Association of BMAL1 clock gene polymorphisms with fasting glucose in children.

BACKGROUND: The brain and muscle Arnt-like protein-1 (BMAL1) gene is an important circadian clock gene and previous studies have found that certain polymorphisms are associated with type 2 diabetes in adults. However, it remains unknown if such polymorphisms can affect fasting glucose in children and if other factors modify the associations. METHODS: A school-based cross-sectional study with 947 Chinese children was conducted. A multivariable linear regression model was used to analyze the association between BMAL1 gene polymorphisms and fasting glucose level. RESULTS: After adjusting for age, sex, body mass index (BMI), physical activity, and unhealthy diet, GG genotype carriers of BMAL1 rs3789327 had higher fasting glucose than AA/GA genotype carriers (b = 0.101, SE = 0.050, P = 0.045). Adjusting for the same confounders, rs3816358 was shown to be significantly associated with fasting glucose (b = 0.060, SE = 0.028, P = 0.032). Furthermore, a significant interaction between rs3789327 and nutritional status on fasting glucose was identified (Pinteraction = 0.009); rs3789327 was associated with fasting glucose in the overweight/obese subgroup (b = 0.353, SE = 0.126, P = 0.006), but not in non-overweight/non-obese children. CONCLUSIONS: BMAL1 polymorphisms were significantly associated with the fasting glucose level in children. Additionally, the observed interaction between nutritional status and BMAL1 supports promoting an optimal BMI in children genetically predisposed to higher glucose level. IMPACT: Polymorphisms in the essential circadian clock gene BMAL1 were associated with fasting blood glucose levels in children. Additionally, there was a significant interaction between nutritional status and BMAL1 affecting fasting glucose levels. BMAL1 rs3789327 was associated with fasting glucose only in overweight/obese children. This finding could bring novel insights into mechanisms by which nutritional status influences fasting glucose in children.

Interaction between lifestyle behaviors and genetic polymorphism in SCAP gene on blood pressure among Chinese children.

BACKGROUNDS: Previous studies had revealed that sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP) rs12487736 polymorphism was associated with blood pressure (BP), but whether rs12487736 could interact with lifestyle behaviors on BP is unknown. METHODS: A case-control study with 1092 Chinese children was conducted. RESULTS: We found an interaction between rs12487736 and high calorie foods intake (fried chips/cakes/cookies) on systolic blood pressure (SBP) (Pinteraction = 0.027), and rs12487736 was associated with SBP in the subgroup having high calorie foods at least once in the last week (b = 2.19, P = 0.025), but not in the subgroup not having high calorie foods. Also, interaction between protein intake (meat/fish/soy beans/egg) and rs12487736 on diastolic BP (DBP) was identified (Pinteraction = 0.049); rs12487736 was associated with DBP in the subgroup consuming protein (meat/fish/soy beans/egg)

The importance of blood lipids in the association between BMI and blood pressure among Chinese overweight and obese children.

We aimed to examine the contribution of blood lipids to the association between BMI and blood pressure (BP) in children with overweight and obesity. Data were collected in elementary and high schools of Chaoyang District, Beijing, China in 2012. Participants' weight, height, BP and fasting plasma lipid profile were measured by standard protocols. Mediation analysis was used to examine the mediation role of blood lipids on the relation between BMI and BP, with age included as a covariate. We found that in boys 8·29 % (mediation effect=0·106, P=0·012) of the association between BMI and systolic BP was mediated through TAG. TAG mediated 12·53 % (mediation effect=0·093, P=0·018) and LDL-cholesterol mediated 7·75 % (mediation effect=0·57, P=0·046) of the association between BMI and diastolic BP was mediated by TAG and LDL-cholesterol, respectively. However, blood lipids did not show the mediation effect in girls. Our findings suggested that there was a sex difference in the contribution of blood lipids to the association between BMI and BP. Controlling TAG or LDL-cholesterol may be beneficial for reducing the risk of the BMI-related high BP in overweight boys; however, this outcome is not the case when controlling TAG or LDL-cholesterol in girls. This study may provide clues to explore the underlying mechanism of the association between obesity and hypertension.

The Influence of Secular Trends in Body Height and Weight on the Prevalence of Overweight and Obesity among Chinese Children and Adolescents.

OBJECTIVE: To explore the influence of secular trends in body height and weight on the prevalence of overweight and obesity among Chinese children and adolescents. METHODS: The data were obtained from five cross-sectional Chinese National Surveys on Students' Constitution and Health. Overweight/obesity was defined as BMI-for-age Z-score of per the Wold Health Organization (WHO) reference values. Body height and weight for each sex and age were standardized to those reported in 1985 (standardized height: SHY; standardized weight: SWY) and for each sex and year at age 7 (standardized height: SHA; standardized weight: SWA) using the Z-score method. RESULTS: The prevalence of overweight/obesity in Chinese children was 20.2% among boys and 10.7% among girls in 2010 and increased continuously from 1985 to 2010. Among boys and girls of normal weight, SHY and SHA were significantly greater than SWY and SWA, respectively (P < 0.001). Among boys and girls with overweight/obesity, SHY was significantly lower than SWY (P < 0.001), and showed an obvious decreasing trend after age 12. SHA was lower than SWA among overweight boys aged 7-8 years and girls aged 7-9 years. SHY/SHW and SHA/SWA among normal-weight groups were greater than among overweight and obese groups (P < 0.001). CONCLUSION: The continuous increase in the prevalence of overweight/obesity among Chinese children may be related to a rapid increase in body weight before age 9 and lack of secular increase in body height after age 12.

