Three out of four Americans' hearts are older than their chronological age, raising the risk of heart disease, stroke and premature death, officials said Tuesday.

An online tool at www.cdc.gov/heartdisease/heartage.htm can help people determine how old their heart is, based on factors like weight, smoking, diabetes and high blood pressure, said the US Centers for Disease Control and Prevention.

For most adults aged 30-74, their predicted heart age is "significantly higher than their chronological age," said the CDC in its Vital Signs report, released Tuesday.

Researchers found that nearly 69 million adults between the ages of 30 and 74 have a heart age older than their actual age.

"That's about the number of people living in the 130 largest US cities combined," the CDC report said.

The average predicted heart age for adult men was nearly eight years older than their chronological age, and 5.4 years older for women, it said.

When researchers divided people according to race, they found the highest heart ages among African-American men and women, who had an average heart age of 11 years older than their chronological age.

RISK FACTOR DATA

Risk factor data was collected from every US state and information from the Framingham Heart Study, which began in Massachusetts in 1948 and has followed thousands of people over time in an effort to identify the causes of cardiovascular disease.

Heart disease is the leading cause of death and serious illness in the United States.

CDC officials said they were releasing the report and the online tool in the hopes that they would encourage people to be aware of their heart health and take measures to prevent heart disease before it is too late.

"The heart age concept was created to more effectively communicate a person's risk of dying from heart attack or stroke — and to show what can be done to lower that risk," the report said.

Maintaining a healthy weight, keeping blood pressure under control, not smoking, getting enough exercise and eating right are the top ways to avoid heart disease, experts say.

"Because so many US adults don't understand their cardiovascular disease risk, they are missing out on early opportunities to prevent future heart attacks or strokes," said Barbara Bowman, director of CDC's Division for Heart Disease and Stroke Prevention.

"About three in four heart attacks and strokes are due to risk factors that increase heart age, so it's important to continue focusing on efforts to improve heart health and increase access to early and affordable detection and treatment resources nationwide."