Did you know cholesterol levels are no more predictive of your risk of a heart attack than flipping a coin. That’s because cholesterol alone does not cause coronary artery disease.
Researchers have known for years that cholesterol levels are very poor predictors of which individuals are at risk for a heart attack. In large populations, the group with higher cholesterol levels will have more heart attacks than the group with lower levels. But, there will still be many people in the high cholesterol group who never develop coronary artery disease. And, there will be a significant number of heart attacks even in the group with the lower cholesterol levels.
The cholesterol and LDL levels in 80% of the patients who have heart attacks are in the same range as patients who don’t have heart attacks. That means that on an individual basis, your cholesterol level is very unlikely to predict whether or not you are developing plaque in your arteries.
This is because in large part the ability of cholesterol to cause damage to your arteries is not due to cholesterol itself but is determined by the proteins in the blood that carry cholesterol.
Cholesterol exists in the blood in multiple forms which are distinguished by the type of particle that is carrying the cholesterol molecule. Each of these particles consists of varying amount of cholesterol, triglyceride and several lipoproteins. HDL cholesterol, which is typically referred to as “good cholesterol” has different lipoproteins than “bad cholesterol” LDL.
Within each of these classes, the particles occur in a variety of sizes and densities. Each person has a spectrum of LDL particle sizes and the distribution of those particle sizes can vary greatly not only from person to person but even from time to time in the same person. The LDL particle size distribution can be affected by diet, physical activity levels, medications and other factors.
Simply measuring the total LDL level does not tell us anything about the number or size of your LDL particles. Large LDL particles carry more cholesterol than small LDL particles. For any given level of LDL you may have a very large number of small, dense LDL particles, a much smaller number of large LDL particles or anything in between. And that is where the danger lies.
It turns out that the ability of cholesterol to penetrate into the lining of the artery wall and start forming plaque is related to the type of lipoproteins carrying the cholesterol and the number of particles. It is not cholesterol that gets you into trouble, it is the lipoproteins, the number of particles and the particle size. The greater the number of lipoprotein particles in the blood the more cholesterol will be deposited in the artery walls. Even if your LDL level is low, and you have been told by your doctor that you are safe from heart disease, if you have predominantly small, dense LDL, along with a high number of LDL particles, your risk is high.
On the other hand, you can have very high levels of LDL but never develop coronary artery disease if you almost all of your LDL is carried by a small number of large particles.
Studies have shown that those patients with an elevated number of LDL particles have double the likelihood of developing coronary artery disease, regardless of what their total LDL level may be. Those patients who have increased particle numbers AND have predominantly small, dense LDL particles have as much as 6 times the likelihood of developing coronary artery disease.
Physicians can classify patients according to LDL particle size. Those who have elevated levels of small, dense LDL (more than about 25% of their total LDL) are called Pattern B. Those with low levels of small, dense LDL are called Pattern A. Approximately 25-40% of the adult population has Pattern B and is at high risk for heart disease even though many of those patients have cholesterol and total LDL levels that are below the current guidelines for treatment with standard cholesterol lowering drugs.
At Princeton Longevity Center, we recommend testing for LDL particle size, as well as a number of other cardiac risk factors, for those patients whose coronary artery scans show significant amounts of plaque. Regardless of whether those patients have cholesterol, HDL and LDL levels that are considered “normal”, determining the cholesterol particle size distribution is a critical factor in optimizing their treatment to stop the progression of their coronary artery disease.
Fortunately, determining whether you are Pattern A or Pattern B is a fairly simple matter. A small number of specialty laboratories around the country offer high quality testing for LDL particle size. All that is required are a few tubes of blood and a knowledgeable physicians to interpret the results and prescribe appropriate treatment.