While Americans continue to grow obese, a new analysis of U.S. health data shows that between 1988 and 2010, average cholesterol levels for U.S. adults have been declining.

The study, published this week in The Journal of the American Medical Association, shows that low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (HDL-C), and total cholesterol (TC) have declined over the past two decades. According to the study, all of these types of cholesterol are risk factors for heart disease.

They also found that from 1988 to 2010, there was an increasing trend in the percentage of adults who were taking lipid-lowering medications. Among Americans age 50 or older the percentage using lipid-lowering medications increased 35%.

However, the lower colesterol seen in the study was “similar” in those not taking lipid-lowering medications and a decline was even seen among the obese.

“The favorable trends in TC, non-HDL-C, and LDL-C may be due in part to a decrease in consumption of trans-fatty acids or other healthy lifestyle changes, in addition to an increase in the percentage of adults taking lipid-lowering medications,” said the study’s authors. “They are unlikely to be the result of changes in physical activity, obesity, or intake of saturated fat,”

The researchers noted that the intake of saturated fat as a percentage of calories did not decrease from 1999 to 2008 and “little progress was made” regarding the leisure-time physical activity level of adults.

The study looked at three U.S. cross-sectional National Health and Nutrition Examination Surveys: one from 1988 to 1994, one from 1999 to 2002, and one from 2007 to 2010. From 1988 to 2010, average levels of TC dropped from 206 mg/dL to 196 mg/dL. These results were the same for age-adjusted average levels in both men and women.