between the sleep and high blood pressure in them. Methods: Data was from the Schoolbased Cardiovascular and Bone Health Promotiow Program (SCVBH) in Beijing. And 13 471 children and adolescents aged 6-16 years were selected from grades 1 to 4 in 8 primary schools, grade 1 in 21 middle schools and senior grade 1 in one twelve-year education school in Dongcheng, Fangshan, Miyun and Tongzhou Districts of Beijing during 2017-2018 by using a cluster sampling method. Self-reported questionnaires were used to collect the demographic characteristics, lifestyle habits of children and adolescents. The blood pressure was measured by electronic sphygmomanometer. Multiple logistic regression model was used to analyze the association between sleep and hypertension risk. Results: The sleep duration was (8.4±1.1) hours. The prevalence of high blood pressure was 15.0%(2 021/13 471). The incidence of mouth breathing, slobber, snoring, and suffocate was 28.4%(3 823/13 471), 23.6%(3 184/13 471) and 18.7%(2 513/13 471), 2.8%(378/13 471) respectively. After adjusting for age, gender, snoring, mouth breaking, slobber, suffocate, the time for bed and sleep duration, we found that snoring and sleep duration (5.0-6.9 h) were both associated with high blood pressure (OR=1.49, 95%CI:1.32-1.69; OR=1.53, 95%CI: 1.28-1.81). Conclusion Snoring and sleep duration were positively associated with high blood pressure in this study. Interventions focusing on sleep status should be developed to reduce the incidence of high blood pressure in children and adolescents.

Objective To understand the association between body fat distribution and calcaneal bone mineral density (BMD) in children and adolescents aged 6-16 years in Beijing. Methods Children and adolescents were selected in 30 schools (8 primary schools, 21 middle schools and one 12?year education school) from Dongcheng, Tongzhou, Fangshan and Miyun districts of Beijing by using a stratified cluster sampling method from November 2017 to January 2018. A total of 15 030 students in grade 1 to 4 of primary school, grade 1 of junior and senior middle school were enrolled after excluding subjects who were not able to participate into this study due to trauma or other uncomfortable physical conditions or with missing key values or with diabetes and kidney diseases. Questionnaire survey, body composition and calcaneus bone mineral density were conducted. The relation of fat mass percentage (FMP), trunk to total fat ratio (TrTFR), trunk to limb fat ratio (TrLFR), limb to total fat ratio (LTFR) and viscera to total fat ratio (VTFR) with calcaneus BMD were assessed using the multivariate linear regression models after adjusting for possible confounding effects. The central fat distribution types were divided into 4 groups including type 1: both trunk fat and visceral fat greater than the sex?and age?specific internal P75; type 2: barely trunk fat greater than P75; type 3: barely visceral fat greater than P75; type 4: both trunk fat and visceral fat greater than P75. The central fat distribution types were included into the model in the form of dummy variables to analyze its relationship with calcaneal BMD. The sex?and age?specific z?scores of fat distribution indicators and BMD were calculated. Results A total of 15 030 participants aged (11.4 ± 3.3) years (50.2% boys) were involved in the analysis. In both genders, after adjusting for age, height, lean mass index, smoking, drinking, physical activity, milk intake, vitamin D and calcium supplementation, FMP, TrTFR, TrLFR and VTFR were negatively correlated with calcaneal BMD (all P value<0.05), while LTFR was positively associated with calcaneal BMD (all P values<0.05). Compared to the central fat distribution type 1, the regression coefficients (95% CI ) of type 2, 3 and 4 were-0.253 (-0.418,-0.087),-0.385 (-0.567,-0.204) and-0.428 (-0.487, -0.369) in boys, respectively; the regression coefficients (95% CI) of type 3 and 4 were -0.158 (-0.301,-0.015) and-0.226 (-0.290,-0.163), respectively. Conclusion Body fat distribution and central fat distribution in children and adolescents were correlated with calcaneus bone mineral density.

Objective To investigate the association between blood lipid and calcaneus bone mineral density (BMD) in children and adolescents aged 6-16 years in Beijing. Methods Children and adolescents were selected in 30 schools (8 primary schools, 21 middle schools and one 12?year education school) from Dongcheng, Tongzhou, Fangshan and Miyun districts of Beijing by using a stratified cluster sampling method from November 2017 to January 2018. A total of 14 303 students in grade 1 to 4 of primary school, grade 1 of junior and senior middle school were enrolled after excluding subjects who were not able to participate into this study due to trauma or other uncomfortable physical conditions or with missing key values or with diabetes and kidney diseases. Questionnaire survey, blood lipid and calcaneus BMD were conducted. Multivariate linear regression was applied to quantify the association between calcaneal BMD as a dependent variable and blood lipid level as an independent variable after adjusting for the potential confounding factors. Furthermore, quantile regression was used to analyze the association between blood lipid level and different percentiles (P25, P50 and P75) of ultrasonic velocity values of bone mineral density, and parallel test was conducted for regression coefficients of different percentiles. Results A total of 14 303 participants aged (11.4 ± 3.3) years (49.9% boys) were involved in the analysis. The mean age of 14 303 participants was (11.0±3.3) years. 7 142 boys accounted for 49.9%. The mean±SD of calcaneal BMD, total cholesterol (TC), low density lipoprotein?cholesterol (LDL?C), and high density lipoprotein?cholesterol (HDL?C) were (1 540.9±33.8) m/s, (3.90±0.76), (2.18±0.62), and (1.40±0.32) mmol/L, respectively. The P50 (P25, P75) of triglyceride (TG) was 0.69 (0.49-0.94) mmol/L. After the adjustment of age, height, smoking, drinking, vitamin D and calcium supplementation, dairy intake, physical activity, FMI, and MMI, a significantly inverse association (P<0.05) between TG level and calcaneus BMD was observed in both genders, which the regression coefficients (95%CI ) in boys and girls were -0.064 (-0.085,-0.044) and-0.073 (-0.094,-0.053), respectively. Conclusion The level of BMD was associated with TG in boys and girls. Therefore, it is important to prevent children from hypertriglyceridemia for the bone health promotion.

