The role of good cholesterol is still questionable, although most experts agree higher levels are desirable.
The Early Show's Dr. Mallika Marshall says although there is no question that bad cholesterol, or Low-Density Lipoprotein (LDL) cholesterol, should be controlled. There are, however, questions about the role of good cholesterol, or High-density Lipoprotein (HDL) cholesterol.
Research shows that when it comes to people with the same levels of bad cholesterol, the one with more good cholesterol is less likely to have heart disease. Scientists have found that LDL and HDL have opposite roles in the body. Both transport cholesterol, but they carry it in opposite directions. LDL takes cholesterol to coronary arteries, where it can build up and cause blockages. HDL takes cholesterol away from arteries to the liver, where it is disposed of.
Medical experts, however, still don't know exactly how the two different types work together, or how HDL cholesterol can affect heart disease if it's really high.
Cholesterol treatments are geared toward lowering bad cholesterol if it's too high.
Marshall says currently the key is to achieve a good ratio of both good and bad cholesterol. The American Heart Association says total cholesterol should be less than 200. Levels of good cholesterol should be above 40. Levels of bad cholesterol should be less than 130, or less than 100 if you already have heart disease or diabetes.
More aggressive treatment may be recommended if there is heart disease and/or multiple risk factors such as family history, high blood pressure or obesity. Marshall says everyone should have a complete cholesterol screening at the age of 20 and every five years thereafter.
Statins, a family of drugs, are used to lower bad cholesterol when diet and exercise don't work. Millions of Americans take statins, and research with conventional doses shows that these drugs work well. Researchers are trying to figure out which drugs and which doses work best for different patients.
Two new studies compared the use of the highest approved doses of two of these drugs -- atorvastatin or Lipitor, and pravastatin or Pravachol. They were tested in high-risk heart disease patients with an urgent need to get their cholesterol under control.
A comparison in the New England Journal of Medicine showed a lower rate of deaths from heart diseases and a steeper drop in bad cholesterol in heart attack patients, who received intensive atorvastatin therapy compared to paravastatin.
Another study in the Journal of the American Medical Association showed heart patients, who got intensive therapy with atorvastatin, had no progression of heart disease and reduced plaque buildup in the arteries compared to those who got moderate treatment with pravastatin.
The lower the cholesterol the better the outcome for heart patients. And, intensive statin therapy can do the job effectively. There are also studies underway to see if certain genetic factors can determine which drugs work best for a person.
Marshall says there is evidence that people with heart disease can benefit from even lower levels of bad cholesterol. In one study, the goal was to get bad cholesterol under a hundred, but it was when it was reduced to 79 that the arteries stopped becoming clogged.
Further research is needed before the guidelines are changed. Diet and lifestyle changes that have even greater potential than drugs to reduce cholesterol are usually suggested first for most younger people without heart disease or other risk factors. If nothing else works, your doctor may prescribe them, but the statin drugs can have side effects including negative effects on the liver and they are also expensive.