LDL can be grouped based on its size: large low density LDL particles are described as pattern A, and small high density LDL particles are pattern B. Pattern B has been associated by some with a higher risk for
coronary heart disease.
[10] This is thought to be because the smaller particles are more easily able to penetrate the
endothelium of
arterial walls. Pattern I, for intermediate, indicates that most LDL particles are very close in size to the normal gaps in the endothelium (26 nm). According to one study, sizes 19.0–20.5 nm were designated as pattern B and LDL sizes 20.6–22 nm were designated as pattern A.
[11] Other studies have shown no such correlation at all.
[12]
Some evidence suggests the correlation between Pattern B and CHD is stronger than the correspondence between the LDL number measured in the standard lipid profile test. Tests to measure these LDL subtype patterns have been more expensive and not widely available, so the common lipid profile test is used more often.[
citation needed]
There has also been noted a correspondence between higher triglyceride levels and higher levels of smaller, denser LDL particles and alternately lower triglyceride levels and higher levels of the larger, less dense ("buoyant") LDL.
[13][14]