[Analysis on awareness of obesity risk factors among children and adolescents].

OBJECTIVE: To analyze the awareness rate of obesity risk factors among children and adolescents, and to provide the basis for preventing their obesity. METHODS: The students selected by using stratified cluster sampling method, were measured for the body height, weight, and waist circumference, and were surveyed for the awareness rate of obesity risk factors by using the questionnaire. The distribution characteristics of awareness on obesity risk factors were analyzed. RESULTS: The awareness rate of obesity risk factors was 74.1%, and there was no significant difference on the awareness rate of obesity risk factors between the males [71.2% (247/347)] and females [77.2% (257/333)], the abdominal obesity students [73.5% (202/275)] and non-abdominal obesity students [74.6% (302/405)], the overall obesity students [74.3% (185/249)] and non-overall obesity students [74.0% (319/431)], respectively. However, the awareness rate of obesity risk factors among the primary school students was 81.9% (272/332) that was higher than that of the middle school students [66.7% (232/348)] (P<0.05). Compared with the primary school students, the non-awareness risk of obesity risk factors would increase among the middle school students (OR=2.23, P<0.05). CONCLUSION: The overall awareness rate of obesity risk factors is not high among children and adolescents, especially among middle school students.

An objective measure to evaluate actual body shape among children and adolescents in China.

OBJECTIVE: The purpose of this study was to explore an objective measure to assess actual body shape of children and adolescents in China. METHODS: Based on the Chinese National Survey on Student's Constitution and Health (CNSSCH) in 2005, 210 927 children and adolescents' (7-18 years) body height, body weight, chest circumference, sitting height, chest circumference-height ratio, chest circumference-sitting height ratio, chest circumference-low limb ratio, and sitting height-low limb ratio measurements were used to develop an objective measure by using transformation variables and explored factor analysis (EFA). Discrimination power of the objective measure was evaluated based on BMI reference and Receiver Operating Characteristic curves (ROC). RESULTS: The objective measure included four dimensions scores: transverse dimension (TD) indicating weight and chest circumference; length dimension (LD) indicating height and sitting height; transverse-length ratio dimension (TLD) indicating chest circumference-height ratio, chest circumference-sitting height and chest circumference-low limb ratio; proportion dimension (PD) indicating sitting height-low limb ratio. The whole dimension (WD) indicating the whole body shape was showed by the average of four dimensions scores. Four dimensions and WD scores were approximately 80 in children and adolescents with normal weight, and higher than those of overweight, obesity, and underweight (all P-values <0.001). Areas under ROC of overweight and obesity compared with normal weight ranged from 0.88 to 1.00 for scores of TD, TLD, and WD. CONCLUSION: The objective measure which included four dimensions was explored, and TD, TLD, and WD had significant discrimination power.

Associations of chronotype with anxiety, depression and insomnia among general adult population: A cross-sectional study in Hubei, China.

BACKGROUND: The relationship between chronotype and anxiety, depression, and insomnia was inconsistent. We aimed to assess the association between chronotype and mental health and the potential moderating effect of age and socioeconomic status (SES). METHODS: A multi-stage sampling cross-sectional study with 12,544 adults was conducted. Chronotype, anxiety, depression, and insomnia were investigated by 5-item Morning and Evening, 7-item Generalized Anxiety Disorder, 9-item Patient Health, and the 7-item Insomnia Severity Index Questionnaires. Logistic regression was conducted. RESULTS: The predominant chronotype was morning chronotype (69.2 %), followed by 27.6 % intermediate and 3.2 % evening chronotype. The prevalence of anxiety, depression, and insomnia was 0.7 %, 1.9 %, and 9.6 %, respectively. Compared with intermediate chronotype, morning chronotype participants had a lower risk of anxiety (OR = 0.28,95%CI:0.18-0.44), depression (OR = 0.54,95%CI:0.41-0.72) and insomnia (OR = 0.67,95%CI:0.58-0.77), while evening chronotype participants had a higher risk of depression (OR = 1.98,95%CI:1.06-3.71) but not anxiety or insomnia. Interactions between chronotype with age and SES on insomnia (Pinteraction < 0.05) were found. A more profound association between morning chronotype and insomnia was observed in <65 years participants (OR = 0.59,95%CI:0.50-0.71) and those with monthly household income ≥10,000yuan (OR = 0.21,95%CI:0.12-0.35), compared with their counterparts. LIMITATIONS: The cross-sectional design limited causal conclusions. Only adults were included; the findings could not be generalized to children. CONCLUSIONS: The morning chronotype might be protective for anxiety, depression, and insomnia, while the evening chronotype might be a risk factor for depression. Future studies are needed to assess the efficacy of chronotype-focused intervention for mental health. Insomnia prevention efforts should pay more attention to the elderly and those with lower incomes.

Predictive Ability of Hypertriglyceridemic Waist, Hypertriglyceridemic Waist-to-Height Ratio, and Waist-to-Hip Ratio for Cardiometabolic Risk Factors Clustering Screening among Chinese Children and Adolescents.

