Nutrition in Chinese-Korean Children and Adolescents.

OBJECTIVE: To study the nutrition habits among Chinese-Korean children and adolescents in Yanbian Autonomous Prefecture, Jilin, China. METHODS: Data were obtained from the Chinese National Survey on Students' Constitution and Health in 1995, 2000, 2005, and 2010 for Chinese-Korean children and adolescents aged 7-18 years. The number of the subjects included was 4789, 4704, 5875, and 5315, respectively. RESULTS: The rate of the occurrence of stunting showed a declining trend from 1995 to 2010 (for boys: urban, 6.3%; rural, 12.7% in 1995 and 3.5% for both in 2010. For girls: urban, 7.8%; rural, 13.4% in 1995 and 4.2% and 5.5%, respectively, in 2010). Although the ratio of wasting did not show significant differences between the urban and rural children and adolescents in 1995, 2000, 2005, and 2010 respectively, the ratio of occurrence of overweight or obesity increased (for boys: urban, 7.3% and 1.3% in 1995, 17.6% and 12.9% in 2010; rural, 7.0% and 1.3% in 1995, 14.6% and 12.8% in 2010, respectively. For girls: urban, 8.1% and 1.0% in 1995, 17.3% and 8.6% in 2010; rural 5.7% and 0.7% in 1995, 16.4% and 7.4% in 2010, respectively). CONCLUSION: The ratio of malnutrition in children and adolescents in Chinese-Korean areas declined from 1995 to 2010, and the distinction in malnutrition between the urban and rural areas was negligible in 2010. Further, the ratio of overweight and obesity increased over this period.

Genetic and environmental influences on the relationship between ADHD symptoms and internalizing problems: A Chinese twin study.

Several twin studies have investigated the overlap between attention deficit hyperactivity disorder (ADHD) and externalizing problems; however, limited information is known regarding the genetic and environmental contribution to the overlap between ADHD and internalizing problems. This study examined the genetic and environmental influences on the variation in and covariation between ADHD symptoms and internalizing problems by using the Child Behavior Checklist (CBCL). We investigated 1,316 child and adolescent twins, including 780 monozygotic twins and 536 dizygotic twins, aged 6 years to 18 years from the Chinese Child and Adolescent Twin Registry. ADHD symptoms and internalizing problems were quantified through parent rating by using the Attention Problems Scale and other three scales, which include Anxious/Depressed, Withdrawn, and Somatic Complaints of CBCL. Genetic and environmental susceptibilities common to ADHD symptoms and internalizing problems were examined through bivariate twin modeling. Results showed that genetic factors substantially influenced the ADHD symptoms with a heritability of 72%. Modest genetic influences and substantial shared environmental influences (20-77%) were observed in the three internalizing problem scales. Common genetic and shared environmental influences were essential for the overlap between ADHD and the three internalizing problems respectively. Approximately one-fifth of the genetic variance of ADHD symptoms was shared with anxiety/depression. In conclusion, substantial genetic and shared environmental influences on ADHD symptoms and internalizing problems were observed in Chinese children and adolescents. Our finding supports a common etiology between ADHD and internalizing problems. This finding can also help explain the co-existence of these behavior problems. © 2015 Wiley Periodicals, Inc.

Relationship between Migration and HIV Risky Behavior: a Comparative Study of Returning Migrants and Non Migrants Based on Rural Out-of-school Youth in Jilin, China.

OBJECTIVE: To estimate the relationship between migration and HIV risky behavior when controlling for gender, age, and educational levels and to evaluate the gender differences in migration, HIV knowledge, and HIV risky behaviors among rural youth in China. METHODS: A cross-sectional, anonymous, investigative questionnaire for 1710 unmarried, out-of-school rural youth, aged between 15 and 24 years, was handed out in Gongzhuling county of Jilin province, China. RESULTS: 58.5% of participants had a history of migration, irrespective of gender. There were gender differences observed in other factors such as drug abuse (4.3% for males and 5.5% for females, P<0.01), multiple sexual partners (24.1% for males and 44.1% for females, P<0.01), and HIV knowledge rate (35.2% for males and 25.5% for females, P<0.001). While controlling for gender, age, and educational levels, the relationships between migration and drug abuse, selling sex, and non usage of condoms during last instance of sexual activity were found to be significant. The cases of premarital sex and multiple sexual partners were both not found to be related to migration. CONCLUSION: Among rural youth, the HIV risky behavior such as drug abuse, selling sex, and lack of condom use, is significantly related to migration, while premarital sex and multiple sexual partners seem unrelated to migration.

