Previous research has suggested that certain genes hold the key a person's longevity, but the new study found that personality traits also play an important role.
"When I started working with centenarians, I thought we'd find that they survived so long in part because they were mean and ornery," said study researcher Nir Barzilai of the Albert Einstein College of Medicine.
"But when we assessed the personalities of these 243 centenarians, we found qualities that clearly reflect a positive attitude towards life," Barzilai was quoted as saying by LiveScience.
The study, which is a part of the Albert Einstein College of Medicine's Longevity Genes Project, looked at more than 500 Ashkenazi Jews aged 95 and older, and 700 of their kids.
This small subset of Eastern European Jews is genetically very similar to each other. In addition, some members of the population are extremely long-lived, so it's easy to compare their genes to the genetics of members of the population who don't fall into that category.
As a person's level of shyness or how open they are to new experiences arise from underlying genetic mechanisms which may also affect health, the team developed a brief measure of personality that they gave to 243 of the centenarians in the study (average age 97.6 years, 75 per cent women).
"Most were outgoing, optimistic and easygoing," Barzilai said. "They considered laughter an important part of life and had a large social network. They expressed emotions openly rather than bottling them up."
In addition, the centenarians had lower scores for displaying neurotic personality and higher scores for being conscientious compared with a representative sample of the US population.
"Some evidence indicates that personality can change between the ages of 70 and 100, so we don't know whether our centenarians have maintained their personality traits across their entire life spans," Barzilai said.
"Nevertheless, our findings suggest that centenarians share particular personality traits and that genetically based aspects of personality may play an important role in achieving both good health and exceptional longevity."
The study was published in the journal Aging.