Interaction of smoking and being bullied on suicidal behaviors: a school-based cross-sectional survey in China

BACKGROUND@#Suicidal behaviors are seriously social issues among adolescents in the world. Exposed to smoking and being bullied are risk factors of suicidal behaviors. The present study was aimed to examine the interaction of smoking and being bullied on suicidal behaviors among Chinese adolescents.@*METHODS@#A total of 18,900 students were involved in the questionnaire study, in four cities of China from November 2017 to January 2018. Suicidal behaviors, smoking, and being bullied were measured by self-reported validated instruments. Chi-square tests and logistic regression were used to analyze the associations of suicidal ideation (SI)/suicidal plan (SP)/suicidal attempt (SA), smoking, and being bullied.@*RESULTS@#The prevalence of smoking, being bullied, SI/SP/SA, were 3.1%, 20.6%, 26.4%, 13.2%, and 5.2% respectively. Interaction analysis indicated that being bullied was associated with a greater increase in the likelihood of suicidal behaviors for adolescents with smoking than for those without smoking.@*CONCLUSIONS@#These finding suggest that smoking exacerbates the association between being bullied and suicidal behaviors. Future research should explore how and why smoking appears to more bully-victims than for those without smoking and how to mitigate it.

Interaction of health literacy and second-hand smoke exposure on psychopathological symptoms of middle school students / 中华预防医学杂志

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 / 中华预防医学杂志

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 / 中华预防医学杂志

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 (<P25), medium level (P25-P75) and high level (>P75), 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.

Association of the health literacy and the incidence of injuries among Chinese middle school students in five provinces / 中华预防医学杂志

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.

Interactive effects between health literacy and mobile phone dependence as well as its relation with unintentional injuries in middle school students / 中华流行病学杂志

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.

Prospective association between childhood abuse experiences and depressive symptoms in adolescence / 中华流行病学杂志

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 sympto ms,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 / 中华流行病学杂志

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.Nonparametric 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 ofAUC:x2=2.747,P=0.253;DCS:x2=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.

Interactive effects between health literacy and mobile phone dependence as well as its relation with unintentional injuries in middle school students / 中华流行病学杂志

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.

Prospective association between childhood abuse experiences and depressive symptoms in adolescence / 中华流行病学杂志

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 sympto ms,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 / 中华流行病学杂志

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.Nonparametric 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 ofAUC:x2=2.747,P=0.253;DCS:x2=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 between hair cortisol concentration and overweight and obesity in 6-9 years old childhood / 中华预防医学杂志

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 P50 (P25-P75) 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 P50 (P25-P75) 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 (χ2=8.24, P=0.016); HCC in P50 (P25-P75) 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 (χ2=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.

Study on relationship between outdoor activities and self-reported myopia among middle school students / 中华预防医学杂志

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 (χ2=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(χ2=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.

Prospective association between early adiposity rebound and adolescent development in girls / 中华预防医学杂志

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 χ2 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/m2. The average age at adiposity rebound was (6.16±0.90) years old and the BMI was (15.33±1.82) kg/m2. 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 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 / 中华预防医学杂志

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.

Investigation of influencing factors associated with neck-shoulder symptoms among middle school students in three cities in China / 中华预防医学杂志

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.

Mediating effect of social support on relationship between childhood abuses and non-suicidal self-injuries in adolescents / 中国心理卫生杂志

Objective:To investigate the relationship among childhood abuses,social support and non-suicidal self-injury (NSSI) in adolescents,and to examine the mediating effect of social support on the relationship between childhood abuses and non-suicidal self-injury.Methods:A total of 9704 middle school students were selected from junior and senior middle schools in Zhengzhou,Guiyang city.The Childhood Trauma Questionnaire-28 item Short Form (CTQ-SF),Non-Suicidal Self-Injury Questionnaire,Social Support Scale for University Students and Multidimensional Sub-health Questionnaire of Adolescents (MSQA) were used to measure the different types of adverse childhood experiences,non-suicidal self-injury,social support and psychopathological status.Results:The CTQ-SF-scores were positively correlated with non-suicidal self-injury scores (r =0.20,P ＜ 0.01) and negatively correlated with social support scores (r =-0.22,P ＜ 0.01).The total scores and factor scores of social supportscale were negatively correlated with non-suicidal self-injury scores in adolescents (P ＜ 0.01).When control of the area,grade,self-reported learning burden,self-reported grades and psychological pathology symptoms,social support in childhood abuse and the relation between the suicide self-injury the mediation effect by the single factor of 17.04％ to 12.57％,the mediation effect of three subcomponents accounted for 7.12％ ～ 13.85％.Conclusion:It suggests that social support may play a mediating effect on the relationship between childhood abuses and non-suicidal selfinjury.