Secular changes of stature in rural children and adolescents in China, 1985-2010.

OBJECTIVE: To analyze and assess secular change in stature in rural children and adolescents in China from 1985 to 2010. METHODS: Data were obtained from the 6 rounds of the Chinese National Survey on Student's Constitution and Health. The subjects enrolled in the study were children and adolescents aged 7-18 years in rural areas of provincial capitals. RESULTS: An overall positive secular trend in stature occurred in rural areas of provincial capitals in China from 1985 to 2010. The overall average increase rates were 3.1 and 2.4 cm/decade for boys and girls, respectively. The total body height increases for grown up boys and girls were 3.6 and 2.3 cm and the increase rates were 1.4 and 0.9 cm/decade, respectively. There were differences in body height increase among eastern, central and western regions. The average body height of the children or adolescents in eastern region was highest, followed by central region and western region. The overall increase rates in central region were highest among the three regions. The difference between eastern/central region and western region was obvious. CONCLUSION: Positive secular trend in stature of children or adolescents has occurred in rural area of China, and rural boys and girls showed a great potential for continuous growth. More attention should be paid to the differences in children's body height between western region and eastern/central region.

Malnutrition prevalence in lasa xizang children and adolescents.

OBJECTIVE: To assess the prevalence of malnutrition among children and adolescents in Xizang (Tibet). METHODS: We analyzed data from the Chinese National Survey on Students' Constitution and Health for the years 1995, 2000, 2005, and 2010 pertaining to Tibetan children and adolescents in lase (Lhasa), aged 7-18 years old. Numbers of survey subjects for these years were: 2393, 2754, 2397, and 2643, respectively. RESULTS: Our results indicated that the rate of occurrence of stunting in Tibet has evidenced a gradual decline: for boys, from 26.8% in 2000 to 9.3% in 2010; and for girls, from 25.8% in 2000 to 10.8% in 2010. In general, the wasting rate for both boys and girls in Tibet has gradually decreased over time: for boys, from 17.7% in 1995 to 4.6% in 2005; and for girls from 12.5% in 1995 to 2.3% in 2005. The stunting rates of boys aged 7-13 years old and of girls aged 7-11 years old were 67.5% and 53.1%, respectively, while these rates for boys aged 14-18 years old and girls aged 12-18 years old were 32.5% and 46.9%, respectively. CONCLUSION: Stunting and wasting rates of Tibetan children and adolescents indicate a gradual declining trend over time. The stunting rates of both boys and girls during early puberty were significantly higher than those during late puberty.

Empirical changes in the prevalence of overweight and obesity among Chinese students from 1985 to 2010 and corresponding preventive strategies.

OBJECTIVE: To determine the extent of the obesity epidemic in school-aged Chinese children in 2010 and track the increasing trend in different socioeconomic regions over the preceding 25 years. Strategies for preventing childhood obesity are suggested. METHODS: We used a dataset provided by the Chinese National Survey on Students' Constitution and Health from 1985-2010. Subjects were 7-18-year-old students randomly selected from urban and rural areas in 30 provinces. Eight subgroups were created according to region and socioeconomic status. RESULTS: Increased rates of the epidemic (overweight and obesity combined) were greatest in large coastal cities-32.6% and 19.1% among males and females, respectively. These rates has neared that of developed countries. Similar increases were found in all other regions, including the once poverty-stricken rural west. The epidemic in most of the rural areas began after 2000, but has spread swiftly over the last decade. In 2010, it was estimated that 9.9% of Chinese school-aged children and adolescents were overweight and that an additional 5.1% were obese, representing an estimated 30.43 million individuals. CONCLUSION: The prognosis for China's childhood-obesity epidemic is dire. To prevent childhood obesity, we suggest several strategies, including reasonable dietary intake, increase physical activity, a change in sedentary lifestyles and corresponding behavioral modifications.

