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.
* 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.