Despite widespread public awareness campaigns aimed at reducing cholesterol, total U.S. cholesterol levels have shown little change in the past decade, according to the Centers for Disease Control and Prevention (CDC).

According to a survey conducted from 1999 to 2000, the average cholesterol level among U.S. adults was 203 milligrams per deciliter of blood (mg/dL), only two-mg/dL lower than the previous survey.

The survey involved 4,000 people whose cholesterol levels were compared with data from a similar 1988-1994 survey that involved 15,000 people.

Researchers found that the age-adjusted average total cholesterol concentration decreased from 205 mg/dL in the 1988-1994 survey to 203 mg/dL in the 1999-2000 survey. However, between the 1998-1994 survey and the previous 1976-1980 surveys, cholesterol levels dropped by eight mg/dL.

According to the American Heart Association (AHA), total cholesterol levels should be below 200 mg/dL, with levels from 200 mg/dL to 239 mg/dL considered borderline high. A total cholesterol of 240 mg/dL and above is considered high.

Also, only about 70 percent of those with total cholesterol of at least 200 mg/dL have had their cholesterol tested, and only 35 percent of this group knew that their cholesterol level was higher than recommended. Among this group, 12 percent were undergoing treatment to lower their cholesterol, according to researchers.

High cholesterol puts people at an increased risk of heart disease, the number-one cause of death in the United States. Other risk factors of heart disease include smoking, excess weight, inactivity and type 2 diabetes.

Researchers were uncertain why there is a slowing trend among declining cholesterol levels, but named less physical activity, poor dietary habits and increasing rates of obesity as potential reasons.

The slowing trend suggests that more efforts are necessary to reduce total cholesterol among the U.S. population, researchers said.

Circulation May 2003;107