Objective: Hypertriglyceridemic waist (HW), hypertriglyceridemic waist-to-height ratio (HWHtR), and waist-to-hip ratio (WHR) have been shown to be indicators of cardiometabolic risk factors. However, it is not clear which indicator is more suitable for children and adolescents. We aimed to investigate the relationship between HW, HWHtR, WHR, and cardiovascular risk factors clustering to determine the best screening tools for cardiometabolic risk in children and adolescents. Methods: This was a national cross-sectional study. Anthropometric and biochemical variables were assessed in approximately 70,000 participants aged 6-18 years from seven provinces in China. Demographics, physical activity, dietary intake, and family history of chronic diseases were obtained through questionnaires. ANOVA, χ 2 and logistic regression analysis was conducted. Results: A significant sex difference was observed for HWHtR and WHR, but not for HW phenotype. The risk of cardiometabolic health risk factor clustering with HW phenotype or the HWHtR phenotype was significantly higher than that with the non-HW or non-HWHtR phenotypes among children and adolescents (HW: OR = 12.22, 95% CI: 9.54-15.67; HWHtR: OR = 9.70, 95% CI: 6.93-13.58). Compared with the HW and HWHtR phenotypes, the association between risk of cardiometabolic health risk factors (CHRF) clustering and high WHR was much weaker and not significant (WHR: OR = 1.14, 95% CI: 0.97-1.34). Conclusion: Compared with HWHtR and WHR, the HW phenotype is a more convenient indicator withhigher applicability to screen children and adolescents for cardiovascular risk factors.

[Influence of diet behaviors on height among children and adolescents in China: a multiple level analysis].

OBJECTIVE: To categorize growth and development stages among children and adolescents based on height, and to explore the influences of diet behaviors on height during different growth and development stages. METHODS: Children and adolescents (7 to 18 years) with normal weights were selected using "Reference Norm for Screening Overweight and Obesity in Chinese Child and Adolescent" set up by WGOC in 2003 and "Reference Norm for Screening Underweight in Chinese Child and Adolescent" from the "2010 National Physical Fitness and Health Surveillance" data, and the variables of height and diet behaviors sorted. The growth and development stages were categorized using the hierachical cluster analysis, and the multilevel model was used to analyze influences of diet behaviors on height at different growth and development stages. RESULTS: Basis on height, there were 4 growth and development stages among the children and adolescents. In the boys, growth and development stages included Pre-GSS (growth spurt stage, GSS) including 7 to 10 years, GSS (11 to 12 years), Post-GSS (13 to 14 years), and growth stability stage (15 to 18 years); in the girls, the stages included the fast velocity GS (growth stage, GS) including 7 to 10 years, GS (11 to 12 years), Post-GS (13 to 15 years), and growth stability stage (16 to 18 years). The results of the multilevel model showed that the students' height in the urban areas were higher than in the rural areas (P<0.01), and the trend of difference between the urban and rural areas with the different growth stages was a parabola shape, the highest differences were 3.36 cm and 3.23 cm in the GSS and the fast velocity GS, respectively. There were significant influences of breakfast on height during the Pre-GSS and the fast velocity GS (P<0.01), and increased 0.40 cm and 0.57 cm, respectively. Excluding the stablility growth stage in the girls, drinking milk increased significantly height during the different growth stages (P<0.01), and the increases were gradual downtrend with the growth stages, the highest increase was 0.91 cm and 0.94 cm in Pre-GSS and the fast velocity GS, respectively. Eating eggs increased significantly height during all the growth stages (P<0.01), and the increases were the gradual uptrend with different growth stages. There were interaction effects among breakfast, drinking milk and eating eggs during the different growth stages, which was the gradual downtrend. CONCLUSION: Breakfast and drinking milk are conducive to growth during early adolescence, and the effect of eating eggs on growth is gradual uptrend with different growth stages.

[Association between early age at menarche and blood pressure in Chinese girls aged 7 to 17 years].

OBJECTIVE: To investigate the association between early age at menarche and blood pressure in Chinese girls aged 7 to 17 years. METHODS: A total of 76 869 girls aged 7 to 17 years old were selected from the national physical fitness and health research in 2010, and probit analyses were used to calculate the average age of menarche for each province. Girls whose age were lower than the P 10 of age at menarche were judged as early age at menarche, and matched with two selected participant without menarche based on the age and the same urban or rural areas. High blood pressure was defined as whose systolic pressure and/or diastolic pressure was higher than P 95 of systolic pressure or diastolic pressure at the same age group. The difference of the rate of high blood pressure in girls with and without menarche by Chi-square test, and multilevel model was used to analyze the relationship between early age at menarche and blood pressure. RESULTS: In 76 869 girls, the values of height and BMI were separately (152.2 ± 10.4) cm and (18.7 ± 3.1) kg/m(2), while the systolic pressure and diastolic pressure were (103.4 ± 11.0) mm Hg (1 mm Hg = 0.133 kPa) and (65.0 ± 9.1) mm Hg respectively. In 47 942 girls (62.4%) had occurred menstruation while 28 927 girls (37.6%) without menstruation. The girls began to report menstruation at the age of 9, and 81.5% (7123/8736) girls had already reported menstruation at the age of 13. The rate of high blood pressure in menstruation group from 11 to 13 years were separately 6.71% (100/1490), 5.99% (265/4423) and 5.38% (383/7123), which was significant higher than 3.78% (265/7005), 3.33% (144/4328) and 4.09% (66/1613) in the same age group of non-menstruation (the values of Chi-square were separately 25.62, 32.36, 4.46, and all P values < 0.05) . The mean age of early age at menarche was 9 to 11 years old, and the rate of high blood pressure, high systolic pressure, and high diastolic pressure at 11 years group was separately 6.08% (49/806), 4.84% (39/806) and 3.35% (27/806), which was significant higher than that in non-menstruation group (separately 3.11% (50/1607), 2.30% (37/1607) and 1.43% (23/1607), and the values of Chi-square were separately 12.02, 11.32 and 9.74, while all P values <0.01). After adjusted by region and age, early age at menarche were separately associated with the rate of high blood pressure (OR = 2.188; 95%CI: 1.254-3.818), high systolic pressure (OR = 1.925; 95%CI:1.097-3.379) and high diastolic pressure (OR = 2.088; 95%CI: 1.072-4.065). CONCLUSION: Early age at menarche may be one of the influence factors of high blood pressure, which may contribute to early age of high blood pressure in Chinese children and adolescents.

