Grieving parents head for an early grave.

(From Agence France Presse)

Parents who lose a child run a major risk of dying prematurely, according to a Danish study which suggests the stress of grief may lead to cancer, heart disease, heavy smoking and reckless drinking.

Health researchers compared mortality rates among 21,062 parents who had lost a child before he or she reached the age of 18 with those of 293,745 parents of similar background who had suffered no such loss.

Mothers were around 40 percent likelier to die within 18 years of the child's death compared with mothers whose remained alive, they found.

The biggest risk period was in the first three years after the child's …