Research indicates that the number one factor in longevity is not social relationships or happiness, but consciousnesses, described as persistence, dependability, and organization.
That quote comes from The Entitlement Cure on page 66. This caught my attention, so I dug a bit deeper. The original source for that statement comes from The Longevity Project, which lays out the findings from a lifelong study of 1,500 people.
That is 1,500 people studied from birth to death. Amazing.
The findings are worded another way in a summary of the book:
If there’s a secret to old age, the authors find, it’s living conscientiously and bringing forethought, planning, and perseverance to one’s professional and personal life.