The contribution of lipids to coronary heart disease in diabetes mellitus

Cardiovascular disease is two to three times more common in diabetic patients than in the non-diabetic population. Although risk factors that affect the general population such as age, cigarette smoking, hypertension, obesity and hypercholesterolaemia also affect diabetic subjects, the increased prevalence of hypertension and obesity in non-insulin-dependent diabetes mellitus (NIDDM) only partially explains the increased morbidity and mortality from coronary heart disease (CHD). Other factors must therefore be considered in this group of patients. Triglyceride concentrations, particularly post-prandial levels, may be important. Diabetic subjects have increased very-low-density-lipoprotein (VLDL), increased intermediate-density-lipoprotein (IDL) and low high-density-lipoprotein (HDL) concentrations, and differences in lipoprotein composition may partly explain increased atherogenesis. Although LDL levels of diabetic patients are not different from those of control subjects. LDL particles are potentially atherogenic as they are smaller, more dense and prone to oxidative modification. NIDDM subjects also have altered apolipoprotein concentrations, including increased apoB, apoC-III, and decreased apoA-I; in addition, apoE-2 may be over-represented in diabetic populations. Thus, apart from the traditional risk factors, there are several lipoprotein compositional abnormalities that may contribute to the increased prevalence of CHD in diabetes.