Correlation Analysis Between Serum C1q/TNF-related Protein-9 (CTRP9) Level And Type 2 Diabetes Mellitus And Obesity

Background and purposeIn recent years,the incidence of diabetes mellitus is on the rise.As the world's third largest chronic disease,second only to cancer and cardiovascular disease,diabetes not only imposes a severe threat to human's health and life,but also puts a heavy financial burden on the government and society.As a chronic metabolic disease caused by multiple factors,obesity has a close relationship with cardiovascular disease,diabetes,skeletal muscle disease,etc.The prevalence of obesity keeps rising every year which threatens human's health as well.The C1q/tumor necrosis related factor-related protein-9(CTRP9)is a newly identified adipokine,which attracts extensive attention in the field of metabolic disease research.Previous animal experiments have confirmed that it has a favorable effect on lowering blood glucose and lipid,improving basal metabolism and insulin resistance.Related human studies have identified that it can help stabilize atherosclerotic plaque and improve myocardial ischemia-reperfusion injury.However,the current research on the serum CTRP9 level in diabetes and obese patients is rare.The aim of this study was to investigate the serum levels of CTRP9 in patients with type 2 diabetes mellitus and obesity and to determine the related influential factors.MethodsUsing the epidemiological method of cluster sampling,1000 permanent residents in Jinan,Shandong Province were selected to participate in this research.Several investigators were trained to carry out physical examinations,laboratory examinations and questionnaire surveys in accordance with the same standards.The basic data of height,weight,waist circumference,blood pressure and other information of all subjects was collected and then analyzed in a descriptive way.Samples of fasting venous blood were collected in order to examine all subjects' fasting plasma glucose(FPG),fasting insulin(FINS),C-peptide,glycosylated hemoglobin(HbA1c),total cholesterol(TC),triglyceride(TG),low density lipoprotein cholesterol(LDL-C),high density Lipoprotein cholesterol(HDL-C),serum creatinine.The subjects then took the oral glucose tolerance test(OGTT)by administrating 75 g glucose orally.Samples of venous blood were taken after two hours and indicators of plasma glucose,insulin and C-peptide were examined.The CTRP9 level of the subjects'fasting serum samples were detected using an ELISA kit.The basic data and the experimental results were compared between type 2 diabetes patients and healthy subjects and between the obese and non-obese group.The correlation analyses were conducted between serum CTRP9 levels and FPG,2hPG and other indicators.The effects of FPG,2hPG,insulin sensitivity index ISI Avignon and BMI on serum CTRP9 level were analyzed by multivariable linear regression analysis.Logistic regression analysis was used to determine whether CTRP9 is an independent risk factor for type 2 diabetes and obesity.SPSS 19.0 software was used for statistical analysisand P<0.05 was considered statistically significant.Results1.1000 subjects were included in this study,44.6%of which are male,and the average age is 53.05 ± 10.38 years old.Among them,201 patients with diabetes,of 24.1 with pre-diabetes,of 621 with obesity,and 197 with overweight.2.According to the selection and exclusion criteria,124 patients with type 2 diabetes mellitus and 124 healthy subjects as the control group were included in this research.The levels of CTRP9,BMI,waist circumference,FPG,2hPG,HbAlc,TG and HOMA-IR in control group were significantly lower than those in type 2 diabetes group,and the differences were statistically significant.The levels of HDL-C and insulin sensitivity index ISI Avignon and eGFR in control group were higher than those in type 2 diabetes group,and the differences were statistically significant.However,the levels of TC,LDL-C,FINS,2hINS,SBP,DBP had no significant difference between these two groups.3.HDL-C and insulin sensitivity index ISI Avignon in obese group were lower than those in non-obese group,and the differences were statistically significant.The BMI,waist circumference,two-hour postprandial insulin,systolic blood pressure,diastolic blood pressure,insulin resistance index HOMA-IR and serum CTRP9 level in obese group were all higher than those in non-obese group,and the differences were statistically significant.There was no significant difference in age,fasting insulin,fasting blood glucose,two-hour postprandial blood glucose,glycosylated hemoglobin,TC and TG between the two groups.4.The correlation analysis results showed that the serum level of CTRP9 was positively correlated with FPG(r=0.178,P= 0.023)and 2hPG(r = 0.173,P=0.027),and the differences were statistically significant.However,there were no significant correlations between CTRP9 and age,gender,TC,TG,HDL-C,LDL-C and HOMA-IR.5.The results of multivariable linear regression showed that the partial regression coefficients of serum CTRP9 level and FPG,2hPG,insulin sensitivity index ISI Avignon and BMI were,respectively,0.128(P=0.016)?0.197(P=0.011)?-0.253(P=0.038)and 2.08(P=0.037).Serum CTRP9 level had no significant correlation with HbA1c,insulin resistance index HOMA-IR,TG,TC,LDL-C and HDL-C.6.After controlling for potential confounding factors,such as age,gender,waist circumference,the results of logistic regression analysis indicated the serum level of CTRP9 was an independent risk factor of type 2 diabetes[OR = 1.52(1.12-2.06),P=0.007].The logistic regression analysis results showed that the serum level of CTRP9 was not an independent risk factor for obesity[OR = 1.19(0.93-1.51),P=0.16]after adjusting for age,glycosylated hemoglobin,fasting blood glucose,two-hour postprandial blood glucose,insulin resistance index HOMA-IR.Conclusion1.Compared with healthy subjects,the serum level of CTRP9 was increased in type 2 diabetes.And the serum CTRP9 level was positively correlated with fasting blood glucose and two-hour postprandial blood glucose and was negatively correlated with insulin sensitivity index ISI Avignon,suggesting that CTRP9 may be an n independent risk factor to type 2 diabetes.2.Compared with non-obese subjects,the serum level of CTRP9 was increased in obese patients,but it was not an independent risk factor for obesity.