Genetics a More Significant Predictor of Heart Attack than Stroke

According to a recent study, human beings are at a greater risk of inheriting a genetic predisposition to having a heart attack than to having a stroke.

The lead author states that the findings suggest a need for individualized risk assessment models for both stroke and heart attack.

"We found that the association between one of your parents having a heart attack and you having a heart attack was a lot stronger than the association between your parent having a stroke and you having a stroke," reported senior author Peter M. Rothwell, M.D., Ph.D., professor of clinical neurology at Oxford University in England. "That suggests the susceptibility to stroke is less strongly inherited than the susceptibility to heart attack."

The researchers went on to perform a second analysis, which included patients' siblings as well as parents; they concluded that the results were the same, as family history was found to be a stronger risk predictor for heart attack than for stroke.

Rothwell reported that the research was conducted in order to clarify and verify previously discovered evidence which implied a vast genetic distinction between predisposition of heart attacks and strokes.

“We had found previously that much of the heritability of stroke is related to the genetics of high blood pressure, which doesn't seem to be the case for heart attack," Rothwell explained.

Hypertension, it would appear, is strongly connected to an individuals’ risk of suffering a stroke over a heart attack, and as such, a family history of hypertension is related to a higher risk of stroke.

All participants were enrolled in the ongoing Oxford Vascular Study (OXVASC) which began in the year 2002 in order to study strokes, heart attacks, and other various acute vascular events.

The study focused on a specific region of Oxfordshire County where more than 91,000 people are served by one hospital. Previous examinations of this population were conducted by lead author of the study, Amitava Banerjee MPH PhD. Each previous study has exhibited a significance of family history in mother-daughter transmission in both heart attacks and stroke.

"Family history of heart attacks and family history of strokes have rarely been studied in the same population," Banerjee said.

For this study, the researchers utilized data from 604 men and 302 women who suffered from acute heart ailments, and 484 men and 531 women who experienced acute cerebral events.

The researchers discovered that:

• 30% of the heart patients had one parent who had suffered a heart attack, while 5% had two parents with heart attack.
• 21% of the heart patients had at least one sibling who had suffered a heart attack and 7% of the patients had two or more siblings who had heart attacks.
• 21% of the patients who had suffered from a stroke or transient ischemic attacks reported to having one parent who had a stroke, whereas 2% had two parents with stroke.
• 8% of stroke patients had at least one sibling with a stroke and 14% had at least two siblings with stroke.

According to the study results, the risk of a sibling going on to suffer from acute heart problems was the same for both the patients with heart attack or stroke.

The risk for an acute cardiac event, however, was six times greater if both parents had suffered a heart attack, and was one-and-a-half times greater if one parent had suffered a heart attack.

Comparatively, the chance of stroke was not altered notably when examining the stroke history of the patient’s parents.

Rothwell stated that if the findings go on to be confirmed in further studies, they will result in two important implications.

"First, the way physicians predict the odds of a healthy person suffering a heart attack or stroke needs refining," Rothwell said. "Currently, most risk models lump a patient's family history of stroke and heart attack together. We probably should model family history of stroke and heart attack separately in the future."

Further, Rothwell continued, this recent data will also suggest that using the same criteria in order to predict both medical events overestimate the risk of stroke.

"The knowledge of genetic factors in stroke lags behind that in coronary artery disease," Rothwell said.

This study was published in Circulation: Cardiovascular Genetics, an American Heart Association journal.