Study of Ocurrence and Components of the Metabolic Syndrome
|School||PLA Postgraduate Medical School|
|Course||Endocrine and metabolic diseases|
|Keywords||Metabolic syndrome Exploring factor analysis Confirmatory factor analysis Factor Analysis|
To evaluate the clustered characteristics of the component s of Metabolic Syndrome(MS)in people with different glucose tolerance or coronary heart disease(CHD),we studied 1254 subjects without DM history(mean aged 60.49 years)who underwent a 75g oral glucose tolerance test(OGTT)during a survey of diabetes and hypertention in Beijing area.Factor analysis was performed using the variables of insulin,blood glucose,total cholesterol(TC), tdglycerides(TG),high density lipoprotein(HDL),systolic blood pressure (SBP),diastolic blood pressure(DBP),waist circumference(WC)and BMI.Four principle factors were derived,including obesity,insulin resistance, dyslipidemia and hypertension.The main factor explaining the most portion of the observed variation of MS always included hyperinsulinemia.The factor patterns in subjects with or without CHD were similar.In the normal glucose group and the CHD group,IR and obesity clustered in one factor explaining 32.95%and 29.25%of the total variation separately.In order to analyse the relationships of the components of the MS,we evaluated and compared four competing models of the underlying factor structure of MS using confirmatory factor analysis(CFA).The study included 1411subjects(645 males and 766 females)during a survey of diabetes and hypertention in Beijing area.CFA was performed using the anthropometric measures variables,insulin,blood glucose,blood lipids and blood pressure(BP). The six models were built according to the studies about the factor analysis on the MS before.The evaluated models were as follows:①two-order model with hypothesized MS and the secondary factors which concluding "insulin resistence (IR)","obesity ","lipids",and " blood pressure";②four-factor model with " IR","obesity","lipids" and " blood pressure";③one-factor model with four secondary modules such as WC,TG/HDL,homeostasis model assessment insulin resistance index(HOMA-IR)and mean arterial pressure(MAP);④one-factor model with four secondary modules which were fasting insulin(FINS),WC, triglyceride(TG)and systolic pressure(SBP);⑤one-factor model with four secondary modules which were fasting blood glucose(FBG),WC,TG and SBP;⑥one-factor model with which secondary modules were FINS,WC, high density lipoprotein(HDL)and SBP.CFAs were performed using SAS software with maximum likelihood estimation and the fit indexes of the different models were compared.The result showed that these one-factor models yielded significantly better data-model fit than four-factor or two-order one.And the model 6 with its subfactors which were FINS、WC、HDL and SBP was the most plausible one among the competing models(comparative fit index,CFI was 0.9945,root mean square residual(RMSR)was 0.0129).The definition of MS are different up to now.We evaluated and compared four hypothesis models of different MS diagnostic criteria using CFA.The subjects came from the former part of the study,including 1411 people(645 males and 766 females).We supposed four modules of MS according to four different diagnostic criteria.The four definitions of MS included Chinese Diabetes Society,the National Cholesterol Eduation Program Adult Treatment PanelⅢ,IDF and WHO.CFAs were performed using SAS software with maximum likelihood estimation.The results showed that the module from the CDS diagnostic criteria(CFI 0.9670,RMSEA 0.0806)yielded significantly better data-model fit than the other ones.The orders were module of NECP-ATPⅢ(CFI 0.9523,RMSEA 0.0870)and WHO(CFI0.8839,RMSEA0.0976).The IDF(CFI0.9432, RMSEA0.1285)module was not good for fitting the study subjects.In conclusion,obesity and insulin resistence(IR)were the most important components of MS.All features of the MS cannot be explained by only one factor. Hyperinsulinemia might play an important role from MS to the diabetes mellitus (DM)or CHD stage,and early treatment to IR may prevent development of MS and CHD in some degree.Our results supported the generally accepted definition of MS.There maybe lay a common factor influenced by the different aspects of MS.And provided some evidence to the thought that the MS is an independent desease. The four MS definitions had almost the same connotations.CDS definition was the best way to find out the MS patients.The MS might show different appearances in distinct people,so one definition may not fit all the population.