A new meta-analysis in Health Psychology finds that people with more conscientious personalities live longer:

Howard Friedman
and Margaret Kern at the University of California at Riverside found
that people who were less conscientious were 50 per cent more likely to
die at any given age, on average, than those of the same age who scored
highly (Health Psychology, DOI: 10.1037/0278-6133.27.5.505). This exceeds the effects of socioeconomic status and intelligence, which are also known to increase longevity.

HT: Eric Crampton, who points out that the joint effect of IQ and personality on health may be enough to wipe out the apparent health effects of income and status.