Association between time spent on physical exercise, sleep, homework and suspected myopia among students / 中华流行病学杂志

Objective To investigate the prevalence of suspected myopia among students and to examine the relationship between time spent on physical exercise,sleep,homework and suspected myopia.Methods A total of 8 030 primary and secondary school students from 4th to 12th grades were selected from the National Student Constitution and Health Survey (NSCHS) in Anhui province in 2014.Time spent on exercise,sleep and homework per day were collected using a self-administrated questionnaire.Visual acuity was examined using the Standard Logarithmic Visual Acuity Chart.Results The overall prevalence of suspected myopia was 69.03％.Prevalence rates of suspected myopia appeared higher in girls,in urban students,with the highest in the 16 to 18 year-old groups.Results from the multiple logistic regression analysis showed that the amount of time spent on physical exercise,sleep and homework per day were all significantly associated with suspected myopia.Suspected myopia was associated with longer time on physical exercise among students aged 8 to 12 years (OR=0.80,95％CI:0.64-0.99),and longer sleep time among students in the age groups of 13 to 15 years and 16 to 18 years (OR=0.73,95％CI:0.56-0.94;OR=0.38,95％CI:0.21-0.68,respectively).Longer time spent on homework significantly increased the risk of suspected myopia among students in the age groups of 8 to 12 years and 13 to 15 years (OR=1.41,95％CI:1.11-1.79;OR=1.74,95％ CI:1.36-2.23,respectively).Conclusion Suspected myopia appeared common among students.Comprehensive intervention programs focusing on sufficient physical exercise and sleep but less homework might help to prevent myopia among students at different ages.

Association between time spent on physical exercise, sleep, homework and suspected myopia among students / 中华流行病学杂志

Objective To investigate the prevalence of suspected myopia among students and to examine the relationship between time spent on physical exercise,sleep,homework and suspected myopia.Methods A total of 8 030 primary and secondary school students from 4th to 12th grades were selected from the National Student Constitution and Health Survey (NSCHS) in Anhui province in 2014.Time spent on exercise,sleep and homework per day were collected using a self-administrated questionnaire.Visual acuity was examined using the Standard Logarithmic Visual Acuity Chart.Results The overall prevalence of suspected myopia was 69.03％.Prevalence rates of suspected myopia appeared higher in girls,in urban students,with the highest in the 16 to 18 year-old groups.Results from the multiple logistic regression analysis showed that the amount of time spent on physical exercise,sleep and homework per day were all significantly associated with suspected myopia.Suspected myopia was associated with longer time on physical exercise among students aged 8 to 12 years (OR=0.80,95％CI:0.64-0.99),and longer sleep time among students in the age groups of 13 to 15 years and 16 to 18 years (OR=0.73,95％CI:0.56-0.94;OR=0.38,95％CI:0.21-0.68,respectively).Longer time spent on homework significantly increased the risk of suspected myopia among students in the age groups of 8 to 12 years and 13 to 15 years (OR=1.41,95％CI:1.11-1.79;OR=1.74,95％ CI:1.36-2.23,respectively).Conclusion Suspected myopia appeared common among students.Comprehensive intervention programs focusing on sufficient physical exercise and sleep but less homework might help to prevent myopia among students at different ages.

Relationships between various forms of childhood abuse and suicidal behaviors among middle school students / 中华流行病学杂志

Objective To study the relationship between various forms of childhood abuse and suicidal behaviors among middle school students.Methods A total of 14 221 cases were retained from an epidemiological study,involving students from junior and senior middle schools in Guangzhou,Xinxiang,Shenyang and Chongqing.Information related to the demographic characteristics,types,number,timing and perpetrators of exposure to childhood abuse and suicidal behaviors was obtained.Logistic regression was used to analyze the relationships of each form of childhood abuse and suicidal behaviors.Results Number of cases (rates) of childhood abuse,physical abuse,emotional abuse,sexual abuse,suicidal ideation,suicidal planning and suicidal attempts among middle school students appeared as 7 246 (51.0％),5 824 (41.0％),5 409 (38.0％),1 039 (7.3％),2 042 (14.4％),1 174 (8.3％) and 548 (3.9％),respectively.Boys reported more physical abuse than girls,while girls reported more emotional abuse and suicide ideation than boys (P＜0.01).However,no gender differences were found in cases as sexual abuse,suicide planning or attempted suicide (P＞0.01).After controlling for confounding variables,experiences on childhood abuse were significantly associated with suicidal ideation (OR=2.03,95％CI:1.72-2.40) and suicidal planning (OR=1.93,95％CI:1.57-2.37) among boys but significantly associated with suicidal ideation (OR=2.45,95％CI:2.12-2.82),suicidal planning (OR=2.46,95％CI:2.02-3.00) and attempted suicide (OR=2.12,95％CI:1.61-2.78) among girls.Results from multivariable logistic regression analysis showed that each type of childhood abuse,occurring at any time within the first 16 years of life,especially with continuous exposure,was significantly associated with suicidal behaviors.A significant graded-relationship was found between number of abusive childhood experiences and suicidal behaviors.Students that had been maltreated by parents or others were at high risk of engaging in suicidal behaviors.Conclusion The findings suggest that the experience of any form of childhood abuse should be considered a risk factor for suicidal behaviors among the middle school students.