Relationship between insulin resistance and subclinical atherosclerosis in individuals with and without type 2 diabetes mellitus

BACKGROUND Insulin resistance is of utmost importance as an underlying mechanism for increased risk of cardiovascular disease (CVD). We assessed the association between Homeostatic Model Assessment (HOMA-IR) and two surrogate subclinical atherosclerosis markers (SCA) among individuals with and without type 2 diabetes (DM), those who did not have any clinical presentation of the CVD. METHODS In a cross-sectional study, 208 participants (105 diabetics and 103 non-diabetics) were enrolled from referred patients with diabetes to an academic outpatient clinic and their non-diabetic relatives in-law. Fasting serum levels of insulin, blood glucose and lipid profile, were measured. Anthropometric and blood pressure were measuremented standardly. Body Mass Index (BMI) and Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) index were calculated. Coronary Artery Calcium Score(CACS) was measured using a Multi-Detctor CT scanner. Flow mediated dilation (FMD) was measured using bimode ultrasonography (with linear transducer 13,000 MHZ). Univariate and multivariate logistic regression models were used to evaluate the association between these SCA markers and HOMA index in adjusting models. RESULTS CACS and HOMA-IR were higher and FMD was lower in diabetic participants than non-diabetic ones (P < 0.01) In a stepwise logistic regression model, CACS and FMD were associated with HOMA-IR (odds ratio = 1.778; 95 % confidence interval (CI): 1.211-2.726 and odds ratio = 1.557; 95 % CI: 1.601-2.275, respectively) in non-diabetics but not among diabetic participants. CONCLUSIONS CACS and FMD are related to insulin resistance among non-diabetic individuals, but we could not find this relationship among diabetic patients.