Losing a spouse forces people into what is often one of the most vulnerable parts of their lives. The negative health consequences of widowhood can stretch years down the line, but in some cases, they don’t get a chance to. The phenomenon in which both halves of a couple die in short succession is so common that it even has a name: the widowhood effect.

How at risk is any given person? That depends on many contributing factors, from their religion to race and even their spouse’s cause of death. But the widowhood effect is generally believed to be a problem primarily affecting closely bonded elderly couples.

However, a study published Mar. 22 in the journal PLOS One finds that younger people—especially men—are even more at risk. Researchers in …