A new report from the Centers for Disease Control and Prevention (CDC) found that the number of Americans with high total cholesterol levels has dropped by over 30 percent in the past two decades, from 18.3 percent of adults in 1999–2000 to 11.4 percent in 2015–2018.



The findings, published on April 22, used data collected yearly from the National Health and Nutrition Examination Survey (NHANES).



The paper indicated that Americans are also making improvements in high-density lipoprotein (HDL) or “good” cholesterol. In 2007–2008 when the agency began tracking HDL, 22.2 percent of the population had low HDL compared with 16 percent in 2017–2018.

“It’s very encouraging,” says Alec J. Moorman, MD, a cardiologist at UW Medicine in Seattle who was not involved in the report. “These numbers show that total cholesterol levels are falling over time in the American population,” which is a good thing, because high cholesterol is a major cause of heart disease.





Margaret Carroll, a researcher at the CDC’s National Center for Health Statistics and the lead author of the report, says this data shows that most groups of Americans are meeting the goals established by the Healthy People 2020 Guidelines , which were established to reduce the proportion of adults with high total cholesterol to 13.5 percent or less. “The only group that failed to meet these guidelines during 2015–2018 was adults 40 to 59 years old,” Carroll told Everyday Health.

This data shows that our national guidelines for cholesterol management are working, according to Dr. Moorman. “They’re influencing decisions that are leading to improved cholesterol health in our population. Having higher HDL is healthy, so it’s encouraging that the prevalence of people with low HDL is also improving,” he says.



RELATED: 9 Things Dietitians Wish You Knew About High Cholesterol



The Difference Between LDL (‘Bad’)

Cholesterol and HDL (‘Good’) Cholesterol





Blood cholesterol is a waxy, fat-like substance that’s essential for your body to function properly and do things like make hormones and digest food. The body makes all the cholesterol it needs, which is why it's recommended that people limit the amount they eat in their diet, according to the CDC

High low-density lipoprotein (LDL) cholesterol can cause plaque to accumulate in the arteries, which can restrict blood flow and even rupture, potentially causing a heart attack.



Whereas low LDL levels are better for heart health, having a low HDL (equal to or less than 40 milligrams per deciliter [mg/dL]) can increase the risk for a heart attack or stroke.



“HDL is thought of as the ‘healthy’ cholesterol because it’s involved in reverse cholesterol transport, when cholesterol is carried back from the bloodstream to the liver,” says Moorman.



RELATED: 8 Foods That Help Lower Your Cholesterol



Cholesterol-Lowering Drugs and Reduced Consumption of Bad Fats Lead to Improvements in Cholesterol



A few factors may be behind the drop in total cholesterol and LDL cholesterol , according to Moorman.

“The first is that there’s just a higher percentage of Americans on cholesterol lowering medications now, and that’s a good thing,” he says. “Our national guidelines have evolved over time to advocate for lower cholesterol targets, and there’s a higher percentage of adult Americans who are eligible for cholesterol treatment now, namely statin medications,” says Moorman. “This data reflects the increased use of medications in an appropriate way,” he adds.





Moorman also suggests that part of this improvement could also be due to our reduced consumption of trans fats . Trans fats in the form of partially hydrogenated oils were outlawed by the FDA in 2018, he notes. “Trans fats had a lot of toxic cardiovascular effects, one of which was raising cholesterol,” says Moorman.

This trend, though positive, is not surprising, notes Carroll. “The findings for high total cholesterol and low HDL-C for 2015–2018 were generally similar to those seen during 2011–2014,” she says.



RELATED: FDA Approves Non-Statin Drug to Treat High Cholesterol



Reduction in Number of People With Low HDL Cholesterol Is Surprising





In the past there has been a lot of interest in developing drugs that can raise HDL and by doing so, reduce the risk of heart attack and stroke, says Moorman. Although there are many drug compounds identified that will raise HDL, none of them were able to reduce the number of heart attacks and strokes when studied in clinical trials, he says. “There’s something about changing HDL with drugs that does not create a functional improvement in HDL. It improves the concentration of HDL, but that doesn’t translate into improved vascular health,” says Moorman. Investigation into how to raise HDL through medication has really fallen off as a result of the failures shown in these studies, he adds.

A review of 12 randomized controlled trials published in 2014 in the journal PLoS One examined whether increasing HDL with drug therapy lowered the risk of heart attack and stroke and found that the medications had no effect on the number of events. The authors of the study concluded that increasing HDL through drugs was not beneficial.



The fact that there is no drug therapy to improve HDL is part of what makes the improvements surprising, says Moorman. “The things that will raise HDL in the population other than medications would be regular exercise and [regular] alcohol consumption, and improved management of other health conditions like the metabolic syndrome, prediabetes or diabetes,” he says.



Between 2015–2018, 26.6 percent of men and 8.5 percent of women had low HDL. In men, the prevalence of low HDL-C was lowest in non-Hispanic black adults, at 31.9 percent. In women, Hispanic adults were most afflicted with low HDL, at 12.3 percent.



Although drinking alcohol is a way to raise HDL, providers don’t suggest that nondrinkers start consuming alcohol to do it, says Moorman. “There’s an ongoing debate in healthcare about how much alcohol is healthy, if any. We know that when you look strictly at cardiovascular events there’s a protective effect of alcohol when it’s consumed in moderation, but some researchers have shown that there are negative health effects associated with any alcohol consumption,” he says.



According to the American Heart Association (AHA), moderation is key. There is no research that has proved a cause-and-effect link between drinking alcohol and better heart health.



More Aggressive Cholesterol Guidelines Mean Fewer Heart Attacks and Strokes



“I would expect this reduction in overall cholesterol to result in fewer deaths by heart attack and stroke in the future — in fact, we’re already seeing that,” says Moorman. “It is clear from decades of research that cholesterol is not only associated with cardiovascular death, it’s a cause of it. This data is one reason that we’ve seen falling cardiovascular death rates, heart attack rates, and stroke rates in the general population,” he says.



More aggressive guidelines have been a big part of this improvement, says Moorman. “Looking at this data beginning in 1999, our cholesterol guidelines called an LDL cholesterol of 100 or lower ‘ideal,’ and we’ve now shifted that target down to an LDL of less than 70 for high-risk patients,” he says.



A high-risk patient is a person who has heart or blood vessel disease or who has a high risk of heart disease due to metabolic syndrome, according to AHA guidelines. “Pushing for lower cholesterol targets in individuals who are at risk does improve overall cardiovascular health and will continue to lower the death rates of cardiovascular disease,” says Moorman.

