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 investigate the relationships between hyperuricemia and the incidence risk for cardiometabolic abnormity 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 at baseline survey. Follow-up investigation was conducted in 2019. Logistic regression model was used to analyze the relationships of uric acid quartiles and change in uric acid levels with incidence risks for cardiometabolic abnormity (hypertension, hyperglycemia and dyslipidemia).Results:A total of 8 807 children (4 376 boys, 4 431 girls) were included in the analysis, the average age of the children was (11.1±3.3) years at baseline survey. The adjusted odds ratios ( ORs) and 95% confidence intervals ( CIs) of incidence risk for hypertension in the third and fourth quartiles of the UA were 1.39 (1.11-1.75) and 1.56 (1.19-1.81), respectively. The ORs and 95% CIs of risk for high LDL-C in the second, third and fourth quartiles were 1.88 (1.16-3.05),1.98 (1.23-3.17) and 2.25 (1.42-3.57). The uric acid level increased by one standard deviation, the risk increased by 17% for hypertension and 27% for high LDL-C. The uric acid level increased by 10 μmol/L, the risk increased by 2.1% for hypertension and 2.9% for high LDL-C. The gender-stratified analysis showed that the similar results. The ORs and 95% CIs were 1.32 (1.09-1.60) and 1.50 (1.05-2.16) for hypertension, 1.90 (1.38-2.60) and 2.96 (1.58-5.52) for high TC, 1.78 (1.26-2.51) and 2.84 (1.60-5.03) for high LDL-C in the groups of newly diagnosed hyperuricemia and persistent hyperuricemia. Conclusions:Higher uric acid level was associated with increased incidence risks for hypertension, abnormal TC and LDL-C. Maintaining optimal uric acid level by children might contribute to the early prevention of cardiovascular diseases.

Objective:To analyze the influence of obesity status on the development of cardiometabolic disorders in school-age children.Methods:Information about children's body weight, body height and cardiovascular risk factors were collected in baseline survey in 2017 and follow-up survey in 2019. The school-age children were divided into four groups based on their baseline and follow-up obesity status, i.e. sustained non-obesity group, restored obesity group, newly classified obesity group, and persistent obesity group. Analysis of covariance was used to compare the difference of change in levels of cardiometabolic factors among the four groups. The multivariate logistic regression model was used to analyze the relationship between obesity status and the incidence risk of cardiometabolic disorders.Results:The present study included 11 379 school-age children (boys accounting for 49.6%). During the 2 years, the incidence of obesity was 3.2% (95% CI: 2.9%-3.5%) with the restoration ratio of obesity of 4.4% (95% CI: 4.0%-4.8%). Compared with the sustained non-obesity group, increases in SBP, DBP, TG, LDL-C and non-HDL-C were much higher in newly classified obesity group and persistent obesity group, but lower in restored obesity groups except for DBP (all P<0.05). In addition, the incidence risk of hypertension, high glucose, dyslipidemia and cardiometabolic disorders (≥2 risks) were much higher in newly classified and persistent obese children than in sustained non-obese children. No difference was found in incidence risks of most cardiovascular disorders between restored obese children and sustained non-obese children, except for hypertension and cardiometabolic risks. Conclusion:Both newly classified obesity and persistent obesity increased the incidence risks for multi cardiovascular disorders, while these risks could be reduced when non-obese status restore.

Objective:To investigate the incidence and risk factors of pediatric fracture in school-age children and adolescents in Beijing.Methods:A total of 12 056 students with complete fracture data of 2017 baseline survey and 2019 follow-up survey of School-based Cardiovascular and Bone Health (SCVBH) Promotion Program in Beijing were selected as study subjects. Logistic regression model was used to analyze associations of fracture incidence with age, BMI, fracture history and lifestyle.Results:The 2-year accumulative incidence rate of pediatric fracture was 3.1% (95% CI: 2.8%-3.4%) in school-age children and adolescents in Beijing, which was much higher in boys (4.1%) than in girls (2.1%) and increased with age in boys but decreased with age in girls. Fractures mainly occurred at upper-limb (69.0%), no gender and age specific significant in fracture sites were observed. Fracture history was the risk factor for fracture incidence in both boys and girls (boys: RR=1.81, 95% CI: 1.18-2.64; girls: RR=3.11, 95% CI: 1.74-5.13). In addition, higher duration and frequency of moderate to vigorous physical activities (≥120 min/day) and frequent consumption of sugar sweetened beverage (≥1 time/week) were also found to increase fracture risk in boys. Conclusion:The incidence of pediatric fracture was associated with gender, age, fracture history and lifestyle habits in school-age children and adolescents in Beijing. Targeted strategies are needed to prevent childhood fracture.

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.

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.

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.