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Genetics provide answers to living exceptionally long lives PDF Print E-mail
Thursday, 12 August 2010 13:15

New research could lead to scientific predictions of whether you will be a centenarian

The ability to predict whether one will live an exceptionally long life may only be a few years away, but that doesn’t make people any more ready to know about it.

Photo courtesy of It’s me...jeff!/
Researchers from Boston University School of Medicine and Boston Medical Center worked for over 15 years on the study, finally emerging last month with findings that suggest living into one’s late 90s or longer can be attributed to certain genetic traits.

Using a model of 150 genetic variants, the research team led by Dr. Thomas Perls and Dr. Paola Sebastiani were able to predict if a person would live to be over 90 years old, even surpassing 100 years, with 77 per cent accuracy, suggesting this could become a widely available service within five years.

“These genetic signatures are a new advance towards personalized genomics and predictive medicine,” said Perls in a statement released at the time the study was published in the July 1 online edition of Science.

However, that service would prove to be quite expensive, at least when first introduced, said Lori Feldman, a research assistant with the study.

“We would have to get your DNA tested first, which would be costly,” admitted Feldman. “In most places that service would run in the thousands of dollars. So obviously not everyone would be able to know this information immediately, but hopefully one day it will be inexpensive enough that everyone could benefit from it.”

According to the latest data provided by Statistics Canada, the average life expectancy for Canadians is 80.7 years; men have generally lived to be 78.3 years of age, while women are reported to be living to 83 years, on average, between 2005 and 2007.

In 2006, there were 3,795 centenarians living in Canada – roughly 0.01 per cent of that year’s total population – although Statistics Canada suggests that number may have risen since then.

If such a centenarian predictability test were available to the general public, it could potentially mean that a 20-year-old could walk into the doctor’s office for a regular check-up, only to leave with the knowledge that he or she can expect to live to be 100 years old.

Naturally, there are many people who aren’t okay with the prospect of learning that information.

“I just think something like that shouldn’t be known,” said Kris Singleton, a 20-year-old labour worker.

“I mean, why ruin the surprise of life? If I know I’m going to live for that long, I’ll just keep putting things off and not care because I’ll be like, ‘Well, I have another 80 years to do it, so why do it now?’”

Even those who have already lived a long life are unsure whether they’d be comfortable with knowing when the end will come.

“I’m enjoying my life, and the time I’ve had here,” said a 70-year-old man who felt uncomfortable with giving his name to a media outlet. “I think I’d lose that lust for life if I was aware how much longer I had to go.”

The psychological impacts of learning what one has in store for them are not lost on specialists in the field of genetic research.

Dr. Oksana Suchowersky, a professor of medical genetics in the faculty of medicine at the University of Calgary, has devoted her research towards discovering the hereditary genetics that could lead to people inheriting such diseases as Alzheimer’s and Huntington’s.

Because of studies done by her and other researchers in her field, tests are already available that can predict whether someone will develop such disorders later in their lives. However, Suchowersky admits much has to be done before such a test can be administered to ensure the test subjects will be comfortable with what they discover.

“Many issues come up before you can even think about going through with such a procedure,” said Suchowersky.

“We put the patient through psychological counselling so there are no violent surprises or episodes, which can happen; people just aren’t prepared to handle the situation most of the time.

“We did a study a few years ago asking people whether they’d be comfortable with hearing such a thing, like, ‘You’re going to develop Alzheimer’s’ or ‘You have inherited this disease, it will hit you in this amount of years, you’ll probably have this long to live.’ We found that 85 per cent would prefer not to know. It’s potentially traumatic.”

Suchowersky points out other factors that need to be taken into account, such as ethical concerns and, of course, cost, when considering taking such a test. However, she also says the cost of sequencing one’s DNA – a procedure needed in order to take such a test, including one for long life – is going down, and may be down considerably in three to five years.

When it comes to a future centenarian test, Suchowersky says many of the same issues arise:

“If you knew you were going to live until 100, are you going to go out and party all night and feel like you don’t have to have a care in the world? Or will you not want to test fate and become a recluse? So many thoughts could go through your mind that your life will never be the same again.”

And although Suchowersky mentioned there are other factors inherent in the ability to survive a whole century, it’s clear one doesn’t have to be a doctor to realize that a long life comes down to much more than good genes.

“What if I found out I have the genes needed to live a long life, but after walking out of the doctor’s office all happy and content, I get hit by a bus,” said Bonnie Jones, a 58-year-old secretary. “Or what if I get food poisoning? There are other things that can kill you other than genetics.

“If I were able to reflect on my life after that, I would wonder why I even bothered learning that information at all.”