[Association between abdominal obesity and blood pressure among 7 to 10 years old Chinese children].

OBJECTIVE: To analyze the association between abdominal obesity and blood pressure among 7-10 years old Chinese children. METHODS: A total of 40 495 children aged 7-10 years with complete height, weight, waist circumference and blood pressure data were chosen from the data of 2010 Chinese National Survey on Students Constitution and Health. Based on the "Reference Norms for Screening Overweight and Obesity in Chinese Children and Adolescents" developed by Working Group Obesity in China (WGOC) and the waist to height ratio reference value for children (WHtR ≤ 0.46) , the children were divided into 4 body types (normal weight, simple abdominal obesity, combined obesity and other types). High blood pressure was defined as the systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) higher than the P 95 blood pressure value of 2010 national student of the same gender and age. The prevalence of simple abdominal obesity, combined obesity and high blood pressure were described. Three groups (with 2165 children in each) of children with normal weight, simple abdominal obesity, combined obesity respectively were selected from the chosen ones matched by gender, age (within ± 0.5 years old) and height (within ± 0.3 cm) at the ratio of 1: 1: 1. The value of blood pressure and prevalence of high blood pressure were described.χ(2) test, analysis of variance and multilevel models were used to analyze the relationship between obesity and blood pressure. RESULTS: A total of 40 475 children were selected from the database, including 20 175 boys and 20 320 girls. The prevalence of simple abdominal obesity was 6.36% (2576/40 495), the prevalence of boys and girls was 7.41% (1494/20 175) and 5.32% (1082/20 320) respectively. The prevalence of combined obesity was 16.33% (6611/40 495), the prevalence of boys and girls was 21.30% (4298/20 175) and 11.38% (2313/20 320) respectively. There were statistical differences in the body type distribution of both boys and girls (χ(2) = 869.01, P < 0.01). The prevalence of high blood pressure was 9.62% (3896/40 495), the prevalence of boys (10.05% (2028/20 175)) was higher than girls (9.19% (1868/20 320)) (χ(2) = 8.59, P < 0.01). The value of SBP and DBP among combined obesity group (boys: (103.8 ± 11.3), (64.7 ± 10.1) mm Hg (1 mm Hg = 0.133 kPa); girls: (102.9 ± 12.1), (64.5 ± 10.0) mm Hg) > simple abdominal obesity group (boys: (99.5 ± 11.2), (61.6 ± 9.9) mm Hg; girls: (99.6 ± 11.4), (62.6 ± 9.3) mm Hg)> normal weight group (boys: (97.4 ± 10.8), (60.5 ± 9.4) mm Hg; girls: (97.2 ± 10.8), (60.8 ± 9.4) mm Hg), and the differences were statistical significant (Fboys: 113.22, 62.05; Fgirls: 54.19, 32.31, P < 0.01). According to the results of multilevel model, among boys, compared with the normal weight group, the SBP of combined obesity group and simple abdominal obesity group was 6.0 and 1.8 mm Hg higher respectively (Wald χ(2): 17.55, 204.94, P < 0.01); the DBP was 4.0 and 0.9 mm Hg higher respectively (Wald χ(2): 6.37, 114.05, P < 0.05). Among girls, the SBP was 5.0 and 2.1 mm Hg higher respectively (Wald χ(2):16.47, 92.52, P < 0.01); the DBP was 3.5 and 1.6 mm Hg higher respectively (Wald χ(2): 12.29, 57.52, P < 0.01). Comparing with normal group, the risk of high SBP among boys with simple abdominal obesity was higher (OR = 1.48; 95%CI: 1.06-2.06), and both the boys (SBP: OR = 3.06; 95%CI: 2.28-4.11) ; DBP: OR = 2.72; 95%CI: 1.99-3.72) and girls (SBP: OR = 2.48; 95%CI: 1.75-3.53; DBP: OR = 2.64; 95%CI: 1.82-3.93) in combined obesity group had a higher risk of high SBP and high DBP. CONCLUSION: Simple abdominal obesity is associated with the increasing of blood pressure in children, and combined obesity has a closer ties than simple abdominal obesity.

[Association between early onset of menarche and anthropometry measurements among adolescent girls in China].

