Biological importance of low-density-lipoprotein subfractions

Low-density lipoproteins (LDLs) exist as discrete subfractions that vary in size and density. A predominance of small, dense LDLs is seen in patients with ischaemic heart disease and non-insulin-dependent diabetes, and is more common in men than in women. Because small, dense LDLs are associated with increased levels of triglycerides and low levels of high-density-lipoprotein cholesterol, their exact role as an independent cardiovascular risk factor is unknown. These lipoproteins exhibit abnormal characteristics, however, such as increased susceptibility to oxidation and decreased LDL receptor binding, which may result in increased atherogenicity.