By Aaron E. Carroll "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...