Immune system directly links personality to long-term mortality risk, study reveals Ground-breaking research led by University of Limerick has revealed for the first time that the immune system directly links personality to long-term risk of death. The study sheds new light on why people who are more conscientious tend to live longer. Results from the new international study published in the journal Brain, Behavior, and Immunity have found that the immune system plays a previously unknown role in the link between personality traits and long-term risk of death. "Personality is known to be associated with long-term risk of death, it is a well replicated finding observed across numerous research studies internationally," explained Principal Investigator on the study Dr Páraic Ó Súilleabháin, from the Department of Psychology and Health Research Institute at University of Limerick, Ireland.