Cholesterol levels of U.S. adults have dropped over the last two decades, according to a new national study.

Between 1988 and 2010, average total cholesterol levels decreased from 206 to 196 milligrams per deciliter. Average levels of low-density lipoprotein (LDL) dropped from 129 to 116 mg/dl over the study period, while high-density lipoprotein (HDL) levels rose from 51 to 53 mg/dl.

High levels of LDL ("bad") cholesterol and low levels of HDL ("good") cholesterol are major risk factors for coronary heart disease.

These "favorable trends" in cholesterol levels are likely due in part to people eating less trans fat, making other healthful lifestyle changes and taking lipid-lowering medications, the researchers wrote in their study, published in the Oct. 17 issue of the Journal of the American Medical Association.

The researchers, led by Margaret Carroll of the Centers for Disease Control and Prevention, used data gathered during three National Health and Nutrition Examination Surveys, conducted in 1988-1994, 1999-2002, and 2007-2010. In these surveys, participants were interviewed and also underwent physical exams, including blood tests. In each survey between 9,500 and 16,500 people participated.

The researchers also found an increase in the percentage of adults receiving lipid-lowering medications, from 3.4 percent in 1988-1994, to 9.3 percent in 1999-2002, and to 15.5 percent in 2007-2010.

Men's average LDL levels were higher than women's in the two early surveys, but the 2007-2010 survey showed there was no longer a sex difference, according to the study.

The changes were "unlikely to be the result of changes in physical activity, obesity, or intake of saturated fat," the researchers wrote in their article.

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This story was originally written for MyHealthNewsDaily and was reprinted with permission here. Copyright 2012 MyHealthNewsDaily, a TechMediaNetwork company. All rights reserved.

Average cholesterol level drops in U.S.
Cholesterol levels of U.S. adults have dropped over the last two decades, according to a new national study.