Increases in low density lipoprotein cholesterol has a direct correlation with coronary heart disease and is considered the main atherogenic particle. Whether isolated raised plasma triglycerides contribute to CHD on their own remains controversial. Cholesterol deficiency is rare in a modern Western diet. Hyperlipidaemia The Frederickson classification of hyperlipidaemia, developed in the 1970s by the World Health Organisation, classifies the type of hyperlipidaemia according to which lipid is raised and by how much. Hyperlipidaemia can be divided further into primary and secondary cases.
Primary hyperlipidaemia is the most prevalent of the two types in causing coronary heart disease.
Causes include familial hyperlipidaemia and excess dietary fat. The Multiple Risk Factor Intervention Trial identified the three major risk factors as high cholesterol, smoking and hypertension. The trial also quantified the risks. Secondary hyperlipidaemia can be a complication of renal disease, liver disease, diabetes mellitus, hypothyroid disease or alcohol and drug abuse. Treatment of secondary hyperlipidaemia is concerned with treating the original disorder and, when this is controlled, the lipid profile should normalise.