Those with insulin resistance or diabetes showed a two- to three-fold increase in large VLDL concentrations. Insulin resistance profoundly affects lipoprotein size and subclass concentrations, and these alterations are moderately exacerbated in type 2 diabetes.
Researchers from the Medical University of South Carolina, Charleston, United States, enrolled 56 insulin-sensitive, 46 insulin-resistant and 46 untreated subjects with type 2 diabetics. The researchers used a conventional analysis of lipid size and concentration as well as a new technique that employs nuclear magnetic resonance (NMR).
Overall, more marked insulin resistance was associated with increases in the size and concentration of very low density lipoprotein (VLDL) as well as decreases in the sizes of both low density lipoprotein (LDL) and high density lipoprotein (HDL). The subgroups of insulin-sensitive and insulin-resistant subjects without diabetes also showed the association. The correlation remained after adjusting for age, body mass index, sex and race.
Compared to insulin-sensitive patients, those with insulin resistance or diabetes showed a two- to three-fold increase in large VLDL concentrations. Medium or small VLDL concentrations did not change. Comparing insulin sensitive patients to those with insulin resistance or diabetes showed either no or minimal differences in LDL cholesterol respectively. No net difference in HDL cholesterol emerged.
The authors concluded NMR analysis reveals markers suggesting an increased risk of cardiovascular disease that "were not fully apparent" using the conventional assessment of size and concentration. They called for further studies assessing whether NMR lipoprotein subclass analysis helps manage risk more effectively. Diabetes 2003;52:2:453-462