Analysis Of Obesity-related Risk Factors And Association Of PTP1B Gene Polymorphisms With Obesity In Children In Kai Fu District In Changsha

Chapter 1 The study on obesity and its risk factors in children in Kai fu District in ChangshaOBJECTIVES:To study the prevalence of overweight and obesity and the risk factors to obesity in children in Kai fu District in Changsha and to provide the scientific evidence for prevention and control of obesity in children.METHODS:A total of 4140 children aged 7 to 12 years old in Kai fu District in Changsha were randomly selected and obesity was assessed by the method of body mass index(BMI).Children were divided into obesity and control groups.A totle of 302 obese and 301 health children were investigated by questionnaires including dietary habits and physical exercise habits.Further,147 obese and 118 health children were selected and their waist circumference(WC),waist to hip ratio(WHR),percentage of body fat(%BF),systolic blood pressure(SBP),diastolic blood pressure (DBP),fasting plasma glucose(FPG),serum triglycerides(TG),total cholesterol(TC),high density lipoprotein-cholesterol(HDL-C)and low density lipoprotein-cholesterol(LDL-C)were tested.RESULTS:â‘ The prevalence rates of overweight and obesity in children in Kai fu District in Changsha were 9.76%and 7.39%respectively, and the obesity rates of boys and girls were 9.37%and 5.13%respectively.â‘¡The risk factors of obesity in boys included fast speed of eating, partiality for western fast food,long time to watch television,partiality for sweet foods,partiality for fried foods and the protective factors included long time to exercise.The risk factors of obesity in girls included excessive drinking and eating,long time to watch television,partiality for sweet foods and the protective factors included long time to exercise.â‘¢Obesity group had higher BMI,WC,WHR,%BF,SBP,TG,LDL-C and lower HDL-C as compared with those of control group.â‘£The multiple stepwise regression analysis showed that BMI,WC and WHR were the main factors for%BF in boys and BMI,WC were the main factors for%BF in girls.CONCLUSION:â‘ The prevalence of obesity is at a high level in China and the rates of overweight and obesity are greater in boys than in girls.â‘¡Unhealthy eating behavior and lack of physical activity are main causes of childhood obesity.â‘¢Obesity group has higher SBP,TG,LDL-C and lower HDL-C in comparison to controls. in children and to determine the effects of PTP1B gene IVS6+G82A and Pro303Pro polymorphisms on the pathogenesis of childhood obesity.METHODS:A totle of 147 obese and 118 health children were selected.The plasma fasting insulin(FINS)levels of children were measured by radioimmunoassay(RIA).Homeostasis model assessment for insulin resistance(HOMA-IR)were calculated.The plasma leptin levels of children were measured by enzyme-linked immunosorbent assay(ELISA). The IVS6+G82A and Pro303Pro polymorphisms of PTP1B gene were tested by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)assay.Samples were randomly selected to direct sequencing to identify the results of PCR-RFLP.RESULTS:â‘ Obesity group had higher FINS,HOMA-IR,leptin levels as compared with those of control group.The multiple stepwise regression analysis showed that BMI,FINS and%BF had main effects on leptin in boys and BMI,FINS had main effects on leptin in girls.â‘¡The allele frequencies of PTP 1B gene IVS6+G82A and Pro303 Pro were 53.4% and 11.0%in control group,respectively.In obese group,the allele frequencies for IVS6+G82A and Pro303Pro were 59.5%and 19.4%, respectively.We did not find any differences in the genotype distributions or allele frequencies of IVS6+G82A polymorphisms between obese and control group.Further analysis showed no association between genotypes of IVS6+G82A and clinical characteristics in obese subjects.There were significant differences in genotype and allele frequencies of the Pro303Pro polymorphism between the two studied groups.In addition,the Pro303Pro polymorphism was associated with BMI,WC,TG and LDL-C in obese subjects.â‘¢The linkage disequilibrium analysis was carried out for IVS6+G82A and Pro303Pro(D':0.441,r~2:0.027),so their linkage disequilibrium was weak.CONCLUSIONS:â‘ Insulin resistance and leptin resistance are present in obese children.â‘¡The distribution characteristics of PTP1B gene IVS6+G82A and Pro303Pro polymorphisms in obese and healthy children are identified.â‘¢There is no significant association of PTP1B gene IVS6+G82A variant with obesity in children.But Pro303Pro variant may be associated with obesity in children and affects the lipid metabolism in obese children.