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Family History of Heart Disease: A Definition

Jan. 29, 2001 -- If family history strongly increases risk of heart disease, it begs the question: What constitutes 'family history'? How many nuclear-family relatives jeopardize our own heart health? If your dad -- a smoker -- died of a heart attack at age 65, how does that affect your fate? What if both parents died of heart disease -- but not until they reached their 90s?

"It's not a black-and-white situation," says Edward Massen, MD, a cardiologist at St. Luke's Episcopal Hospital/Texas Heart Institute in Houston. "I think what we're looking at is a spectrum of risk."

A parent with an early-age heart attack should be a red flag for you and your siblings, Massen tells WebMD. "If your father had a heart attack at age 40, that's different from a father with a heart attack at age 65 or a grandfather at 90." However, he adds, even late-age heart attacks in relatives might elevate your risk.

"The more family members you have with [blood vessel] problems, the closer they are related to you, and probably the younger the age when they had their problems -- those are the significant risk factors," says Massen.

"We define 'early heart attacks' as a man under age 55 or a woman under age 65," says Laurence Sperling, MD, director of preventive cardiology at Emory University School of Medicine in Atlanta.

If your first-degree relative -- father, mother, brother, sister -- had the heart attack, other details become important, Sperling tells WebMD. "We further try to define other risk factors: Was that person a smoker, diabetic? If the answer is 'no' to both of those, we ask about cholesterol problems," he says. "If there were none, then you -- simply because of family history -- definitely are at higher risk for heart problems. If you have multiple relatives who had early heart attacks, that increases the magnitude of risk."

The largest database for this research comes from Utah, where thousands of families were studied. "Family history was a potent risk factor," says Sperling. "Having a one-degree relative with a heart attack under age 55 increased risk by 33%; two relatives increased risk by 50%."

Whereas family history indicates a genetic predisposition to heart attack, "it also means that you may be genetically vulnerable to developing other contributing risk factors, like a genetic cholesterol abnormality, obesity, high blood pressure -- all of which can create a predisposition to diabetes, too, which also increases risk of heart disease," Sperling tells WebMD.

When heart attack occurs in a relatively young family member, it's important that all first-degree relatives are screened, says Sperling. Case in point: a recent patient -- a 31-year-old mother who had a heart attack and subsequent heart bypass surgery. "She was not a smoker, not diabetic, but she did have family history of heart disease," he says. "We found she had a genetic predisposition to high cholesterol -- that it was over 500. We screened this woman's children, and found they had high cholesterol."

Massen's advice: "If you do have a strong family history [of heart attacks], particularly at a young age, it's in your best interest to make sure your blood pressure is under control. Get your cholesterol checked. Do those things we know can lower your risk."

"It may well be that as we break the genetic code, there will be genes that make you more susceptible to [heart disease] problems," Massen tells WebMD. "But even at that point, if we locate a gene that makes you susceptible, we will also find that lifestyle can modify that gene's effect."