Secular change in stature of urban Chinese children and adolescents, 1985-2010.

OBJECTIVE: Research evidence shows a secular trend in Chinese physical growth in recent years. The aim of this study was to analyze and assess changes in stature of children and adolescents during the 25 years from 1985-2010, using national data. METHODS: Data came from successive cycles of the Chinese National Survey on Students' Constitution and Health (CNSSCH). Subjects were 7- to 18-year-old children and adolescents. RESULTS: An overall positive secular trend occurred in urban China during 1985-2010. The overall average rates of increment were 2.4 and 1.7 cm/decade for boys and girls, respectively. Total increases in adult stature for boys and girls were 2.6 and 1.7 cm, yielding rates of 1.0 and 0.7 cm/decade, respectively. Cities with different socioeconomic levels had different characteristic trends. Mean stature increases in big cities were larger than those in moderate and small cities, and boys and girls in moderate and small cities showed greater potential for growth in stature. CONCLUSION: An overall positive secular growth trend was associated with socioeconomic progress and differed with area socioeconomic levels. School policies and strategies should be developed based on increased stature, and should continue narrowing the inequity between different socioeconomic populations.

Secular changes on the distribution of body mass index among Chinese children and adolescents, 1985-2010.

OBJECTIVE: To analyze the change in Body Mass Index (BMI) distribution among Chinese children and adolescents for the development of more effective intervention for childhood obesity. METHODS: Data on the national students' constitution and health survey between 1985 and 2010 was used for this study. Subjects were students aged 7-18 randomly selected from 30 provinces in China. BMI for-age curves were developed by LMS method, and the trend of BMI distribution was determined by comparing the upper BMI percentiles and analyzing the skew shift of distribution between 1985 and 2010. RESULTS: An overall positive swift trend of BMI between 1985 and 2010 was observed among the Chinese school-age children and adolescents. The average median of the BMI increased from 16.8 and 17.0 kg/m2 to 18.2 and 17.9 kg/m2 in 25 years, with increments 0.56 and 0.36 kg/m2 per decade for males and females, respectively. The more obvious increments were found at the high BMI. The total increments of BMI in this period were 4.03 and 2.20 kg/m2 at the 85th, 6.14 and 3.57 kg/m2 at the 95th, and 6.99 and 4.27 kg/m2 at the 97th percentiles, for males and females, respectively. CONCLUSION: Obvious increments were observed at high BMI of the Chinese children and adolescents. More effective interventions should be taken for control and prevention of obesity and its health consequence for these subgroups. It is necessary to establish a risk-complex system consisting of the identification of BMI scope, the screen of the disease risk factors and the assessment of excessive adiposity.

Longitudinal study on infants' temperament and physical development in Beijing, China.

The objective of this longitudinal study is to explore the relationship between temperament and physical development among infants in Beijing, China. A total of 1117 term, normal and singleton infants were followed regularly for 12 months. Body weight and horizontal length were measured at 42 days and monthly from the third to twelfth month of their lives. Infants' temperament was assessed using the revised Chinese infants' temperament scale when the infants were 6 months. There was a significant difference on temperament dimensions between infants' genders (P < 0.05). Infants' weight and length were significantly related to their parents' weight and height. Infants with positive temperaments (easy and intermediate) were heavier than those with negative temperaments (difficult and slow to warm up) (P < 0.05). The horizontal length of boys was related to their temperament categories (P < 0.05). Infants' weight and length were significantly related to their temperament category and parents' weight and height.

[Comparative study of sexual behaviors of high school students between urban and rural China].

