Uncomplicated hyperlipidaemia seldom presents as an acute illness,
except when plasma triglyceride levels are extremely high, and usually causes no symptoms. However, even quite moderate degrees of
hypercholesterolaemia over the years can cause an acceleration of the ageing
process which affects our blood vessels, known as atherosclerosis. One of
the main features of this process is the gradual deposition of cholesterol in
the walls of the arteries, which narrows their calibre and reduces the amount
of blood which can flow through them. Atherosclerotic narrowing of the
coronary arteries, which supply the heart itself with blood, is the underlying
cause of most ‘coronaries’ or heart attacks, the most serious complication of
hyperlipidaemia.
In general the higher the level of cholesterol in the blood the more
rapidly it gets deposited in the arterial wall. This especially applies when
hypercholesterolaemia is due to an increase in LDL, which transports
cholesterol from the liver to other parts of the body. However, the opposite
occurs when there is an increase in HDL, which transports cholesterol from
the arterial wall back to the liver for disposal. Thus one way of preventing
atherosclerosis is to keep LDL levels as low as possible and HDL levels as
high as possible. This is especially important in people with other risk
factors such as high blood pressure or cigarette smoking.