[Application of entropy weight TOPSIS comprehensive method in the evaluation of students' physical health level].

Objective: To comprehensively evaluate the physical health level of students of different school-age segments in four regions of Anhui province using the entropy weight approximation ideal solution ranking method (TOPSIS), and to provide a scientific method and basis for conducting school health work evaluation. Methods: Using the physical fitness survey data of four regions in Anhui province, the entropy weight method was used to draw the weights of various indicators for different school-age segments of men and women. Then, the TOPSIS method was used to evaluate the school-age segments of men and women in the four regions. Finally, the physical health level of students in four regions was classified according to the results of entropy weight TOPSIS and the rank sum ratio method. Results: A total of 10 127 students were included in this study, with an average age of (11.85±3.82) years, including 5 050 males (49.8%) and 5 072 urban students (50.1%). The results of the entropy weight method showed that the weight of body mass index of boys was similar to that of girls in each school-age segment. According to the TOPSIS and rank sum ratio analysis, the physical health level of students in the four regions of Anhui province was different. The physical health score of Suzhou was 0.617 4 points, which was classified as the best grade. The scores of Hefei and Wuhu were 0.556 3 and 0.411 2, which were classified as middle. Jiju City scored 0.381 9 points, which was classified as poor. Conclusion: TOPSIS combined with rank sum ratio can reflect the level of students' physical health, which can be applied to the evaluation of students' physical health and provide a basis for monitoring students' physical health.

[Association between exposure patterns of adverse childhood experiences and anxiety symptom trajectories in medical college students].

Objective: To analyze the association between exposure patterns of adverse childhood experiences (ACEs) and anxiety symptom trajectories in medical college students. Methods: A survey was conducted on first-year students from Anhui Medical College and Anqing Medical College, using the Childhood Abuse Questionnaire, Family Disability Questionnaire, Childhood Adverse Social Experience Item, and Anxiety Self Rating Scale. The baseline survey was conducted from November to December 2019, and two follow-up visits were conducted once every six months until November to December 2020. The latent class analysis (LCA) was used to analyze the exposure patterns of ACEs. The latent class growth analysis (LCGA) was used to analyze the development trajectory of anxiety symptoms. The multiple logistic regression model was used to analyze the correlation between different exposure patterns of ACEs and the trajectory of anxiety symptom trajectories. Results: A total of 3 662 college students aged (19.2±1.0) were surveyed. The LCA showed that the exposure patterns of ACEs could be divided into the "high ACEs" group (13.4%), "high neglect/emotional abuse" group (25.7%), "high family dysfunction" group (6.9%), "high neglect" group (27.1%), and "low ACEs" group (26.3%). The LCGA divided anxiety trajectories into four groups: "high anxiety decline" (7.1%),"anxiety increase "(4.1%), "moderate anxiety"(52.9%), and "low anxiety"(35.9%). Using the low ACEs group as a reference group, compared with the low anxiety trajectory, the high ACEs group, high neglect/emotional abuse group, high family dysfunction group, high neglect group, and medium to high-level anxiety trajectory were all associated with an increased risk (P<0.05). Conclusion: There is heterogeneity in ACEs exposure patterns among medical college students, and ACEs exposure patterns are important influencing factors for anxiety symptom trajectories.

[The development and national norm of the assessment of spinal health of youths].

Objective: To develop the Assessment of Spinal Health of Youths (ASHY), and evaluate its reliability and construct validity and further definite the national norm. Methods: According to literature review and expert consultation, the ASHY included 37 items within 4 dimensions, named symptoms of neck-shoulder and low back, the dysfunction of neck-shoulder and low back, daily risk behaviors and health-seeking behaviors. Between December 2015 and March 2016, a total of 15 096 students were purposively selected from Shenyang, Zhengzhou, Shenzhen and Jiangxi province. Item analysis, factor analysis and reliability evaluation methods were used to select items and evaluate the questionnaire. Between November 2017 and January 2018, a total of 14 500 students were purposively selected from Shenzhen, Zhengzhou, Nanchang and Guiyang. These data were used to develop a national norm of ASHY in adolescents. Results: The ASHY consisted of 4 dimensions covering 34 items. Variance cumulative contribution rate was 68.37%. Internal consistency test showed that Cronbach's α coefficient of the questionnaire was 0.91 and Cronbach's α coefficient of each dimension was between 0.76 and 0.93. The split-half coefficient of the questionnaire was 0.78 and ranged from 0.62 to 0.77 for each dimension. Confirmatory factor analysis results showed that the value of RMSEA was 0.067, and the values of NFI, RFI, CFI, GFI, AGFI were all above 0.80, which had a good fitting degree. The 90th percentile was used as the cutoff point about total scores of 92 for junior high school students, 102 for senior high school students and 98 for the overall middle school students. Conclusions: The ASHY is consistent with the evaluation standard of psychometrics. It can be used as a tool to evaluate the spinal health in adolescents.

