The following originally appeared on The Upshot (copyright 2017, The New York Times Company).
Of all the possible tragedies of childhood, losing a sister or brother to early death is almost too awful to contemplate. Yet it is startlingly common. In the United States, 5 to 8 percent of children with siblings experience such a loss.
The immediate effects of a sibling’s death, and the grief that follows, are obvious to all. But the consequences are more than emotional and can last for decades. They are even associated with an increased risk of death in those who remain.
A recent study in JAMA Pediatrics followed all children in Denmark and Sweden from 1973 through 2013. More than 55,000 of these children experienced the death of a sibling before they turned 18. In the 37 years of follow-up, these children were more than 70 percent more likely to die as well. Although the overall risk of death remained low throughout these years, it was highest in the first year after a sibling’s death. During that period, children who lost a sibling have a mortality rate two and a half times that of other children.
Why are children who lose siblings more likely to die, even decades later? One of the reasons is probably genetic. In the study, many of the children who died later, even those who died within a year of each other, died of the same disease as their sibling.
Another factor could be the emotional impact and its effects on mental health, especially in the short term. Children who lose their parents are more likely to engage in alcohol and substance abuse not long after, often because of greater functional impairment, or to experience depression or post-traumatic stress disorder.
That emotional damage can linger. A study of young adults who lost siblings to cancer found that most still had not worked through their grief, even nine years later.
A case control study of children in Scandinavia found that children who experience the death of a parent had twice the chance of committing suicide. That increased risk lasted at least 25 years.
The risk of suicide in children who had lost a parent was 4 in 1,000 for boys and 2 in 1,000 for girls.
Emotional damage can have a physical impact as well. In 2013, researchers published work in PLoS One that showed that both men and women who had lost a sibling in adulthood had an elevated risk of death from stroke, potentially stress related, in the 18 months after the sibling’s death. For women, that increased risk got worse over time, still increasing 18 years later. Sibling death from external causes (mostly accidents and suicides) was also associated with an increased risk of death from heart attacks in women years later.
Families who lose a child are more likely to show problems that already existed, like evidence of social deprivation and poor health. Health care professionals may want to consider that the death of a child can exacerbate problems, and signify long-term social, behavioral and environmental risks for the survivors.
These warning signs exist in other familial relationships. Research has shown that losing a child increases the mortality rate in mothers more than a decade later, both from natural and unnatural causes. It increases the mortality rate in fathers, too, but only from unnatural causes. Losing a parent does the same.
But death may be harder for children. As a parent, I can imagine nothing worse than the loss of a child. But as I watch my children grow up together, I’m struck by the fact that their bond is, at times, stronger than their bonds to my wife and me. They’re together at school. They’re together at camp. They’re together when they play. They have secrets and shared experiences as they grow and develop together. They also have known almost no life without each other.
They are also far less capable of handling a loss than I or my wife would be. A study in the late 1990s examined how children responded to the loss of a parent versus a sibling. Girls, in general, were more affected by the loss of a sibling — especially a sister. Preteens showed higher levels of depression and anxiety, and adolescents had more attention problems and anger.
Given all these data, it may be time for us to pay more attention to the long-term effects of a child’s death. We can take hope from research showing that most children do thrive and overcome adversity, even after such a loss. Too many do not, though. We ought to monitor those who lost siblings as children for possible health consequences for many years to come.