Objective: To estimate the dietary salt and potassium intake by two 24 hour urine salt and potassium excretion in primary and secondary school students. Methods: The boarders from Grade 5 to 6 in a rural primary school and Grade 1 to 3 in a rural middle school in Changde City, Hunan Province were recruited from October to December in 2017. Subjects who had 2 and more urinary incontinence episodes or a history of kidney disease or diarrhea and girls in menstruation were excluded. The final analysis included 284 subjects. Questionnaires on basic demographic information were collected, and height and weight were examined. Two inconsecutive 24-hour urine specimens were collected in weekdays. The differences and consistency between two 24-hour urine were tested and dietary salt and potassium intake were assessed by the average of two 24-hour urine collections. Results: A Total of 284 participants was (12.1±1.5) years old, of which 148 (52.1%) were boys and 36 (12.7%) were overweight. In the first 24-hour urine, the volume [P₅₀ (P₂₅, P₇₅)=670 (513, 868) ml], potassium concentration [P₅₀ (P₂₅, P₇₅)=29 (21, 39) mmol/L] and potassium excretion [P₅₀ (P₂₅, P₇₅)=0.7 (0.6, 1.0) g] were similar to those in the second 24-hour urine [P₅0 (P₂₅, P₇₅) values were 660 (490, 916) ml, 30 (21,40) mmol/L, and 0.8 (0.6, 1.0) g, respectively]. But the sodium and creatinine concentrations, salt excretion in the first 24-hour urine [P₅₀ (P₂₅, P₇₅) values were 175 (123, 219) mmol/L, 7.20 (5.15, 10.86) mmol/L and 6.6 (5.0, 8.7) g, respectively] were lower than those in the second 24-hour urine [P₅₀ (P₂₅, P₇₅) values were 188 (133, 248) mmol/L, 8.66 (5.99, 12.47) mmol/L and 7.3 (5.2, 9.2) g, respectively] (all P values<0.05). The intraclass correlation coefficients between salt and potassium excretions in the two 24-hour urine were 0.534 (95%CI: 0.412-0.631) and 0.478 (95%CI: 0.341-0.587) (P<0.001), respectively. The mean±SD of salt consumed was (7.3±2.5) g (range: 2.3 to 18.8 g) per day by all participants. Overweight children consumed more salt [(8.2±2.6) g/d] than those non-overweight [(7.2±2.4) g/d] (P<0.05). The mean±SD of potassium consumed was (1.1±0.3) g (range: 0.4 to 2.3 g) per day. Boys consumed more potassium [(1.1±0.3) g/d] than girls [(1.0±0.3) g/d] (P<0.05), and overweight children had higher potassium intake [(1.2±0.3) g/d] than those non-overweight [(1.0±0.3) g/d] (P<0.05). A total of 212 participants (74.6%) consumed more salt than the recommended level and all participants had inadequate potassium intake. Conclusion The problem of excessive salt intake and insufficient potassium intake of rural primary and middle school students was serious.

