High levels of cholesterol in the blood may be a major risk for stroke and heart disease. Desirable levels vary from individual to individual, depending on other health factors. But having your cholesterol at an optimal level is a major preventative strategy for heart disease.
In addressing cholesterol concerns, there is a two-for-one benefit for you: with a 10% reduction in total cholesterol, say from the measure of 6.0 down to 5.4, there is a 20% reduction in risk over the ensuing ten years.
Cholesterol is the component of fat or lipids which is carried in the blood, together with triglycerides, and is measured with a blood test. Having “high” cholesterol simply means having a high level in the blood. It is a chemical, essential to the body, and is produced by the metabolism of dietary fat by the liver. Cholesterol provides the chemical backbone for the production cell membranes, and bodily hormones. However, excess production of cholesterol leads to a build up in the walls of our arteries, and eventually to blockages. It is a combination of fat in our diet, and our inherited metabolism, that results in low, normal or high cholesterol in the blood.
Cholesterol is measured in terms of “good” high density lipoproteins (HDL) and “bad” low density lipoproteins, which together make up one’s total cholesterol (TC).
We can think of these as similar to the liver sending out a fleet of empty oil tankers (HDL) to gather up cholesterol deposits from blood vessels around the body, returning to the liver as full oil tankers (LDL). It is beneficial to have lots of empty tankers (the good HDLs) travelling around the body to do the collecting of the bad (LDLs) and returning these for processing to the liver. So the HDLs have a balancing function to offset the LDLs, and the sum is reflected in the Total Cholesterol measure.
The level at which our total cholesterol should be maintained differs according to our level of risk. We are said to be at higher risk if we have existing conditions such as coronary heart disease, diabetes, hypertension and peripheral vascular disease; are in an older age bracket; or have a relevant family history.
For those at high risk, our goals (measured in mmol/l) will be:
For moderate and low risk individuals, these goals will probably vary, and you would be advised accordingly.
Ideally, we should be able to recognise high cholesterol when it is merely a risk factor – long before blocked arteries have become a reality.
In the at risk stage, it is then necessary to evaluate the contributiion of the other factors such as blood pressure, smoking, overweight, and family history into the risk equation. If a moderate risk was to be found, then a total cholesterol of 5.0 would be reasonable.
On the other hand, where an event such as a mini-stroke, heart attack, or poor limb circulation has already occurred, then lowering cholesterol aggressively to a more ambitious target becomes essential to preserve and protect the remaining good vessels. Then a treatment goal of total cholesterol under 4.0 is targetted.
Hence, having a cholesterol check implies more than just a blood test, but includes a good look at all risk factors, and a physical examination, with attention to target organs, the heart and major arteries.