Objective To describe the characteristics of sexual debut among college students in China to provide appropriate sex education in that population. Methods An anonymous questionnaire survey was conducted among 33 653 college students selected by multi-stage stratified cluster sampling method in 18 provinces and cities of China. Results The percentage of students who had initiated sexual intercourse before age 14 was 1.9%. Overall, male students (2.8%) were significantly more likely to have initiated sexual intercourse before age 14, than female students (1.1%). The percentage of students who had initiated sexual intercourse from age 15 to 18 was 6.4% in males versus 2.1% in females. while the rates of students who had initiated sexual intercourse after age 19 were 6.9% in males and 2.6% in females. The first sexual intercourse was significantly associated with parental educational attainment, geographic location and family structure. Students whose parents were relatively well educated, living in the western areas of the country China, or with nucleus/extensive families were more likely to have early sex in their puberties. Conclusion Sexual education should be strengthened especially in the western areas, and targeted on the students whose parents with relatively higher educational background or who were from extensive families.

Objective To investigate the distribution and constituent of drug‐resistant bacteria of lower respiratory tract in‐fection among different regions (outpatient department ,wards ,RICU) to provide the basis for the clinical reasonable application of antimicrobial agents .Methods The K‐B disc diffusion method and the instrument method (VITEK‐TWO) were adopted and the detection results were interpreted according to the standards of CLSI 2010 .The detection data of 480 drug‐resistant strains isolated from the sputum ,branchoalveolar lavage fluid samples submitted in 3 regions of respiratory outpatients department by bacterial cul‐ture identification and drug susceptibility test were analyzed by using the WHONET5 .6 statistical software .Results The distribu‐tion and constituent of drug‐resistant bacteria of lower respiratory tract infection had obvious difference among 3 different regions . The top 4 of drug resistant bacteria were dominated by Gram‐negative bacteria .The drug resistance rate of Klebsiella pneumoniae in RICU was higher than that in the respiratory outpatients department and wards(P<0 .05) ,the resistance rate in the respiratory outpatients department ,wards and RICU to commonly used antibacterial drugs was similar;the multiple drug resistance of ESBLs‐producing strains was obviously higher than that of non‐ESBLs‐producing strains (P<0 .05) .Pseudomonas aeruginosa maintained the higher antibacterial activity to quinolone ,aminoglucosides ,cefepime ,imipenem ,cefoperazone/sulbactam ,and piperacillin/tazobactam ,but the resistance rate in RICU was significantly higher that in the respiratory outpatient department and wards (P<0 .05);the drug resistance of Acinetobacter baumanii in the respiratory wards and RICU was higher than that in the respiratory out‐patient department ,the resistances to imipenem were 64 .6% and 70 .4% respectively .The resistance of MRSA to rifampin in RICU was higher than that in the respiratory outpatient department and wards(P<0 .05) .Conclusion The distribution constituent and drug‐resistance rates have obvious differences among the respiratory outpatient department ,wards and RICU .Except being familiar with the drug resitant bacterial distribution and drug resistance rate monitoring situation ,clinical doctors should grasp the drug re‐sistance situation of drug resistant bacteria among different areas in various departments of own unit in order to rationally and effec‐tively use antibacterial drugs .

Objective To investigate the influence of competitive flow at different lelves on wall shear stress (WSS) of left internal mammary artery graft after coronary artery bypass grafting. Methods The left internal mammary artery (LIMA) left anterior descending (LAD) anastomotic model was extracted and reconstructed from CT images based on thresholding method by using SimVascular software. The competitive flow was divided into three groups according to different stenosis of LAD, including no competitive flow group (100% stenosis of LAD), mild competitive flow group (50% and 75% stenosis of LAD) and severe competitive flow group (0% and 30% stenosis of LAD). The hemodynamic performace of the anastomotic model under different conditions of competitive flow was observed by computational fluid dynamics (CFD) method. Results With the increment of competitive flow, the value of WSS was decreased gradually while the oscillation of WSS was increased remarkably in LIMA graft. The time average WSS (TAWSS) of LIMA graft in severe competitive flow group (0% stenosis: 2.73 Pa, 30% stenosis: 2.85 Pa) was lower than that in the mild competitive flow group (50% stenosis: 4.77 Pa, 75% stenosis: 6.01 Pa) and no competitive flow group (100% stenosis: 8.64 Pa), while its oscillatory shear index (OSI) (0% stenosis: 0.206; 30% stenosis: 0.085) was much higher than that in other two groups (50% stenosis: 0.014; 75% stenosis: 0.013; 100% stenosis: 0.006). Conclusions When the stonosis of LAD was smaller than 50%, the WSS in LIMA graft was obviously lower and oscillatory due to severe competitive flow. Such unfavorable feature of WSS may influence the long term-patency of LIMA graft and long term-survival of operations.

