Objective: To evaluate the effect of a dietary and exercise intervention on cognition and behaviors among primary school students, and to further explore the mediating role of family support, in order to provide scientific evidence for future effective intervention strategies. Methods: A dietary and exercise intervention program for childhood obesity prevention was carried out in 24 primary schools in Beijing, Changzhi and Urumqi from 2018 to 2019, and 1 392 children in grade four as well as their parents were included. Family support and children s cognition and behaviors were collected through questionnaire. To carry out diet and exercise behavior intervention on the three levels of school, family and individual in the intervention group,and children s dietary and exercise knowledge, eating habits, physical activities, as well as sedentary and screen behaviors were evaluated. The linear mixed model was used to analyze the effect of intervention on children s cognition and behaviors, and the mediation model was used to explore the role of family support. Results: The proportion of children with higher score of dietary and exercise knowledge ( OR= 2.34 , 95%CI =1.71-3.21), eating habits ( OR=2.58, 95%CI =1.75-3.82), and sedentary and screen behaviors ( OR=1.91, 95%CI =1.35-2.68) increased in the intervention group after one year intervention ( P <0.01), compared with the control group, respectively. The intervention also increased the proportion of children s family support in the intervention group compared with the control group ( OR=3.45, 95%CI =2.19-5.45), and the support from children s fathers ( OR=2.70, 95%CI =1.68-4.35), mothers ( OR=3.71, 95%CI =2.28-6.04), paternal grandmothers ( OR=1.65, 95%CI =1.00-2.70), and maternal grandmothers ( OR= 2.14, 95%CI =2.12-2.16) increased significantly ( P <0.05). The mediation analysis showed that family support played a mediating role in association between comprehensive intervention and children s eating habits as well as sedentary and screen behaviors. Conclusion The dietary and exercise intervention effectively promoted children s cognition and behaviors, and family support played an important mediating role.

Objective: To explore the mediation effect of eating behavior in the personality obesity association, so as to provide scientific evidence for preventing childhood obesity in China. Methods: This study investigated 1 271 children in September 2018 among Beijing, Changzhi and Urumuqi. By used NEO five Factor Inventory to assess characteristics of personality and used Children Eating Behavior Questionnaire to measure eating behaviors in children. Five obesity related indicators [body mass index (BMI), BMI Z score, waist circumference, waist to hip ratio and body fat percentage] were derived from physical examination. Results: After adjusting for sex, age and region, the standardization scores of conscientiousness were negatively associated with BMI( B= -0.227 , 95%CI =-0.422--0.031), BMI Z score( B=-0.081, 95%CI =-0.158--0.006), waist circumference( B=-0.720, 95%CI = -1.281--0.159), waist to hip ratio( B=-0.004, 95%CI =-0.007--0.001) and body fat percentage ( B=-0.727, 95%CI = -1.293--0.162)( P <0.05). Results from the mediation analysis showed that the associations between conscientiousness and BMI, BMI Z score, waist circumference, waist to hip ratio and body fat percentage were partly mediated through food responsiveness and emotional eating behaviors; with effects ranged from 27.5%-47.1% and 0.9%-18.0%( P <0.05). Conclusion Conscientiousness is associated with lower risk of childhood obesity and food responsiveness and emotional eating behaviors show mediating effect in the association between childhood personality and obesity. Health education should be carried out in time for children with low conscientiousness in order to prevent the occurrence of obesity in the early stage.

Objective: To analyze the effect of a comprehensive intervention on the accuracy of children s body size perception, so as to provide a theoretical basis for child body size perception improvement. Methods: The participants were selected from a cluster randomized controlled trial (September 2018 to June 2019). A total of 1 287 children in 24 primary schools (clusters) equally distributed among three regions (Beijing, Changzhi and Urumqi) were selected, which included 12 intervention schools (648 students) and 12 control schools (639 students). The accuracy of body size perception was measured by Ma figural stimuli. A linear mixed model was employed to analyze the effect of the comprehensive intervention on the accuracy of children s body size perception. Results: At baseline, the accuracy rate of body size perception among children in the intervention group and the control group was 56.6% and 51.5%, respectively. The underestimation rate was 42.0% and 47.7%, and the overestimation rate was 1.4% and 0.8%. After the intervention, compared with the control group, the inaccuracy rate ( OR=0.50, 95%CI=0.37-0.68, P <0.01) and the underestimation rate in the intervention group decreased ( OR=0.37, 95%CI=0.26-0.54, P <0.01). There was no significant difference in the overestimation rate between the two groups( P =0.51). The results of the stratified analysis showed that the intervention could improve the accuracy of children s body size perception, regardless of their gender, nutritional status, region, or whether or not they were only child( P >0.05). Conclusion The inaccuracy rate of children s body size perception, which mainly involved underestimation was high. A comprehensive intervention can effectively reduce body size underestimation and improve the accuracy of children s body size perception.

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.

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.

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 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 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.