The Prevalence Of Metabolic Syndrome And The Association Among Ghrelin, Adipocytokines And Metabolic Syndrome In 8-10 Years Old Children In Beijing

BackgroundThe metabolic syndrome is a clinical construct characterized by a clustering of cardiovascular disease risk factors and is associated with an increased risk of type 2 diabetes.Obesity,insulin resistance,dyslipidemia,and hypertension are common to all. The prevalence of overweight among children and adolescents has dramatically increased worldwide as are the consequences that include risk of the metabolic syndrome and mortality presented among early childhood.Studies have established that the prevalence of MS in children and adolescents is increased markedly and it tracks into adulthood and also predicts the metabolic syndrome in adults.Adipose tissue has an active role in energy balance and body weight regulation.The adipocyte secretes polypeptides,such as leptin,adiponectin,which comprise a complex network with gastric peptide ghrelin that may be associated with the development of obesity,insulin resistance,and diabetes.However,there is not much information on the prevalence of MS in children and the relationship between MS and socioeconomic status in Chinese children,especially in studies with large samples.In addition,no research about associations between leptin,adiponectin,ghrelin,insulin and pediatric MS has been done among 8-10 years old children in China.ObjectivesThe main aim of the study is to investigate the prevalence of MS and its components in children aged 8-10 years and to evaluate the relationship between SES and MS in children and to provide the fundamental data for the prevention and management of MS.Secondly,we examined the effect of different degrees of ghrelin, leptin,adiponectin,insulin in children on the prevalence of the metabolic syndrome. This could better illuminate its pathophysiology and relationship to MS and these putative surrogate markers of future cardiovascular disease. Subjects and methodsA cross-sectional study was carried out in this study.A total of 1000 children aged 8-10 years were randomly selected.Their weight,height,waist circumference and blood pressure(BP) were measured,and their body mass index(BMI) was calculated.Fasting triglycerides,HDL-cholesterol,ghrelin,leptin,adiponectin,glucose,insulin concentrations were determined.All participant children were inquired puberty development,their parent educational level and household income.MS was defined as≥3 of the following:(1) waist circumference＞75th percentile for age and gender;(2) systolic or diastolic blood pressure＞90th percentile for gender, age,and height;(3) fasting triglycerides≥100 mg/dl;(4) HDL-C≤50 mg/dl(girls),≤45 mg/dl(boys);(5) fasting glucose≥110 mg/dl.The degree of insulin resistance was determined with the use of a homeostatic model(homeostatic model assessment:insulin resistance).Means and standard errors were calculated for waist circumference,systolic blood pressure,diastolic blood pressure,fasting glucose concentration,triglycerides concentration,HDL-cholesterol concentration.Independent T-tests and general linear model(GLM) were performed to determine significant differences of all variables among groups,adjustment for sex,age,pubertal status.Serum ghrelin,leptin, adiponectin,insulin concentrations and HOMA-IR are expressed as median and range (interquartile),and nonparametric statistics were applied.Prevalence values were compared using the Cochran-Mantel-Haenzsel(CMH) test for proportions for those children with and without MS and metabolic abnormity.Multiple logistic-regression analysis was used to determine the odd ratio for MS in various quartiles among obese children and adolescents,adjustment for sex,age,pubertal status.Spearman correlation was utilized to assess the relationships between all variable。Principal-component factor analysis was used to investigate the relations among the correlated risk factors for the metabolic syndrome in all children.Extraction of the initial set of uncorrelated components was accomplished with the principal-factor method,and then the varimax rotation method was chosen.Components was used to facilitate interpretation.The number of components retained was based on eigenvalue values greater than 1.We defined factor loadings above 0.25 as indicating strong correlation. Results1 The prevalence of MS in children aged 8-10 years in BeijingThe prevalence rates of MS and metabolic abnormity in children aged 8 years,9 years,10 years were as the following:14.4%,15.8%and 16.5%for MS;37.1%,37.0% and 28.9%for central obesity;18.2%,21.0%and 25.7%for hypertension;26.5%, 34.0%and 34.7%for hypertriglyceridemia;31.1%,25.7%and 24.3%for low HDL-C;. The prevalence of MS was comparable for boys and girls(16.4%versus 15.4%, respectively).The prevalence rates of MS and metabolic abnormity in underweight,normal weight,overweight,obese children were as the following:0,2.1%,16.5%and 46.7% for MS;0,1.7%,48.8%and 95.5%for central obesity;4.8%,14.0%,23.3%and 42.1% for hypertension;4.8%,21.0%,39.0%and 58.3%for hypertriglyceridemia;4.8%, 19.3%,30.5%and 38.8%for low HDL-C.The prevalence rates of MS and metabolic abnormity in children with junior high school or lower,senior high school or occupational school,technical secondary school or college and university or higher