Report on Childhood Obesity in China (4) Prevalence and Trends of Overweight and Obesity in Chinese Urban School-age Children and Adolescents, 1985-2000

Objective To describe the nationwide prevalence of childhood overweight/obesity, and their group variations and trends over the past 20 years in the Chinese urban population. Methods Data sets of boys and girls at the age of 7-18 years collected from the series of Chinese national surveillance on students＇ constitution and health （CNSSCH） between 1985 and 2000 were divided into five socioeconomic and demographic groups, while BMI classification reference proposed by Working Group on Obesity in China （WGOC） was used as screening reference to calculate the prevalence and trends of overweight/obesity in these groups. Results In 2000, the prevalence of obesity and overweight in boys aged 7-18 years was 11.3% and 6.5% in Beijing, 13.2% and 4.9% in Shanghai, 9.9% and 4.5% in coastal big cities, and 5.8% and 2.0% in coastal medium/small-sized cities, respectively, while the prevalence of of obesity and overweight in girls of the same age group was 8.2% and 3.7% in Beijing, 7.3% and 2.6% in Shanghai, 5.9% and 2.8% in coastal big cities, and 4.8% and 1.7% in coastal medium/small-sized cities, respectively. The prevalence of obesity was low in most of the inland cities at an early stage of epidemic overweight. The epidemic manifested a gradient distribution in groups, which was closely related to status （SES） of the study population. However, a dramatic and steady increasing trend was witnessed among all sex-age subgroups in the five urban groups, and such a trend was stronger in boys than in girls, and much stronger in children than in adolescents. Conclusion Although China is at an early stage of epidemic obesity by and large, the prevalence of obesity in her urban population, particularly in coastal big cities has reached the average level of developed countries. The increasing trend has been rapid since early 1990s, and the increments in obesity and overweight are exceptionally high. The prospect of epidemic obesity in China is in no way optimistic. Therefore, preventive program should be focused on the improvement of the balance between caloric intake and energy expenditure, and interventions aimed at changing children＇s life styles.

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.

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.

Report on Childhood Obesity in China (7) Comparison of NCHS and WGOC

Objective To test the validity of Working Group on Obesity in China （WGOC） reference in screening childhood obesity using obesity-related metabolic syndrome （MS） and its components as disease risk evidence. Methods A total of 2020 adolescents （1007 boys and 1013 girls） aged 14-16 years were sampled in Beijing, China. Anthropometric and biochemical measurements, as well as blood pressure parameters were available. Prevalence of overweight/obesity and related MS risk factors were analyzed across different body mass index （BMI） categories. The sensitivity and specificity of the WGOC cut-offs were compared with those of National Central Health Statistics （NCHS）. Results Significantly high prevalence of MS and its components were found both in the obesity and overweight groups, which were classified by the WGOC and NCHS references. Similar distribution pattern of MS risk factors existed among different BMI categories, but the frequency and clustering of these factors in the obesity group classified by the NCHS were much higher. Owing to its irrelevant high cut-offs for overweight/obesity （especially for girls since the mid- adolescence）, the NCHS reference had a high specificity but a low sensitivity. By contrast, the WGOC reference with a high sensitivity （90.1% for boys and 89.2% for girls） and a relative high specificity （96.4% and 92.8% for obese boys and girls, 78.1% and 68.9% for overweight boys and girls respectively） was more suitable to support the need for early screening, intervention, and treatment of childhood obesity in China. Conclusion High sensitivity is more important than specificity in choosing appropriate screening tools for childhood obesity. Validity test demonstrates that it is rational to use the WGOC reference, established on the basis of the Chinese own reference population as a uniform screening tool for childhood obesity, which can effectively overcome the unnecessary treatment and psychosociai implications of stigmatization caused by misclassification.

Parental Anxiety and Quality of Life of Epileptic Children

Objective To investigate the prevalence of parental anxiety associated with epileptic children, and to explore whether and how this specific condition affects children＇s quality of life （QOL）, and what are the significant determinants for parental anxiety. Methods Three hundred and forty parents whose children were affected with known epilepsy were enrolled in the study. Questionnaires for quality of life in childhood epilepsy （QOLCE）, and hospital anxiety and depression （HAD） of parents were used to collect demographic data of both children and their parents, as well as clinical manifestations of epilepsy and family status. Results Parental anxiety （of any severity） was observed in 191 subjects at interview, giving a prevalence rate of 56.2%. Of the 191 subjects, 18.5% reported mild anxiety, 24.4% moderate anxiety, and 13.2% severe anxiety. Factors associated with parental anxiety included frequency of seizure in children, average monthly income per person and parents＇ knowledge about epilepsy （P〈O.05）. Parental anxiety significantly （P--O.O00） correlated with quality of life of children with epilepsy. Conclusion Parents of children with epilepsy are at high risk of having anxiety. Factors associated with parental anxiety originate both from children and from parents. Parental anxiety is significantly related with children＇s QOL. It is important for experts concerned to recognize such a relationship to improve the QOL of children and their parents.

Autism and Mental Retardation of Young Children in China

To understand the prevalence and rehabilitation status of autism and mental retardation in China. Methods Screening test and clinical assessment were conducted for the diagnosis of autism and mental retardation. The assessment included investigation of the histories of medical conditions and development of these two disorders, utilization and needs for the rehabilitation service, and related intellectual and behavioral appraisal. Results Among the 7345 children investigated, the prevalence of autism disorder was 1.10 cases per 1000 children aged 2-6 years （95% CI=0.34 to 2.54）, and the prevalence of mental retardation was 10.76 cases per 1000 children （95% CI=8.40 to 13.12）. All the children suffering from autistic disorder were intellectually disabled, whereas 31.0% of the non-autism mental retardates had other disabilities. The medical conditions prior to birth and perinatal period were important potential factors for autism. Half of the autistic children and 84% of the children with non-autism mental retardation had never received any rehabilitative service. Conclusions The prevalence of autistic disorder in children aged 2-6 years in Tianjin is rather high. It is urgent to improve the status of the autistic and intelligently disabled young children in China. In order to upgrade the level of early diagnostic and improve the intervention to autism and mental retardation, public awareness and training courses should be heightened.

Association of β3 Adrenergic Receptor and Peroxisome Proliferator-activated Receptor Gamma 2 Polymorphisms With Insulin Sensitivity:A Twin Study

Objective To study the effect of β3 adrenergic receptor （β3AR） Trp64Arg and peroxisome proliferator activated receptor gamma 2 （PPAR72） Prol2Ala polymorphisms on insulin resistance. Methods One 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. Results The genotype frequencies of Trp64Trg, Trp64Arg, and Arg64Arg were 72.3%, 23.8%, and 3.9%, respectively, while the genotype frequencies of Pro12Pro, Pro12Ala, and Ala12Ala were 89.9%, 9.6%, and 0.5%, respectively. For β3AR 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 HOMA4R had statistic significance. For PPAR3t2 Prol2Ala 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. Condusions β3AR Trp64Arg and PPAR）,2 Pro 12Ala 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.