The life expectancy test

[MacNimon]

From The Independent

Concerns grow over DNA test that determines your lifespan

By Steve Connor, Science Editor

Scientists and medical ethicist are warning of the dangers posed by a new blood test for determining how fast someone is ageing, as revealed by The Independent yesterday.

The £435 test, due to go on sale to the general public in Britain later this year, measures the length of a person's telomeres, the structures on the tips of the chromosomes which get progressively shorter with age. Short telomeres are linked with age-related diseases and premature death.

Experts are worried that people may misunderstand the limitations of the test, which purports to measure a person's true "biological" age rather than the usual chronological age. They are also concerned that the information may be used by insurance companies and organisations trying to sell fake anti-ageing remedies.

"I'm sceptical and concerned about this test mainly because of the lack of evidence that this information is useful and yet this test touches on really significant issues, such as predictions of life expectancy," said Colin Blakemore, an Oxford neuroscientist and former head of the Medical Research Council.

"My pressing concern is just how reliable these tests are in terms of anything significant. We need to know an awful lot more before we make predictive statements. People worry about how predictive it is."

Thomas Von Zglinicki, a professor of cellular gerontology at Newcastle University, said that it is not yet clear how accurate such telomere tests are when applied to individuals. "To sell this to the public is premature and I will not buy it," Professor Von Zglinicki said.

Medical ethicist Piers Benn, formerly of Imperial College London, said there are wider philosophical dangers of using a test that may estimate how long a person has left to live.

"If we knew when and how we will die, that would influence the way we lived; we shape our future in the light of the uncertainty in which we live," Dr Benn said.

"We need to avoid the fatalism which says that I'm going to die on a certain date so why should I give up smoking or avoiding bad foods."

The Independent revealed yesterday that the Spanish company behind the test, Life Length, is in discussions with a company that operates in Britain to market the test over the counter later this year.

The test's inventor, Maria Blasco of the Spanish National Cancer Research Centre in Madrid, said the test is accurate in detecting dangerously short telomeres which are linked with age-related diseases and premature death.

"We know that people who are born with shorter telomeres than normal also have a shorter lifespan. We know that shorter telomeres can cause a shorter lifespan," Dr Blasco said.

But Josephine Quintavale, of the pressure group Comment on Reproductive Ethics, warned that such tests might be used to marginalise the elderly.

"Sadly, the elderly are already not the most popular members of society when it comes to healthcare allocation and I could definitely foresee a culture of not spending resources on those with short telomeres," she said.

Telling signs

* Telomeres are structures that cap the ends of the cell's chromosomes to stop them from "fraying". They get progressively shorter each time the cell divides until they become so short the cell dies.

* Measuring the length of a person's telomeres is a useful way of determining an individual's "biological" age, rather than their chronological age. A telomere test could therefore be used to assess a person's risk of age-related diseases and premature death.

* Drawbacks to a telomere test focus on how accurate it really is and what information it can provide. Some experts are concerned that they may be used to market anti-ageing products, or they may change the way people live if they believe they have only a certain amount of time before dying.

The test is clearly and simply explained in one of the comments on the article: "Basically, because of the way DNA replication works, some information is lost from the end of the strand each time the DNA replicates (This happens every time a cell divides).
Very simply, the telomere is the bit at the end of the DNA strand that we can afford to lose. When a strand runs out of telomere, the DNA strand starts to lose meaningful coding information and the cell can no longer replicate successfully. Thus telomere length is an indicator of how many successful divisions a given strand is likely to have left before failure.
If your cells cannot be repaired and replaced, organs fail and you die. Hence telomere length provides a rough indicator of how many divisions, and therefore how much time you have remaining in ideal circumstances."

Despite the fact that you could obviously die in an accident and thus confound the results, would you take the test? Would you really want to know what sort of life-expectancy you have?

[Jason Thompson]

The test is clearly and simply explained in one of the comments on the article:

Except that it's a bit of an oversimplification.

The bottom line is that the ageing process is nowehere near well-enough understood, and there are so many other variables at work, that the result is rendered near enough meaningless. The problem, as the article points out, is that some people will not realise this and others will exploit the results in callous or in scientifically dubious ways.

