Report on Childhood Obesity in China (2) Verification of BMI Classification Reference for Overweight and Obesity in Chinese Children and Adolescents

Objective To verify Working Group for Obesity in China （WGOC） recommended body mass index （BMI） classification reference for overweight and obesity in Chinese children and adolescents using the data of 2002 China Nationwide Nutrition and Health Survey. Methods PediaWic metabolic syndrome （MetS） and abnormality of each risk factor for MetS were defined using the criteria for US adolescents. Definition of hyper-TC, LDL, and dyslipidemia in adults was applied as well. The average level and abnormality rate of the metabolic indicators were described by BMI percentiles and compared with general linear model analysis. Receiver operating characteristic analysis was used to summarize the potential of BMI to discriminate between the presence and absence of the abnormality of these indicators. Results There was neither significantly increasing nor significantly decreasing trend of biochemical parameter levels in low BMI percentile range （〈65th）. Slight increasing trend from the 75th and a significant increase were found when BMI≥85th percentile. In general, the prevalence of the examined risk factors varied slightly when BMI percentile〈75th, and substantial increases were consistently seen when BMI percentile≥75th. As an indicator of hyper-TG, hypertension and MetS, the sensitivity and specificity were equal at the point of BMI〈75th percentile, and the Youden＇s index of risk factors also reached peak point before 75th percentile except for MetS. When the BMI percentile was used as the screening indicator of MetS, Youden＇s index reached peak point at 85th percentile, just the point in the ROC graph that was nearest to the upper left comer. Conclusion The BMI classification reference for overweight and obesity recommended by WGOC is rational to predict and prevent health risks in Chinese children and adolescents. Lower screening cut-off points, such as 83th percentile or 80th percentile, should not be excluded when they are considered as overweight criteria in future intervention or prevention studies.

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 ≥ 1.7 mmol/L, TC ≥ 5.18 mmol/L, and HDL-C ≤ 1.04 mmol/L） and elevated glucose level （fasting plasma glucose ≥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.

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, noah 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.

A Study on Bisphenol A,Nonylphenol,and Octylphenol in Human Urine amples Detected by SPE-UPLC-MS

Objective To establish a comprehensive analytical method based on SPE‐UPLC‐MS for the simultaneous determination of bisphenol A （BPA）, nonylphenol （NP）, and octylphenol （OP） in urine samples. Methods Sixty urine samples collected from healthy subjects were analyzed for BPA, NP, and OP concentrations. The samples were de‐conjugated by adding β‐glucuronidase and sulfatase. After the enzymatic treatment, the samples were subjected to the OASIS HLB column solid phase extraction cartridges so as to be cleaned and concentrated. The UPLC separation was performed on a Acquity UPLCTM BEH C18 column （2.1×100 mm, 1.7 μm） with a gradient elution system of methanol‐water as the mobile phase. Triple‐quadrupole mass spectrometry analyzer was used for the qualitative and quantitative analysis of UPLC‐MS/MS system. Results The limit of detection of BPA, NP, and OP was 0.10, 0.10, and 0.15 ng/mL, respectively. The recoveries of BPA, NP and OP were 80.1%‐108%, 81.3%‐109%, and 81.5%‐98.7%, respectively. Among the 60 urine samples, BPA was detected in 8 samples at the level of 0.297‐32.7ng/mL, NP was detected in 29 samples at the level of 1.69‐27.8 ng/mL, and OP was detected in 17 samples at the level of 0.407‐11.1 ng/mL. Conclusion The method is simple with high sensitivity and selectivity, and is suitable for the determination of BPA, NP, and OP in urine. As shown by our analysis , BPA, NP, and OP appear to be prevalent in human urine. This is particularly true for NP. The results from our study is therefore valuable for future studies to assess the exposure to BPA, NP, and OP in the general population.

