The death of a brother or sister, especially from a heart attack, may increase your own risk of heart-attack death, a study finds. The study focused on 1.6 million Swedes, ages 40 to 69. Among women, those who lost a sibling were 25% more likely to die of a heart attack in the next several years than women whose siblings were living. For men, the increased risk was 15%. If the sibling died of a heart attack, women's own risk of heart-attack death jumped 62%. This risk doubled among men who lost a sibling to a heart attack. The increased risk began 4 to 6 years after a sibling's death for women and in 2 to 6 years after for men. Researchers don't know why heart attack risk might be higher after a sibling's death. The study does not show that one caused the other. Of course, siblings share many genes. Most also have the same exposures growing up and may have formed similar lifestyle habits. Grief also could affect health, researchers said. The Journal of the American Medical Association published the study. HealthDay News wrote about it February 27.

By Robert H. Shmerling, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Heart disease is the No. 1 cause of death in the United States. So it's important to know what factors increase risk and to change them if you can.

Well-established factors that increase the risk of heart and blood vessel disease include:

• High blood pressure (hypertension)
• Diabetes
• Unfavorable cholesterol levels (for example, high LDL and low HDL)
• A family history of heart and blood vessel disease
• Smoking

A new study could add a new item to this list: the death of a brother or sister.

The study was based on information from more than 1.6 million Swedish adults, ages 40 to 69. It found a significantly higher rate of fatal heart attack among people who had lost a sibling. In addition:

• The results varied by gender. The risk was 15% higher for men and 25% higher for women.
• The increased risk of a fatal heart attack did not begin right away. For women, the increased risk couldn't be detected until 4 years after the sibling's death. For men, the risk rose 2 years after the sibling's death.
• The higher risk lasted for 6½ years after the death of a sibling.
• The risk was highest when the sibling died of a heart attack. Risk of a fatal heart attack was 62% higher for women and 98% higher for men after a sibling's fatal heart attack.

These observations raise several questions.

Are these findings simply the result of shared genes that control the risk of heart disease and early death among siblings? Or is there an influence from the shared environment as siblings grew up together? For example, secondhand smoke and an unhealthy diet might increase the future risk of early heart disease and death for siblings.

Another possible explanation is that the stress of a sibling's death somehow translates into an earlier death for the grieving survivor. Perhaps people faced with the loss of a sibling tend to adopt unhealthy habits. Or maybe the stress of losing a sibling has a direct impact on the heart or other organs that takes its toll over time.

Regardless of the explanation, these findings are intriguing. But it's not clear to me whether they are important enough to recommend changes in preventive measures or treatment.

What Changes Can I Make Now?

I would not recommend any changes based on this new study.

Even so, it's a good idea to make changes in factors that affect your risk of heart and blood vessel disease if possible. Based on this study, it may be even more important if your brother or sister has passed away.

You can make these changes now. They may lower your risk of future heart and blood vessel disease:

• Don't smoke.
• Get your blood pressure and blood cholesterol checked. If levels are high, follow your doctor's instructions about diet, exercise and, if necessary, medicines.
• Get your blood sugar checked. If you have diabetes, take your medicines as prescribed and keep your blood sugar well controlled.
• Increase your activity. Exercise can help you to maintain a healthy weight. It also helps to prevent or treat other factors that increase the risk of heart and blood vessel disease
.
• Have regular checkups. This is especially important if you have factors that increase the risk of heart and blood vessel disease.

If you already have heart disease, changing these risk factors and taking your medicines as prescribed are particularly important.

What Can I Expect Looking to the Future?

This new study should inspire future research. Studies should examine why the loss of a sibling may have an important impact on how long someone lives. It would be most helpful to know whether this risk can be reduced with more aggressive screening and treatment.

In the future, we may have standard interventions for people who have lost a sibling. They might include stress management, treatment to reduce heart disease risk factors or both.

In the future, I am hopeful that we'll have a better understanding of connections between the mind and body. Heart disease in people who have lost a sibling may turn out to be a good example. We also may find that other stressful events, such as the loss of a spouse or parent, have an even more profound impact on the risk of heart disease and early death.