OBJECTIVETo study the effects of the divided functional recipes of Dahuang Zhechong pill( DHZCP) on atherosclerosis in rabbits.

METHODThe atherosclerotic model was established by the combination of hypercholesterol feeding and immune-injured endothelium in rabbits. Male New Zealand rabbits were randomly divided into nine groups: normal group, model group, Danshen group (0. 5 g x kg(-1) ), the low-dose(0. 5 g x kg(-1) ) and high-dose( 1.0 g - kg(-1) ) groups of the first divided recipe, the low-dose(0. 75 g x kg-' ) and high-dose(1. 5 g x kg(-1)) groups of the second divided recipe, the low-dose(0. 8 g x kg(-1) ) and high-dose( 1.6 g x kg(-1) ) groups of the third divided recipe. The effects of the divided functional recipes of DHZCP were observed in macropathology, histopathology and ultrastructure. Image analyzing system was used to determine atherosclerotic plaque area, intima thickness(IT) and intima-media thickness(IMT) in rabbit aorta.

RESULTThe divided functional recipes of DHZCP could significantly decreased the deposit of lipid and the atherosclerotic plaque area in aorta intima, relieve the histopathological changes of atherosclerosis, and inhibited the proliferation of vascular smooth muscle cells and collagen to reduce pachynsis of vascular intima. The divided functional recipes of DHZCP also reduced IT, IMT and IT/MT and reversed the contractive vascular remodeling.

CONCLUSIONThe divided functional recipes of DHZCP produce the different anti-atherosclerotic action, among which the first divided functional recipe exhibits more effective action.

Animals ; Aorta ; drug effects ; pathology ; ultrastructure ; Atherosclerosis ; pathology ; prevention & control ; Cell Proliferation ; drug effects ; Cockroaches ; chemistry ; Dose-Response Relationship, Drug ; Drug Combinations ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; therapeutic use ; Male ; Medicine, Chinese Traditional ; Microscopy, Electron ; Myocytes, Smooth Muscle ; drug effects ; pathology ; ultrastructure ; Plants, Medicinal ; chemistry ; Rabbits ; Random Allocation ; Rheum ; chemistry ; Tunica Intima ; drug effects ; pathology

OBJECTIVEIn order to develop strategies on prevention and cure for obesity, a study regarding dynamic analyses on the prevalence of obesity and overweight of Chinese children and adolescents was carried out.

METHODSData of more than 980 thousands students of Han nationality, aged 7 through 18 years old were collected from National Surveys on Chinese Students' Constitution and Health which were carried out in 1985, 1991, 1995 and 2000. Samples were divided into four groups as "metropolis", "medium and small sized cities", "prosperous village" and "below-averaged village". Study targets were screened using the new criterion-the "Reference Norm for Screening Overweight and Obesity in Chinese Children and Adolescents" which was set up by the Working Group on Obesity in China. The prevalence of overweight and obesity in various groups in different years were compared and analyzed.

RESULTSThe prevalence rates of obesity in 1985 including from the metropolis area, were only 0.2% and 0.1% for boys and girls, and the prevalence of overweight was between 1% and 2% indicating that was no trend of obesity epidemic then. However, a rapid increase of overweight prevalence has been noticed since the early 1990s, and the increments were more seen in the urban than in the rural areas and more in boys than in girls. In the most developed cities including Beijing, the prevalence rates of obesity appeared to be 4.7%, 3.8% and 3.2%, among three groups with higher risk: the 7 - 9, 10 - 12 year-old boys and 7 - 9 year-old girls, respectively. Both high prevalence rates of malnutrition and overweight were also found in that period. Around 1995, a large scale of increments of overweight were found both in the urban and rural groups. In the most developed metropolis, the prevalence of overweight was two to three folds more than that of 10 years ago. The prevalence of obesity were 6% - 8% for boys and 4% - 6% for girls, respectively. Since 2000, most of the Chinese metropolis have started the so called 'overall increment period' of obesity. The prevalence rates of obesity plus overweight had reached 25.4%, 25.5%, 17.0% and 14.3% for boys aged 7 - 9 years and 10 - 12 years, and girls aged 7 - 9 years and 10 - 12 years, respectively. Among them, the prevalence rates of obesity were 12.9% and 9.1% for boys aged 7 - 9 and 10 - 12 years, which had already reached the average level seen in the medium-developed countries in the world. Although the increments of overweight were high, the prevalence of obesity was still low in most of the other groups: 4.8% for boys and 2.6% for girls in the "medium sized" group, 1.5% for boys and 1.7% for girls in the "prosperous village" group, and 0.9% for boys and 1.2% for girls in the "below-averaged village" group, respectively.

