Analysis of awareness of HIV/AIDS-related knowledge and related behavior among men who have sex with men (MSM) in Changsha / 中华疾病控制杂志

@# Objective To understand the awareness of HIV/AIDS-related knowledge and characteristics of sexual behaviors among men who have sex with men (MSM) in Changsha City. Methods By a snowball sampling method, volunteers were recruited in two social public welfare organizations in Changsha (Qingcai and Zhongda Sunshine) and interviewed by anonymous electronic questionnaires. Data were analyzed using software SPSS 19.0. Results Among 150 MSM, the overall awareness rate of HIV/ AIDS-related knowledge was 86.0% (129/150). For different demographic characteristics, higher age group, higher education level and higher income groups had significantly higher rates of awareness about HIV/AIDS related knowledge, compared with the reference groups, respectively. For the sexual behaviors, 32.7% of the investigated MSM population had their first MSM sexual intercourse at age of <18 years old, the rate of ≥18 years old group was significantly higher than the <18 years old group (2=4.315, P=0.038), 46.7% of the MSM population had more than 1 sexual partner during the past six months, the ratio of MSM used condoms in the sexual intercourse occasionally or never was 29.3% and 6.7%, respectively. Conclusions Young age, relatively low educational level and low income MSM in Changsha had a relative low awareness of HIV/AIDS-related knowledge. MSM in Changsha City had first MSM sexual intercourse at a very younger age. There is an urgent need to take well-targeted measures to improve the HIV/AIDS-related knowledge with special MSM population, and develop effective intervention measures for the high-risk sexual behaviors among MSM.

The Influence of Secular Trends in Body Height and Weight on the Prevalence of Overweight and Obesity among Chinese Children and Adolescents / 生物医学与环境科学（英文）

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

An objective measure to evaluate actual body shape among children and adolescents in China / 生物医学与环境科学（英文）

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

Association between abdominal obesity and blood pressure among 7 to 10 years old Chinese children / 中华预防医学杂志

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

Analysis of influencing factors on physical endurance of Chinese primary and middle school students aged 10 to 17 / 中华预防医学杂志

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

Association between early menarche and physical fitness among adolescent girls in China / 中华预防医学杂志

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

Association between early onset of menarche and anthropometry measurements among adolescent girls in China / 中华预防医学杂志

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

Association between early age at menarche and blood pressure in Chinese girls aged 7 to 17 years / 中华预防医学杂志

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