Might You Live to 100? Gene Test Tells
Genetic Signature IDs 77% With 'Exceptional Longevity'
July 1, 2010 -- Do you have what it takes to live 100 years -- or more?
A new test tells whether a person has the "genetic signature" of exceptional longevity. About 77% of centenarians -- people 100 years old or older -- have this genetic profile.
"Our genetic profile ... is essentially a picture, and one can interpret this picture in terms of how many exceptional longevity variants a person carries in his genetic code," study researcher Paola Sebastiani, PhD, of Boston University, says at a news teleconference.
A preliminary study suggests that about 15% of people of European descent have better than a 50% chance of seeing 100 candles on their birthday cakes.
But genes are not destiny. In industrialized nations, only one in 6,000 people -- 0.016% -- lives to age 100. And only one in 7 million people lives to be a "super centenarian" of age 110 or older. Clearly lifestyle choices, the environment, and plain luck have a lot to do with longevity, says Thomas T. Perls, MD, MPH, head of the New England Centenarian Study at Boston University.
"If 15% of people have an increased probability of living to 100, and they are not hit by a bus or killed in a war, maybe they get to fulfill that," Perls said at the news conference. "Now maybe these people need not to smoke and not to be obese and to have other lifestyle factors as well. So a lot goes into the question of whether 15% of the population will go on to be 100 or not."
Another factor that matters is sex: 85% of centenarians are women, Perls said.
Longevity Genes Trump Disease Genes
Nevertheless, having the exceptional longevity genetic signature is good news for anyone. The centenarians in the study remained healthy until the very end of their very long lives.
"We often think, 'Who would want to live to 100?'" Perls said. "But these people do not have Alzheimer's. In fact, 90% are disability free at an average age of 93. They compress their diseases to the very end of their lives. And super centenarians compress disease to even later in life."
That does not appear to be luck. Centenarians are just as likely as anyone else to have genetic risks for diseases of aging such as dementia, high blood pressure, diabetes, and stroke. But their exceptional-longevity genes seem to cancel out disease risks.
"The enrichment and presence of these longevity-associated genetic variants could trump or cancel the effect of some of these disease-associated variants," Perls said.
Sebastiani, Perls, and colleagues began their study by analyzing the genomes of 801 centenarians -- the world's largest collection of extremely old people. Eventually they identified 150 tiny genetic changes linked to extreme old age.
These changes did not point to any single longevity gene. Instead, the changes were scattered across the 23 chromosomes that carry the human genome. Genes carrying these genetic changes have a wide range of functions.