OBJECTIVE: To analyze the situation of sexual behavior in urban and rural Chinese high school students, and to make suggestions for providing appropriate sexual education in the future. METHODS: An anonymous questionnaire survey was conducted in 224 770 high school students selected by using multi-stage stratified cluster sampling method in 28 provincial units of China. RESULTS: Overall, 5.9% high school students reported that they had had sexual intercourses, and the prevalence rate of having had sexual intercourses was higher in the urban students (6.2%) than in the rural (5.2%) students (χ(2)=83.290, P<0.01), and higher in the boys (8.8%) than in the girls (3.3%, χ(2)=2 944.456, P<0.01). Of all the subjects, 44.6% reported that they had forced sex; the prevalence rates were 43.5% and 47.5% in the urban and rural students (χ(2)=16.237, P<0.01), respectively, and lower in the boys (39.7%) than in the girls (55.8%, χ(2)=285.089, P<0.01). Boys, higher grades, vocational schools, living without their parents and in areas of West China were found to be the risk factors to sexual intercourses in the urban and rural students. The pattern of forced sexual intercourses was slightly different between the urban and rural students, however, girls, ordinary schools, living without their parents and in areas of West China were the risk factors. CONCLUSION: Sexual education should be taken as soon as possible by using scientific as well as systematic methods in the occupational school students, and students living without their parents and in areas of West China.

The epidemiology of alcohol consumption and misuse among Chinese college students.

AIMS: To understand alcohol-related risk behaviours among Chinese college students. METHODS: As part of the first China National Youth Risk Behaviour Survey, undertaken in 2009, 52,150 students at 119 colleges were randomly sampled. Information was obtained from self-administered questionnaires. RESULTS: Prevalences were: lifetime drinkers 80.8%, current drinkers 49.3% (drank alcohol in past 30 days) and binge drinkers 23.5% ('binge drinkers' reporting at least five alcoholic drinks on a single occasion at least six times during the past 30 days). Multinomial logistic analysis revealed the contribution of sociodemographic factors to three high-risk drinking behaviours: odds ratio (95% confidence interval) = 3.64 (2.69-4.60) with frequent drinking; 3.27 (1.82-4.72) with binge drinking; and 5.48 (3.20-7.77) with heavy binge drinking. These three rates were greater among males than females, in the Western more than the Eastern region, among students living off-campus and among those whose mothers had higher education. Heavy drinking was linked to lower academic self-rating. CONCLUSION: There is a trend towards risky drinking among Chinese college students. Measures such as a minimum drinking age, advertisement restrictions, taxation, drunk-driving penalties and campaigns to heighten public awareness of alcohol-related health risks should be instituted in order to improve the situation on college campuses where alcohol abuse is particularly prevalent.

[Relationship between waist circumference and body mass index and metabolic syndrome related traits among middle school students in Beijing].

OBJECTIVE: To analyze the relationship between waist circumference (WC) and metabolic syndrome (MS) related traits among middle school students in Beijing and to provide the proof for making WC cut-offs among Chinese children and adolescents. METHODS: In the study, 1 427 students aged 13-18 years were investigated. The indexes included height, weight, WC, blood pressure, total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol and fasting blood glucose. The subjects were divided into three WC groups by using P(75) and P(90) of WC reference norms for Chinese children and adolescents. Obesity and MS components were assessed with the criteria of Working Group on Obesity in China and International Diabetes Federation, respectively. RESULTS: HDL-cholesterol in high WC group was lower than that in low WC group, and other MS related traits showed the opposite direction. Excepting fasting glucose, female total cholesterol and triglycerides, MS related traits were different significantly within the WC groups. Excepting raised fasting blood glucose and female raised triglycerides, the prevalence of MS components increased and aggregated in high WC group significantly. The distribution of different WC groups was correlated with that of obesity groups based on body mass index criterion. CONCLUSION: The P(75) and P(90) of WC reference norms could well indicate the increase of the prevalence of MS components, suggesting the increased risk for cardiovascular disease.

[Analysis of HIV/AIDS related risk behaviors and their impact factors among out-of-school adolescents in outflow areas].