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 estimate the dietary salt and potassium intake by two 24 hour urine salt and potassium excretion in primary and secondary school students. Methods The boarders from Grade 5 to 6 in a rural primary school and Grade 1 to 3 in a rural middle school in Changde City, Hunan Province were recruited from October to December in 2017. Subjects who had 2 and more urinary incontinence episodes or a history of kidney disease or diarrhea and girls in menstruation were excluded. The final analysis included 284 subjects. Questionnaires on basic demographic information were collected, and height and weight were examined. Two inconsecutive 24?hour urine specimens were collected in weekdays. The differences and consistency between two 24?hour urine were tested and dietary salt and potassium intake were assessed by the average of two 24?hour urine collections. Results A Total of 284 participants was (12.1±1.5) years old, of which 148 (52.1%) were boys and 36 (12.7%) were overweight. In the first 24?hour urine, the volume [P50 (P25, P75)=670 (513, 868) ml], potassium concentration [P50 (P25, P75)=29 (21, 39) mmol/L] and potassium excretion [P50 (P25, P75)=0.7 (0.6, 1.0) g] were similar to those in the second 24?hour urine [P50 (P25, P75) values were 660 (490, 916) ml, 30 (21, 40) mmol/L, and 0.8 (0.6, 1.0) g, respectively]. But the sodium and creatinine concentrations, salt excretion in the first 24?hour urine [P50 (P25, P75) values were 175 (123, 219) mmol/L, 7.20 (5.15, 10.86) mmol/L and 6.6 (5.0, 8.7) g, respectively] were lower than those in the second 24?hour urine [P50 (P25, P75) values were 188 (133, 248) mmol/L, 8.66 (5.99, 12.47) mmol/L and 7.3 (5.2, 9.2) g, respectively] (all P values<0.05). The intraclass correlation coefficients between salt and potassium excretions in the two 24?hour urine were 0.534 (95%CI : 0.412-0.631) and 0.478 (95%CI :0.341-0.587) (P<0.001), respectively. The mean± SD of salt consumed was (7.3±2.5) g (range: 2.3 to 18.8 g) per day by all participants. Overweight children consumed more salt [(8.2±2.6) g/d] than those non?overweight [(7.2±2.4) g/d] (P<0.05). The mean± SD of potassium consumed was (1.1±0.3) g (range: 0.4 to 2.3 g) per day. Boys consumed more potassium [(1.1±0.3) g/d] than girls [(1.0±0.3) g/d] (P<0.05), and overweight children had higher potassium intake [(1.2±0.3) g/d] than those non?overweight [(1.0±0.3) g/d] (P<0.05). A total of 212 participants (74.6%) consumed more salt than the recommended level and all participants had inadequate potassium intake. Conclusion The problem of excessive salt intake and insufficient potassium intake of rural primary and middle school students was serious.

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 estimate the dietary salt and potassium intake by two 24 hour urine salt and potassium excretion in primary and secondary school students. Methods The boarders from Grade 5 to 6 in a rural primary school and Grade 1 to 3 in a rural middle school in Changde City, Hunan Province were recruited from October to December in 2017. Subjects who had 2 and more urinary incontinence episodes or a history of kidney disease or diarrhea and girls in menstruation were excluded. The final analysis included 284 subjects. Questionnaires on basic demographic information were collected, and height and weight were examined. Two inconsecutive 24?hour urine specimens were collected in weekdays. The differences and consistency between two 24?hour urine were tested and dietary salt and potassium intake were assessed by the average of two 24?hour urine collections. Results A Total of 284 participants was (12.1±1.5) years old, of which 148 (52.1%) were boys and 36 (12.7%) were overweight. In the first 24?hour urine, the volume [P50 (P25, P75)=670 (513, 868) ml], potassium concentration [P50 (P25, P75)=29 (21, 39) mmol/L] and potassium excretion [P50 (P25, P75)=0.7 (0.6, 1.0) g] were similar to those in the second 24?hour urine [P50 (P25, P75) values were 660 (490, 916) ml, 30 (21, 40) mmol/L, and 0.8 (0.6, 1.0) g, respectively]. But the sodium and creatinine concentrations, salt excretion in the first 24?hour urine [P50 (P25, P75) values were 175 (123, 219) mmol/L, 7.20 (5.15, 10.86) mmol/L and 6.6 (5.0, 8.7) g, respectively] were lower than those in the second 24?hour urine [P50 (P25, P75) values were 188 (133, 248) mmol/L, 8.66 (5.99, 12.47) mmol/L and 7.3 (5.2, 9.2) g, respectively] (all P values<0.05). The intraclass correlation coefficients between salt and potassium excretions in the two 24?hour urine were 0.534 (95%CI : 0.412-0.631) and 0.478 (95%CI :0.341-0.587) (P<0.001), respectively. The mean± SD of salt consumed was (7.3±2.5) g (range: 2.3 to 18.8 g) per day by all participants. Overweight children consumed more salt [(8.2±2.6) g/d] than those non?overweight [(7.2±2.4) g/d] (P<0.05). The mean± SD of potassium consumed was (1.1±0.3) g (range: 0.4 to 2.3 g) per day. Boys consumed more potassium [(1.1±0.3) g/d] than girls [(1.0±0.3) g/d] (P<0.05), and overweight children had higher potassium intake [(1.2±0.3) g/d] than those non?overweight [(1.0±0.3) g/d] (P<0.05). A total of 212 participants (74.6%) consumed more salt than the recommended level and all participants had inadequate potassium intake. Conclusion The problem of excessive salt intake and insufficient potassium intake of rural primary and middle school students was serious.

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 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.