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Cholesterol in the body is carried around the bloodstream in the form of what are called 'lipoproteins'. The two main lipoproteins are so-called low-density lipoprotein cholesterol (LDL-cholesterol) and high-density lipoprotein cholesterol (HDL-cholesterol). Conventional wisdom tells us that HDL-C is a marker for cholesterol being cleared from the inside of the arteries, while LDL-C has the capacity to deposit itself in the artery wall. Because of this, HDL-C and LDL-C are often dubbed 'good' and 'bad' cholesterol respectively.

Many doctors have been encouraged to focus on LDL-C, and ensure that their patients' levels of this substance remain below a predetermined set point. However, the fact remains that no studies have ever tested the effect of treating LDL-C levels (with medication and/or diet) to below a certain point. It will seem far-fetched to some that the core strategy used in cholesterol management has not been adequately tested, and things get even more unbelievable when it turns out that LDL-C is not even a particularly good marker for heart disease.

While it is often said that LDL-C causes heart disease, this appears to be a gross oversimplification. To begin with, LDL-C comes in different sizes, ranging from small, dense to large 'buoyant' forms. The former are believed to be potentially damaging to artery walls, while the latter not so. Also, there has been increasing interest in the idea that the build-up of plaque on the inside of the arteries is promoted by the process known as inflammation. Some scientists have suggested that inflammation is the key underlying process in the development of 'atherosclerotic plaque'.

With these concepts in mind, some have argued that measuring inflammation in the body might better identify those at risk for heart disease than measuring LDL levels. So I was interested to read a study recently which supports this concept.

In this study, blood samples were drawn from 100 individuals who had been confirmed as having had a heart attack. Blood samples were also taken for comparison from 100 individuals who had not had a heart attack. Each blood sample was tested for levels of LDL-C, as well as a marker for inflammation known as high-sensitivity C-reactive protein (HS-CRP). The results showed:
    1. No significant difference in LDL-C levels between those who had had a heart attack and those that had not. Actually, LDL-C levels were almost identical between the two groups.

    2. There was, however, a significant difference between the two groups with regard to HS-CRP levels. In fact, on average, levels were about six times higher in those who had had a heart attack, compared to those who had not.
This study supports the idea that LDL-C is not a very reliable indicator regarding the risk of having a heart attack. It also supports the idea that inflammation may indeed be the process that drives heart disease and perhaps should be targeted for the most effective prevention. By focusing on LDL levels, we might be looking in all the wrong places.

Here's to a healthy heart.