[Predictive effects of pubertal timing and tempo on adolescent depressive symptoms: a 6-year prospective cohort study].

Objective: To examine the prospective association of pubertal timing and tempo with depressive symptoms in adolescents. Methods: Since 2013, 2 084 students in grade 1-3 were selected from two primary schools in Bengbu, Anhui Province were selected by using convenience sampling method to establish the adolescence pubertal development cohort. Followed up for 6 years, physical examination, secondary sexual development evaluation (testicular volume for boys and breast development for girls) and depressive symptoms were evaluated biennially. Non-linear growth model was used to estimate pubertal timing and tempo for boys and girls respectively. Depressive symptoms were interviewed by using the Short Mood & Feeling Questionnaire (SMFQ) at baseline and Mood & Feeling Questionnaire (MFQ) during follow-up for students in grade 1-2. Children Depression Inventory (CDI) was used for students in grade 3 at baseline and during follow-up. Depressive symptom scores were standardized by using the Z-score method. Multivariate linear regression model was used to analyze the predictive effects of modeling pubertal timing and tempo on depressive symptoms of adolescence boys and girls. Results: There were 1 909 students with complete questionnaire and puberty development information, including 1 052 boys (59.19%) and 857 girls (43.81%), with average age about (13.94±0.87) years and 91.60 percent follow-up rate. The average modeling pubertal timing of girls (11.25 years) was earlier than that of boys (12.70 years), and the average pubertal tempo of girls about 1.47 Tanner stage/year was faster than that of boys about 1.28 Tanner stage/year. After controlling for depressive symptoms, maternal education and adverse childhood experiences at baseline and age, body mass index (BMI) classification and sleep time during follow-up, this predictive effect of pubertal timing and tempo on depressive symptoms was only significant among girls. Compared with girls with on time pubertal timing, girls in the delay timing group had a lower level of depressive symptoms (ß=-0.19, 95% CI:-0.34,-0.01). Compared with girls in average pubertal tempo group, the fast tempo group associated with an increasing risk of depressive symptoms (ß=0.23, 95%CI: 0.05, 0.40), while the slow tempo group associated with an decreasing risk of depressive symptoms (ß=-0.21, 95％CI:-0.39,-0.03). Insignificant effects were found in puberty timing and tempo on depressive symptoms of boys (P>0.05). Conclusion: Fast pubertal tempo increases the risk of development of depressive symptoms of adolescent girls. There is no predictive effect of pubertal timing and tempo on depression symptoms of adolescent boys.

[Investigation of human brucellosis cases in newly affected counties in Sichuan province, 2015-2017].

Objective: To understand the discovery of human brucellosis cases in new affected counties in Sichuan province, 2015-2017, and provide evidences for prevention and control of human brucellosis. Methods: The incidence data and outbreak data of human brucellosis in Sichuan were collected from Chinese Infectious Disease Surveillance Reporting System, and face to face interview, telephone interview and on-line survey were conducted to collect the case information, such as epidemiological characteristics, medical care seeking. Results: The incidence of human brucellosis in Sichuan has increased obviously since 2013, and 103 counties reported human brucellosis cases for the first time. A total of 23 cases of human brucellosis were investigated, and the common symptoms of the cases was fever, accounting for 91.30% (21/23). The cases mainly sought medical care in hospitals under county-level for the first time, accounting for 73.91% (17/23), and the misdiagnosis rate was 91.30% at the first diagnosis (21/23). The median interval between onset and diagnosis was 52 days, and the longest one was 142 days. Only 4.35% (1/23) cases knew human brucellosis, and when they contacted with suspected livestock, the use rate of protective clothing was 30.43% (7/23), the use rate of gloves was 8.70% (2/23), the use rate of mask was 4.35% (1/23), and the rate of washing hands with disinfectant after contact with livestock was 4.35% (1/23). Goat was suspected to be the infection source of all the cases, and 34.75% (8/23) of the cases were from Gansu, Qinghai and other provinces. The overall awareness rate of human brucellosis in the doctors was 34.58% (102/295), and the training rate was 58.31% (172/295). Only 33.33% (11/33) of the hospitals could perform laboratory diagnosis of human brucellosis and 34.78% (8/23) of county CDCs could carry out laboratory test of human brucellosis. Conclusions: The prevention and control of human brucellosis is facing challenge in Sichuan. The misdiagnosis rate was very high in newly affected counties, and the diagnosis were delayed obviously. The awareness of human brucellosis was low in the cases, and their awareness of self-protection was poor. The awareness rate about human brucellosis in doctors was low and they need more training; the capacity of brucellosis laboratory diagnosis in hospitals and CDCs at county-level should be improved.

