Dyslipidemia in diabetes mellitus

Patients with diabetes mellitus have a higher rate of mortality than the general population. This higher mortality may be attributed mainly to cardiovascular disease. A high prevalence of dyslipidemia in diabetics can be one of the reasons for this. The most commonly recognized lipid abnormality in non-insulin-dependent diabetics (NIDDM) is hypertriglyceridemia, which is known to be an independent risk factor for coronary heart disease in diabetics. Hypertriglyceridemia can be produced by two mechanisms, increased synthesis of very-low-density lipoprotein (VLDL) triglyceride and removal defect of plasma triglyceride. It has been a matter of debate whether insulin always stimulates hepatic VLDL secretion but it is generally accepted that insulin deficiency results in an impairment of plasma triglyceride clearance. Considerable attention has recently been focused on the atherogenecity of postprandial hyperlipidemia, remnant lipoproteins, small, dense LDL, lipoprotein (a) [Lp(a)] and isolated hypo-alphalipoproteinemia in NIDDM subjects. Several reports suggested that these atherogenic lipoprotein abnormalities are present in NIDDMs even if they are apparently normolipidemic. Association of visceral fat obesity, insulin resistance and nephropathy may aggravate the atherogenic lipoprotein profile. Therefore, we propose here that plasma lipid levels of diabetic subjects must be more strictly controlled than for the non-diabetic population in order to avoid an increased risk for coronary heart disease. If they are obese or associated with insulin resistance or nephropathy, these conditions should be carefully controlled.