The number of coronary heart disease cases reported in the United States has decreased by 20 percent over the past 28 years, reports a recent study.

A number of measures to create awareness on CHD, including blood pressure guidelines, benefits of cholesterol-lowering drugs and emphasis on risks of diabetes and smoking, were introduced in the country over the past three decades. However, the impact of these measures among people had been relatively unknown all the while.

To find if the efforts are really paying off, the researchers pooled data from five different cohort studies from Data Repository Information Coordinating Center and National Heart, Lung, and Blood Institute Biologic Specimen for an exclusive study.

Coronary Heart Disease Study

The study included 14,009 pairs of healthy participants aged between 40 and 79 years who had no prior history of CHD. One set of participants were followed for 12 years from 1983, and the remaining people were followed for another 12 years from 1996 to look for the onset of CHD among these healthy adults, reported in a press release.

Notably, the researchers observed 20 percent decline in CHD rate in the study population between 1983 and 2011. The CHD conditions considered in the study were coronary insufficiency, angina, heart attack and coronary death.

Michael J. Pencina, the senior author of the study from Duke University, said that remarkable progress in the incidence of CHD is achieved over the past three decades. However, "continued vigilance" is necessary to manage the underlying causes of different types of heart problems.

Coronary Heart Disease Risk Factors

Interestingly, a drop in important heart disease risk factors such as high blood pressure and smoking were also observed in the study. It was also found in earlier studies that mortalities due to heart diseases have also dropped significantly over the past couple of decades.

Heart disease risk associated with diabetes is observed to have decreased largely, and the researchers suggest that it could be because the condition is diagnosed and treated effectively than before. Though incidence of diabetes has increased over time, there is awareness among people about the condition, and the patients also get better primary prevention these days.

Decline In Coronary Heart Disease

Meanwhile, the author noted that though 20 percent decline in CHD appears good, it is not sufficient just yet.

"Twenty percent is good, but it's nowhere near where we could or would like to get," Pencina said. "There is still a lot of room for improvement."

The study is published in the Journal of the American Medical Association on Nov. 15.