The body remembers what the mind tries to process.
A large-scale study of more than two million Danes has confirmed what grief has long whispered to those who carry it: the loss of a sibling in childhood does not stay in the past. Published in January 2024, the research found a 17 percent higher risk of cardiovascular disease among those bereaved in early life, offering scientific weight to the understanding that the heart keeps its own record of sorrow. The findings invite medicine to look beyond cholesterol and blood pressure and ask, more gently, what a person has lost.
- A 17-year study of over two million people has drawn a direct line between childhood sibling loss and measurably higher cardiovascular disease risk in early adulthood.
- The danger is sharpest for those who lost a twin or a younger sibling, suggesting that the intimacy of the bond amplifies the physiological wound left by grief.
- Chronic stress born from unresolved bereavement can silently damage the heart over decades — long after the acute pain of loss has faded from view.
- Cardiologists are now being urged to treat sibling loss as a permanent, non-modifiable risk factor and to ask about bereavement when assessing a patient's heart health.
- Researchers and clinicians alike are calling for sustained mental health support for bereaved siblings — not just in the weeks after a death, but across years of ongoing healing.
A study published in JAMA Network Open in January 2024 followed more than two million Danish individuals for seventeen years and found that losing a sibling in childhood was associated with a 17 percent higher risk of developing cardiovascular disease by early adulthood. Conducted by researchers from Fudan University and the Chinese University of Hong Kong, the study was large enough to detect patterns that smaller efforts might miss — and what it found was a clear, persistent link between early bereavement and heart health that held even after accounting for other variables.
The risk was highest among those who had lost a twin or a younger sibling, pointing to the possibility that the closeness of the relationship, or the particular shock of outliving someone younger, deepens the body's response to loss. The average age of the siblings who died was eleven — a detail that gives the statistics a quiet weight.
Experts not involved in the study recognized its significance immediately. David Schonfeld, a leading voice in childhood bereavement, noted that decades of research on adverse childhood experiences has shown how early trauma reshapes physical health long into adulthood. Cardiologist Jonathan Kahan explained the mechanism directly: grief hardens into chronic stress, and chronic stress damages the heart. He referenced broken-heart syndrome as evidence that emotional trauma can physically stun the heart — but warned that the greater danger lies in the years of unresolved grief that follow, not the acute moment of loss.
What sets this finding apart clinically is that sibling loss cannot be undone. Unlike high cholesterol or smoking, it is a permanent part of a patient's history. Kahan called on fellow cardiologists to ask about bereavement when taking family histories, and to recognize that a patient who lost a sibling years ago may still be carrying that loss in their cardiovascular system. The researchers concluded that bereaved siblings deserve sustained attention — and that the work of healing, for both heart and mind, extends far longer than medicine has traditionally assumed.
A team of researchers tracking the health outcomes of more than two million Danes has found something that cardiologists are only beginning to understand: the death of a sibling in childhood leaves a mark on the heart that can last decades. The study, published in JAMA Network Open in January 2024, followed people born between 1978 and 2018 for seventeen years and discovered that those who had lost a brother or sister faced a 17 percent higher risk of developing cardiovascular disease by early adulthood.
The researchers—from Fudan University in Shanghai and the Chinese University of Hong Kong—focused on a population large enough to detect patterns that smaller studies might miss. Among the siblings who died, the average age at death was eleven. What emerged from the data was a clear association: childhood bereavement and early cardiovascular risk were linked in ways that went beyond simple genetics or lifestyle factors. The connection held even when researchers accounted for other variables. The risk was steeper still for those who had lost a twin or a younger sibling, suggesting that the closeness of the relationship or the particular shock of losing someone younger intensified the effect.
David Schonfeld, director of the National Center for School Crisis and Bereavement at Children's Hospital Los Angeles, was not part of the research but recognized its significance. He pointed out that decades of work on adverse childhood experiences has shown how early trauma reshapes physical health in adulthood. The death of a sibling, he noted, ranks among the most severe stressors a child can endure—one that disrupts psychological development, emotional adjustment, and the trajectory of how a child grows. The body remembers what the mind tries to process.
Jonathan Kahan, a cardiologist at Delray Medical Center in Florida, explained the mechanism plainly: grief becomes chronic stress, and chronic stress damages the heart. The loss of a sibling can trigger survivor's guilt, persistent anxiety, and a state of emotional dysregulation that the body carries forward into adulthood. He referenced Takotsubo cardiomyopathy, sometimes called broken-heart syndrome, a condition where acute emotional trauma can actually stun the heart muscle into temporary failure. But the real danger, Kahan suggested, lies not in the acute phase but in what comes after—the years of unresolved grief and the physiological toll of living with loss.
What makes this study significant for clinical practice is that sibling loss is a risk factor doctors can identify but cannot change. It is not like high cholesterol or smoking, which patients can modify. It is a permanent part of someone's history. Kahan urged his colleagues to expand their thinking about cardiovascular risk, to ask about bereavement when taking a family history, and to recognize that a patient who lost a sibling years ago may still be carrying the weight of that loss in their cardiovascular system. For people who have experienced such loss, he emphasized the importance of seeking support—emotional, physical, and social—in the years after the death, not just in the immediate aftermath. The researchers concluded their findings highlight a need for sustained attention and care directed toward bereaved siblings, recognizing that the work of healing extends far longer than most people assume.
Notable Quotes
The findings highlight the need for extra attention and support to the bereaved siblings to reduce CVD risk later in life.— Researchers from Fudan University and Chinese University of Hong Kong
Chronic stress or chronic guilt is directly linked to cardiovascular disease. A traumatic event like the loss of a sibling can carry over in a significant way into adulthood.— Dr. Jonathan Kahan, cardiologist at Delray Medical Center
The Hearth Conversation Another angle on the story
Why would losing a sibling in childhood affect the heart specifically, decades later?
It's not really about the heart being uniquely vulnerable—it's that grief becomes a chronic stressor. The body stays in a state of heightened alert, and over years, that constant activation of stress hormones damages blood vessels and the heart muscle itself.
But people lose siblings all the time. Why do some develop heart disease and others don't?
That's the question the study can't fully answer. The 17 percent increase is a population-level finding. Individual resilience, access to support, whether someone processed the grief—those things matter enormously. The study shows the risk exists, not that it's inevitable.
The study mentions the risk is higher for losing a twin or younger sibling. What's the difference?
A twin is essentially a mirror—the loss feels like losing part of yourself. A younger sibling triggers a different guilt: you were supposed to protect them. Both create a deeper wound than losing someone older, who was supposed to outlive you.
So what should a doctor actually do with this information?
Ask about it. When someone comes in with early heart disease, ask if they lost a sibling young. Then take it seriously—not as something to fix, but as context for understanding their risk and what kind of support they might need.
Is there a way to prevent the heart disease if you've lost a sibling?
Not prevent, exactly. But manage the grief actively—therapy, community, physical activity, stress reduction. The study doesn't prove those things work, but the cardiologists quoted believe that addressing the underlying trauma and chronic stress is where the real intervention lies.