When a husband or wife dies, the surviving spouse faces a higher risk of dying over the next few months as well, according to a new report.
Previous studies have looked at the so-called widowhood effect. But it wasn't completely clear how long the effect lasts.
"The widowhood question is interesting because it is ubiquitous. At some point or the other one partner will die leaving the other and this will happen to everyone regardless of class, caste, socioeconomic status," Dr. S. V. Subramanian said in an email. He worked on the study at the Harvard School of Public Health in Boston.
Researchers still don't know what exactly causes the widowhood effect.
"It's possible it's a grief-related mechanism, or that providing care for the sick spouse causes illness in the surviving spouse, or that, as one's spouse gets sicker, the surviving spouse stops taking care of their own health," Subramanian said.
For the new analysis, the researchers looked at data from the University of Michigan Health and Retirement Study, which surveys more than 26,000 Americans over age 50 every two years.
They focused on 12,316 of the participants who were married in 1998. Subramanian and his colleagues followed those people through 2008 to determine which participants became widows or widowers, then recorded when they died.
There were 2,912 deaths during the study period. Of those, 2,373 were among married people who left a widow or widower behind. The other 539 deaths were among people who had become widows and widowers themselves.
Fifty of those people died within three months of losing their spouse, 26 died between three and six months later and 44 died between six and 12 months later.
Widows and widowers were more likely to die than people whose spouses were still living, on average. The effect was strongest during the first three months after a spouse's death, when they had a 66-percent increased chance of dying.
Earlier research showed men were at greater risk of dying soon after a spouse than women, but the authors of this study didn't find a difference. That could be because they took into account participants' income and wealth, which may have influenced past findings, they said.
Because this study only looked at people over age 50, it isn't clear whether younger people would face the same risks after a spouse's death. But Subramanian said some evidence suggests the widowhood effect is actually stronger among younger people.
Family and friends can help a surviving spouse by being supportive and attentive, researchers said.
"What insulates people from grief and stress is a good sense of support. Be around for this person," Dr. Ken Doka said. He is a gerontologist at the Graduate School of The College of New Rochelle in New York and a senior consultant to the Hospice Foundation of America.
"Grief is extraordinarily stressful and when you're older and frailer it's harder to cope with stress," Doka, who wasn't involved in the new study, said.
The loss of a loved one might make for drastic changes in lifestyle habits. Doka advises friends and family to keep an eye on the surviving spouse to see how the person is handling those changes.
"Maybe they used to go for a walk every night but now they're not doing that anymore. Maybe they're not sleeping well, or maybe not taking their medications," said Doka. It helps to be there for them and to be supportive.
Spirituality and religion may also help some people get through a crisis, he said.
Doka said surviving male spouses may feel especially lonely because they don't know they need to be proactive about finding company.
"One of the problems widowers often have is the lack of support and one of the reasons is that very often the wife, historically, is the keeper of the kids," said Doka.
"She's the one that called the kids up and said they should come over for dinner, so it's not unusual that widowers will often say no one ever stops over any more, because they didn't realize someone else was calling and inviting them," he said.