CONCLUSIONSThe prevalence of obesity in Chinese children and adolescents was considered to be still relatively low. However, the rapid increasing of both obesity and overweight, in both urban and rural areas would arouse special attention. Comprehensive strategies of intervention should include periodical monitoring, education on pattern of nutrition, oxygen-consuming physical exercises and healthy dietary behavior. Two areas on obesity prevention to protect the child from becoming overweight in early ages, and to control the tendency of obesity from overweight, should be emphasized in order to improve the health status and life quality of the Chinese children and adolescents.

Adolescent ; Age Factors ; Child ; China ; epidemiology ; Female ; Humans ; Male ; Obesity ; epidemiology ; Prevalence ; Rural Population ; Sex Factors ; Time Factors ; Urban Population

Objective To study the distribution of waist circumference (WC) in a representative group of Chinese children for establishing the Chinese WC cut-off points. Methods Cross-sectional data obtained from 15 mainland provinces and Hong Kong were collected. There were 178 865 children and adolescents, aged 7-18 years-old in total. All subjects were divided into five regional groups- costal city, non-coastal city, northern rural, southern rural, and Hong Kong, for analyzing the distribution of WC. Results Large variations in WC distribution were found among the five groups for both sexes. The coastal city group had the highest P85 WC values consistently from the early school age to 18-year-old, when comparing with other groups. In contrast, southern rural group had P85 values consistently lagged behind, in both city group and in 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 northern rural groups. Catch-up trend was found in the two rural groups since peak puberty. These disparities were caused not only by factors related to socioeconomic and urban-rural but also to the geographic differences between the noah and the south. Because of the regional variation of WC, a "gradient" prevalence of central obesity was prospected among these groups. Closed associations were found between WC and height, weight and BMI in all age period. Comparison on the WC distributions between people from China, U.S.A or the Netherlands demonstrated the necessity of setting up China's own WC cutoffs.Sex and age-specific percentiles were obtained and smoothed by using the LMS method.Conclusion Data obtained from this study could be used to develop the national WC cutoff points for Chinese children and adolescents.

OBJECTIVETo identify the current epidemiological situation of injuries among adolescents in China and to provide basis for prevention and control.

METHODSAn anonymous questionnaire survey was conducted among 170 602 middle school students in 18 provinces and cities of China.

RESULTSThe overall incidence of injuries among middle school students was 43.7% while the incidence of recurrent injuries was 20.9%. The incidence of boys was higher than that of girls mainly because of the difference of the recurrent injuries incidence. The incidence of injuries decreased with age in our investigation, especially the recurrent injuries. The main causes of injuries were fall and collision, and the most frequent results of injuries were cut and bone-joint injuries among boys and girls. Key school, nucleic family and higher education level of mothers were protective factors to injuries.

CONCLUSIONAdolescents seemed high-risk population for injuries. Some preventive measures should be carried out to decrease the incidence of injuries especially on recurrent injuries.

Adolescent ; China ; epidemiology ; Female ; Humans ; Incidence ; Male ; Risk ; Students ; Wounds and Injuries ; epidemiology

OBJECTIVETo study the effect of beta3 adrenergic receptor (beta3AR) Trp64Arg and peroxisome proliferator activated receptor gamma 2 (PPARgamma2) Prol2Ala polymorphisms on insulin resistance.

METHODSOne hundred and eight dizygotic twin pairs were enrolled in this study. Microsatellite polymorphism was used to diagnose zygosity of twins. Insulin sensitivity was estimated with logarithm transformed homeostasis model assessment (HOMA). PCR-RFLP analysis was performed to detect the variants. As a supplement to the sib-pair method, identity by state (IBS) was used to analyze the association of polymorphisms with insulin sensitivity.

RESULTSThe genotype frequencies of Trp64Trg, Trp64Arg, and Arg64Arg were 72.3%, 23.8%, and 3.9%, respectively, while the genotype frequencies of Prol2Pro, Prol2Ala, and Alal2Ala were 89.9%, 9.6%, and 0.5%, respectively. For beta3AR Trp64Arg the interclass co-twin correlations of Waist-to-hip ratio (WHR), blood glucose (GLU), and insulin (INS), homeostasis model assessment insulin resistance index (HOMA-IR) of the twin pairs sharing 2 alleles of IBS were greater than those sharing 0-1 allele of IBS, and HOMA-IR had statistic significance. For PPARgamma2 Pro12Ala most traits of twin pairs sharing 2 alleles of IBS had greater correlations and statistic significance in body mass index (BMI), WHR, percent of body fat (PBF) and GLU, but there were low correlations of either insulin or HOMA-IR of twin pairs sharing 1 or 2 alleles of IBS. The combined effects of the two variations showed less squared significant twin-pair differences of INS and HOMA-IR among twins sharing 4 alleles of IBS.

