This is your life: blood test that reveals your destiny

A simple blood test could predict how long you will live by measuring the "fuse" on the end of your body's DNA.

A simple blood test could predict how long you will live by measuring the "fuse" on the end of your body's DNA.

New research by American scientists on 20-year-old blood samples has found a strong link between the length of a stretch of DNA called the telomere, found at the tips of all 26 chromosomes in a cell, and the likelihood of living for 15 or more years after 60.

Every time the cell divides, the telomere shortens by a set length; when it cannot shorten any more, the cell dies. In humans, only cancer cells, sperm and eggs do not "burn down" their telomeres. People over 60 with shorter telomeres were nearly twice as likely as others to die over the next 15 years or so, especially from heart disease or pneumonia.

The test, which can produce a result in less than six hours from one drop of blood, could revolutionise the life insurance and health industries.

But Richard Cawthon, the scientist who led the project, fears that if telomere length turns out to be a reliable predictor of lifespan from an early age, people could be turned down for insurance or charged more for health care.

"In the UK nobody would deny you coverage because you've got the National Health Service," said Dr Cawthon, of the human genetics department at the University of Utah. "I wish it were like that here in the US – life or healthcare insurers might ask you to take a telomere test before they would give you coverage."

Professor Rob Newbold, a cancer specialist at the University of Brunel who specialises in telomere studies, said: "It's the sort of statistic that makes your ears prick up.

"Short telomeres do predispose to chromosome fusions and genetic instability. As the individuals aged, one might expect a disproportionate increase in death through cancer, for example, in those that had shorter telomeres at age 60."

Other scientists said that the sample was too small to draw definitive conclusions but that they would be interested to see wider studies.

The Utah team's report in today's Lancet shows an analysis of the telomeres from blood samples collected 20 years ago by people for genetic studies, and then followed up to see how long they had survived. The telomeres ranged in length from 1,930 to 4,310 "base pairs" of DNA; each year, that shortened by about 14 base pairs.

Intriguingly, women, who tend to live longer than men, had telomeres about 3.5 per cent longer than men of the same age.