Inter-relationship between low-density lipoprotein phenotype and carotid intima-media thickness in North Indian type 2 diabetic subjects

Abstract

Aims Diabetic dyslipidemia is characterized by a preponderance of small dense LDL which is highly atherogenic. The aim of this study was to examine the interrelationship between LDL Phenotype and atherosclerosis; to determine the factors determining LDL phenotype; and evaluate LDLc:apo-B ratio as a surrogate for the assessment of LDL phenotype in a group of North Indian Type 2 diabetic subjects. Methods 285 diabetic subjects attending the outpatient Endocrine Clinic were subjected to detailed anthropometry and fasting serum lipid and apo-B was measured. The carotid intima-media thickness (IMT) was determined using a high resolution B-mode Ultrasonography. LDLc:apo-B ratio was taken as a surrogate index for LDL size. Results 29.5% patients with normal triglyceride levels and 52.1% patients with normal LDLc levels showed the presence of small dense LDL or Phenotype B as estimated by the LDL cholesterol/apo-B ratio. The mean IMT in Phenotype B group was higher (0.88 mm vs. 0.68 mm). Triglycerides was the most important predictor variable predicting carotid IMT ( R 2 = 0.15, β = 0.376) as well as LDL phenotype B ( R 2 = 0.28, β = 0.561). Conclusions Triglycerides and HDLc contribute independently to the variability in LDL particle size, and LDL particle size was associated with preclinical atherosclerosis as determined by carotid IMT in North Indian Type 2 diabetic subjects. LDL cholesterol/apo-B ratio serves as an easy clinical tool to determine the elevated small dense LDL.