CONCLUSIONSBeta3AR Trp64Arg and PPARgamma2 Pro12Ala polymorphisms might be associated with insulin resistance and obesity, and there might be slight synergistic effects between this two gene loci, and further studies are necessary to confirm this finding.

Adolescent ; Child ; Child, Preschool ; Genotype ; Humans ; Insulin Resistance ; genetics ; Obesity ; genetics ; PPAR gamma ; genetics ; Polymorphism, Genetic ; Receptors, Adrenergic, beta-3 ; genetics ; Twins, Dizygotic ; genetics ; metabolism

OBJECTIVETo assess the genetic and environmental influences on the somatotype of children and adolescents, and the effects of sex and age.

METHODSThe components of somatotype were calculated by using Heather-Cater method in a total of 376 twin pairs of Han nationality, including 245 monozygotic (MZ) and 131 like-sex dizygotic (DZ) twin pairs aged 6 to 18 years. Model-fitting method by Mx package was performed to evaluate the proportion of variance components and to analyze the effects of sex and age on each component of somatotype using the adjusted data for other two somatotype components. The heritability of each component in different development periods divided by growth spurt was also evaluated.

RESULTSThe estimated heritabilities of endomorphic, mesomorphic and ectomorphic components were 0.45, 0.80, 0.44 in boys, 0.82, 0.79 and 0.81 in girls respectively after adjusting age. In boys, the heritability of endomorphic component during late puberty was significantly higher than that during pre-puberty (t = 4.99, P < 0.01) and puberty (t = 6.16, P < 0.01), while the heritability of ectomorphic component during late puberty was significantly lower than that during pre-puberty (t = 3.35, P < 0.01) and puberty (t = 4.12, P < 0.01). In girls, the heritability of endomorphic (t = 2.77, P < 0.01) or mesomorphic (t = 2.08, P < 0.05) component during pre-puberty was significantly higher than that in early puberty.

CONCLUSIONThe genetic influence on somatotype of girls should be much more than that of boys, especially on the endomorphic and ectomorphic components. For boys, the mesomorphic component is mainly determined by genetic factors, but the other components are mainly affected by environmental ones. The effects of the development periods on the heritability of somatotype should be paid much attention to.

Adolescent ; Asian Continental Ancestry Group ; Child ; China ; Female ; Humans ; Male ; Somatotypes ; genetics ; Twins ; genetics ; Twins, Dizygotic ; genetics ; Twins, Monozygotic ; genetics

OBJECTIVESTo study the contribution of the genes and environment to variation of serum levels of lipids and lipoprotein.

METHODSOne hundred and forty-three healthy monozygotic (MZ) twin pairs and 93 dizygotic (DZ) ones aged 5 to 19 [with a mean of (11.2 +/- 3.4) years]. Microsatellite polymorphism (STR) was used to diagnose zygosity of twins, and intraclass correlation coefficient method and Falconer formula were performed to investigate heritability of serum lipids and lipoproteins unadjusted or adjusted for age and sex. Logarithmic transformation was used for data with skewed distribution. Influence of relevant physical and biochemical indicators on serum lipids and other components was analyzed with partial coefficients of correlation adjusted for age and sex.

RESULTSIn the twin samples, difference in serum level of triglycerides (TG) between MZ and DZ was not statistically significant with intraclass variation and intraclass correlation. There was significant difference in serum levels of total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and lipoprotein [Lp(a)] between MZ and DZ, with their heritability estimates of 0.56, 0.55, 0.49 and 0.58 unadjusted, respectively, and 0.63, 0.63, 0.55 and 0.64 adjusted for age and sex, respectively. Serum levels of TC, HDL-C, LDL-C and Lp(a) correlated reversely with age. Serum levels of TC, HDL-C and LDL-C in girls were slightly higher than those in boys. Most indicators for serum levels of lipids and lipoprotein, except for serum level of Lp(a) correlated with body mass index (BMI), body fat ratio, Pelidisi index, and other indexes such as blood pressure, blood sugar, serum level of calcium, adjusted for age and sex.

CONCLUSIONSSerum levels of TC, HDL-C and Lp(a) were influenced more greatly by genetic factors, and serum level of TG was mainly influenced by environmental ones. Levels of blood lipids in children were influenced by age and sex, and correlated with indicators that reflect their body fat and nutritional status.

Adolescent ; Adult ; Age Factors ; Child ; Cholesterol, HDL ; blood ; genetics ; Cholesterol, LDL ; blood ; genetics ; Female ; Humans ; Lipids ; blood ; genetics ; Lipoproteins ; blood ; genetics ; Male ; Sex Factors ; Triglycerides ; blood ; genetics ; Twin Studies as Topic ; Twins, Dizygotic ; Twins, Monozygotic