[Rob McCow]

I don't think this test is useful in any way! Who dies in 'ideal circumstances' anyway? If I'd already reached 120, then it might be interesting. But whether it's through cancer, cars, dementia or blood poisoning caused through tooth decay, death tends to come a little earlier than the point of organ failure.

[Dirk Gently]

I think this research is interesting...but would be far more interested if someone was working on a way to improve a persons telomere length & thus put off such premature deaths.
What I'd like more than knowing when I'm going to die is can I do anything to lengthen my life. We all die at some time, I just want to live a long time.
My goal at the moment is to live to 103....or die trying.

[Jon Masters]

I think this research is interesting...but would be far more interested if someone was working on a way to improve a persons telomere length & thus put off such premature deaths.

Massively but years ago I started working on a 6th Doctor DW story where someone was trying to achieve immortality by syphoning off other people's telomeres to maintain their own.
The victims would drop down dead a set time later as a result of the process.

Sadly (or perhaps not you say) the other major idea of the story (a war that people think has been going on for generations but in fact is only a year long) was nicked / homaged / pre-empted by The Doctor's Daughter

It had Draconians and cybernetically enhanced rodent-like people in it too

[SiHart]

It sounds much better than The Doctor's Daughter!

[Paul Monk]

Ridiculous quackery that doesn't serve any useful purpose as far as I can see. There's so many different factors to aging that it seems to me to be a bit like saying that you can determine the life of your car by looking at the battery.
I think this is just as accurate.

http://www.deathclock.com/

[Dirk Gently]

I did that Death Clock thing & put Sadistic out of the options...it appears I died July 19 2008.

[SiHart]

I don't think I'd want to know. It'd make me ever so pessimistic and miserable to know when it's time to go. I'd rather wait and see and keep hoping I'm going to go on forever!

[Stuart Wallis]

I wonder if this test is strictly accurate, even factoring out things like war, pestilence, accidents etc. It reminds me of the newspaper report of the man who was told he was dying of cancer, spent all his savings on one final binge, got better and sued the medical authorities for the money he'd spent.

[Jason Thompson]

It's not even vaguely accurate. It takes one measure of ageing, as if that's the only one, and produces a result based on that. What it doesn't do is describe the research into telomeres, the variations in cell division rates, the spread of the data so far obtained about the correlation between telomere length and number of remaining divisions, etc.

It is a pointless money-making scheme. The test serves no useful purpose whatsoever, and is just a way to fleece people out of money. The more sinister aspect is that many of those people will take that result as if it is a proper one and act accordingly. I think marketing such a test verges on criminal irresponsibility, personally.

[Perry Vale]

It sounds much better than The Doctor's Daughter!

I agree!

[Stuart Wallis]

It's not even vaguely accurate. It takes one measure of ageing, as if that's the only one, and produces a result based on that. What it doesn't do is describe the research into telomeres, the variations in cell division rates, the spread of the data so far obtained about the correlation between telomere length and number of remaining divisions, etc.

It is a pointless money-making scheme. The test serves no useful purpose whatsoever, and is just a way to fleece people out of money. The more sinister aspect is that many of those people will take that result as if it is a proper one and act accordingly. I think marketing such a test verges on criminal irresponsibility, personally.

It's nice to know we agree on some things!

[Jason Thompson]

It's doubly pointless, since apparently we're all going to die tomorrow evening anyway....

[Stuart Wallis]

As long as it's after Doctor Who...

[Dirk Gently]

The world ends at 6pm apparently...I'm just not sure which time zone that 6pm relates to.

[Paul Monk]

Thats just the Rapture. The non believers have longer to hang around as the God destroys his creation in a girly strop

[Stuart Wallis]

Well, either it didn't happen, or the afterlife looks just like the old one - in which case I demand my money back!

[Ralph]

Excellent it's just what we need to plan for our pensions!

Everybody in the private sector can now know how many years they'll have to work before they die....

[Stuart Wallis]

Excellent it's just what we need to plan for our pensions!

Everybody in the private sector can now know how many years they'll have to work before they die....

I died years ago...