[Interaction of health literacy and second-hand smoke exposure on psychopathological symptoms of middle school students].

Objective: To explore the interaction of health literacy and second-hand smoke exposure on psychopathological symptoms of middle school students. Methods: From November 2015 to January 2016, 22 628 middle school students from Shenyang of Liaoning Province, Bengbu of Anhui Province, Xinxiang of Henan Province, Ulanqab of Inner Mongolia Autonomous Region, Chongqing Municipality, and Yangjiang of Guangdong Province were enrolled by using the multi-stage cluster convenience sampling method. A questionnaire was used to collect the data including demographic information, health literacy, second-hand smoke exposure, and psychopathological symptoms. A multivariate logistic regression model was used to analyze the interaction of health literacy and second-hand smoke exposure on psychopathological symptoms of middle school students. Results: The age of students was (15.36±1.79) years old, of which 10 990 were boys, accounting for 48.6% of total students. The detection rate of psychopathological symptoms was 29.1% (6 581/22 628). The detection rate of psychopathological symptoms in those who were exposed to second-hand smoke was 38.1% (2 401/6 304), which was higher than that in the non-second-hand smoke exposure group [25.6% (4 180/16 324)] (P<0.001). The OR (95%CI) of the interaction between medium and low levels of overall health literacy, low level of interpersonal dimension of health literacy and second-hand smoke exposure was 1.19 (1.15-1.24), 2.00 (1.92-2.10) and 1.59 (1.52-1.66), respectively. Conclusion: There was a positive interaction between middle and low levels of overall health literacy, low level of interpersonal dimension of health literacy and second-hand smoke exposure on psychopathological symptoms of middle school students.

[Association of health literacy and smoking behaviors among middle school students in six cities of China].

Objective: To explore the association between the health literacy (HL) and smoking behaviors in middle school students. Methods: From November 2015 to January 2016, middle school students in Shenyang City of Liaoning Province, Bengbu City of Anhui Province, Xinxiang City of Henan Province, Ulanqab City of Inner Mongolia Autonomous Region, Chongqing City and Yangjiang City of Guangdong Province were enrolled by using a multistage stratified cluster sampling method. A total of 23 137 questionnaires were issued and 22 628 questionnaires were valid. A questionnaire survey was conducted to collect demographic information, HL and smoking behaviors. The low, middle, and high-level group were classified according to the tertile of HL score. A multiple logistic regression model was conducted to explore the association between the HL and smoking behaviors. Results: The age of subjects was (15.4±1.8) years old, and HL score was (104.1±18.7) points. The proportion of former smoking, recent smoking and passive smoking was 9.2% (2 071), 2.8% (635) and 27.9% (6 304), respectively. The proportion of former smokers who tried to quit smoking was 50.1% (1 037/2 071). Compared to the high-level HL, the low-level HL increased the risk of former smoking [OR (95%CI): 1.85 (1.61-2.13)], recent smoking [OR (95%CI): 1.68 (1.33-2.14)] and passive smoking [OR (95%CI): 1.34 (1.23-1.46)], and decreased the likelihood of smoking cessation [OR (95%CI): 0.70 (0.53-0.92)], after adjusting for the gender, school type, registered residence, household structure, accommodation type, educational level of patients, and self-reported family economic status. Conclusion: The HL of middle school students was related to their smoking behaviors.

[Correlation of health literacy and mobile phone use dependence with psychopathological symptoms in middle school students].