Detection of Genetically Modified Crops by Combination of Multiplex PCR and Low-density DNA Microarray

Objective To develop a technique for simultaneous detection of various target genes in Roundup Ready soybean by combining multiplex PCR and low-density DNA microarray. Methods Two sets of the multiplex PCR system were used to amplify the target genes in genetically modified （GM） soybean. Seventeen capture probes （PCR products） and 17 pairs of corresponding primers were designed according to the genetic characteristics of Rroundup Ready soybean （GTS40-3-2）, maize （MonS10, Nk603, GA21）, canola （T45, MS1/RF1）, and rice （SCK） in many identified GM crops. All of the probes were categorized and identified as species-specific probes. One negative probe and one positive control probe were used to assess the efficiency of all reactions, and therefore eliminate any false positive and negative results. After multiplex PCR reaction, amplicons were adulterated with Cy5-dUTP and hybridized with DNA microarray. The array was then scanned to display the specific hybridization signals of target genes. The assay was applied to the analysis of sample of certified transgenic soybean （Roundup Ready GTS40-3-2） and canola （MS1/RF1）. Results A combination technique of multiplex PCR and DNA microarray was successfully developed to identify multi-target genes in Roundup Ready soybean and MS 1/RF1 canola with a great specificity and reliability. Reliable identification of genetic characteristics of Roundup Ready of GM soybean from genetically modified crops was achieved at 0.5% transgenic events, indicating a high sensitivity. Conclusion A combination technique of multiplex PCR and low-density DNA microarray can reliably detect and identify the genetically modified crops.

Relationship of Body Mass Index, Waist Circumference and Cardiovascular Risk Factors in Chinese Adult

Objective To compare the relative risk of waist circumference （WC） and/or BMI on cardiovascular risk factors. Methods A cross-sectional data of 41 087 adults （19 567 male and 21 520 female） from the 2002 China National Nutrition and Health Survey were examined. According to the obesity definition of WGOC （BMI, 24 kg/m^2 and 28 kg/m^2; WC, male 85 cm and 95 cm for male, 80 cm and 90 cm for female）, the study population were divided into 9 groups. The prevalence and odds ratio （ORs） of cardiovascular disease （CVD） risk factors （hypertension, high fasting plasma glucose and dyslipidemia） were compared among these 9 groups. Stepwise linear regression analyses were used to compare the likelihood of BMI and/or WC on CVD risk factors. Results Both the indexes levels and the odds ratios of CVD risk factors were significantly increased （decreased for HDL-C levels） along with the increase of WC and/or BMI, even when the effect of age, sex, income, education, sedentary activity and dietary factors were adjusted. The variances （R2） in CVD risk factors explained by WC only and BMI only were quite similar, but a little bit larger when WC and BMI were combined. The standard fl was higher of BMI when predicting systolic BP and was higher of WC when predicting TG, TC and HDL. Conclusions BMI and WC had independent effects on CVD risk factors and combination of BMI and WC would be more predictive. Findings from the present study provided substantive evidence for the WGOC recommendation of a combined use of BMI and WC classifications.

Studies on BN rats model to determine the potential allergenicity of proteins from genetically modified foods

AIM: To develop a Brown Norway (BN) rat model to determine the potential allergenicity of novel proteins in genetically modified food.METHODS: The allergenicity of different proteins were compared, including ovalbumin (OVA), a potent respiratory and food allergen, bovine serum albumin (BSA), a protein that is considered to have a lesser allergenic potential,and potato acid phosphatase (PAP), a non-allergenic protein when administered to BN rats via different routes of exposure (intraperitoneally or by gavage). IgG and IgE antibody responses were determined by ELISA and PCA,respectively. An immunoassay kit was used to determine the plasma histamine level. In addition, possible systemic effect of allergens was investigated by monitoring blood pressure.RESULTS: OVA provoked very vigorous protein-specific IgG and IgE responses, low grade protein-specific IgG and IgE responses were elicited by BSA, while by neither route did PAP elicit anything. In either routes of exposure,plasma histamine level in BN rats sensitized with OVA was higher than that of BSA or PAP. In addition, an oral challenge with BSA and PAP did not induce any effect on blood pressure, while a temporary drop in systolic blood pressure in few animals of each routes of exposure was found by an oral challenge with OVA.CONCLUSION: BN rat model might be a useful and predictive animal model to study the potential allergenicity of novel food proteins.

