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WASHINGTON (Reuters) - Researchers have found a pattern of genes that predicts with more accuracy than ever before who might live to be 100 or older -- even if they have other genes linked with disease.
Their findings, published in Friday's issue of the journal Science, offer the tantalizing possibility of predicting who might hope for a longer life. They also cast doubt on the accuracy of tests being marketed now that offer to predict a person's risk of chronic diseases such as Alzheimer's.
Several teams of researchers have identified gene patterns linked with extreme old age. But the researchers led by Paola Sebastiani and Dr. Thomas Perls at Boston University say theirs provides the best accuracy yet.
They studied more than 1,000 people who lived to be 100 or more and matched them to 1,200 other people to identify the genetic patterns more common in the 100-year-olds using an approach called a genome-wide association study
To their surprise, the longest-lived people had many of the same genes linked with diseases as everyone else. Their old-age genes appeared to cancel out the effects of the disease genes.
"A lot of people might ask, 'well who would want to live to 100 because they think they have every age-related disease under the sun and are on death's doorstep, and certainly have Alzheimer's', but this isn't true," Perls told reporters in a telephone briefing.
"We have noted in previous work that 90 percent of centenarians are disability-free at the average age of 93. We had long hypothesized that to get to 100 you have to have a relative lack of disease-associated variants. But in this case, we're finding that not to be the case."
They identified 19 patterns among about 150 genes and said these patterns predicted with 77 percent accuracy who would be in the extreme old-age group.
"Some signatures correlate with the longest survival, other signatures correlate with the most delayed age of onset of age-related diseases such as dementia or cardiovascular disease or hypertension," Sebastiani said.
The researchers stressed that having these genes is unlikely to give a person a free pass to smoke, drink and overeat.
Sebastiani said Seventh Day Adventists have an average life expectancy of 88, eight years more than their average U.S. contemporaries.
"They get there by virtue of the fact that they have a religion that asks them to be vegetarian, they regularly exercise, they don't drink alcohol, they tend to manage their stress well through religion and time with family and they don't smoke," she said. "It really does speak to the incredible importance of lifestyle factors."
The Boston researchers said they do not plan to market a test for the long-life genes and are working to design a free website where people who have had their DNA sequenced can check and see if they have any of them.
"The methodology that we developed can be applied to other complex genetic traits, including Alzheimer's disease, Parkinson's, cardiovascular disease and diabetes," Sebastiani said.
Currently about 1 in 6,000 people live to be 100 and 1 in 7 million makes it to 110. The researchers said beliefs that certain populations in places such as Russia or Azerbaijan are more likely to have centenarians have been shown to be untrue.
Perls said he does not see the findings leading to youth elixirs, but hopes they may be used to help delay the start of age-related diseases like Alzheimer's.
Editing by Xavier Briand