OBJECTIVE: To explore the association between early menarche with anthropometry measurements among adolescent girls in China. METHODS: Research material was selected from the data of 2010 Chinese National Surveys on Students Constitution and Health. Probability unit regression method was used to calculate the age of 10th percentile (P 10) at menarche and menarche age before the P 10 was defined as early menarche(9.0-11.6 years old). A total of 1072 girls with early menarche were screened. Each girl with early menarche was frequency matched with two girls who hadn't achieved menarche and with the age difference less than 0.1 yr and from the same urban or rural locations. A total of 2144 girls without menarche were screened. Participants' data of height, weight, sitting height, chest circumference, body mass index(BMI) and height and sitting height index were analyzed. t test and wilcoxon test were used to analyze the anthropometry measurements differences between the two groups, Chi square test was used to analyze the differences of overweight and obesity between the two groups. Multilevel model was used to explore the association between early menarche with anthropometry measurements and overweight and obesity. RESULTS: A total of 1072 girls with early menarche and 2144 girls without menarche. Early menarche girls' height, sitting height, chest circumference, weight and BMI were (151.42 ± 7.46) cm, (80.86 ± 4.21) cm, (73.88 ± 7.72) cm, (44.32 ± 9.35) kg, and (19.18 ± 3.03) kg/m(2), while they were (144.86 ± 7.55) cm, (76.96 ± 4.05) cm, (67.25 ± 6.94) cm, (36.07 ± 7.88) kg and (16.64 ± 2.48) kg/m(2) in girls without menarche. The difference between two groups were significant(Z values were -22.20, -23.69, -24.38, -23.12, -20.17, -6.33 respectively with all P values < 0.01). Multilevel analysis results showed that in 9.0-11.6 years old girls early menarche was associated with anthropometry measurements(all P values < 0.05). Compared with girls without menarche, girls with early menarche had a relative higher height, sitting height, weight, chest circumference, with increments of 5.28 cm, 3.37 cm, 5.53 cm, 6.37 kg, 1.79 kg/m(2). Within subgroup analysis, there were parabolic trends with age in the height, weight and sitting height differences and "U" trend in chest circumference difference between girls with early menarche and girls without menarche.In 9.0-10.8 years old, 10.9-11.0 years old and 11.1-11.2 years old groups, the risk of overweight and obesity among girls with early menarche were 2.98 (95%CI:1.92-4.63) times, 6.76 (95%CI:2.79-16.39) times, 2.99 (95%CI:1.40-6.40) times of girls without menarche. CONCLUSION: The early onset of menarche is related with height, sitting height, weight and chest circumference, and it is closely associated with overweight and obesity among adolescent girls in China.

[Analysis of influencing factors on physical endurance of Chinese primary and middle school students aged 10 to 17].

OBJECTIVE: To explore the influencing factors on physical endurance among Chinese primary and middle school students aged 10-17. METHODS: Data was used from "2010 National Physical Fitness and Health Surveillance", from which 68 458 primary and middle school students with complete information were selected. Good physical endurance was defined as endurance running time ≤ P 25 of same gender and age, poor physical endurance as ≥ P 75 of same gender and age. Difference of endurance running time in different physical endurance groups was compared; chi-square test, logistic regression and multiple level model were used to analyze influence of region, BMI, diet, exercise and exercise willingness on physical endurance. RESULTS: There were 34 293 (50.0%) students of good physical endurance and 34 219 (50.0%) ones of poor physical endurance in 68 458 subjects. Percentage of good physical endurance was 53.8% (18 285/33 996) in rural students, higher than urban ones (46.3% (15 954/34 462)) (χ(2) = 384.16, P < 0.01). Percentage of good physical endurance was 12.2% (448/3660) in obese students, lower than normal (55.2% (28 183/51 028)), overweight (29.3% (2012/6874)) and emaciated ones (52.1% (3596/6896)) (χ(2) = 3840.08, P < 0.01). Percentage of good physical endurance was 52.5% (25 534/48 679) in students having breakfast everyday, higher than ones never having breakfast or 1-2 times per week (41.3% (3209/7768))(χ(2) = 438.31, P < 0.01). Percentage of good physical endurance was 51.7% (11 580/22 379) in students having milk everyday, slightly higher than ones never or sometimes having milk (49.2% (22 659/46 079)) (χ(2) = 39.84, P < 0.01). Percentage of good physical endurance was 55.3% (18 961/34 314) in students with adequate physical education class, higher than ones with inadequate class (44.7% (15 278/34 144)) (χ(2) = 756.41, P < 0.01). Percentage of good physical endurance was 58.6% (9484/16 195) in students with one hour exercise or more per day, higher than ones with less than one hour exercise (47.4% (24 755/52 263)) (χ(2) = 619.82, P < 0.01). Percentage of good physical endurance was 60.1% (19 287/32 118) in students who were "very willing" to take part in endurance running, higher than "generally willing" ones (45.4% (10 569/23 272)) and "not willing" ones (33.5% (4383/13 068)) (χ(2) = 2909.61, P < 0.01). Multiple level analysis revealed that risk of poor physical endurance was lower in rural students (OR = 0.80, 95%CI: 0.77-0.82) than urban ones. Risk in emaciated students (OR = 1.11, 95%CI: 1.05-1.17), overweight students (OR = 2.69, 95%CI: 2.55-2.85) and obese students (OR = 7.71, 95%CI: 6.97-8.52) was higher than normal ones. Concerning diet, risk of poor physical endurance in students never having breakfast or once to twice per week was highest (OR = 1.20, 95%CI: 1.13-1.26), followed by students having breakfast three to five times per week (OR = 1.13, 95%CI: 1.08-1.18); risk in students having one bag of milk per day was higher (OR = 1.09, 95%CI: 1.02-1.17) than ones having two bags. Concerning exercise, risk of poor physical endurance in students with inadequate physical education class (OR = 1.20, 95%CI: 1.13-1.26) and less than one hour exercise per day (OR = 1.34, 95%CI: 1.29-1.40) was higher than ones with adequate physical education class and one hour exercise or more respectively. Risk of poor physical endurance in students who were "generally willing" (OR = 1.67, 95%CI: 1.61-1.73) and "not willing" (OR = 2.72, 95%CI: 2.60-2.85) to take part in endurance running was higher than "very willing" ones. CONCLUSION: Urban and rural residence, BMI, breakfast, milk, physical education class, exercise time and exercise willingness were related to primary and middle school students'physical endurance.