Report on Childhood Obesity in China (5) Body Weight, Body Dissatisfaction, and Depression Symptoms of Chinese Children Aged 9-10 Years

Objective To investigate the relationship between body weight, body dissatisfaction and depression symptoms among Chinese children. Methods The fasting body weight and height of the third and fourth grade students （n=3886, aged 9 or 10 years） from 20 schools in Beijing, China, were measured, and the students were asked to choose the figures of body image and to complete the self-reported children＇s depression inventory （CDI） questionnaire. Results The CDI Cronbach＇s alpha was 0.81. The total CDI score was 9.60±7.50, 13.2% of children （boys 16.7% vs girls 9.5%） were at risk of developing depression symptoms. Overweight girls, but not boys, had significantly higher total CDI score than their normal weight counteparts. Both obese girls and boys showed a higher negative self-esteem score. More than one fifth underweight girls still wanted to be thinner while more than one third obese boys still wanted to be heavier. Children who wanted to be thinner showed slightly higher scores of ineffectiveness and negative self-esteem. After introducing the body dissatisfaction into the model, overweight was still associated with total CDI score among girls and obesity was still associated with negative self-esteem among both boys and girls. Conclusion Overweight girls show a significantly higher depression symptom score than their normal weight counterparts, which maybe partially explained by body dissatisfaction. Obese boys and girls are both more likely to suffer from low self-esteem, which is partially explained by body dissatisfaction.

Report on Childhood Obesity in China (9): Sugar-sweetened Beverages Consumption and Obesity

Objective To explore the associations between sugar-sweetened beverage （SSB） consumption and obesity as well as obesity-related cardiometabolic disorders among children in China. Methods A total of 6974 （boys 3558, girls 3412） children aged 6-13 years participated in the study. Each participant’s height, weight, waist circumference, fasting glucose, triglycerides, total cholesterol, high- density lipoprotein cholesterol, and low-density lipoprotein cholesterol were measured. The type of beverage consumption was determined using a self-administered questionnaire. Results SSBs were consumed regularly by 46.1% of the children. The prevalence [adjusted odds ratio （95% confidence internal （CI）] of obesity was 7.6% [as the reference group （ref.）], 10.1% [1.36（1.07, 1.74）], and 11.6% [1.46（1.21, 1.75）], among children who regularly drank milk, other beverages and SSBs, respectively. Regularly drinking SSBs elevated the likelihood of abdominal obesity [adjusted odds ratio （95% CI）： 1.36 （1.17, 1.59）]. The prevalence [adjusted odds ratio （95% CI）] of obesity among children who regularly drank sports/caloric beverages, carbonated beverages, sweet tea, and plant protein beverages was 16.8% [2.00（1.31, 3.07）], 12.7% [1.52（1.23, 1.88）], 11.5% [1.52（1.18, 1.95）], and 10.4% [1.41（1.03, 1.94）], respectively, which was higher than that of regular milk drinkers [7.6 % （ref.）]. The prevalence [adjusted odds ratio （95% CI）] of abdominal obesity among children who regularly drank sweet tea, fruit/vegetable juices, and carbonated beverages was 17.7% [1.55（1.26, 1.90）], 16.2% [1.36（1.09, 1.70）], and 15.3% [1.24（1.03, 1.50）], respectively, which was much higher than that of regular milk drinkers [12.8% （ref.）]. Conclusions Regular SSB consumption was positively related to obesity and abdominal obesity. This relationship should be investigated further using a longitudinal study design.