Objective: To explore the correlation of health literacy and mobile phone use dependence with psychopathological symptoms in middle school students. Methods: 22 628 middle school students in Shenyang, Bengbu, Xinxiang, Ulanqab, Chongqing and Yangjiang were enrolled by multistage cluster sampling method from November 2015 to January 2016. Chinese Adolescent Interactive Health Literacy Questionnaire (CAIHLQ), Self-rating Questionnaire for Adolescent Problematic Mobile Phone Use (SQAPMPU) and Multidimensional Sub-health Questionnaire of Adolescents (MSQA) were applied to acquire basic characteristics, health literacy, mobile phone use dependence and psychopathological symptoms of subjects. Subjects were classified into three groups, low level (P(75)), according to the percentile of the questionnaire score. Multivariate logistic regression model was used to analyze the correlation of health literacy, mobile phone with psychopathological symptoms. Results: The students were (15.4±1.8) years old with 10 990 boys (48.6%). The score of health literacy of students were (104.1±18.7) points. The rate of mobile phone use dependence was 25.4% (5 752/22 628) and the rate of psychopathological symptoms was 29.1% (6 581/22 628). Compared with high health literacy level, medium and low health literacy levels were related to psychopathological symptoms, with OR (95%CI) about 2.30 (2.10-2.52) and 5.40 (4.89-5.97), respectively. Compared with mobile phone use independence, mobile phone use dependence was related to psychopathological symptoms, with OR (95%CI) about 3.60(3.37-3.85). The highest rate of psychopathological symptoms occurred in students with mobile phone use dependence and low health literacy level [68.0% (1 345/1 977)], with OR (95%CI) about 19.59 (17.07-22.48). Conclusion: Health literacy and mobile phone use dependence are related factors of psychopathological symptoms in middle school students.

[Genetic characteristic of hemagglutinin of avian influenza A (H7N9) virus in Guizhou Province in 2017].

The number of H7N9 bird flu cases was high and the situation was grim in guizhou province in 2017. To understand the molecular characteristics of the hemagglutinin gene (HA) and the risk of human infection with avian influenza virus A(H7N9) in Guizhou Province, 2017. Homology, genetic evolution and pivotal sites related to receptor binding regions, pathogenicity and potential glycosylation of 14 avian influenza viruses A(H7N9) were analyzed by a series of bioinformation softwares. It was cleared that there was 95.9%-100% similarity among 14 strains in nucleotide of the HA gene, and there were 96.8%-97.8% and 96.8%-97.9% similarities with vaccine strains A/Shanghai/2/2013 and A/Anhui/1/2013 recommended by WHO, respectively. Phylogenetic analysis showed that 14 HA genes were directly evolved in the Yangtze River Delta evolution branch, but they could be derived from five diffenrent strains. Then 13 of 14 strains cleavage site sequences of HA protein revealed they were low pathogenic avian influenza viruses, while A/Guizhou-Weining/CSY01/2017 was high pathogenic avian influenza virus. Mutation G186V at the receptor binding sites in the HA was found in all 14 strains, and mutation Q226L in 13 strains besides A/Guizhou-Weining/CSY01/2017. All five potential glycosylation motifs in the HA were conservative.

[Interactive effects between health literacy and mobile phone dependence as well as its relation with unintentional injuries in middle school students].

Objective: To investigate the interaction between health literacy, mobile phone dependence and unintentional injuries in middle school students, and to provide guidance for prevention on unintentional injuries in adolescents. Methods: From November 2015 to January 2016, a questionnaire survey was conducted among 22 628 middle school students in Shenyang of Liaoning province, Bengbu of Anhui province, Xinxiang of Henan province, Ulanqab of Inner Mongolia Autonomous Region, Chongqing and Yangjiang of Guangdong province. Chinese Adolescent Interactive Health Literacy Questionnaire (CAIHLQ), Self-rating Questionnaire for Adolescent Problematic Mobile Phone Use (SQAPMPU), and Unintentional Injuries Assessment Scale and demographic variables were used to measure the health literacy, mobile phone dependence and unintentional injuries among the Chinese middle school students. Results: The detection rates of mobile phone dependence and unintentional injuries were 25.4% and 46.7%, respectively. The rates of unintentional injuries of middle school students with mobile phone dependence and with low, medium and high health literacy were 53.6%, 44.4% and 48.8%, 48.1%, 41.7%. Factors as mobile phone dependence, low and middle health literacy were positively related to unintentional injuries (OR=1.452, 1.196, 1.364). However, the multiplicative interaction between mobile phone dependence and health literacy on unintentional injuries was noticed significant (OR=1.217, 95%CI: 1.041-1.422). Conclusions: Our results showed that the prevalence of unintentional injuries was relatively high in middle school students. Health literacy and mobile phone dependence seemed related to unintentional injuries. Interaction between health literacy and mobile phone dependence on unintentional injuries appeared significant.

[Genetic characteristics of hemagglutinin and neuraminidase of avian influenza A (H7N9) virus in Guizhou province, 2014-2017].