[Association between early menarche and physical fitness among adolescent girls in China].

OBJECTIVE: To explore the association between early menarche and physical fitness among adolescent girls in China. METHODS: Research material was selected from the data of "2010 National Physical Fitness and Health Survey". Probability unit regression method was used to calculate the age of 10th percentile at menarche and menarche age before the 10th percentile was defined as early menarche(9.0-11.6 years old). A total of 1072 girls with early menarche were selected. Each girl with early menarche was matched with one girl from the same urban or rural locations who hadn't achieved menarche with the age difference less than 0.1 years. A total of 1072 girls without menarche were selected. Indicators of physical fitness included 50 m running, standing broad jump, 50 m×8 shuttle running and sit-ups. Differences of physical fitness between early menarche and without menarche were analyzed using t test stratified by age and urban/rural area. The multilevel models of single dependent variable and multiple dependent variables were used to analyze association between early menarche and physical fitness. RESULTS: A total of 2144 students were put in this research. Among girls (11.0-11.6 years old) in urban areas, 50 m running, standing broad jump and sit-ups was (9.78 ± 0.85) s, (153.81 ± 18.59) cm, and 27.79 ± 10.25, respectively for those with early menarche, while in girls without menarche was (10.01 ± 0.90) s, (149.71 ± 18.72) cm and 26.28 ± 10.11, respectively. There were significant differences between two groups on all above variables (t values were 4.02, 3.43 and 2.31, respectively with all P values <0.01). Among girls in rural, 50 m×8 shuttle-running and sit-ups was (125.22 ± 15.57) s and 24.96 ± 8.97 for those with early menarche, while it was (120.92 ± 13.06) s and 22.96 ± 9.83 for those without menarche. There were significant differences between two groups on both variables(t values were 3.89 and 2.77 with both P values < 0.01). In addition, 50 m×8 shuttle-running in girls (10.0-10.9 years old) with early menarche was (128.52 ± 15.74) s and it was (123.89 ± 13.50) s in girls without menarche. The difference was significant (t = 2.14, P < 0.05). The multilevel analysis showed that 50 m running, standing broad jump and sit-ups in girls with early menarche was 0.12 s, 3.14 cm and 1.11 higher than girls without menarche (Waldχ(2) values were 4.00, 6.22 and 4.07, respectively with all P values < 0.05). But 50 m×8 shuttle-running in girls with early menarche was 1.95 s less than girls without menarche (Waldχ(2) = 3.96, P < 0.05). CONCLUSION: Early menarche may be associated with higher speed fitness, leg power and muscle power and lower physical stamina.

Association between napping and 24-hour blood pressure variability among university students: A pilot study.

Background: Blood pressure variability (BPV) has been reported to be a predictor of cardiovascular and some cognitive diseases. However, the association between napping and BPV remains unknown. This study aimed to explore the association between napping and BPV. Materials and methods: A cross-sectional study including 105 university students was conducted. Participants' 24 h ambulatory blood pressure monitoring (24 h ABPM) were measured, and napping behaviors were investigated. BPV were measured by the 24 h ABPM, included standard deviation (SD), coefficient of variation (CV), and average real variability (ARV). Results: Among the participants, 61.9% reported daytime napping. We found that nap duration was significantly associated with daytime CV of diastolic blood pressure (DBP) (r = 0.250, P = 0.010), nighttime CV of systolic blood pressure (SBP) (r = 0.217, P = 0.026), 24 h WCV of DBP (r = 0.238, P = 0.014), 24 h ARV of SBP (r = 0.246, P = 0.011) and 24 h ARV of DBP (r = 0.291, P = 0.003). Compared with the no napping group, 24 h WCV of DBP, daytime CV of DBP, and daytime SD of DBP were significantly higher in participants with napping duration >60 min. With multiple regression analysis we found that nap duration was an independent predictor for 24 h ARV of SBP (ß = 0.859, 95% CI, 0.101-1.616, P = 0.027) and 24 h ARV of DBP (ß = 0.674, 95% CI, 0.173-1.175, P = 0.009). Conclusions: Napping durations are associated with BPV among university students. Especially those with napping durations >60 min had a significantly higher BPV than those non-nappers.

