The death of a brother or sister in childhood has been linked to a significant increased risk of premature death for the surviving sibling, highlighting a need for greater emotional support for bereaved children.
A Danish study published in journal JAMA Pediatrics tracked the health of more than five million children over 37 years.
Among this group, 55,000 experienced the death of a sibling at the average age of seven.
The study found they were 71 per cent more likely to die themselves over the study period.
The highest risk was in the first year after the sibling's death and siblings of the same sex were also at greater risk of dying prematurely.
As expected, individuals who experienced the death of a sibling also had a particularly high risk for death from the same cause as their deceased sibling.
The relative risks were the highest for endocrine, nutritional, and metabolic diseases, and diseases of the circulatory system, the authors wrote.
"We also found a much higher mortality risk for suicide among individuals whose deceased siblings died of suicide."
The magnitude of grief felt after loosing a brother or sister as a child is comparable to the death of a parent, if not greater.
"Sibling relationships generally last longer than other familial relationships and may have a significant influence on one's social and emotional lifetime development," they said.
Bereaved siblings, they suggest, might also be indirectly affected through their parents'reaction to the death of the child.
"In fact, we found that the overall mortality risk after sibling death in childhood was slightly higher than overall mortality risk after parental death in childhood."
The researchers say greater social support may help to reduce the level of grief and minimise potential adverse health effects on bereaved children.
"Healthcare professionals should be aware of children's vulnerability after experiencing sibling death, especially for same-sex sibling pairs and sibling pairs with close age," they said.
Recent research by CanTeen, published in journal Psycho-Oncology, showed young people dealing with a parent or sibling with cancer are three to six times more likely to face mental health issues like depression and anxiety than their peers.
Dr Pandora Patterson, General Manager of Research and Youth Cancer Services at CanTeen says people aged 12-24 tend to feel incredibly isolated and alone but are often "overlooked" by the health system.
"They tend to feel incredibly isolated and alone, but often don't acknowledge their own need for support. Many are focused on their family member's cancer and don't want to add to the burden with their feelings of anxiety or fear," she said.
"That's why we're calling on the community to identify young people who might need support and help them connect with the vital services that CanTeen offers," said Dr Patterson.
Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14. Suicide Call Back Service 1300 659 467. Kids Helpline 1800 55 1800 (for young people aged 5 to 25).
