U.S. researchers followed stroke survivors for an average of five years after the event and found those who were never married, remarried, divorced or widowed had significantly higher risks of dying compared to those who had a long-term stable marriage.

Losing two or more marriages to death or divorce raised the odds of mortality after stroke still higher, though never-marrieds had the highest risk of all.

“A handful of recent studies have shown how social stress, such as job loss and marital loss, increase the risk of suffering a serious health event such as a heart attack or stroke,” said lead study author Matthew Dupre of the Duke Clinical Research Institute in Durham, North Carolina.

For men and women who had never married, the risk of dying after a stroke was 71 percent greater than those who were continuously married. Those who were divorced, remarried or widowed were about 23 percent more likely to die after a stroke, though the risks associated with divorce decreased over time.

Stroke is one of the top causes of death in the U.S. More than 800,000 adults will experience a stroke this year, according to the American Heart Association, and about 7 million U.S. adults are currently stroke survivors.

Obesity, high blood pressure and smoking are known risk factors for having a stroke. Past research suggests that social support, such as marriage, can also influence both risk for stroke and the likelihood of recovery, Dupre and colleagues write in the Journal of the American Heart Association.

“This is the first (study) to show that marital history can have significant consequences for prognosis after a stroke,” Dupre told Reuters Health. “And a somewhat unexpected finding was that remarriage doesn’t seem to reduce the risks from past divorce or widowhood.”

Dupre and colleague Renato Lopes investigated data from the Health and Retirement Study, a survey by the National Institute of Aging that follows U.S. adults older than age 50. They looked at 2,351 adults who experienced a stroke between 1992 and 2010 and documented factors such as age, gender, race and ethnicity, geographic location, education, household income, weight and chronic illness. The researchers also tracked psycho-social factors such as having children, nearby friends or relatives, depressive symptoms and religious service attendance, as well as behavioral factors such as smoking, drinking, exercise and hypertension medication adherence.

Of the original group of stroke survivors, 1,362 died during the follow-up period. Overall, those who died were likely to be older, less educated and have lower levels of income. They also were more likely to have no children, to have more depressive symptoms, more limitations in their daily activity, other chronic illnesses, and less likely to take blood pressure medication.

“A growing body of work shows how our social relationships have immediate and lasting consequences for our health,” Dupre said. “It’s important for stroke survivors to understand how their marital history may impact their recovery.”

This study builds on previous research that indicates those with marital loss are at the highest risk for cardiovascular disease. People with multiple marital losses are the most vulnerable, said Zhenmei Zhang at Michigan State University in East Lansing, who was not involved with the study.

“People with multiple marital losses have a higher likelihood of cardiovascular disease and will need significant formal and informal care as they advance into old age,” she said.

More research is needed to understand the full implications of the study, particularly related to social support and psychological distress, Dupre said. The surveys are based on self-reported data and don’t include information about the type or severity of stroke, the treatment of hypertension or diabetes, and other factors such as rehabilitation after a stroke.

“Until then, we have a greater awareness of this association and can help health care providers better recognize and treat patients who may be at an especially high risk of dying after suffering a stroke,” he said.