Study On The Serum Oxidized Low-density Lipoprotein Levels In Premenopausal And Postmenopausal Women With Different Glucose Tolerance And Their Related Factors

Objective:Cardiovascular disease(CVD) has been the leading cause of mortality in patients with diabetes. Compared to diabetic men, the diabetic women(especially postmenopausal women) have the more cardiovascular risk, but, the mechanisms are still not known. Many studies have found that the people in pre-diabetes have the same high cardiovascular risk of mortality. Oxidized low density lipoprotein(ox-LDL) is a biomarker of oxidative stress, an important factor in the development of atherosclerotic pathogenesis, and is known as an important predictor of CHD. The purpose of this study is to compare of serum ox-LDL level and study correlations between ox-LDL and blood glucose, blood lipids, blood pressure and homocysteine in premenopausal and postmenopausal women with different glucose tolerance, and provides new research direction for prevention and treatment of diabetic complication in premenopausal and postmenopausal women.Methods:Women from January 2013 to March 2014 in endocrinology department, hospital and physical examination center in our hospital, aged 45 to 65 were enrolled by oral glucose tolerance test and whether amenorrhea or not. 248 subjects selected in this study included 80 women(40 premenopausal, 40 postmenopausal) with normal glucose tolerance(NGT), 82 women(40 premenopausal, 42 postmenopausal) with impaired glucose regulation(IGR) and 86 women(44 premenopausal, 42 postmenopausal) with type 2 diabetes mellitus(T2DM). Oxidized low-density lipoprotein(ox-LDL) was measured using enzyme-linked immunosorbent assay(ELISA). Body mass index(BMI) and blood pressure were all measured in each group. Blood lipids(TG, TCH, HDL-C, LDL-C)were measured with Automatic Biochemical Analyzer. Blood glucose(FBG) was measured by Glucose Oxidase and homocysteine(Hcy) was measured by high performance liquid chromatography.Results:1 Comparison baseline data, biochemical characteristics and level of ox-LDL in premenopausal and postmenopausal women with different glucose tolerance1.1 Comparison baseline data, biochemical characteristics and level of ox-LDL in premenopausal women with different glucose toleranceCompared with NGT group, the levels of BMI, LDL-C,SBP, DBP, ox-LDL and FBG were all higher in IGR group and T2 DM group, and the level of HDL-c was lower(all P<0.05), in addition, the levels of TG and Hcy in T2 DM group were significantly higher than that in NGT group, the difference was statistical significance(P<0.05). Compared with IGR group, the levels of TG, ox-LDL and FBG were all higher in T2 DM group, and the level of HDL-c was lower(P<0.05), whereas, the difference of Hcy between two groups was not statistical significance(P>0.05). The differences of age between three groups were also not statistical significance(P>0.05).1.2 Comparison baseline data, biochemical characteristics and level of ox-LDL in postmenopausal women with different glucose toleranceCompared with NGT group, the levels of LDL-C,SBP, DBP,ox-LDL and FBG were all higher in IGR group and T2 DM group(all P<0.05), in addition, the levels of TG and Hcy in T2 DM group were significantly higher than that in NGT group, the level of HDL-c was lower, and the differences were all statistical significance(P<0.05). Compared with IGR group, the levels of TG, LDL-C,ox-LDL and FBG were all higher in T2 DM group, and the level of HDL-c was lower(P<0.05), whereas, the differences of Hcy, SBP and DBP between two groups were not statistical significance(P>0.05). The differences of age and BMI between three groups were also not statistical significance(P>0.05).1.3 Comparison of baseline data, biochemical characteristics and levels of ox-LDL between premenopausal and postmenopausal women with different glucose toleranceThe levels of SBP, DBP, Hcy and age of postmenopausal women in NGT group,IGR group and T2 DM group were all higher than that of premenopausal women in their group, the level of LDL-C and ox-LDL of postmenopausal women in IGR group and T2 DM group were all higher than that of premenopausal women and the differences were all statistical significance(P<0.05).2 The linear correlation analysis and multiple linear regression analysis of ox-LDL with its related factors in premenopausal and postmenopausal women with different glucose tolerance2.1 The linear correlation analysis of ox-LDL with its related factors in premenopausal and postmenopausal women with different glucose toleranceSerum ox-LDL was positively related to serum Hcy、LDL-C、FBG in premenopausal women with different glucose tolerance, and negatively related to serum HDL-C(P<0.05). Serum ox-LDL was positively related to serum TG and TCH in T2 DM group(P<0.05). Serum ox-LDL was positively related to Hcy、SBP、FBG in postmenopausal women with different glucose tolerance, and negatively related to serum HDL-C(P<0.05). Serum ox-LDL was positively related to serum TG, TCH and LDL-C in IGR group and T2 DM group(P<0.05), in addition, serum ox-LDL was positively related to DBP in IGR group(P<0.05).2.2 Multiple linear regression analysis of ox-LDL with its related factors in premenopausal and postmenopausal women with different glucose toleranceThe ox-LDL in premenopausal women as dependent variable, and TG, TCH,HDL-C,LDL-C,FBG,SBP,DBP, Hcy and BMI as independent variables in multiple linear regression equation, The result is, ox-LDL=2.786 Hcy +19.846LDL-C+2.340 FBG, There was independently positive correlation between serum ox-LDL and Hcy, LDL-c, FBG in premenopausal women with different glucose tolerance(P<0.05). The same way, The multiple linear regression equation in postmenopausal women was ox-LDL=3.434 Hcy +11. 465LDL-C-19.123HDL-c+0.893SBP+9.967 FBG. There was independently positive correlation between serum ox-LDL and Hcy, LDL-c, SBP, FBG in postmenopausal women with different glucose tolerance, and independently negative correlation between serum ox-LDL and HDL-c(P<0.05).Conclusion:1 The levels of ox-LDL in premenopausal or postmenopausal women are all increasing with the gradual worsening of abnormal glucose tolerance,.2 Compared with premenopausal women, postmenopausal women with different glucose tolerance has the higher levels of ox-LDL, blood pressure, homocysteine and worse dyslipidemia, therefore, that may be one of causes of more cardiovascular risks for postmenopausal women.3 Premenopausal and postmenopausal women with impaired glucose regulation(prediabetes) have not only hyperglycemia but also obvious dyslipidemia and hypertension, and premenopausal and postmenopausal women with diabetes have worse metabolic disturbance of those substances and hyperhomocysteinemia.4 There were close correlations between ox-LDL and blood lipids, blood pressure, blood glucose, homocysteine in premenopausal and postmenopausal women with different glucose tolerance.