Cholesterol

LDL-cholesterol:
An elevated level of low-density lipoprotein cholesterol (LDL-C) has been shown to be strongly associated with an increased risk of developing atherosclerosis and cardiovascular disease (CVD), leading to cardiovascular events (e.g. acute coronary syndrome (ACS), myocardial infarction (MI), stroke etc.). A 10% increase in LDL-C is associated with an approximate 20% increase in the risk of developing coronary heart disease (CHD).¹

Most of the cholesterol present in plasma is found in LDL particles, which vary in size with the amount of cholesterol they contain. Smaller particles contain less cholesterol per particle and are denser than the larger particles. These smaller, denser LDL particles are more atherogenic than larger, buoyant particles.² The cardiovascular risk associated with an elevated LDL-C level is considerably increased by additional risk factors, including low levels of high-density lipoprotein cholesterol (HDL-C), age, gender, family history, smoking, obesity, hypertension, diabetes and metabolic syndrome.¹

HDL-cholesterol:
As HDL particles have a protective effect against atherosclerosis, there is a strong inverse association between plasma HDL-C concentration and cardiovascular risk. This has been shown in both patients with established CVD and individuals who remain asymptomatic, and is independent of LDL-C and other risk factors. Low concentrations of HDL-C are also associated with additional risk factors as HDL-C is lowered by smoking, obesity and physical inactivity.³ Concentrations of HDL-C tend to be low when triglycerides are high, so a combination of high plasma triglycerides and low HDL-C predicts a high cardiovascular risk, especially if the total cholesterol to HDL-C ratio is greater than 5.¹

References:
1. Wood D et al, for the Joint European Committee, Second Task Force of European and other Societies. Atherosclerosis 1998; 140: 199-270.
2. In: Fast Facts - Hyperlipidaemia. Eds Durrington P, Sniderman A. Health Press Ltd, Oxford, Second Edition, 2002. 7-12.
3. Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. JAMA 2001: 285; 2486-2497.