Controversial new heart health guidelines could lead to 12.8 million more Americans taking cholesterol-lowering statin drugs.

Under the new guidelines about half of all Americans between the ages of 40 and 75 could be eligible to receive statins, Reuters reported. Those who have a 7.5 percent or higher chance of developing a heart condition within the next 10 years would be eligible for a statin prescription. 

The new guidelines suggest that instead of working to simply lower "bad" LDL cholesterol to "numerical target" medical researchers should use a new calculation that factors in other health factors such as smoking and obesity.

Critics argued these new guidelines could lead to overuse of statins.

"It shows there is a huge expansion of the number of people for whom statins are recommended," he said in a telephone interview.

Researchers looked at 3,773 participants in the National Health and Nutrition Examination Surveys (NHANES) who were between the ages of 40 and 75. The team "compared recommendations for statin use under the new guidelines and the prior guidelines and extrapolated that number to the U.S. population of 115 million adults aged 40 to 75," Reuters reported.

The team found the increase in statin users was most prevalent in over 60s; about 77 percent of people in this age range could be taking statins under the new guidelines compared to the previous guidelines.

Just because one is eligible for statins does not mean that they will necessarily be prescribed.

"The risk estimator doesn't determine the statin prescription. It determines the need for a risk discussion," Doctor Neil Stone, a professor of preventive cardiology at Northwestern University's Feinberg School of Medicine, told Reuters.

"As the new guidelines correctly suggest, before initiation of statin therapy in these patients, physicians should first have a conversation about diet and exercise, and if relevant, smoking cessation and blood pressure control," they said in a statement," Doctor Paul Ridker and Doctor Nancy Cook of Brigham and Women's Hospital said in a statement, Reuters reported.