Change of BMD after Weaning or Resumption of Menstruation in Chinese Women with Different FokI VDR-genotypes:A Randomized,Placebo-controlled,Calcium Supplementation Trial

Objective To investigate the effect of calcium supplementation on bone mineral density （BMD） in Chinese women with different Fokl vitamin D receptor （VDR） genotypes （FF, Ff, and ff） after weaning or resumption of menstruation during lactation. Methods A total of 40 subjects with the same Fokl VDR genotype were randomly divided into two groups： one received calcium tablet （600 mg once daily as CaCO3） and the other placebo tablet once daily for 1 year. At baseline, BMD was measured by dual-energy X-ray absorptiometry at lumbar spine （L2-L4） and at left hip whereas serum PICP, serum OC, and urinary CTX, serum 25（OH）VitD3, and serum estradiol were measured at weaning and I year thereafter. Results After the intervention, BMD at lumbar spine and at left hip increased significantly in all these women with a trend among different Fokl VDR genotypes such as FF 〉 Ff 〉 ff （P〈O.05, 〈0.01, and 〈0.001, respectively）. BMD at lumbar spine in women with FF VDR genotype increased much more rapidly than in those with ff VDR genotype （P〈0.05）. Compared with the control group women with the FF genotype regained more BMD after calcium supplementation （P〈0.05）. Conclusion Daily calcium 600 mg supplementation has beneficial effect on the bone health of women with FF VDR genotype.

Association between High Fat-low Carbohydrate Diet Score and Newly Diagnosed Type 2 Diabetes in Chinese Population

Objective To study the association between high fat-low carbohydrate diet score and newly diagnosed type 2 diabetes in Chinese population. Methods Data about 20 717 subjects aged 45-59 years from the cross-sectional 2002 China National Nutrition and Health Survey were analyzed. High fat-low carbohydrate diet was scored according to the energy of carbohydrate, fat, and protein. Results Of the 20 717 subjects, 1 332 were diagnosed with hyperglycemia and 662 were newly diagnosed with type 2 diabetes. Multivariate adjusted analysis showed that the highest score of type 2 diabetes patients was 2.75 （95% CI： 2.09-3.61）. The score of type 2 diabetes patients was 1.87 （95% CI： 1.35-2.58） after further adjustment for their socioeconomic status and physical activity. No significant difference was found in the odds ratio after further adjustment for BMI, blood pressure, lipid level, and energy intake. No evidence was observed for the relation between high fat-low carbohydrate-diet score in type 2 diabetes patients due to high family income, less education, physical activity, overweight, hypertension, high TG, or low HDL level. Conclusion High fat-low carbohydrate diets, far different from traditional Chinese diets, are associated with the high incidence of type 2 diabetes in Chinese population.

Report on Childhood Obesity in China(8):Effects and Sustainability of Physical Activity Intervention on Body Composition of Chinese Youth

Objectives To determine whether a large-scale physical activity intervention could affect body composition in primary school students in Beijing, China. Methods The study design was one-year cluster randomized controlled trial of physical activity intervention （20 rain of daily exercise in the classroom） with an additional year of follow-up among 4 700 students aged 8-11 years at baseline. Results After the one-year intervention, BMI increased by 0.56 kg/m2 （SD 1.15） in the intervention group and by 0.72 kg/m^2 （SD 1.20） in the control group, with a mean difference of-0.15 kg/m^2 （95% CI： -0.28 to -0.02）. BMI z score decreased by -0.05 （SD 0.44） in the intervention group, but increased by 0.01 （SD 0.46） in the control group, with a mean difference of-0.07 （-0.13 to -0.01）. After another year of follow up, compared to the control group, children in the intervention group had significantly lower BMI （-0.13, -0.25 to -0.01 ）, BMI z score （-0.05, -0.10 to -0.01）, fat mass （-0.27 kg, -0.53 to -0.02） and percent body fat （-0.53, -1.00 to -0.05）. The intervention had a more pronounced effect on weight, height, BMI, BMI z score, and body composition among obese children than among normal weight or overweight children. Compared to the control group, the intervention group had a significantly higher percentage of children who maintained or reduced their BMI z score at year 1 （P-0.008） and year 2 （P=-0.04）. Conclusions These findings suggest that 20 min of daily moderate to vigorous physical activity during the school year is a feasible and effective way to prevent excessive gain of body weight, BMI, and body fatness in primary school students.

