TUESDAY, Aug. 30, 2016 (HealthDay News) -- The risk of early death after a heart attack has lessened over the past 30 years among those younger than 50. But it's still nearly twice as high as the general public, Danish researchers report.

This higher risk is driven mainly by conditions such as high blood pressure, diabetes and obesity, which are more common among people who've had a heart attack, said lead researcher Dr. Morten Schmidt.

"Patients with a heart attack in young age should be advised that an excess risk of fatal events persists, warranting compliance to their prescribed medicine and efforts to reduce modifiable lifestyle-related risk factors, particularly smoking," said Schmidt, a researcher at Aarhus University Hospital in Denmark.

Schmidt's team looked at long-term survival of nearly 22,000 Danes who'd had a heart attack before age 50. The patients were followed for roughly 11 years, and compared with almost 217,000 people in the general population.

The researchers found some good news. Between 1980-1989 and 2000-2009, premature deaths within the first 30 days after a heart attack dropped from 13 percent to 3 percent. Deaths from 31 days to one year fell from about 5 percent to 1.6 percent, while deaths from one to 10 years after a heart attack declined from 24 percent to 9 percent.

"About half of the decline in deaths from heart attacks since 1980 is due to prevention, in particular reductions in the number of people who smoke," Schmidt said.

The other half is likely due to a combination of factors, such as early treatment to restore blood flow to the damaged part of the heart, improved hospital care and better management of high blood pressure and high cholesterol, he said.

However, some bad news emerged from the report, too. Within the first year after a heart attack, the overall risk of death was nearly two times higher compared to the general population. Women were three times more likely to die if they'd had a heart attack compared with those who hadn't, and men had twice the risk.

The reason for this gender difference is not known, Schmidt said.

Overall, more people who had a heart attack before 50 had more risk factors for heart disease than the general public, the researchers said.

For instance, 12 percent of heart attack patients suffered from intermittent chest pain (angina); 11 percent had high blood pressure; 7 percent were diabetic, and almost 5 percent were obese. These conditions affected only about 1 percent or less of the general population, according to the report.

Among the under-50 patients, more than eight out of 10 who'd had a heart attack were between 40 and 49. Only 2 percent were under 30, the researchers found.

The results were published online Aug 30 in the journal Circulation.

"It is well-established that individuals who have a heart attack at a younger age, even if surviving the initial episode, remain at higher risk for long-term mortality compared to those who have not had a prior heart attack," said Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles.

These findings highlight why a focus on heart heath and primary prevention of heart attack is essential among people of all ages, said Fonarow, a spokesman for the American Heart Association.

"This can be accomplished by maintaining healthy blood pressure, cholesterol levels and weight, along with not smoking and remaining physically active," he said.

More information

The U.S. National Heart, Lung, and Blood Institute has tips on heart attack prevention.