By Will Dunham
WASHINGTON (Reuters) - How do some people live past 110 years old? Is it superior genes, clean living, good luck or some combination of those?
Scientists studying these "supercentenarians" said on Wednesday they sequenced the genomes of 17 people ages 110 to 116 to try to determine whether they possess genetic traits that may account for their membership in this exclusive club that worldwide includes only about 75 individuals, nearly all women.
"This marks the beginning of the search for key genes for extreme longevity," said Stuart Kim, a professor of developmental biology and genetics at Stanford University whose study was published in the scientific journal PLOS ONE.
The answer was not so simple. The study did not identify a common genetic characteristic in them, and the findings underscored the idea that living to extreme old age may involve lots of factors, the researchers said.
"Our hope was that we would find a longevity gene," Kim said. "We were pretty disappointed."
The study was the first to look at the genomes of multiple supercentenarians. Three prior studies looked at the genomes of either one or two such people, Kim said.
The research involved 16 women and one man, all of whom lived in the United States. Fifteen were white, with one black and one Hispanic. All have died since the study began.
Kim said he believes there is a genetic underpinning to extreme longevity but it probably is not as simple as a single gene mutation that slows the aging process in certain people.
"These supercentenarians have a different clock where they are staying really highly functional for a long time. We wanted to know what they had. It's pretty clearly genetic," said Kim, who collaborated with Stephen Coles of the Gerontology Research Group and other researchers.
"The results indicate that the genetic effect must be complex. It must be many genes, or different genes in each supercentenarian, that gives them the edge to live an extremely long time," Kim added.
Kim said the 17 supercentenarians did not report obvious health habits that explain their longevity. As a group, he said, they did not have especially healthy eating or exercise habits.
"About half of them were smokers," Kim added.
Misao Okawa, a 116-year-old Japanese woman born in 1898, is recognized as the world's oldest person. At her birthday this year in Osaka, she credited sushi and sleep for her longevity.
SOURCE: http://bit.ly/1oMieoc PLOS ONE, online November 12, 2014.