Q. There is a history of heart problems in my immediate family, but my cholesterol test results have all been normal. Can I assume that I'm safe?
A. Not necessarily. A person's risk of heart disease is assessed in many different waysFor decades, the standard lipid panel—or cholesterol blood test—that looks at levels of total cholesterol, triglycerides, and the amount of cholesterol found in the high- and low-density lipoproteins (HDL-c and LDL-c), has been a major indicator of risk.
You're probably familiar with your LDL number, since that's the one that everyone keeps an eye on. If you're "normal", your LDL may be at an acceptable level. Higher levels of LDL have been shown to be associated with higher heart-disease risk. HDL, on the other hand, is known as "good cholesterol," as higher levels of HDL-c indicate decreased risk.
But new research is showing that there are other, perhaps better, indicators of your chances of building up plaque in your arteries and developing heart disease. These newer markers might be at abnormal levels when the traditional cholesterol numbers are not. This could explain why some people who look good 'on paper' have cardiac events anyway.
- LDL particle size and number: The size of the LDLs matters, too. LDLs can be small and dense, or bigger and fluffier. If they are small, they can more easily enter the walls of the arteries and start to accumulate and build plaque. A new measure of LDLs—LDL-p, or the LDL particle number, assesses how many there are, not just their size and/or the amount of cholesterol they contain. Even if they are smaller and denser, and therefore more easily transported to artery walls, a lower number indicates a lower risk that plaque will accumulate.
- Apo-A or Lipoprotein (a): People aim for higher HDL-c, but some studies have not shown that a higher number is automatically beneficial. This may be because other components of HDL molecules may, in fact, play a more important role in their function. Apo-A, contained within HDLs, helps sweep away cholesterol that helps plaque build up in the artery walls. A test for levels of Apo-A is already used as a screening tool in Europe. Guidelines published in a 2010 issue of the European Heart Journal recommend screening for levels of Apo-A in people who are at an intermediate or greater risk for cardiovascular disease.
- Apo-B or Lipoprotein (b): This is found in different cholesterol components including the LDLs. Studies comparing levels of Apo-B and particle number versus LDL-c levels alone show that the former two are better at predicting risk than the latter, the standard measure currently used.
- Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme associated with inflammation and found in plaque in arteries. A 2010 meta-analysis of 80,000 people published in The Lancet showed that elevated levels were predictive of heart disease.
The problem is that you are not likely to be tested for these markers when you undergo a standard blood test because they are not recommend by the National Heart Lung and Blood Institute's National Cholesterol Education Program (NCEP) panel, which are the guidelines most doctors use. A 2008 position stand from the American Diabetes Association and the American College of Cardiology Foundation has addressed some of these new ways to measure risk and recommended that some of the newer assessment of risk be used in people that are at-risk.
The NCEP guidelines were last established in 2001, and some of these markers may be added to the upcoming NCEP guidelines that are expected to be released in 2012. You can ask your doctor totest you, although you may have to fork out your own money for the tests as, currently, testing for these markers is not covered all insurance.
There are other ways to improve heart-disease risk, too: exercising on most days of the week, increasing your daily activity so that you are less sedentary, and eating nutritious foods most of the time.
