Sudden cardiac death is perhaps one of the most shocking and terrifying events when it comes to a person's health, in part because it occurs so suddenly and unexpectedly. They often come with no warning signs and can affect anyone, even seemingly healthy young athletes. New research published in the Journal of the American Heart Association identifies risk factors associated with unexpected death due to loss of heart function.

Researchers looked at long-term data collected from more than 5,200 men and women between the ages of 28 and 62, who participated in the Framingham Heart Study, a decades-long cardiovascular study. None of the participants had cardiovascular disease when they first enrolled in the study. For the current study, researchers focused on four major risk factors — blood pressure, total cholesterol, smoking, and diabetes — to calculate overall cumulative lifetime risk estimates for sudden cardiac death. Among its findings, the study revealed that men faced a significantly higher lifetime risk of sudden cardiac death than women: one in nine men will experience premature death due to sudden cardiac death compared to one in 30 women. What’s more, men with two or more major risk factors were 12 percent more likely to suffer a heart attack.

“These numbers should raise a red flag,” said Dr. Donald Lloyd-Jones, senior study author and chair of preventive medicine at Northwestern University Feinberg School of Medicine, in a statement. “We often screen for conditions that are less common and much less deadly than sudden cardiac death. For instance, the lifetime risk of colon cancer is about one in 21, and for this reason everyone over the age of 50 is told to have a colonoscopy. But by comparison, the lifetime risk of sudden cardiac death for men is one in nine, and yet we’re not really screening for it.”

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Sudden cardiac death, aka sudden cardiac arrest, occurs when the heart suddenly loses the ability to function. It is the number one cause of natural death in the U.S., claiming up to 450,000 lives each year, according to the study. The Mayo Clinic states many cases of sudden cardiac arrest occur in people with coronary artery disease, the most common form of heart disease. However, researchers said most people who experience sudden cardiac death have no prior symptoms of cardiovascular disease.

“Sudden cardiac death has been very hard to study because most patients had no history of heart problems and were not being monitored at the time of their death,” Lloyd-Jones explained. “The majority of all cases occur before age 70; this is obviously sudden and devastating for families, with a burden that can be quite severe.”

Past research revealed that some patients may experience signs or symptoms before a sudden cardiac death occurs, including loss of consciousness, chest pain or difficulty breathing within the four weeks prior to their cardiac arrest or death, but those warning signs often go ignored.

The study also revealed that high blood pressure alone or in combination with other cardiovascular risk factors, such as smoking and diabetes was associated with a higher lifetime risk of sudden cardiac death. Researchers also noted that high blood pressure levels helped them identify risks more accurately in both men and women, indicating that hypertension may, unsurprisingly, be strongly linked to sudden cardiac arrest and death.

Source: Bogle B, Ning H, Mehrotra S, Lloyd-Jones D, Goldberger J. Lifetime Risk for Sudden Cardiac Death in the Community. Journal of the American Heart Association. 2016.