education level in their father were as the following: 11.6%,19.0%,19.0%and 23.7%for MS;24.9%,32.4%,39.8%and 36.0%for central obesity;17.5%,23.6%,24.9%and 25.9%for hypertension;30.2%,34.0%,33.2%and 37.4%for hypertriglyceridemia;24.9%,28.4%,24.8%and 25.2%for low HDL-C.The prevalence rates of MS and metabolic abnormity in children with junior high school or lower,senior high school or occupational school,technical secondary school or college and university or higher education level in their mother were as the following: 22.4%,20.4%and 16.4%for MS;20.9%,36.6%,37.3%and 36.4%for central obesity; 19.8%,20.6%,29.2%and 18.6%for hypertension;27.3%,37.8%,36.6%and 28.6%for hypertriglyceridemia;25.7%,32.6%,24.0%and 20.0%for low HDL-C;10.7%.The prevalence rates of MS and metabolic abnormity in children with junior high school or lower,senior high school or occupational school,technical secondary school or college and university or higher education level in their mother were as the following: 10.7%,22.4%,20.4%and 16.4%for MS;20.9%,36.6%,37.3%and 36.4%for central obesity;19.8%,20.6%,29.2%and 18.6%for hypertension;27.3%,37.8%,36.6%and 28.6%for hypertriglyceridemia;25.7%,32.6%,24.0%and 20.0%for low HDL-C.The prevalence rates of MS and metabolic abnormity in children with family income lower than 1999,2000-3999,4000-5999 and higher than 6000 Yuan per month were as the following:17.4%,17.9%,20.3%and 17.9%for MS;33.9%,40.7%,46.6% and 33.9%for central obesity;22.9%,23.3%,25.5%and 18.8%for hypertension; 33.9%,29.5%,37.6%and 36.6%for hypertriglyceridemia;30.3%,23.5%,26.2%and 20.5%for low HDL-C.The most frequent combination of MS was central obesity+hypertriglyceridemia+ low HDL-C and central obesity+hypertension+hypertriglyceridemia.There was only 1 boy having hyperglycemia.63.4%of all subjects had at least 1 metabolic abnormality, 36.9%of all subjects had at least 2 metabolic abnormalities,36.9%of all subjects had at least 3 metabolic abnormalities,four or more abnormalities were found in 4 children (4.0%);no child had all 5 criteria.The prevalence of having at least 1,2,3,4 metabolic abnormalities in overweight children were 86.0%,49.4%,21.3%and 4.9%,respectively. The prevalence of having at least 1,2,3,4 metabolic abnormalities in obese children were 99.6%,79.8%,48.8%and 12.0%,respectively.2 The association among ghrelin,leptin,adiponectin,insulin and pediatric MSExcept for serum HDL-C concentration,there was a significant positive association between WC,SBP,DBP,serum TG concentration,FBG,HOMA-IR and leptin.With increasing leptin level,the prevalence of obesity,hypertension, hypertriglyceridemia,low HDL-C and MS increased significantly.Increasing leptin levels were significantly related to the risk of MS.The OR was significantly elevated with high leptin level.Except for serum HDL-C concentration,there was a significant negative association between WC,SBP,DBP,serum TG concentration,HOMA-IR and adiponectin.With increasing adiponectin level,the prevalence of obesity,hypertension, hypertriglyceridemia,low HDL-C and MS decreased significantly.Decreasing adiponectin levels were significantly related to the risk of MS.Except for serum HDL-C concentration,there was a significant negative association between WC,SBP,serum TG concentration,HOMA-IR and ghrelin.With increasing ghrelin level,the prevalence of obesity,hypertension,hypertriglyceridemia, low HDL-C and MS decreased significantly.Decreasing ghrelin levels were significantly related to the risk of MS.Except for serum HDL-C concentration,there was a significant positive association between WC,SBP,DBP,serum TG concentration,HOMA-IR and insulin as well as HOMA-IR.With increasing insulin level and HOMA-IR,the prevalence of obesity,hypertension,hypertriglyceridemia,low HDL-C and MS increased significantly. Increasing insulin levels and HOMA-IR were significantly related to the risk of MS. The OR was significantly elevated with high insulin and HOMA-C level.The univariate analysis showed WC,SBP,DBP,TG,HDL-C and FBG were associated strongly with leptin than insulin,HOMA-IR,adiponectin,and ghrelin.There were strong correlations between insulin,HOMA-IR,adiponectin,ghrelin and leptin. Adiponectin was not associated with ghrelin.Four factors were sufficient to explain correlations between variables.The first factor was obesity and dyslipidemia,reflecting strong correlation with leptin,WC,insulin,TG,HDL-C,adiponectin.The second factor was leptin,WC,SBP,DBP,reflecting a positive correlation of obesity and hypertension. The third factor was leptin,WC,insulin and FBG,reflecting a positive correlation with obesity and glucose metabolism.Ghrelin loaded the fourth factor significantly only with leptin.ConclusionsThe prevalence of pediatric MS was a severe problem in 8-10 years old children. There is a clustering of metabolic abnormities among overweight and obese children. The prevalence of MS in children was different in different parent education level and family income.Ghrelin,leptin,adiponectin and insulin were associated with MS and metabolic abnormities.Low ghrelin level,high leptin level,low adiponectin level,high insulin level would predict development of MS in children.Leptin is a novel link between obesity and other metabolic abnormities.High serum leptin concentration is likely a pathophysiological underlying facter in pediatric MS.