Michael J. Poulin of the University at Buffalo; Stephanie L. Brown and Dylan M. Smith of Stony Brook University; and Amanda J. Dillard of Grand Valley State University examined data from 846 participants in a study in the Detroit area.
The study participants completed baseline interviews that assessed past-year stressful events such as non-life-threatening illness, burglary, job loss, death of a family member and whether the participant had provided tangible assistance to friends or family members.
Participant mortality and time to death was monitored for five years afterwards via newspaper obituaries and monthly state death records.
After factoring for age, baseline health, functioning and key psycho-social variables, the researchers found a significant interaction between helping behavior and stressful events.
The study, published online in the American Journal of Public Health, found those who had helped others during the previous year were less likely to die than those who had not helped others.
"Our conclusion, was helping others reduced mortality specifically by buffering the association between stress and mortality," Poulin said in a statement. "These findings go beyond past analyses to indicate that the health benefits of helping behavior derive specifically from stress-buffering processes, and provide important guidance for understanding why helping behavior specifically may promote health and, potentially, for how social processes in general may influence health."