Objective: To understand the molecular characteristics of hemagglutinin (HA) and neuraminidase (NA) as well as the disease risk of influenza virus A H7N9 in Guizhou province. Methods: RNAs were extracted and sequenced from HA and NA genes of H7N9 virus strains obtained from 18 cases of human infection with H7N9 virus and 6 environmental swabs in Guizhou province during 2014-2017. Then the variation and the genetic evolution of the virus were analyzed by using a series of bioinformatics software package. Results: Homology analysis of HA and NA genes revealed that 2 strains detected during 2014-2015 shared 98.8%-99.2% and 99.2% similarities with vaccine strains A/Shanghai/2/2013 and A/Anhui/1/2013 recommended by WHO, respectively. Two strains detected in 2016 and 14 strains detected in 2017 shared 98.2%-99.3% and 97.6%-98.8% similarities with vaccine strain A/Hunan/02650/2016, respectively. Other 6 stains detected in 2017 shared 99.1%-99.4% and 98.9%-99.3% similarities with strain A/Guangdong/17SF003/2016, respectively. Phylogenetic analysis showed that all the strains were directly evolved in the Yangtze River Delta evolution branch, but they were derived from different small branch. PEVPKRKRTAR↓GLF was found in 6 of 24 strains cleavage site sequences of HA protein, indicating the characteristic of highly pathogenic avian influenza virus. Mutations A134V, G186V and Q226L at the receptor binding sites were found in the HA. All the strains had a stalk deletion of 5 amino acid residue "QISNT" in NA protein, and drug resistance mutation R294K occurred in strain A/Guizhou-Danzhai/18980/2017. In addition, potential glycosylation motifs mutations NCS42NCT were found in the NA of 9 of 24 strains. Conclusions: HA and NA genes of avian influenza A (H7N9) virus showed genetic divergence in Guizhou province during 2014-2017. The mutations of key sites might enhance the virulence of the virus, human beings are more susceptible to it. Hence, the risk of infection is increasing.

[Prospective association between childhood abuse experiences and depressive symptoms in adolescence].

Objective: To evaluate the prospective association between childhood abuse experiences and depressive symptoms in adolescence. Methods: Students in grade 3 and 4 from three primary schools were selected, with informed consent, through convenience cluster sampling in Bengbu, Anhui province in May 2013. The students' body height, weight were assessed. Childhood abuse experiences including emotional, physical or sexual abuses, as well as depressive symptoms were reported by children themselves. Data on parental educational background and household economic status were collected through parent questionnaire. A follow up was conducted 4 years later after baseline survey. Depressive symptoms were evaluated by using Children's Depression Inventory at baseline survey, and by using Mood and Feeling Questionnaire at follow-up. Logistic regression model was used to analyze the relationship between childhood abuse experiences and depressive symptoms in adolescence. Results: A total of 1 172 students were included in baseline survey, and a follow-up was conducted for 87.1% of them (n=1 021). Among 1 126 students with complete information on childhood abuse experiences at baseline survey, the reported rates of physical, emotional and sexual abuses were 12.8% (144/1 126), 11.1% (125/1 126) and 10.9% (123/1 126), respectively. The prevalence of depressive symptoms at baseline survey and follow-up was 7.0% (82/1 172) and 12.3% (126/1 021), respectively. After adjusted for baseline depressive symptoms, age at follow-up, sex, the only-child in family, household economic status, divorce of parents and BMI, childhood emotional and physical abuse experiences were significant risk factors for depressive symptoms in mid-adolescence, with the ORs were 1.86 (95%CI: 1.03-3.36, P=0.039) and 2.37 (95%CI: 1.39-4.03, P=0.001), respectively. Conclusion: Childhood physical and emotional abuse might increase the risk of depressive symptoms in adolescence.

[Developmental characteristics of circadian rhythms in hypothalamic-pituitary-adrenal axis during puberty].

Objective: To explore the developmental characteristics of circadian rhythms in hypothalamus-pituitary-adrenal (HPA) axis during puberty. Methods: A total of 1 070 students from Grade 2-3 in 3 primary schools in Ma'anshan city, Anhui province, were selected for physical examination and circadian rhythm of HPA axis checked from 2015 to 2017. Saliva samples were collected at each of the following three time points: immediately upon wakening, 30 minutes after wakening and bedtime, with the index of circadian rhythm of HPA axis calculated, which including cortisol awake response (CAR), cortisol in puberty priming and diurnal cortisol slope (DCS). Testicular volume, palpation and visual inspection of breast development were used to assess the state of purbety development on boys and girls. Information on gender, date of birth, time to fall asleep, wake-up time and weekly physical activity were gathered through questionnaire survey. Non-parametric test was used to compare the differences of baseline, follow-up period and different adolescent developmental processes of each index on circadian rhythm of HPA axis. Results: During the period of follow-up program and comparing with the continuous undeveloped group, CAR and the changes of CAR showed significantly increase, both in the puberty priming group and continuous development group, with statistically significant differences (CAR: Z=8.551, 4.680, respectively; P<0.01; the changes of CAR: Z=4.079, 2.700, respectively, P<0.01). There were no significant differences noticed in CAR and the changes of CAR between puberty priming group or continuous development group. The area under the curve (AUC) of cortisol in puberty priming group was slightly higher than that in the persistent undeveloped group (Z=2.591, P=0.010). Both the changes of daily cortisol slope (DCS) in puberty priming group and continuing developed group decreased significantly, when comparing with those in continuous undeveloped group (Z=-2.450, Z=-2.151; all P<0.05). There was no significant difference noticed in the changes of cortisol in puberty priming and DCS between different puberty development stages (the changes of AUC: χ(2)=2.747, P=0.253; DCS: χ(2)=4.554, P=0.032). Conclusions: The indexes of circadian rhythm of HPA axis were associated with the development of puberty. Both the cortisol awakening response and the total amount of diurnal cortisol secretion showed an increase, along with the puberty development. The change of diurnal cortisol slope declined with the development of puberty.

