Prevalence Of Overweight And Obesity And Its Impact On Target Organ Damage In Children And Adolescents Aged 6-17 Years In Urban Region Of Jinan

BackgroundWith the rapid development of economy and changes of lifestyle,overweight and obesity among children and adolescents has been a serious public health issue worldwide.The prevalence of overweight and obesity in children and adolescents increased significantly in both developed and developing countries.The Body Constitution Research in Chinese Students showed an upward trend in the prevalence of overweight and obesity among 7-18 year old school-aged students,ranging from 1.2%in 1985 to 14.6%in 2010.It has been indicated that childhood overweight and obesity might cause early target organ damage(TOD),including carotid intima-media thickening(cIMT),atherosclerosis,and left ventricular hypertrophy(LVH).Meanwhile,overweight and obesity can track from childhood into adulthood.Moreover,overweight and obesity in childhood increases the risk of cardiovascular disease(CVD,including coronary heart disease and stroke)in adulthood.It was estimated that the risk of elevated cIMT of the carotid artery increased by 58%for per 1kg/m2 increase of BMI in childhood.Therefore,the early identification of overweight and obesity in children,and the implementation of the prevention strategies in early stage,may reduce the risk of adulthood CVD from the origin.Consequently,we recruited 7840 students aged 6-17 years in urban area of Jinan,in order to describe the distribution of overweight and obesity based on four BMI screening criteria(Chinese criteria,CDC criteria,IOTF criteria and WHO criteria),and to examine the impact of overweight and obesity in children and adolescents on early TOD,thereby providing scientific basis for the early screening and intervention of TOD in children and adolescents in Jinan.Objectives1.To describe the prevalence of overweight and obesity in 7840 children and adolescents aged 6-17 years in urban area of Jinan based on four BMI screening criteria(Chinese criteria,CDC criteria,IOTF criteria and WHO criteria).2.To examine the influence of overweight and obesity on early TOD in children and adolescents.Subjects and methods1.Based on the 12th Five Year National Science and Technology Support Program-"Early warning,diagnosis and treatment of cardiovascular disease in children",a total of 4 public middle-level schools(2 primary schools,1 junior school,and 1 senior high school)were selected in urban area of Jinan by using convenient cluster sampling method.Participants who had a registered permanent residence in Jinan or lived in Jinan for more than one year were recruited to the survey.Finally,a total of 7840 eligible students(boys:4082,girls:3758)were included.In addition,333 students(boys:238,girls:95)who had hypertension were selected to examine the impact of overweight and obesity on TOD in children and adolescents.2.Anthropometric measurements,biochemical indicators and TOD indicators assessment were conducted.Anthropometric measurements included the average value of two measurements of height and weight.Then,four BMI screening criteria were used to identify overweight and obesity.Biochemical indicators assessments included urine biochemical test and blood biochemical test.TOD assessment included cardiac examination,vascular examination and liver examination.3.Data were collected and analyzed by SPSS 16.0.The categorical variables were presented as percentage(%),while the continuous variables were expressed as mean±SD.The t-test was used to compare continuous variables between two groups.Covariance analysis was performed to compare continuous variables after covariates'adjustment.Kappa test was conducted to assess the consistency of four BMI screening criteria of overweight and obesity.Trend Chi-square test was used to analyze the trend in prevalence of TOD indices and abnormal biochemical indices with BMI changes.After adjustment for age,gender,blood pressure and heart rate,Logistic regression analysis was used to evaluate the impact of overweight and obesity on TOD(P<0.05 was considered as significant difference.).Results1.Prevalence and consistency of overweight and obesity in children and adolescents aged 6-17 years old based on four BMI screening criteria in urban area of JinanThe prevalence of overweight and obesity in children and adolescents aged 6-17 years old in urban area of Jinan reached high level based on the four criteria.Slight difference was found in prevalence of overweight based on four criteria(Chinese criteria:21.0%,CDC criteria:17.2%,IOTF criteria:21.0%,WHO criteria:22.1%).The prevalence of obesity in Chinese criteria was higher than that in IOTF criteria(19.9%vs.12.4%).The prevalence of obesity was 17.4%and 18.6%according to CDC criteria and WHO criteria,respectively,which was marginally higher than that by IOTF criteria.Moreover,the prevalence of overweight and obesity was higher in boys than that in girls.The kappa values of girls aged 9-11 years between Chinese criteria and IOTF criteria,and boys aged 9-11 years between WHO criteria and IOTF criteria were less than 0.6,while other each two groups based on four criteria were all higher than 0.6,indicting a high agreement.2.Impact of overweight and obesity on TOD in children and adolescentsAfter adjustment for age and gender,covariance analysis indicated that with the change of BMI,the levels of left ventricular mass(LVM),left ventricular mass index(LVMI),relative wall thikness calculated by total wall thickness(RWTm),carotid intima-media thickness(cIMT),alanine aminotransferase(ALT),total cholesterol(TC),triglyceride(TG)and low density lipoprotein cholesterol(LDL-C)showed an upward trend,while high density lipoprotein cholesterol(HDL-C)showed an inverse trend(P<0.05).Overall,compared to normal weight children,the risk of elevated LVMI increased for overweight and obese children(P<0.05),and the odd ratios(ORs)and 95%confidence intervals(CIs)were 4.52(95%CI:1.17-17.46)and 9.35(95%CI:2.73-32.07),respectively.Compared to non-obese group,total obesity,obesity in boys and obesity in children aged 6-11 years increased the risk of elevated RWTm(P<0.05).The ORs and 95%CIs were 3.39(95%CI:1.34-8.57),5.91(95%CI:1.32-26.48)and 6.58(95%CI:1.45-29.82),respectively.The risk of elevated cIMT thickening in obese group increased when compared to the non-obese group(OR:3.09(95%CI:1.13-8.46)).The ORs of fatty liver risk in overall obese group,obese boys and obese adolescents aged 12-17 years were respectively 7.54(95%CI:2.21-25.69),6.15(95%Cl:1.78-21.25)and 8.25(95%CI:1.85-36.79)times that of non-obese group.Conclusion1.The overall prevalence of overweight and obesity in children and adolescents aged 6-17 years old were at a high level in urban area of Jinan based on four BMI criteria.The results demonstrate that the overweight and obesity are prevalent in urban area of Jinan.2.Overweight and obesity increase the risk of early elevated LVM,LVMI,RWTm and cIMT.Compared to non-obese group,the risk of elevated LVMI,RWTm,cIMT and fatty liver all increased dramatically in obese children and adolescents.