The American Heart Association (AHA), in November, released new guidelines for cholesterol treatment in people at risk of heart disease. Rather than focusing on “specific target levels of low-density lipoprotein, commonly known as LDL, or ‘bad cholesterol’ … it focuses on defining groups for whom LDL lowering is proven to be most beneficial,” said Dr. Neil J. Stone, chair of the panel that wrote the guidelines, at the time. He also predicted that more people “who would benefit” from cholesterol-reducing statins (HMG-SoA reductase inhibitors). Now, a new study finds that there will indeed be many more people taking the medications — as many as 13 million more.

“We sought to do a principled, scientific study to try to answer how the new guidelines might affect statin use, particularly as they focused eligibility on patients with an increased risk of developing cardiovascular disease,” said Dr. Michael J. Pencina, a professor of biostatistics at Duke University’s Clinical Research Institute, in a statement. “By our estimate, there might be an uptake in usage as a result of the guidelines, from 43.2 million people to 56 million, which is nearly half of the U.S. population between the ages of 40 and 75.”

The guidelines offered steps anyone could take to reduce their cholesterol — including eating fruits, vegetables, whole grains, and nuts. But they also suggested that people who had LDL cholesterol levels of 190 mg/dL or higher, who had type 2 diabetes, or who had a 10-year risk of heart disease of 7.5 percent or higher take part in statin therapy. Compared to other therapies, statins were chosen because “their use has resulted in the greatest benefit and the lowest rates of safety issues.”

The AHA’s guidelines were met with some controversy as many wondered how many more people would be taking statins, and how many would be taking them unnecessarily. Some studies have shown that there are more harms than benefits to taking statins. One of them, for example, found that statins counteracted the benefits of exercise, and that exercise alone was better for the obese people who were most likely to go on statins. Meanwhile, another one linked it to developing cataracts. Their benefits, however, still seem to outweigh the risks.

Pencina and colleagues came to their conclusions after looking at data from the National Health and Nutrition Examination Surveys (NHANES), focusing on the fasting cholesterol levels and blood tests of 3,773 people between 40 and 75 years old. The 13 million extra Americans who qualified for stain use comprised of 77 percent of adults over age 60 who didn’t have cardiovascular disease — a jump from 48 percent under the old guidelines. Qualifying participants between 40 and 60 years old rose from 27 percent to 30 percent.

When the participants were broken down by gender, 87 percent of older men qualified for statins under the new guidelines, compared to 30 percent with the old. The change among women wasn’t as drastic, jumping from 21.2 percent to 53.6 percent. “The biggest surprise of the research was the age-dependent split for those affected by the new guidelines,” Pencina said in the release. “We anticipated that the impact would be age-dependent, but not to the degree observed. The changes for both men and women in the older age groups were huge compared to those between the ages of 40 and 60.”

As cholesterol moves through the blood stream, it begins to collect on artery walls, creating plaques that make blood flow more difficult. Eventually this leads to heart attacks, stroke, and other complications of heart disease. Almost 71 million Americans have high cholesterol, according to the Center for Disease Control and Prevention, with only one in three having it under control. While it’s important to get checked for high cholesterol, and speak about possible treatments with health care providers, not everyone will go on statins. “Recommendations are just that — recommendations,” Pencina said.