The study, which tracked cholesterol information from more than 32,000 adults, was published Monday in the Journal of the American College of Cardiology.
During the study period, the use of cholesterol-lowering statins by people with diabetes - who are at increased risk for heart attack - rose from less than half to more than 60%, the AP reported.
The findings are "very heartening," said study leader Dr. Pankaj Arora, of the University of Alabama at Birmingham. "But there is more to do."
"These are surprisingly impressive results" that together predict a 15% to 20% reduction in risk of heart attacks and strokes, Dr. Michael Miller, preventive cardiology chief at the University of Maryland Medical Center, told the AP. He wasn't involved with the study.