Dr. Ilene Siegler and colleagues at Duke University Medical Center analyzed data for 4,802 people who took part in the University of North Carolina Alumni Heart Study -- an ongoing study of individuals born in the 1940s.
The study authors were particularly interested in stability and change in patterns of marital and non-marital status during midlife, controlling for personality at college entry, socioeconomic status and health risk behaviors.
The study, published in the journal Annals of Behavioral Medicine, found having a partner during middle age was protective against premature death. Those who never married were more than twice as likely to die early than those who had been in a stable marriage throughout their adult life.
Being single, or losing a partner without replacement, increased the risk of early death during middle age and reduced the likelihood that one would survive to be elderly.
Even when personality and risky behaviors were taken into account, marital status have a major impact on survival.
"Social ties during midlife are important to help us understand premature mortality," the study authors wrote in the study.