OBJECTIVE: To analyze HIV/AIDS related risk behaviors among unmarried outside school adolescents and the impact factors in outflow areas, in order to provide basis for related health education. METHODS: Using cluster sampling method, we investigated a vocational training center for all 15- to 24-year-old unmarried outside school youths in one county. The structured questionnaire based on the Theory of Reasoned Action was anonymous, which filled envelopes on the spot. A total of 1 800 questionnaires were recovered, and 1 712 questionnaires were valid. Epidata 3.0 was used for establishing a database and SPSS 13.0 for statistical analysis. RESULTS: (1) The incidence of HIV/AIDS risk behaviors of the outside school adolescents was high: 18.0% of the respondents had sexual behavior, 27.3% had never used condom when sexed in the past three months, 31.0% had multiple sexual partners, and 9.7% had drug abuse experience; the rate of HIV/AIDS-related knowledge was only 25.1%; peer environment of respondents was poor. (2) The use of condoms was correlated with those who had higher score of AIDS knowledge, and who could talk about condoms in sexual intercourse; The multiple sexual partners' behavior was correlated with age, friends who were themselves multiple sexual partners, high score of the attitude, and the subjective norm; The commercial sex was correlated with the family address, high score of the HIV/AIDS-related knowledge, friends who had commercial sex, the subjective norm and the intention of behavior, The drug abuse behavior was correlated with age, high score of the HIV/AIDS-related knowledge, drug abuse among their friends, the subjective norm, and the intention of behavior. (3) Subjective norms and behavioral intentions could better predict the occurrence of HIV/AIDS risk behaviors. CONCLUSION: The outside school adolescents are at risk in lack of HIV/AIDS-related knowledge and coping skills of negative peer pressure, so providing the related health education before they go and work outside their home is the "critical period".

Regional, socioeconomic and urban-rural disparities in child and adolescent obesity in China: a multilevel analysis.

AIM: To study socio-demographic patterns of obesity in Chinese children and adolescents. METHODS: Data came from the 2005 cycle of the Chinese National Survey on Student's Constitution and Health. In all, 231,326 subjects aged 7-18 years, distributed across 622 schools and 30 provinces, were analysed. Multilevel modelling was used to estimate variations at individual, school area and province levels. RESULTS: The prevalence of obesity varied enormously across different areas. Young people living in high socioeconomic and urban areas had higher body mass index (BMI) and higher odds of overweight and obesity than those living in lower socioeconomic and rural areas. Subjects living in provinces with a higher standard of living, as indicated by less perinatal mortality, lower Engel coefficient, and higher personal expenditure on health had higher BMI and higher odds of overweight and obesity than those living in less affluent provinces. An interaction between gender and urbanicity revealed that boys in urban areas were especially prone to obesity. CONCLUSION: In contrast to most present-day high income countries, obesity among young people in China is associated with affluence and urban residence. Intervention and strategy for obesity prevention should be targeting high socioeconomic families in urban areas, perhaps with particular focus on boys.

Sexual intercourse and high-risk sexual behaviours among a national sample of urban adolescents in China.

BACKGROUND: To describe the characteristics of a population with high-risk sexual behaviours and associations between sexual intercourse, high-risk sexual behaviours and socio-demographic characteristics among Chinese urban adolescents. METHODS: In 2005, 109,754 students in grades 10-12 and 33,653 college students were anonymously surveyed using a Chinese Youth Risk Behaviour Survey. Demographic variables and indicators of forced sex, condom use and unintended pregnancy were analysed with multiple logistic regressions. RESULTS: Of students surveyed, median age was 17.6 (range 14-24 years) and 76,233 were female (53.2%); 4.8% of high school students reported had experienced sexual intercourse; of these, 32.8% reported had forced sex; 11.3% of college students reported had experienced sexual intercourse and of these, the prevalence of forced sex, condom use and unintended pregnancy were 23.5, 49.7 and 24.2%, respectively. School type and socioeconomic status were found to be independently associated with sexual intercourse and forced sex for high school students. For college students, educational level, school type, family structure, maternal education and socioeconomic status were independently associated with high-risk sexual behaviours. CONCLUSION: This study highlights the association between high-risk sexual behaviours and school type and socioeconomic status. These results strongly suggest the importance of providing sex education in high schools and lower socioeconomic areas.

