The more outgoing and optimistic you are, the longer you may live, a new study suggests. Researchers have found that personality traits like being outgoing, optimistic, easygoing, and  enjoying laughter as well as staying engaged in activities may be an important part of the longevity genes mix.

"When I started working with centenarians, I thought we'd find that they survived so long in part because they were mean and ornery," study researcher Nir Barzilai, of the Albert Einstein College of Medicine, said in a statement. "But when we assessed the personalities of these 243 centenarians, we found qualities that clearly reflect a positive attitude towards life."

The study is a part of the Albert Einstein College of Medicine's Longevity Genes Project, which includes more than 500 Ashkenazi Jews ages 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. [ 7 Ways the Mind & Body Change With Age ]

By analyzing the genes of these people, researchers are discovering why some of them live so long, and others don't.

Previous studies of this population have found other genetic reasons for their longevity, including genes related to cellular repair mechanisms. Another study found that these centenarians don't necessarily behave any better than the general population when it comes to health habits: They smoke, drink and eat just as badly as the rest of us.

So why look at personality? A person's level of shyness or how open they are to new experiences, say, arise from underlying genetic mechanisms, which may also affect health, the researchers said. So Barzilai and colleagues developed a brief measure of personality, which they gave to 243 of the centenarians in the study (average age 97.6 years, 75 percent women).

"Most were outgoing, optimistic and easygoing," Barzilai said of the centenarians. "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 U.S. 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 results were published May 21 in the journal Aging.

More from LiveScience:

• Extending Life: 7 Ways to Live Past 100
• 5 Ways Your Cells Deal With Stress
• 7 Things That Will Make You Happy 

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