A Study Of The Associations Between Triglyceride-Glucose Index And Its Combined Anthropometric Index And The Development Of Type 2 Diabetes Mellitus

Objective:This study aimed to investigate the associations between triglyceride-glucose（TyG）index and its combined anthropometric index and type 2 diabetes mellitus（T2DM）and the dose-response relationship.To analyze whether the association between TyG,triglyceride glucose-body mass index（TyG-BMI）,triglyceride glucose-abdominal circumference（TyG-AC）index and T2DM differs among subgroups,and to compare the ability of TyG,TyG-BMI and TyG-AC to predict T2DM and to provide a scientific basis for early screening of people at risk for T2DM.Methods:A total of 13348 cases of physical examination in the Health Management Center of the grade A tertiary hospital in Dalian,Northeast China from January 2015 to December 2017 were included in this research,and to collect their baseline physical examination data.Using a matched nested case-control study design,209 patients with new-onset T2DM during the follow-up period from January 2018 to April 2021 were used as the case group,and 418 cases were selected as the control group by matching 1:2among those without new-onset T2DM,endocrine system diseases and malignancies during the same follow-up period according to the same gender and age±2 years,and a total of 627 research subjects were finally included in this nested case-control.The TyG,TyG-BMI,and TyG-AC were calculated based on their baseline data.The quartile method was used to classify TyG,TyG-BMI,and TyG-AC into four groups（Q1,Q2,Q3,and Q4）.The Cox regression fitted conditional logistic regression models were used to explore the association of TyG,TyG-BMI,TyG-AC and T2DM.Restricted cubic spline regression models were used to analyze the dose-response relationship between continuous changes in TyG,TyG-BMI,TyG-AC and T2DM and to plot the dose-response relationship.The likelihood-ratio test was used to analyze the differences of the relationships between TyG,TyG-BMI,TyG-AC and T2DM among subgroups.Receiver operating characteristic（ROC）curves were used to explore and calculate the predictive value,predictive power,and optimal cut-off point of TyG,TyG-BMI,and TyG-AC for T2DM.Results:1.A total of 5727 individuals,aged（41.02±11.20）years,of whom 3596（62.79%）were males and 2131（37.21%）were females,had complete baseline and follow-up data for this study.The median follow-up time was 2.92（2.90,2.94）years,and 209 patients with T2DM were detected cumulatively,the incidence rate of T2DM was 3.65%.The incidence rate of T2DM was 5.03%in males and 1.31%in females,and the incidence rate of T2DM was higher in males than in females.There was a difference in the incidence rate between age groups（P<0.05）,and in general the incidence rate increased with age,but decreased after 59 years of age.2.A total of 627 research subjects with a mean age of（47.49±9.64）years were finally included in this study,including 543 males（86.6%）and 84 females（13.4%）.There were no significant differences in mean age,gender,and height between the new-onset case group and control group（P>0.05）.Compared with the control group,weight,body mass index,abdominal circumference,systolic blood pressure,diastolic blood pressure,fasting glucose,triglycerides,total cholesterol,low-density lipoprotein cholesterol,TyG,TyG-BMI,TyG-AC levels were significantly higher and high-density lipoprotein cholesterol levels were significantly lower in the new-onset case group（P<0.05）.3.The results of Cox regression fitted conditional logistic regression analysis showed that TyG,TyG-BMI,and TyG-AC were significantly associated with the occurrence of T2DM after adjustment for univariate and multivariate regression,regardless of continuous or quartile forms（P<0.05）.Taking Q1 as the reference group,the risk of T2DM in the Q4group of TyG was 3.180 times（95%CI 1.760-5.747,P<0.05,P trend<0.001）higher than the Q1 group;the risk of T2DM in the Q4 group of TyG-BMI was 5.340 times（95%CI2.387-11.947,P<0.05,P trend<0.001）higher than the Q1 group;and the risk of T2DM in the Q4 group of TyG-AC was 3.118 times（95%CI 1.550-6.273,P<0.05,P trend<0.001）higher than the Q1 group.4.The results of restricted cubic spline regression analysis showed a linear dose-response relationship between TyG,TyG-BMI,TyG-AC and T2DM,and a linear positive correlation in the shape of the dose-response relationship(P_TOTAL<0.05,P_Nonlinear>0.05).The risk of T2DM gradually increased when TyG,TyG-BMI,and TyG-AC levels exceeded 8.838,229.364,and 795.553.5.The results of subgroup analysis showed that no significant differences were observed between TyG,TyG-BMI,TyG-AC and risk of T2DM across age groups（P interaction>0.05）,and significant differences were observed between groups for gender and BMI（P interaction<0.05）,especially in female and low body mass index（BMI<24kg/m²）populations to predict T2DM more sensitively.6.The results of ROC curve analysis showed that TyG,TyG-BMI,and TyG-AC all had predictive value for T2DM（P<0.05）.The areas under the ROC curves（AUC）of TyG,TyG-BMI,and TyG-AC were 0.696（95%CI:0.658-0.732）,0.725（95%CI:0.688-0.760）,and 0.708（95%CI 0.671-0.744）,respectively.The optimal cutoff value for TyG,TyG-BMI,and TyG-AC to predict T2DM were 8.650,224.859,and 806.347,respectively.Conclusion:Increased TyG,TyG-BMI,and TyG-AC levels are independent risk factors for T2DM,showing a linear positive dose-response relationship with T2DM.In addition,it is also important to elevate the focus on females and people with low body mass index（BMI<24 kg/m²）during early screening for T2DM.TyG,TyG-BMI,and TyG-AC all have predictive value for T2DM,and TyG-BMI may be a better predictor if the basic characteristics of the subjects,the strength of association of risk,AUC,and clinical impact of screening results are taken into account.