Waist circumference distribution of Chinese school-age children and adolescents.

BACKGROUND: Waist circumference (WC), a proxy measure of central body fat, is a better predictor than overall body fat for cardiovascular risk factors in both adults and children. WC cutoffs have been established in many countries, but the national WC reference has not been developed in China. OBJECTIVE: To study the distribution of WC in a representative group of Chinese children for establishing Chinese WC cutoff points. METHODS: Cross-sectional data obtained from 15 mainland provinces and Hong Kong were collected. There were 160,225 children and adolescents aged 7-18 years old in total. The subjects were divided into five regional groups namely costal city, other city, north rural, south rural, and Hong Kong, for analyzing the distribution of WC. RESULTS: A large variation in WC distribution was found among the five groups for both sexes. Coastal city group had the highest P85 WC values consistently from the early school ages to 18-year-old compared with other groups. In contrast, south rural group had P85 values consistently lagged behind not only the city groups but also the north rural group. Hong Kong group had a high P85 WC at early ages, but because of the smaller increments of WC during adolescence, the P85 curve was gradually exceeded by the north rural groups. Catch-up trend was found in the two rural groups since the peak of puberty. These disparities were caused by not only socioeconomic and urban-rural factors but also north-south differences. Because of the regional variation of WC, a "gradient" prevalence of central obesity was prospected among these groups. Comparisons of WC distributions between the Chinese and the U.S.A. or Netherlands demonstrated the necessary of setting up China's own WC cutoffs. Sex and age-specific percentiles were obtained and smoothed by using LMS method. CONCLUSION: The data obtained from this study could be used to develop national WC cutoff points for Chinese children and adolescents.

Waist circumference reference values for screening cardiovascular risk factors in Chinese children and adolescents.

OBJECTIVES: To explore the optimal threshold values of waist circumference (WC) for detecting cardiovascular (CV) risk factors among Chinese children and adolescents. METHODS: Association of WC with CV risk factors was studied among 65,898 children aged 7-18 years whose data were pooled from nine previous studies in China. CV risk factors in this study included hypertension (blood pressure above 95 percentile levels), dyslipidemia (with one or more of the following three indexes: TG > or = 1.7 mmol/L, TC > or = 5.18 mmol/L, and HDL-C < or = 1.04 mmol/L) and elevated glucose level (fasting plasma glucose > or = 5.6 mmol/L). Receive-operating characteristic analysis (ROC) and logistic regression were employed to derive optimal age- and sex-specific waist circumference references for predicting CV risk factors. RESULTS: A slight increasing trend of CV risk factors was observed starting from the 75th percentile of waist circumference in the study population, while a remarkable increasing trend occurred from the 90th percentile. The optimal waist circumference thresholds for predicting high blood pressures were at the 75th percentile for both boys and girls, which was at the 90th percentiles for detecting at least two of the above three CV risk factors. In comparison with children with waist circumference below the 75th percentile, the odds ratio of two CV risk factors doubled among children with waist circumference between the 75th and the 90th percentile, and increased by 6 times among children with waist circumference above the 90th percentile. The trend of high blood pressure increasing with waist circumference remained significant after having been stratified by BMI category. CONCLUSION: The 75th and the 90th percentiles of WC are the optimal cut-off points for predicting an increased and a substantially increased risk of CV factors in Chinese children and adolescents, respectively.

Genetic and environmental influences on serum lipids and the effects of puberty: a Chinese twin study.

AIM: To study the contribution of genes and environment on the variation of serum lipids and the effects of puberty. METHODS: In total, 314 same-sex twin pairs aged 5-18 years were studied. Puberty was marked physiologically by spermarche/menarche, and model fitting was used to analyse the genetic and environmental variance and its difference before and after puberty. RESULTS: Lipid levels were different before and after puberty. The genetic factor had an important influence on lipid levels; the heritability estimates of total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), lipoprotein(a) (Lp(a)) and apolipoprotein E (ApoE) were between 49 and 86%. The total phenotypic variances of TC, HDL, LDL, Lp(a) and ApoE decreased after puberty, mainly as a result of decrease of genetic variance, even though the common environmental variance for HDL, Lp(a) and ApoE increased. CONCLUSION: Genes and the environment have different effects on the levels of different lipids. The shared environmental effects on lipids are very important in children. The role of puberty on lipids deserves future study.