[Association of the health literacy and the incidence of injuries among Chinese middle school students in five provinces].

Objective: The purpose of this study was to examine the association between health literacy (HL) and the incidence of injuries in middle school students in China. Methods: From November 2013 to February 2014, middle school students in Liaoning, Henan, and Guangdong provinces, Chongqing municipality, Xinjiang Uygur Autonomous Region were selected by using cluster sampling method. A total of 27 044 questionnaires were issued and 25 378 questionnaires were valid. According to the Chinese Adolescent Interactive Health Literacy Questionnaire (CAIHLQ), scores were conducted a tripartite group. Multiple logistic regression analyses were conducted to examine the association between HL and injuries. Results: The scores of CAIHLQ were 103.55±23.91 among 25 378 students. The detection rate of self-injuries and unintentional injuries was 27.5% (n=6 971) and 47.8% (n=12 119). Compared with the students with high HL, the OR (95%CI) values of self-injuries among students with low and middle HL were 2.56 (2.35-2.79) and 1.96 (1.81-2.12). Compared with the students with high HL, the OR (95%CI) values of unintentional injuries among students with low and middle HL were 1.63 (1.53-1.73) and 1.47 (1.37-1.58). Conclusion: The risk of self-injuries and unintentional injuries of middle school students is related to HL.

[Association between hair cortisol concentration and overweight and obesity in 6-9 years old childhood].

Objective: To determine the possible relations between hair cortisol concentration (HCC) as a biomarker of chronic stress and childhood overweight and obesity. Methods: Children from grade 1 to 3 from 2 primary schools in Bengbu were invited to participate in the study; and those who suffer from mental disorders, endocrine diseases and those who took hormone drugs were excluded. Parental questionnaire was implemented to collect information on physical activity, screen time, sleep duration, sugar-beverage consumption, as well as socio-economic status. Height and weight were examined. Eligible hair samples from 1 263 children (598 boys and 665 girls) were obtained, and the cortisol content was determined. Multivariate logistic regression model analysis was recruited to examine the association between HCC quartiles and overweight and obesity among boys and girls, respectively. Results: HCC in P(50) (P(25)-P(75)) among girls and boys was separately 11.86 (10.57-13.15) and 11.71 (10.54-13.09) µg/kg (Z=-0.886, P=0.376); HCC in P(50) (P(25)-P(75)) among non-overweight, overweight and obesity boys was separately 11.62 (10.45-12.82), 12.24 (10.88-13.55) and 12.30 (10.99-13.53) µg/kg (χ(2)=8.24, P=0.016); HCC in P(50) (P(25)-P(75)) among non-overweight, overweight and obesity girls was separately 11.35 (10.06-12.62), 12.07 (11.04-13.21) and 12.59 (11.12-13.63) µg/kg (χ(2)=36.16, P<0.001). After age, physical activity, screen time, sleep duration, sugared beverages and socio-economic status adjusted, compared with HCC in Q1 level, girls whose HCC in Q2, Q3 Q4 level had higher rates in overweight, with OR (95%CI) at 1.10 (1.04-3.32), 2.59 (1.51-4.45) and 3.16 (1.79-5.57), respectively. Girls with HCC in Q3 and Q4 level had higher rates in obesity, with OR (95%CI) at 2.22 (1.16-4.26) and 5.62 (3.04-10.41). Among boys, highest quartiles in HCC was risk factor for overweight, OR (95%CI) was 2.14 (1.18-3.90). Conclusion: Hair cortisol had a significant relation with overweight and obesity in 6-9 years old childhood especially among girls.

[Investigation of influencing factors associated with neck-shoulder symptoms among middle school students in three cities in China].