Application of the WHO Growth Reference (2007) to Assess the Nutritional Status of Children in China

Objective To assess the nutrition status of children and adolescents in China using the WHO growth reference （2007） in comparison with that defined by the International Obesity Task Force （IOTF） and the Working Group on Obesity in China （WGOC）. Methods Overweight and obesity were defined by age-, sex-, specific BMI reference developed by WHO （2007）, IOTF （2000）, and WGOC （2004）, respectively. Stunting and thinness were defined as height and BMI less than two standard deviations （SD） of the WHO growth reference （2007）, respectively. Data of children and adolescents aged 5 to 19 years （n=54 857, 28 273 boys, 26 584 girls） from the 2002 China National Nutrition and Health Survey （CNNHS） were used in the study. Results The prevalence of overweight, obesity, stunting and thinness among Chinese children and adolescents aged 5-19 years was 5.0%, 1.2%, 13.8%, and 7.4%, respectively when the WHO growth reference （2007） was used, whereas the estimated absolute total number affected by these 4 conditions were 14.6, 3.7, 40.6, and 21.8 million, respectively. The prevalence of overweight and obesity was 18.1% in large cities, while the stunting prevalence was 25.1% in rural 4. Obesity prevalence assessed by the WHO growth reference was higher than that as assessed by the IOTF reference, and obesity prevalence assessed by the WGOC reference was lower than that as assessed by the IOTF reference. Conclusion The nutritional status of children and adolescents is not equal in different areas of China. Stunting is still the main health problem of the poor, while overweight and obesity are the main health problems in large cities.

An Assessment of Androgenic/Anti-androgenic Effects of GH Transgenic Carp by Hershberger Assay

Objective To evaluate the androgenic and anti-androgenic effects of GH （growth hormone） transgenic carp in male rats.Methods Hershberger assay was carried out in castrated male SD rats aged 4-5 weeks.Testosterone propionate （TP） （0.4 mg/kg BW） was administrated for a positive control,GH transgenic carp （3.0 g/kg BW）＋TP （0.4 mg/kg BW）,parental carp （3.0 g/kg BW） ＋ TP （0.4 mg/kg BW）,and flutamide （Flu） （3.0 g/kg BW） were used for negative controls,and vehicle was administered orally for a blank control.All groups were administrated for 10 consecutive days.At the end of the test,animals were anesthetized,then weights of accessory sex organ were measured.Serum testosterone （T）,luteinizing hormone （LH）,and Follicle-Stimulating Hormone （FSH） levels were detected.Results The weights ratios of the accessory sex organs and body weights showed no significant differences between the solvent control and the GH transgenic carp-treated groups.Serum concentrations of FSH,LH,and T of the rats treated with GH transgenic carp ＋ TP showed no significant changes,compared with those treated with TP only.Conclusion GH transgenic carp does not have any androgenic agonist or antagonist properties in vivo screening tests.

Interactions Between Effects of Estrogen Receptor Gene Polymorphisms on BMD and Experiences of the First Spermorrhea in Chinese Han Boys

Objective To study the interaction between polymorphisms of estrogen receptor （ER） gene and puberty on bone mineral density （BMD）. Methods One hundred and forty-six boys aged 13-17 years were divided into two groups according to their first sperrnorrhea. DNA was analyzed for Xba I and Pvu 1/genotypes by PCR-RFLP. BMD of the total body, forearm and lumbar spine was measured by dual-energy X-ray absorptiometry （DXA）. The relationship between polymorphisms of ER gene and BMD in these two groups was analyzed. Results The BMD at all sites in the sperrnorrhea group was significantly higher than that in the un-sperrnorrhea group. The independent contribution of ER genotypes to BMD at two pubertal stages was analyzed after adjusting co-variables. In the un-sperrnorrhea group, the BMD at distal 1/10 and 1/3 forearm of those carrying pp genotype was significantly higher than that of the non-carries, whereas in the sperrnorrhea group BMD in those carrying the same genotype was significantly lower than that in the non-carriers. Similar results were obtained by haplotype analysis. Multiple stepwise regression analysis showed that body weight, age and the first sperrnorrehea were the dominant determinants for BMD. BMD at forearm might be influenced by interaction between ER genotype and the first spermorrehea. Conclusion The polymorphisms of ER gene play a different role in BMD influenced by the first spermorrhea. Chinese boys carrying p or x allele should pay more attention to their bone mass.