Prospective association between 24-hour movement behaviors and mental health among overweight/obese college students: a compositional data analysis approach.

Background: 24-h movement behaviors, including light physical activity (LPA), moderate-to-vigorous physical activity (MVPA), screen-based sedentary behavior (SSB), non-screen-based sedentary behavior (NSB) and sleep are crucial components affecting mental health. This study aimed to examine the associations of movement behaviors with mental health outcomes among overweight/obese college students using a compositional data analysis approach. Methods: Using a prospective design, 437 Chinese college students (20.1 ± 1.7 years, 51.7% female) completed a two-wave online data collection, where demographics and movement behaviors (LPA, MVPA, SSB, NSB, sleep) were collected at baseline, while depression, anxiety and stress were measured at the 2-month follow-up (Apr-Jul 2022). Compositional data analyses were implemented using R. Results: Depression, anxiety, and stress were negatively associated with time spent in MVPA and sleep (p < 0.001) and positively associated with time spent in SSB and NSB (p < 0.001). Reallocating 15 min to MVPA from LPA, SSB and NSB predicted improvements in depression (LPA: -0.234 unit; SSB: -0.375 unit; NSB: -0.249 unit), anxiety (LPA: -0.092 unit; SSB: -0.284 unit; NSB: -0.165 unit), and stress (LPA: -0.083 unit; SSB: -0.312 unit; NSB: -0.191 unit). For dose-response relationships of 5-55 min isotemporal substitution, when time was reallocated to MVPA from LPA, NSB, and SSB, the estimated detriments to mental health were larger in magnitude than the estimated benefits of time reallocation from MVPA to LPA, NSB, and SSB. Conclusion: The findings emphasize the importance of participating in MVPA to improve mental health in overweight/obese college students during the post-COVID-19 era. The compositional analysis produced clear targets for the time allocation of these behaviors for future interventions and policymaking.

Does a Healthy Lifestyle Lower the Elevated Risk of Obesity Caused by Caesarian Section Delivery in Children and Adolescents?

Background: Both caesarean section (CS) and lifestyle were linked with child adiposity. This study aimed to investigate whether CS delivery is linked with elevated risk of child adiposity regardless of a healthy lifestyle. Methods: All the subjects in this study came from a baseline survey of a national school-based program on healthy lifestyle interventions against adiposity among Chinese children and adolescents. A questionnaire was used to collect the information on delivery mode and lifestyle. According to the weighted lifestyle score, subjects were categorized into healthy, intermediate, and unhealthy lifestyle. Results: A total of 44,961 children aged 6−18 years were enrolled in the current study. Overall, 41.9% (18,855/44,961) of children were delivered by CS. Compared with children delivered by vaginal delivery, children delivered by CS had a higher adiposity risk (OR = 1.56; 95%CI: 1.46−1.66; p < 0.001) after adjustment for age, sex, region, mother adiposity, ethnicity, and weighted lifestyle factors. Compared with children with a healthy lifestyle, children with an unhealthy lifestyle had a higher risk of child adiposity (OR = 1.31; 95%CI: 1.19−1.44). Children delivered by CS who had an unhealthy lifestyle had a 106% higher (OR = 2.06; 95%CI: 1.79−2.37) risk of child adiposity compared with children delivered by vaginal delivery who had a healthy lifestyle. However, keeping a healthy lifestyle in later life seems not to offset the increased risk of child adiposity caused by CS (OR = 1.59; 95%CI: 1.39−1.82). Conclusions: Both CS and unhealthy lifestyle were linked with child adiposity risk. Keeping a healthy lifestyle did not counteract the elevated risk of child adiposity caused by CS.

Association between Metabolic Syndrome Components and Cardiac Autonomic Modulation among Children and Adolescents: A Systematic Review and Meta-Analysis.

