An estimated 790,000 Americans suffer a heart attack, or acute myocardial infarction, each year, according to the Centers for Disease Control and Prevention. While the problem is more common in older adults, a new study published in the journal Circulation reveals that the cardiovascular condition is on the rise among young women, reports CNN.

A heart attack occurs when blood flow to the heart is blocked—most often by a buildup of fat, cholesterol and other substances that forms a clot—a result of heart disease, which is the leading cause of death in the United States.

For the inquiry, researchers checked data in the Atherosclerosis Risk in Communities Study on more than 28,000 hospitalizations for heart attack in patients ages 35 to 74 between 1995 and 2014 in the communities of Forsyth County, North Carolina; Washington County, Maryland; Jackson, Mississippi; and eight northwest suburbs of Minneapolis.

More specifically, scientists focused on individuals 35 to 54 years old, as this age group accounted for 30 percent of those admitted to hospitals. Results showed a decrease in the annual incidence of heart attack hospitalizations among young men and an increase among young women.

In addition, these younger women were more likely to be Black and have medical insurance, a history of hypertension, diabetes, chronic kidney disease and stroke and less likely to be smokers.

While risk factors such as type 2 diabetes and high blood pressure might explain the increase in heart attack among young women, experts stressed that further research must be conducted to determine the driving factor contributing to the rise.

Nieca Goldberg, MD, a cardiologist and the medical director of the Joan H. Tisch Center for Women’s Health at NYU Langone Health in New York City, who was not involved in the study, said the risk factors and symptoms for heart attack are complex.

“Are the risk factors and symptoms being recognized by the providers? Are the patients, although they have insurance, taking the time out to make an appointment? Was it difficult to get an appointment, so they just gave up?” she asked.

Goldberg told CNN it’s also key to consider other behaviors among this age group, such as people spending more time sitting and not being physically active.

Researchers noted several limitations of the study, including that information was sourced from just four communities and restricted to medical records and that the investigation didn’t explore obesity, another known risk factor for heart attack.

Click here to learn how an underdiagnosed condition is a key reason why women suffer cardiac problems.