Foodborne Pathogens in Retail Oysters in South China

Objective To investigate the occurrence of important foodbome pathogens in shellstock Pacific oysters in the food markets in South China. Methods From July 2007 to June 2008, retail oysters were collected in different seasons from South China and analyzed for the prevalence and levels of Listeria monocytogenes, Vibrio vulnificus and Vibrio parahaemolyticus. Results None of L. monocytogenes could be detected in any of the 202 oyster samples tested, while E vulnificus and E parahaemolyticus could be detected in 67 （54.9%） and 109 （89.3%） of the 122 oyster samples analyzed, respectively, with an MPN （most probable number） value greater than or equal to 3. V. wdnificus and Eparahaemolyticus with a more than 102 MPN/g were found in 36 （29.5%） and 59 （48.4%） of the 122 oyster samples, respectively. The tdh and trh genes were detected in 4 （0.3%） and 8 （0.6%） of the 1 349 V. parahaemolyticus isolates, respectively. Of the 122 samples, 4 （3.3%） was positive for either tdh or trh. The levels of E vulnificus and total V. parahaemolyticus in oysters in South China varied in different seasons. Conclusion V. vulnificus and pathogenic V. parahaemolyticus are frequently found in oysters in south China, which may pose a potential threat to public health. Data presented here will be useful for the microbiological risk assessment in oysters in China.

Modification and Evaluation of Brucella Broth Based Campylobacter jejuni Transport Medium

Reliable transport of Campylobocter jejuni isolates is critical to microbial epidemiology research, especially in developing countries without a good temperature control mailing system. Various factors, including oxygen, temperature, transport medium composition, could affect the survival of C jejunL In this study, the protective effects of different ingredients in C. jejuni transport media at 4 ℃ and 25 ℃ and under aerobic condition were quantitatively evaluated respectively. The results showed that enriched medium, supplementation with 5% blood and being kept at 4 ℃ could improve the viability of different C. jejuni strains during transport. In addition, supplementation with 25 mmol/L L-fucose in Wang＇s transport medium could significantly improve the survival of C.

Disease Risks of Childhood Obesity in China

Objective To estimate the relative risks of dyslipidemia, hypertension, diabetes mellitus, and metabolic syndromes among overweight and obese Chinese children compared with their normal weight counterparts. Methods Overweight and obesity were defined by age- and sex-specific BMI classification reference for Chinese children and adolescents. Pediatric metabolic syndrome （MetS） and each risk factor for MetS were defined using the criteria for US adolescents. Definition of hyper-TC, LDL, and dyslipidemia for adults was applied as well. General linear model factor analysis and chi-square test were used to compare the difference in metabolic indicators among normal weight, overweight, and obese groups. Multiple logistic regression analysis was performed to estimate the odds ratio of metabolic abnormalities between obesity, overweight, and normal weight children, after adjustment for living area, family economic level, age, sex, and daily exercise time and TV watching time, as well as different dietary indices in the model. Results Significant increases in blood lipids, glucose, and blood pressure were found among overweight and obese children as compared with their counterparts with normal weight. By applying WGOC-recommended BMI classification, the risks for hypertriglyceridemia, low HDL and dyslipidemia among overweight children were 1.9, 1.4, and 1.5 times, and was 3.3, 1.5, and 1.8 times among obese groups compared to their counterparts with normal weight after adjustment for age, sex, region, socioeconomic status, physical activity, and dietary intakes. The overweight and obese children （15-17.9 years） had a high-risk of developing hypertension, which was 2.3 and 2.9 times higher than their counterparts with normal weight. Above 90% obese adolescents had abdominal obesity, while less than 1% normal weight ones had abdominal obesity. No obese adolescents were free from any risk factors for MetS, while 36.9% of normal weight adolescents were from the risk factors. 83.3% obese boys and all obese girls had metabolic syndrome, while only 15.5% normal weight boys and 18.8% normal weight girls had metabolic syndrome. Four risk factors for metabolic syndrome were found in 8.3% obese boys while none in normal weight boys and girls. The prevalence of MetS among normal weight, overweight, and obesity groups was 1.5%, 18.3%, and 38.1% respectively. Conclusion The cardiovascular disease （CVD） risk factors are clustered in obese Chinese children. Our observations strongly suggest that efforts should be made to prevent the onset of overweight and its associated diseases during early childhood.

