In a better world, researchers who presently spend their time figuring out how and why personality traits correlate to life expectancy would instead be working on rejuvenation treatments. Alas, most of the study of aging is just that - study, with little to no interest in producing treatments. Here, scientists provide additional data to support the usual explanation as to why conscientious people live longer: they are taking better care of their health by refraining from smoking, engaging in regular exercise, not carrying excess fat tissue, and so forth. No doubt they are also making better use of available preventative and other medical services, but that isn't examined in this study.
Personality traits predict both health behaviors and mortality risk across the life course. However, there are few investigations that have examined these effects in a single study. Thus, there are limitations in assessing if health behaviors explain why personality predicts health and longevity. Utilizing 14-year mortality data from a national sample of over 6,000 adults from the Midlife in the United States Study, we tested whether alcohol use, smoking behavior, and waist circumference mediated the personality-mortality association.
After adjusting for demographic variables, higher levels of Conscientiousness predicted a 13% reduction in mortality risk over the follow-up. Structural equation models provided evidence that heavy drinking, smoking, and greater waist circumference significantly mediated the Conscientiousness-mortality association by 42%. The current study provided empirical support for the health-behavior model of personality - Conscientiousness influences the behaviors persons engage in and these behaviors affect the likelihood of poor health outcomes.