Adults with high levels of artery-clogging "bad" cholesterol decreased by a third between 1999 and 2006, new research finds.

At the same time, though, researchers found that many adults still have very high cholesterol levels and are not being treated for them. This, despite the widespread use of drugs known as statins, which lower bad cholesterol levels.

While the use of such medications increased from 8 percent to 13.4 percent over the study period, screening rates remained unchanged at less than 70 percent, the researchers write in the article published in today's Journal of the American Medical Association,

Researchers from the CDC studied 7,044 men and women 20 years and older and examined their levels of "bad" cholesterol, or LDL.

Overall, the prevalence of people with bad cholesterol decreased from 31.5 percent in 1999 to 21 percent in 2006. But about two-thirds of people in the highest risk categories -- susceptible to heart attack and other problems -- were not on medication, the authors found.

Why are so many people at risk not getting treated?

An accompanying editorial suggests that screening guidelines are too confusing and need to be simplified. Doctors evaluate patients with a fixed threshold of LDL levels. As a result, doctors sometimes miss people with high risk factors for developing heart disease even if their LDL levels aren't high enough to meet the threshold. In another editorial, other experts suggest factoring age into the equation -- offering generic statins (cheaper than the name brands and therefore more accessible) to all adults above a particular age.

Baltimore Sun photo