Objective: The aim of this study was to describe the distribution of neck-shoulder symptoms among middle school students, and to explore its influence factors. Methods: A cross-sectional survey was conducted on 24 middle schools in Shenyang, Zhengzhou and Shenzhen by purposive sampling method. In each middle school, 3 to 4 classes were selected from each grade all the students in the selected class would be recruited to the survey to investigate the demographic characteristics, neck-shoulder symptoms, physical exercise time, academic stress, screen behavior, sedentary behavior and other information by questionnaire. A total of 10 566 questionnaires were issued and 10 270 valid questionnaires were withdrawn. The prevalence of neck-shoulder symptoms among students were compared by different characteristics. Logistic regression models were applied to examine influencing factors associated with neck-shoulder symptoms. Results: The prevalence of neck-shoulder symptoms among middle school students was 19.2% (1 968/10 270), while it was 22.6% (1 137/5 039) among girls and 15.9% (831/5 231) among boys; the difference showed statistical significance (P<0.001). The prevalence of neck-shoulder symptoms was separately 13.3% (253/1 901) in seventh grade, 16.8% (326/1 942) in eighth grade, 18.5% (299/1 617) in ninth grade, 21.8% (417/1 915) in sophomore, 21.4% (345/1 611) in junior, 25.5% (328/1 284) in senior; the difference showed statistical significance (P<0.001). The multivariate logistic regression analysis showed that in the last 3 months, students who always playing mobile phone ≥40 min continuously (OR=4.66, 95%CI: 3.95-5.49), watching TV ≥40 min continuously (OR=4.01, 95%CI: 3.39-4.73), using computer ≥40 min continuously (OR=3.61, 95%CI: 3.09-4.23), doing homework ≥60 min continuously (OR=3.25, 95%CI: 2.79-3.79), the average daily sitting time ≥10 h (OR=4.95, 95%CI: 4.25-5.77), and always sitting ≥90 min continuously (OR=5.18, 95%CI: 4.42-6.06) were risk factors of neck-shoulder symptoms. Conclusion: The prevalence of neck-shoulder symptoms was high among middle school students in China, especially girls in senior grades. Long time, high frequency video behaviors and sedentary behaviors were related to the occurrence of neck-shoulder symptoms among middle school students.

[Study of association between adverse experiences in childhood, social support, and physical and psychological sub-health status among middle school students in 3 cities in China].

Objective: To explore the relationship between adverse experience in childhood, social support, and physical and psychological sub-health status among middle school students in 3 cities in China. Methods: 15 278 adolescents were selected as subjects from 20 junior and senior middle schools located in 3 cities of China by stratified cluster sampling method. The survey collected the demographic information, ACEs, social support and physical-psychological status. A total of 14 820 valid questionnaires were retained for analysis. We assessed ACE score (count of six categories of childhood adversity), social support (adolescent social support questionnaire), and the prevalence of two outcomes: physiological and psychological sub-health status. Logistic regression was used to analyze the relationship between adverse childhood experiences, social support, and physiological and psychological sub-health status. Results: The prevalence of physiological and psychological sub-health status were 26.4% (3 917/14 820) and 24.1%(3 572/14 820), respectively. A total of 89.4% (13 247/14 820) reported at least 1 adverse childhood experiences. The rates of physiological and psychological sub-health status were higher among girls (28.1%(2 092/7 443), 26.0%(1 932/7 443)) than boys (24.7%(1 825/7 377), 22.2%(1 640/7 377)). Among adolescents without ACEs, the rate of physiological and psychological sub-health status were 15.4%(243/1 573) and 10.4%(163/1 573), for those with 5-6 ACEs, the rate were 40.9%(636/1 556) and 43.6%(678/1 556). Among adolescents with higher social support, the rate of physiological and psychological sub-health status were 19.9%(724/3 635) and 13.0%(474/3 635) for those with lower social support, the rate of physiological and psychological sub-health status were 35.9%(1 403/3 913) and 39.0%(1 528/3 913). The rates of physiological and psychological sub-health status were higher with more ACE exposure or less social support. At each level of ACE exposure, physiological and psychological sub-health status were less in those with greater social support. For example, among adolescents reporting 5-6 ACEs, those in the lowest tertile of social support increased the risk of physiological sub-health status than those in the highest tertile (adjusted prevalence ratio (95%CI)=1.79 (1.23-2.56)); for those reporting no ACEs, the ratio was 3.04 (1.91-4.83). Among adolescents reporting 5-6 ACEs, those in the lowest tertile of social support increased the risk of psychological sub-health status than those in the highest tertile (adjusted prevalence ratio (95%CI)=3.77 (2.57-5.52)); for those reporting no ACEs, the ratio was 3.97(2.33-6.76). Conclusion: The findings suggest that ACEs should be considered as risk factors for physiological and psychological sub-health status among middle school students. Across a range of exposures to ACEs, less social support was associated with more physiological and psychological sub-health status. Identifying those with ACE exposure who also have lower social support could be used to improve the health of adolescents.