BACKGROUND: the clustering of metabolic syndrome (MetS) risk factors is becoming more prevalent in children, leading to the development of type 2 diabetes (T2D) and cardiovascular diseases in early adulthood. The impact of MetS risk factors on cardiac autonomic modulation (CAM) or vice versa has been noted to track from childhood to pre-adolescence and adolescence. Understating associations in this age group may help to improve the clinical outcomes of the MetS, even when MetS symptoms are not visible. Potential damage from each individual MetS component and the ability to predict early cardiac damage or upcoming cardiovascular events is very important. Therefore, the present systematic review and meta-analysis investigated the associations between CAM and MetS risk factors individually to verify which of the MetS risk components were significantly correlated with heart rate variability (HRV) indices before or at the onset of the MetS among young people. The purpose of this review was to outline the importance of potentially screening HRV indices in young people even with only one MetS risk factor, as a pre-indicator for early cardiovascular risk stratification. METHODS: cross-sectional studies that examined the relationship of MetS risk factors with HRV indices were searched using four databases including PubMed, the Cochrane clinical trials library, Medline and the Web of Science. Correlation coefficients with 95% confidence intervals (95% CI), and random effects meta-analyses of the association between MetS risk factors with HRV indices were performed. RESULTS: out of 14 cross-sectional studies and one case-control study, 8 studies (10 data sets) provided association data for the meta-analysis. Our results indicated significant positive correlations for systolic blood pressure (SBP) (correlation coefficient 0.13 (95%CI: 0.06; 0.19), I2 = 47.26%) and diastolic blood pressure (DBP) (correlation coefficient 0.09 (95%CI: -0.01; 0.18), I2 = 0%) with a Low Frequency/High Frequency ratio (LF/HF). Significant negative correlations for waist circumference (WC) (correlation coefficient -0.12 (95%CI: -0.19; -0.04), I2 = 51.50%), Triglycerides (TGs) (correlation coefficient -0.09 (95%CI: -0.15; -0.02), I2 = 0%) and ≥2 MetS risk factors (correlation coefficient -0.10 (95%CI: -0.16; -0.03), I2 = 0%); with high frequency (HF) were revealed. Significant positive correlations for high density lipoprotein (HDL) (correlation coefficient 0.08 (95%CI: 0.05; 0.11), I2 = 0%) and significant negative correlations of ≥2 MetS risk (correlation coefficient -0.04 (95%CI: -0.12; 0.03), I2 = 0.0%) with low frequency (LF) were revealed. Significant negative correlations for TGs (correlation coefficient -0.09 (95%CI: -0.23; 0.05), I2 = 2.01%) with a mean square root of the sum of differences between mean time between two successive intervals (rMSSD) and significant positive correlation of HDL (correlation coefficient 0.09 (95%CI: -0.01; 0.19), I2 = 0.33%) with standard deviation of the time between two successive intervals (SDNN) were also revealed. An Egger's test indicated that there was no obvious publication bias for any of the above relationships except for TGs and rMSSD. The significance level stipulated for the meta-analysis was p < 0.05. CONCLUSIONS: lipid profiles (HDL and TGs), WC and BP were associated with CAM in young people up to the age of 19 years. The use of HRV indices to predict future MetS risk, and relationships with individual risk factors including HDL, BP, WC and TGs, were established. Future studies related to young people (up to the age of 19 years) are recommended to explore the associations reported here further.

A Healthy Lifestyle Offsets the Increased Risk of Childhood Obesity Caused by High Birth Weight: Results From a Large-Scale Cross-Sectional Study.

Objective: To investigate whether a healthy lifestyle is associated with the lower childhood obesity regardless of birth weight. Methods: Participants were selected from a large-scale cross-sectional study conducted in the seven provinces across China. Birth weight and lifestyle factors were collected through a questionnaire. A weighted healthy lifestyle score was calculated and categorized into favorable, intermediate, and unfavorable lifestyles. Results: A total of 47,768 participants were enrolled in this study. Overall, 16.4% of the participants followed a favorable lifestyle, 62.8% followed an intermediate lifestyle, and 20.8% followed an unfavorable lifestyle. Compared with the participants who were born normal birth weight (NBW), participants who were born high birth weight (HBW) (OR = 1.58; 95% CI 1.48-1.77) and very high birth weight (VHBW) (OR = 1.79; 95% CI: 1.47-2.18) had higher obesity risk, however, the participants who were born low birth weight (LBW) had lower obesity risk (OR = 0.81; 95% CI: 0.68-0.96). Participants with an unfavorable lifestyle were associated with a higher risk of childhood obesity compared with the participants with favorable lifestyle (OR = 1.25; 95%CI: 1.14-1.38). Participants who were born VHBW and with an unfavorable lifestyle had 2.76 times (95% CI: 1.78-4.28) further risk of childhood obesity compared with the participants who were born NBW and with a favorable lifestyle. However, adherence to a favorable lifestyle seems to counteract the elevated risk of childhood obesity by VHBW (OR = 1.37; 95% CI: 0.84-2.24). Conclusion: Both the HBW and unfavorable lifestyle were significantly associated with risk of childhood obesity. Adherence to a favorable lifestyle decreased the risk of childhood obesity among the participants with VHBW. A more longitudinal study is required to repeat the finding to inform tailored prevention programs.

Prevalence of Hyperhomocysteinemia in China: An Updated Meta-Analysis.

We conducted a meta-analysis to systematically assess the prevalence of hyperhomocysteinemia (HHcy) in China, its change over time, and its determinants. Literature searches were conducted using English databases (PubMed, Embase, and Web of Science) and Chinese databases (CNKI, CBM, VIP, and Wanfang). The time ranges were from Jan 2014 to Mar 2021 in China. We adopted the random effects model to estimate the pooled positive rates of HHcy and corresponding 95% confidence intervals (95% CI). To find the sources of heterogeneity, we performed subgroup analysis and meta-regression. A total of 29 related articles were identified involving 338,660 participants with 128,147 HHcy cases. The estimated prevalence of HHcy in China was 37.2% (95% CI: 32.6-41.8%, I2 = 99.8%, p for heterogeneity < 0.001). The trend of HHcy prevalence was gradually upward over time, with increases during 2015-2016 (comparison to 2013-2014, p < 0.001), but steady between 2015-2016 and 2017-2018. Subgroup analysis showed that the prevalence was higher in the elderly over 55 years old, males, and residents in the north, inland, and rural China (for each comparison, p < 0.001). Meta-regression analysis revealed that age and area of study contributed to 42.3% of the heterogeneity between studies. The current meta-analysis provides strong evidence that the prevalence of HHcy is increasing in China, and varies substantially across different ages, genders, and geographic distribution. Accordingly, high-risk population groups should be focused on, and public health policies and strategies should be carried out to prevent and control HHcy in China.