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Genes Hold Key to Living Longer Than 100

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Exceptional longevity results from favourable genes much more than from a healthy lifestyle and environment, according to the first extensive genetic analysis of people who lived past the age of 100.

Researchers at Boston University have identified 150 genetic variants that, taken together, can predict exceptional longevity with 77 per cent accuracy.

The scientists compared the genomes of 1,055 centenarians with a similar number of control subjects, using DNA-scanning technology. They distilled the differences down to 150 life-extending changes, each affecting one chemical “letter” in the 3bn letters of the human genetic code.

These changes run right across the human genome. A few affect genes associated with age-related diseases, such as the ApoE and Alzheimer’s but many have unknown functions.

“Longevity is an extremely complex genetic trait involving many biological processes,” said Thomas Perls, co-author of the paper and director of the New England Centenarian Study. “We’re a long way from understanding them.”

The research confirmed that there could be no simple “elixir” to extend life, he added.

The scientists were surprised to find that, on the whole, the centenarians did not have fewer genetic variants known to trigger disease than the controls.

“What makes a difference is more the positive enriching effect of genetic variants that protect against disease than the absence of disease-associated variants,” said Dr Perls.

Although the details remain a mystery, what seems to happen as people age is that lifestyle and environment – such as healthy eating, exercising and avoiding smoking and obesity – are important in determining lifespan up to the 80s. After that, genes play an increasingly important role.

DNA rather than lifestyle is almost entirely responsible for generating “super-centenarians” who survive beyond 110. They make up one in 7m people in the industrial world.

Eighty-five per cent of centenarians and 90 per cent of super-centenarians are women. In spite of claims of people living to 140 or 150 in places from the Andes to the Caucasus, Jeanne Calment, who died in France in 1997 at the age of 122, remains the world’s oldest documented person.

Paola Sebastiani, professor of biostatistics at Boston University, said all data from the longevity study would be available without restrictions. “We have no financial interests in it and we are not planning to patent anything here,” she said.

Researchers will put up a web page this month where people can calculate their prospect of longevity. They also expect companies that sell genetic tests to consumers quickly to include a longevity assessment.

Source : Financial Times. July 1st.2010

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News on Health & Science

Aging: You Can Hurry it, but You Can’t Slow it

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Nothing in gerontology comes close to fulfilling the promise of a dramatically extended life span — despite bold claims to the contrary.
“I have little doubt that gerontologists will eventually find a way to avoid, or more likely, delay, the unpleasantries of extended life,” says S. Jay Olshansky, author of “The Quest for Immortality: Science at the Frontiers of Aging.” But they’re not there yet.

For now, what researchers are finding is that, although we can certainly accelerate the aging process, we can’t stop it.

People don’t like to accept that our life spans are generally preset by genetics. “The only control we have over our life span is to shorten it,” says Olshansky, an epidemiology professor at the University of Illinois at Chicago School of Public Health. We do this by being sedentary, smoking, gaining weight and abusing drugs.

Olshansky adds: “If we do everything right, the best we can do is live out our potential with as little age-related disease and disability as possible.”

In the United States today the average life span for women is 80 and for men it’s 75. Of the planet’s current 6.5 billion inhabitants, no more than 25 people are older than 110. Jeanne Calment of Arles, France, who died in 1997 at age 122 1/2 , set the record for the greatest documented age reached by any human.

Researchers who study centenarians (people who live to 100) and super centenarians (those who live beyond 110) appreciate how rare it is to attain that age. They also understand how ridiculous it is to claim that people alive today can expect to live to age 125, which is what some longevity proponents claim is achievable.

“Saying that is inconceivably irresponsible,” says Tom Perls, a geriatrician and director of the New England Centenarian Study. That said, he does believe we can borrow from the successes, if not the genes, of people who’ve lived to be 100. “I wouldn’t be devoting my life to studying centenarians if I didn’t think something would come of it.”

There isn’t a cure for aging because it isn’t a disease, says Laurence Rubenstein, geriatrician at UCLA Medical Center. “It’s a natural and complex process that involves every system in the body.” That individuals age unevenly at vastly different rates suggests that genes, lifestyle and disease can all affect the rate of aging.

Our risk of dying increases as we get older because more can go wrong, says Olshanksy, citing what those in the field call increased competitive risks. “If you do an autopsy on an 85-year-old who died of a stroke, you will find five other things that person was about to die from.”

While research continues to look at ways to help people live longer and healthier, Perls is looking at populations that seem to do that better than most.

The Seventh-day Adventists are such a group: They live to an average age of 88, or about 10 years longer than other people in the country. They don’t smoke. They tend to be lean and fit and get regular exercise. They eat a largely vegetarian diet and spend a lot of time involved with family and religion, which scientists think helps them manage stress.

“If everyone in our country adopted those behaviors, the payoff would be huge,” said Perls, an associate professor of geriatrics at Boston University Medical Center. He would add one more piece of advice to the list:

“Avoid anti-aging quacks like the plague.”

Source: Los Angeles Times

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