[Prospective association between early adiposity rebound and adolescent development in girls].

Objective: To determine possible relations between early adiposity rebound and adolescent development. Methods: Prospective children cohort from 2 kindergartens selected through clustering convenience sampling method in Anhui Province was established since Sep. 2010. Participants were classified as Cohort 1 (2010), Cohort 2 (2011) and Cohort 3 (2012) according to the recruiting year. Till Sep. 2015, a toal of 802 girls were included in this study, and received follow-up till primary school. During kindergarten period, physical examination was carried out every 3 months, 8 times in total. In primary school, physical examination was carried out annually; till Sep.2015, the cohort 1, 2, 3 took physical examination for 12, 11, 10 times, respectively. Information on household economic status and child physical activity was acquired through parents questionnaire survey, and breast development were assessed through visual inspection and palpation. Adiposity rebound was determined according to Rolland-Cachera's method for each girl. Differences between early adiposity rebound and normal adiposity rebound groups were compared by using t test and χ(2) test. Multivariate regression analysis was applied to explore the association between early adiposity rebound and breast development. Results: The average age of participants was (8.90±0.87) years old and the BMI was (17.48±2.70) kg/m(2). The average age at adiposity rebound was (6.16±0.90) years old and the BMI was (15.33±1.82) kg/m(2). Premature breast development was found significantly higher in girls in early adiposity rebound group (27.8%, 54/802) than it in normal adiposity rebound group (13.7%) (P<0.001). After current adiposity, age, household economic status, childhood physical activity adjusted, the OR of premature beast development in early adiposity rebound group was 2.41(95%CI: 1.41-4.12). Conclusion: Early adiposity rebound increases the risk of premature puberty in girls.

[Study on relationship between outdoor activities and self-reported myopia among middle school students].

Objective: To examine the relationship between the prevalence of self-reported myopia and outdoor activities among middle school students and to explore the influence factors of the self-reported myopia. Methods: A total of 12 979 participants were recruited from junior and senior middle school students in in Shenzhen, Nanchang, Zhengzhou and Shenyang by random cluster sampling method between December 2015 and March 2016. All participants completed an anonymous questionnaire to collect the information of demographic characteristics, self-reported myopia, outdoor activities, etc. 12 603 out of 12 979 copies of questionnaire were valid. The prevalence of self-reported myopia was compared among middle school students with different characteristics. Logistic regression models were used to analyze the relationship between myopia and outdoor activities. Results: The prevalence of self-reported myopia among middle school students was 69.6% (8 766/12 603); which was separately 52.1% (1 216/2 335) in seventh grader, 61.6% (1 459/2 369) in eighth grader, 69.0%(1 470/2 129) in ninth grader, 80.0% (1 812/2 265) in freshmen, 79.4% (1 622/2 042) in sophomore, and 81.1%(1 187/1 463) in junior. The prevalence of self-reported myopia showed an increasing trend with the increase of grade (χ(2)=639.67, P<0.001). The prevalence of self-reported myopia was separately 63.5%(4 927/7 756) in non-myopic parents group, 78.0%(2 664/3 415)in either myopic parent group, and 82.1%(1 175/1 432) in both myopic parents group(χ(2)=328.28, P<0.001). Outdoor activities were associated with self-reported myopia. Binary logistic regression analysis showed that the risk of self-reported myopia was significantly increased by always staying at home in extracurricular time among the middle school students (OR=1.58, 95%CI: 1.36-1.82). The risk of self-reported myopia were significantly decreased by always physical exercise and recreational activities after school among middle school students: the ORs were separately 0.67 (95%CI: 0.57-0.78) for physical exercise and 0.77 (95%CI: 0.64-0.92) for recreational activities. After stratified analysis by the parents' myopia status, in non-myopic parents group, exercise and recreational activities after school among middle school students decreased the risk of myopia: the ORs were separately 0.68 (95%CI: 0.55-0.82) for physical exercise and 0.76 (95%CI: 0.61-0.95) for recreational activities; in either myopic parent group, OR(95%CI) were separately 0.65 (0.47-0.90) and 0.68 (0.47-0.98). Conclusion: Outdoor activities was negatively associated with self-reported myopia among middle school students. However, the parents' myopia status may affect the protective effect.