People age 50 and younger have almost twice the risk of premature death after a heart attack — mainly due to heart disease and other smoking-related diseases, according to new research.

The study is based on data from 21,693 heart attack survivors age 50 and younger who were compared to 216,930 people from the general population and followed for an average of 11 years. Four of every five heart attack survivors were men and their average age was 45. The majority of heart attack survivors — 83.6 percent — were 40-49 years old and 1.8 percent were under age 30.

Researchers found:

  • In 1980-89 and 2000-09, heart attack deaths declined from 12.5 percent to 3.2 percent within 30 days, 5.1 percent to 1.6 percent within 31-365 days and 24.2 percent to 8.9 percent within one-10 years.
  • Patients age 50 and younger had a 1.89 times greater risk of death among one-year survivors compared to the general population.
  • Among one-year survivors, women were three times more likely and men 1.7 times more likely to die after a heart attack compared to the general population. Researchers said the reason for this difference is unclear.

“Although 30-day risk of death following a heart attack has decreased markedly in the last 30 years, younger patients should still have concerns about their long-term health,” said Morten Schmidt, M.D., Ph.D., lead study author and a researcher at the Aarhus University Hospital in Denmark.

“It is estimated that half of the decline in deaths from heart attacks since 1980 is attributable to primary prevention and, in particular, the reduction in the number of patients who smoke. The other half is likely attributable to a combination of things such as the introduction of early treatments that restore blood flow to the part of the heart muscle damaged during a heart attack, improvement in hospital organization and better management of high blood pressure and high cholesterol.”

Cardiovascular disease risk factors were higher among the heart attack group than the general population, including angina (11.7 percent versus 0.4 percent); high blood pressure (10.6 percent versus 1.2 percent); diabetes (7.4 percent versus 1.1 percent); and obesity (4.6 percent versus 0.8 percent).

The risk of heart attack can be greatly reduced by quitting smoking, exercising and following a healthy diet — behaviors that also help prevent a second heart attack.

“Even though you survive a heart attack at an early age, you remain at an increased risk of another attack later in life,” Schmidt said. “For the same reason, it is important that patients make efforts to reduce this long-term risk by adhering to the prescribed medical therapy and by improving their lifestyle, especially by stopping smoking,”

The study is published in the American Heart Association journal Circulation: Cardiovascular Quality and Outcomes.