Other Lipoproteins Being Studied

While there is no official target level for Lp(a), studies suggest that for many people, levels starting at 30mg/dl may raise your risk of heart diseases.African-Americans are the exception; their levels are typically two to three times higher than those of Caucasians.

If you have a family history of heart disease, especially if you’re a woman nearing menopause or postmenopause, ask your doctor about having your Lp(a) level tested,

With all of that said, there’s not much you can do to modify your Lp(a) level. Unlike other kinds of cholesterol, Lp(a) in the blood is mainly determined by genes, so drugs and dietary changes have little effect on it, But that doesn’t mean there’s no point in finding out your level. If, for instance, you have high Lp(a) with another CHD risk factor, like smoking or being overweight, that could justify setting an even lower goal for your LDL or being more aggressive in your efforts to change your lifestyle.

Apolipoproteins

As noted earlier, cholesterol can’t get around the body without hooking up with proteins that act as transporters. Different types of cholesterol tend to hook up with different types of proteins. HDL pairs with apolipoprotein A—or apo(a) for short— and LDL bonds with apolipoprotein B—apo(b). So it’s no big surprise that a low level of apo(a) and a high level of apo(b) may indicate trouble.

One large study of people who had had heart attacks found that low apo(a) and high apo(b) levels quadrupled the odds of a second heart attack. The combination may also pose dangers for those who haven’t had a heart attack. In fact, research suggests that your apolipoprotein levels may predict your likelihood of having a heart attack even better than your LDL or HDL levels.

At some point docters may start relying more on these protein levels as a sign of CHD risk. But right now the test is still relatively new, expensive, and not standardized for the basic doctor’s office, so don’t expect to have one; it isn’t part of the typical complete lipid profile, either. The exception is if you have a high triglyceride level. That can make it more difficult to get an accurate reading of non-HDL cholesterol.

Thus, a high apo(b) level may be the tiebreaker to help your doctor decide whether to start you on cholesterol lowering drugs, There’s also some thought that apo(b) may actually turn out to be a very accurate indicator of heart disease risk in women, whose triglyceride levels tend to run high to begin with.

Normal ranges for apo(a) are 101-199 mg/dl for women and 94-178 mg/dl for men. For apo(b) normal ranges are 49-103 mg/dl forwomen and 52-109 mg/dl for men.

Remnant-Like Particle

Cholesterol One other form of cholesterol that researchers are studying is remnant-like particle cholesterol, referred to as RLP-C. These are lipoproteins that contain the greatest proportion of tigiveerides, chylomicrons, chylomicron remnants, VLDL, VLDL remnants, and IDL. They’re veritable stuffed balloons of risk factors for heart disease. In one major Japanese study, researchers measured levels of total cholesterol, LDL, HDL, triglycerides, Lp(a), and RLP-C in the blood of 208 patients, of whom 57 had high cholesterol and 151 had normal cholesterol. They found that an unfavorable ratio of RLP-C to HDL (a normal ratio is less than 1:4) in patients with overall normal cholesterol levels was highly associated with narrowing of the coronary arteries. In other words, here’s a clear example of why having a normal total cholesterol level may not be good enough to prevent heart disease Currently, there is no readily available test for RLP-C levels, although as more research emerges on its role in cardiac disease, thal w ill change