Objective:To investigate the association between vitamin D nutritional status and the body muscle mass in children.Methods:Data were obtained from School-based Cardiovascular and Bone Health Promotion Program. In 2017, a total of 15 391 children aged 6-16 years in Beijing were selected through stratified cluster sampling in baseline survey. A follow-up investigation was conducted in 2019. The questionnaire survey and the detection of serum 25-hydroxyvitamin D [25(OH)D] level were conducted. The bioelectrical impedance analysis (BIA) apparatus was used to measure body muscle mass, and muscle mass index (MMI) was calculated. Multivariable linear models were used to analyze the association of vitamin D nutritional status with the baseline and follow-up MMI measures.Results:A total of 10 890 children aged (11.5±3.3) years(boys accounting for 49.6%) were included in the analysis. The average 25(OH)D level was (35.4±12.0) nmol/L, with an adequacy ratio of 11.1%. After multivariate linear regression adjustment for age, sex, body fat mass, smoking status, alcohol use status, dairy supplement, calcium supplement, physical activity, and pubertal development, no statistically significant association between vitamin D nutritional status and baseline MMI level was observed ( P>0.05). For the follow-up MMI, the Z-score increased by 0.008 ( P=0.058) for per 10 nmol/L increase in 25(OH)D, which were 0.002 ( P=0.815) and 0.037 ( P=0.031) higher in children with insufficient and adequate vitamin D than those with vitamin D deficiency, respectively ( P for trend =0.089). Subgroup analysis showed that in the normal BMI group, for per 10 nmol/L increase in 25 (OH) D, the MMI at baseline survey and MMI Z-score at follow-up of children with adequate vitamin D and increased by 0.019 and 0.014, respectively (both P<0.05). Conclusions:Vitamin D nutritional status was related to muscle mass in children, and children with adequate vitamin D tended to obtain higher MMI. Children and adolescents are encouraged to maintain sufficient vitamin D levels, strengthen nutrition and exercise to promote body health.

Objective:To investigate the relationships between vitamin D nutritional status and the calcaneal bone mineral density (BMD) in children.Methods:Data were obtained from School-based Cardiovascular and Bone Health Promotion Program. In 2017, a total of 15 391 children aged 6-16 years in Beijing selected through stratified cluster sampling were included in the baseline survey. A follow-up investigation was conducted in 2019. The questionnaire survey, detection of serum 25-hydroxyvitamin D [25(OH)D] level and ultrasound measurement of calcaneal BMD were conducted. Multivariable linear and logistic regression models were used to analyze the relationships between baseline vitamin D nutritional status and the follow-up calcaneal BMD.Results:A total of 10 914 children aged (11.5±3.3) years (boys accounting for 49.6%) were included in the analysis. The average 25(OH)D level was (35.4±12.0) nmol/L, and the deficiency rate was 36.1%. After the adjustment for age, gender, body mass index, smoking status, alcohol use status, dairy products intake, vitamin D supplement, calcium supplement, physical activity, pubertal development, and baseline calcaneal BMD Z-score, for per 10 nmol/L increase in 25(OH)D, the follow-up calcaneal BMD Z-score increased by 0.01( P=0.041), and the OR(95% CI) of decreased calcaneal BMD Z-score after 2 years was 0.96 (0.93-1.00)( P=0.030). Compared with vitamin D adequacy, the follow-up calcaneal BMD Z-score of children with vitamin D insufficiency and deficiency decreased by 0.03( P=0.307) and 0.06 ( P=0.046), and the risk of decreased calcaneal BMD Z-score after 2 years increased by 15%( P=0.037) and 21%( P=0.006), respectively ( P for trend<0.05). Conclusions:Vitamin D nutritional status was closely related to calcaneal BMD, and children with adequate vitamin D nutritional status tended to obtain higher BMD. Children and adolescents are encouraged to maintain sufficient vitamin D levels, strengthen nutrition and exercise to promote bone health.

Objective:To investigate the association of vitamin D with distribution of body fat in children and adolescents.Methods:Data were obtained from the baseline survey of School-based Cardiovascular and Bone Health Promotion Program in 2017. Multiple linear regression and multinomial logistic regression models were applied to analyze the relationships of body mass index (BMI), fat mass index (FMI), trunk fat mass index (TFMI), appendicular fat mass index (AFMI), and visceral fat area(VFA) with vitamin D level and status in children and adolescents.Results:A total of 11 960 children and adolescents were included in the analysis (boys accounting for 49.7%). The average age and serum vitamin D level of study population were (11.0±3.3) years and (35.0±11.9) nmol/L, respectively. The deficiency rate of vitamin D was 37.2%. Gender-specific associations of BMI, FMI, TFMI, and AFMI with vitamin D level were found ( P for interaction <0.05): they were inversely associated with vitamin D level in boys (BMI: β=-0.56; FMI: β =-0.59; TFMI: β=-0.60; AFMI: β=-0.59; all P<0.05), but not in girls ( P>0.05). VFA was positively associated with vitamin D deficiency and insufficiency in both boys and girls, and the risks of vitamin D deficiency and insufficiency all increased by 17%(95% CI: 9%-25%) for per increment of standard deviation in VFA. Conclusions:The higher level of visceral fat was associated with the lower vitamin D levels in children. Abdominal obese children and boys with excessive body fat are the key population in the prevention and control of vitamin D deficiency.