Report on Childhood Obesity in China (10): Association of Sleep Duration with Obesity

Objectives To explore the association of sleep duration with obesity among children in urban areas of China.Methods A total of 6 576 children（3 293 boys and 3 283 girls） aged 7-11 years were randomly selected from 36 primary schools in 6 metropolitan cities in China.A 7-day Physical Activity Recall was used to assess the sleep duration and physical activity level.The height,weight,waist circumference（WC） and percentage of body fat（%BF,as determined by bioelectrical impedance analysis technique） were measured by following the standardized operation procedures.The information on demography,lifestyle and eating habits was collected with a self-administered questionnaire from participants and their parents.Results The average sleep duration per night in the children was 9.7 h with the decreasing trends along with the increase of age（P0.05）.The sleep duration was negatively associated with body mass index（BMI） and WC in both boys and girls after adjustment for confounders（β value-0.23 and-0.82 for boys,-0.24 and-0.91 for girls,respectively,P0.01）.However,no significant association of sleep duration with %BF was found.Children who slept less than 9.0 h per night had a higher risk for overweight and obesity（OR=1.29,95% CI：1.01,1.64） and abdominal obesity（OR=1.38,95% CI：1.04,1.83） as compared with those who slept for 10.0-10.9 h.Conclusions Short sleep duration is associated with obesity.It is important to ensure adequate sleep duration of children and foster their healthy lifestyle at an early stage of life.

Particle-bound PCDD/Fs in the Atmosphere of an Electronic Waste Dismantling Area in China

Objective Particulate samples from the atmosphere in an electronic waste dismantling area were collected to investigate the levels and sources of polychlorinated dibenzo‐p‐dioxins and dibenzofurans （PCDD/Fs）. Methods Particulate samples including total suspended particulates （TSP） and particulate matter 2.5 μm diameter （PM2.5） were collected on selected non‐rainy days in summer （Jul 10–12, 2006） and winter （Jan 11–13, 2007） from Fengjiang （FJ）, an electronic waste （e‐waste） dismantling area in eastern China, and an adjacent area Luqiao （LQ）. The samples were analyzed by isotope dilution‐high resolution gas chromatography / high resolution mass spectrometry （HRGC/HRMS）. Results In FJ, the mean PCDD/F concentrations （mean TEQ values） were 280.6 pg Nm‐3 （3.432 pg WHO‐TEQ Nm‐3） for the TSP samples and 223.3 pg Nm‐3 （3.180 pg WHO‐TEQ Nm‐3） for the PM2.5 samples. The total PCDD/F concentrations and TEQs in the PM2.5 samples were about 66.8%‐108.0% of the TSP samples, indicating that the fine particles contained higher levels of PCDD/Fs than coarse particles. The PCDD/F levels in FJ were much higher than those detected in common urban areas around the world, suggesting that the study area was heavily polluted by PCDD/Fs. Furthermore, the total average daily PCDD/F intake in FJ was estimated at 62.11 pg WHO‐TEQ kg‐1·day‐1 for adults and 110.11 pg WHO‐TEQ kg‐1·day‐1 for children, which greatly exceeds the WHO （1998） tolerable daily intake of 1–4 pg of WHO‐TEQ kg‐1·day‐1. Conclusion The PCDD/F homologues and congener profiles confirmed that the PCDD/Fs in FJ originated from crude e‐waste recycling activities. The severe dioxin pollution present in FJ has also substantially influenced the adjacent area of LQ through atmospheric transport. Open burning of medical waste was another source of PCDD/Fs identified in LQ.