Secular growth changes in stature and weight for Chinese Mongolian youth, 1964-2005.

BACKGROUND: A secular growth trend has been demonstrated in China during the past half century. However, few studies have involved minority ethnicity. AIM: This study demonstrates secular changes in stature and weight for Chinese Mongolians from 1964 to 2005, and analyses the correlations with environmental factors, revealing inequalities within populations. SUBJECTS AND METHODS: Data were gathered from 7- to 18-year-old students in the Inner Mongolian Autonomous Region of China, both from local records in 1964 and from the 1985, 1991, 1995, 2000 and 2005 cycles of the Chinese National Survey on Students' Constitution and Health. RESULTS: During the past 41 years, the average rates of stature increments for 7- to 17- year-olds are 1.9 and 2.0 cm per decade, of weight are 2.2 and 1.5 kg per decade and of BMI are 0.5 and 0.3 kg/m(2) per decade, for males and females, respectively. The overall increments of stature in 18-year-old males and females from 1985 to 2005 are 2.3 and 2.1 cm, respectively. The rate of change of stature is stronger in the first three decades, while that of weight and BMI are greater in the last decade. Evidence strongly suggests that changes may have occurred since the late 1970s. CONCLUSION: The positive growth changes of Chinese Mongolian people are closely related to urbanization, socio-economic progress and living improvements.

[Investigation of HIV/AIDS related knowledge and attitude among 6,487 high school students].

OBJECTIVE: To investigate HIV/AIDS related knowledge and attitude among high school students in China, and to preliminarily evaluate the effects of the special HIV/AIDS prevention education programme. METHODS: A total of 6487 high school students from 24 high schools of Beijing, Zhengzhou and Tangshan were investigated by using questionnaire, among which, 6487 students completed the questionnaire (96.08%). chi(2) test, t test and one way ANOVA were used to test the group differences and logistic regression was employed for further analysis. P < 0.05 was considered as statistically significance. RESULTS: The mean knowledge and attitude scores of the students were separately 14.42 out of 20 and 6.47 out of 10. Students from Tangshan had the significantly (P < 0.001) highest knowledge and attitude level (average score of knowledge = 15.11, average score of attitude = 7.21) followed by Beijing (average score of knowledge = 14.62, average score of attitude = 6.15) and Zhengzhou (average score of knowledge = 13.56, average score of attitude = 6.07). The significant differences were observed in all except the varying attitude between Zhengzhou and Beijing (Knowledge comparison: t(Tangshan vs Beijing) = 0.49, P < 0.001, t(Tangshan vs Zhengzhou) = 1.56, P < 0.001, t(Zhengzhou vs Beijing) = 1.07, P < 0.001; Attitude Comparison: t(Tangshan vs Beijing) = 1.06, P < 0.001, t(Tangshan vs Zhengzhou) = 1.14, P < 0.001, t(Zhengzhou vs Beijing) = 0.08, P = 0.282). Boys had higher knowledge scores (average score of knowledge = 14.61) than those of girls (average score of knowledge = 14.23, t = 4.22, P < 0.001) but no significant difference was found (average knowledge score of boys = 6.47, average knowledge score of girls = 6.48, t = 0.16, P = 0.869). Higher knowledge level (OR = 1.21, P < 0.001) and being a rural student (OR = 1.31, P < 0.001) were significantly associated with higher attitude level, while higher grade (OR = 0.85, P = 0.003) and better academic performance (OR = 0.94, P = 0.003) were negative predictors of attitude. CONCLUSION: The HIV/AIDS related knowledge among high school students in China was relatively limited and instability positive attitude under the pressure of social desirability. It is necessary to tailor the special education strategies for further education effect improvement.