A meta-analysis of 10 prospective studies involving a total of 136,265 older adults (average age 67) has found that having a high sense of purpose in life was significantly associated with lower mortality and cardiovascular events.
Most of the studies came from the United States or Japan. The US studies evaluated a sense of purpose or meaning in life, or "usefulness to others." The Japanese studies assessed the concept of ikigai, translated as "a life worth living."
Cohen, R., Bavishi, C., & Rozanski, A. (2016). Purpose in Life and Its Relationship to All-Cause Mortality and Cardiovascular Events: A Meta-Analysis. Psychosomatic Medicine, 78(2), 122–133. http://doi.org/10.1097/PSY.0000000000000274